Therapeutic nuclear medicine uses radionuclides to treat various conditions like hyperthyroidism and thyroid cancer. Common isotopes used include iodine-131, phosphorus-32, and strontium-89. Administration procedures and internal dosimetry calculations are important considerations. The MIRD formalism provides a framework for calculating absorbed dose to target regions from radioactive sources. Key factors include cumulative activity, residence time, and absorbed fraction. Assumptions of uniform activity distribution and average absorbed dose are limitations but the MIRD approach is simple and easy to use.
Radiation safety in diagnostic nuclear medicineSGPGIMS
1. Radiation is a form of energy emitted by atoms in the form of electromagnetic waves or particles. Ionizing radiation can eject electrons from atoms and produce ions, while non-ionizing radiation excites electrons.
2. People are exposed to ionizing radiation from natural and man-made sources. Naturally occurring sources include terrestrial radiation, cosmic radiation, and internal radiation. Medical procedures such as CT scans, nuclear medicine exams, and fluoroscopy account for over 90% of man-made radiation exposure.
3. Radiation protection aims to take advantage of the benefits of radiation use while preventing deterministic effects and limiting stochastic effects to acceptable levels. Occupational dose limits are higher than public limits, and some populations like
This document summarizes key aspects of acceptance testing and commissioning for a new radiation therapy machine. It describes the necessary measurement equipment, including radiation survey meters, ionization chambers, and phantoms. Acceptance tests and commissioning involve measuring various beam properties to ensure the machine meets specifications and performs reliably before clinical use. This process establishes the machine's baseline performance values which are then monitored ongoing through periodic quality assurance tests.
Nuclear medicine uses radioactive tracers and imaging techniques to examine organ and tissue function. Tracers are introduced into the body and detected with gamma cameras to produce images. Common studies include cardiac perfusion, bone scans, and renal or lung function tests. Precautions are taken to minimize radiation exposure and ensure patient and staff safety.
This document discusses central axis depth doses in water for both SSD and SAD techniques. For SSD technique:
- Percentage depth dose (PDD) curves measure attenuation at different depths and are affected by beam quality, field size, and SSD.
- Buildup region occurs as secondary electrons deposit energy downstream, increasing dose with depth until maximum.
- Depth dose maximum (zmax) depends on beam energy and field size.
- PDD increases with larger field sizes due to increased scatter radiation.
- PDD increases with longer SSD due to the inverse square law of radiation intensity.
This document provides an overview of nuclear medicine and radiology concepts. It discusses atomic and nuclear structure, radioactive decay processes like alpha, beta, and gamma decay, and how radiation interacts with matter through processes like the photoelectric effect and Compton scattering. It also describes common radiation detectors like gas-filled detectors and scintillation detectors. Finally, it summarizes several nuclear medicine imaging systems like planar imaging with gamma cameras and emission computed tomography with SPECT and PET.
The document discusses various factors that affect image quality in nuclear medicine imaging, including spatial resolution, contrast, and noise. It describes methods for evaluating spatial resolution such as using bar phantoms or line spread functions. Modulation transfer functions can also be used to characterize spatial resolution and compare different imaging systems. Image contrast and noise are affected by factors like radiopharmaceutical uptake, scatter radiation, and count rates. Quality assurance tests are important for ensuring optimal system performance and image quality.
Radiation protection in nuclear medicine.ppt 2Rad Tech
This document provides guidance on radiation protection procedures for radionuclide therapy, including administration of therapy, management of radioactive patients, and optimization of protection for medical staff, visitors, and the hospitalized patient. Key points addressed include justifying therapy based on clinical benefits, ensuring proper training and responsibilities of medical personnel, constraining doses to comforters and visitors, providing instructions to hospitalized patients, and surveying rooms prior to releasing patients or decommissioning areas.
Radiation safety in diagnostic nuclear medicineSGPGIMS
1. Radiation is a form of energy emitted by atoms in the form of electromagnetic waves or particles. Ionizing radiation can eject electrons from atoms and produce ions, while non-ionizing radiation excites electrons.
2. People are exposed to ionizing radiation from natural and man-made sources. Naturally occurring sources include terrestrial radiation, cosmic radiation, and internal radiation. Medical procedures such as CT scans, nuclear medicine exams, and fluoroscopy account for over 90% of man-made radiation exposure.
3. Radiation protection aims to take advantage of the benefits of radiation use while preventing deterministic effects and limiting stochastic effects to acceptable levels. Occupational dose limits are higher than public limits, and some populations like
This document summarizes key aspects of acceptance testing and commissioning for a new radiation therapy machine. It describes the necessary measurement equipment, including radiation survey meters, ionization chambers, and phantoms. Acceptance tests and commissioning involve measuring various beam properties to ensure the machine meets specifications and performs reliably before clinical use. This process establishes the machine's baseline performance values which are then monitored ongoing through periodic quality assurance tests.
Nuclear medicine uses radioactive tracers and imaging techniques to examine organ and tissue function. Tracers are introduced into the body and detected with gamma cameras to produce images. Common studies include cardiac perfusion, bone scans, and renal or lung function tests. Precautions are taken to minimize radiation exposure and ensure patient and staff safety.
This document discusses central axis depth doses in water for both SSD and SAD techniques. For SSD technique:
- Percentage depth dose (PDD) curves measure attenuation at different depths and are affected by beam quality, field size, and SSD.
- Buildup region occurs as secondary electrons deposit energy downstream, increasing dose with depth until maximum.
- Depth dose maximum (zmax) depends on beam energy and field size.
- PDD increases with larger field sizes due to increased scatter radiation.
- PDD increases with longer SSD due to the inverse square law of radiation intensity.
This document provides an overview of nuclear medicine and radiology concepts. It discusses atomic and nuclear structure, radioactive decay processes like alpha, beta, and gamma decay, and how radiation interacts with matter through processes like the photoelectric effect and Compton scattering. It also describes common radiation detectors like gas-filled detectors and scintillation detectors. Finally, it summarizes several nuclear medicine imaging systems like planar imaging with gamma cameras and emission computed tomography with SPECT and PET.
The document discusses various factors that affect image quality in nuclear medicine imaging, including spatial resolution, contrast, and noise. It describes methods for evaluating spatial resolution such as using bar phantoms or line spread functions. Modulation transfer functions can also be used to characterize spatial resolution and compare different imaging systems. Image contrast and noise are affected by factors like radiopharmaceutical uptake, scatter radiation, and count rates. Quality assurance tests are important for ensuring optimal system performance and image quality.
Radiation protection in nuclear medicine.ppt 2Rad Tech
This document provides guidance on radiation protection procedures for radionuclide therapy, including administration of therapy, management of radioactive patients, and optimization of protection for medical staff, visitors, and the hospitalized patient. Key points addressed include justifying therapy based on clinical benefits, ensuring proper training and responsibilities of medical personnel, constraining doses to comforters and visitors, providing instructions to hospitalized patients, and surveying rooms prior to releasing patients or decommissioning areas.
This document provides an overview of nuclear medicine and the technologies used. It discusses radiopharmaceuticals, which consist of a chemical molecule and radionuclide, and are used in nuclear medicine to provide information about organ function. Gamma cameras are described as detecting radiation emitted from radiopharmaceuticals and producing images, while SPECT involves a gamma camera rotating around the patient to generate 3D tomographic images. The key components of gamma cameras and their operation are also summarized.
In 2000 IAEA published another International Code of Practice.
“Absorbed Dose Determination in External Beam Radiotherapy” (Technical Report Series No. 398)
Recommending procedures to obtain the absorbed dose in water from measurements made with an ionisation chamber in external beam radiotherapy (EBRT).
Brachytherapy involves placing radioactive sources inside or near a tumor to deliver radiation. It has advantages over external beam radiation in better targeting the tumor while sparing surrounding healthy tissue. The document discusses the history of brachytherapy and the types of sources, implants, and machines used. It also covers dosimetry systems for gynecological cancers like cervical cancer, which commonly uses intracavitary implants of radioactive sources in an applicator. Interstitial brachytherapy directly implants radioactive sources in the tumor. Remote afterloading machines allow safely implanting and removing radioactive sources.
This document discusses various time-dose models used in radiotherapy, including the Strandqvist, Cohen, NSD, and TDF models. It explains the need for these models to optimize treatment regimes for tumor control while sparing normal tissues. The document also covers gap correction factors used when treatment schedules are interrupted and the various factors that can affect tumor control outcomes due to gaps in treatment. Compensatory methods like accelerated scheduling and increased dosing are presented to account for treatment gaps.
This document provides an overview of planning systems in radiotherapy and discusses various topics related to clinical treatment planning using computerized treatment planning systems. It begins with an introduction to the author and their experience with different treatment planning systems. It then covers definitions and concepts important for clinical treatment planning such as volumes, dose specifications, patient data acquisition, beam combinations, and dose statistics. The document also discusses virtual simulation, image fusion, treatment aids, oblique incidence corrections, and portal imaging. It provides details on the hardware, calculations algorithms, and commissioning of computerized treatment planning systems. In summary, the document offers a comprehensive review of clinical treatment planning processes and considerations for computerized treatment planning systems.
This document provides information on teletherapy machines used to treat cancer with radiation. It discusses cobalt-60 teletherapy machines and linear accelerators. Cobalt-60 machines use a radioactive cobalt-60 source to generate gamma rays for treatment. Linear accelerators use microwave energy to accelerate electrons, which are then used to generate x-rays or electron beams for treatment. Both types of machines aim focused radiation beams at tumors while minimizing dose to surrounding healthy tissue using collimators and other targeting mechanisms. Linear accelerators have advantages over cobalt machines like more sharply defined beam edges and ability to vary dose rates.
The document discusses recommendations from ICRP 60 & 103 regarding radiation protection. It begins with background on natural and artificial radiation sources and their effects. It then summarizes the evolution of ICRP recommendations over time, from early annual dose limits of 1000 mSv reduced gradually to current limits. Key concepts discussed include justification of practices, optimization of protection, and application of dose limits. Occupational, public, and medical exposure dose limits are provided. ICRP 103 introduced changes like new tissue weighting factors and computational phantoms.
Electron beam therapy uses accelerated electrons to treat superficial tumors. Electrons interact with matter through inelastic collisions that cause ionization and excitation, and elastic collisions that scatter the electrons. This gives electron beams a characteristically sharp dose drop-off beyond the tumor depth. Key applications of electron beams include treatment of skin cancers, chest wall irradiation for breast cancer, and boost doses to lymph nodes.
The document discusses various types of radiation dosimetry including film dosimetry. Film dosimetry uses photoemulsions like silver bromide dispersed in gelatin that form latent images when exposed to radiation. During development, sensitized grains are converted to metallic silver making the tracks visible. The optical density of the film is proportional to the absorbed dose based on Beer's law. A characteristic H-D curve describes the film performance in terms of speed, contrast, latitude and resolution. Film dosimetry provides high spatial resolution and flexibility but response varies with energy and processing conditions.
Nuclear medicine uses radioactive substances to diagnose and treat disease. In diagnostic nuclear medicine, a radiopharmaceutical is administered to the patient and detected by a gamma camera to produce images of organ function. Positron emission tomography (PET) uses radiopharmaceuticals that emit positrons to produce highly accurate images of metabolic activity in the body, making it effective for cancer diagnosis, staging, assessing treatment response, and detecting recurrence. PET's most common radiopharmaceutical is fluorodeoxyglucose (FDG), which is taken up by metabolically active cells including many cancers.
This document discusses various radiation units used to quantify radiation exposure and its effects. It defines units of radioactivity like curie and becquerel, exposure units like roentgen, absorbed dose units like rad and gray, and equivalent and effective dose units like rem and sievert used to account for radiation type and organ sensitivity. It also discusses concepts like attenuation, kerma, absorbed dose, and weighting factors used to calculate equivalent and effective doses from radiation exposure.
This document discusses image-guided radiation therapy (IGRT) and its evolution and applications. It begins by defining IGRT as external beam radiation therapy using imaging prior to each treatment fraction to verify patient positioning. IGRT allows for reduction of safety margins by compensating for set-up errors and organ motion. The document then reviews the history of IGRT from early portal imaging to modern cone-beam CT and other volumetric imaging techniques. It provides examples of IGRT protocols and clinical outcomes for sites such as prostate, lung, liver, and central nervous system tumors.
QUALITY ASSURANCE IN LINAC AND CYBERKNIFE.pptxSuryaSuganthan2
This document discusses quality assurance procedures for a linear accelerator (linac) and CyberKnife system. It outlines the various QA tools used, including phantoms for checking beam parameters like flatness, symmetry and output. Daily, weekly, monthly and yearly QA tests are described for parameters like lasers, optical distance indicator and radiation output. Tolerance levels are provided. Procedures for specific tests using tools like the Pentaguide and SunNuclear profiler are detailed step-by-step. Results of sample daily output and beam profile measurements are also shown.
The document discusses key concepts in radiobiology relevant for radiotherapy. It defines important treatment volumes including the gross tumour volume (GTV), clinical target volume (CTV), planning target volume (PTV), treated volume (TV), irradiated volume (IV), and organs at risk (OARs). It also describes biological factors that influence radiation effects on tissues, known as the "5 Rs": repair, repopulation, reoxygenation, redistribution, and radiosensitivity. Fractionated radiotherapy takes advantage of these factors to maximize tumor cell kill while minimizing damage to normal tissues.
Beam modification devices are used to alter the spatial distribution of radiation within a patient. The main types are shielding, compensation, wedge filtration, and flattening. Shielding blocks parts of the beam to protect tissues, compensation adjusts for tissue heterogeneity, wedge filtration produces tilted isodose curves, and flattening adjusts the natural beam profile. Materials used for beam modification include lead blocks, Cerrobend custom blocks, wedges, and multileaf collimators. Proper selection and design of these devices is needed to modify the beam as desired while minimizing transmission and penumbra effects.
Brachytherapy involves placing radioactive sources inside or near the target tissue. It began in 1898 with radium and has evolved with different radioactive isotopes and delivery methods. Common isotopes used today include iridium-192, cesium-137, palladium-103, iodine-125, and gold-198, which are used for interstitial, intracavitary, or permanent implantation depending on the clinical application and isotope properties.
Linear Energy Transfer (LET) refers to the energy deposited by ionizing radiation per unit distance traveled through a material. High LET radiation like neutrons and alpha particles deposit energy densely along their tracks, while low LET radiation like x-rays and gamma rays deposit energy sparsely. High LET radiation is more destructive to biological tissue due to localized DNA damage. The relative biological effectiveness (RBE) of radiation, defined as the ratio of doses needed to produce an equal biological effect, increases with LET up to around 100 keV/μm, where DNA damage is maximized. The oxygen enhancement ratio, which quantifies radiation damage under hypoxic versus oxygenated conditions, decreases with increasing LET and reaches unity for LETs over 200 keV
1. Different units are used to measure various properties of ionizing radiation, including the curie, becquerel, roentgen, rad, gray, rem, and sievert.
2. The roentgen measures exposure to gamma or X-rays, while the rad measures absorbed dose, accounting for different materials. The gray is now the SI unit for absorbed dose, replacing the rad.
3. The rem accounts for the different biological effects of various types of ionizing radiation based on their quality factor, and is used to measure equivalent dose. The sievert, replacing the rem, measures stochastic health risks from radiation exposure.
Internal radiation dosimetry describes calculating absorbed doses in organs from internally ingested radionuclides, either from medical procedures or accidents. It involves determining the cumulated activity in each organ from the time-activity curve and residence time of radionuclides, and calculating the absorbed fraction and mean energy released per transition to determine the absorbed dose in each organ from various radiations. The organ receiving the highest absorbed dose is considered the critical organ.
This document discusses radiotherapy (radiation therapy) and its use in treating cancer. It covers the origins and physics of radiotherapy, how radiation affects cells, and methods to improve radiation therapy outcomes. These methods include using radiosensitizers and radioprotectors, hyperbaric oxygen therapy, altered fractionation schedules, and combining radiation with chemotherapy or hyperthermia. The document also addresses complications and dental care considerations related to radiotherapy.
This document provides an overview of nuclear medicine and the technologies used. It discusses radiopharmaceuticals, which consist of a chemical molecule and radionuclide, and are used in nuclear medicine to provide information about organ function. Gamma cameras are described as detecting radiation emitted from radiopharmaceuticals and producing images, while SPECT involves a gamma camera rotating around the patient to generate 3D tomographic images. The key components of gamma cameras and their operation are also summarized.
In 2000 IAEA published another International Code of Practice.
“Absorbed Dose Determination in External Beam Radiotherapy” (Technical Report Series No. 398)
Recommending procedures to obtain the absorbed dose in water from measurements made with an ionisation chamber in external beam radiotherapy (EBRT).
Brachytherapy involves placing radioactive sources inside or near a tumor to deliver radiation. It has advantages over external beam radiation in better targeting the tumor while sparing surrounding healthy tissue. The document discusses the history of brachytherapy and the types of sources, implants, and machines used. It also covers dosimetry systems for gynecological cancers like cervical cancer, which commonly uses intracavitary implants of radioactive sources in an applicator. Interstitial brachytherapy directly implants radioactive sources in the tumor. Remote afterloading machines allow safely implanting and removing radioactive sources.
This document discusses various time-dose models used in radiotherapy, including the Strandqvist, Cohen, NSD, and TDF models. It explains the need for these models to optimize treatment regimes for tumor control while sparing normal tissues. The document also covers gap correction factors used when treatment schedules are interrupted and the various factors that can affect tumor control outcomes due to gaps in treatment. Compensatory methods like accelerated scheduling and increased dosing are presented to account for treatment gaps.
This document provides an overview of planning systems in radiotherapy and discusses various topics related to clinical treatment planning using computerized treatment planning systems. It begins with an introduction to the author and their experience with different treatment planning systems. It then covers definitions and concepts important for clinical treatment planning such as volumes, dose specifications, patient data acquisition, beam combinations, and dose statistics. The document also discusses virtual simulation, image fusion, treatment aids, oblique incidence corrections, and portal imaging. It provides details on the hardware, calculations algorithms, and commissioning of computerized treatment planning systems. In summary, the document offers a comprehensive review of clinical treatment planning processes and considerations for computerized treatment planning systems.
This document provides information on teletherapy machines used to treat cancer with radiation. It discusses cobalt-60 teletherapy machines and linear accelerators. Cobalt-60 machines use a radioactive cobalt-60 source to generate gamma rays for treatment. Linear accelerators use microwave energy to accelerate electrons, which are then used to generate x-rays or electron beams for treatment. Both types of machines aim focused radiation beams at tumors while minimizing dose to surrounding healthy tissue using collimators and other targeting mechanisms. Linear accelerators have advantages over cobalt machines like more sharply defined beam edges and ability to vary dose rates.
The document discusses recommendations from ICRP 60 & 103 regarding radiation protection. It begins with background on natural and artificial radiation sources and their effects. It then summarizes the evolution of ICRP recommendations over time, from early annual dose limits of 1000 mSv reduced gradually to current limits. Key concepts discussed include justification of practices, optimization of protection, and application of dose limits. Occupational, public, and medical exposure dose limits are provided. ICRP 103 introduced changes like new tissue weighting factors and computational phantoms.
Electron beam therapy uses accelerated electrons to treat superficial tumors. Electrons interact with matter through inelastic collisions that cause ionization and excitation, and elastic collisions that scatter the electrons. This gives electron beams a characteristically sharp dose drop-off beyond the tumor depth. Key applications of electron beams include treatment of skin cancers, chest wall irradiation for breast cancer, and boost doses to lymph nodes.
The document discusses various types of radiation dosimetry including film dosimetry. Film dosimetry uses photoemulsions like silver bromide dispersed in gelatin that form latent images when exposed to radiation. During development, sensitized grains are converted to metallic silver making the tracks visible. The optical density of the film is proportional to the absorbed dose based on Beer's law. A characteristic H-D curve describes the film performance in terms of speed, contrast, latitude and resolution. Film dosimetry provides high spatial resolution and flexibility but response varies with energy and processing conditions.
Nuclear medicine uses radioactive substances to diagnose and treat disease. In diagnostic nuclear medicine, a radiopharmaceutical is administered to the patient and detected by a gamma camera to produce images of organ function. Positron emission tomography (PET) uses radiopharmaceuticals that emit positrons to produce highly accurate images of metabolic activity in the body, making it effective for cancer diagnosis, staging, assessing treatment response, and detecting recurrence. PET's most common radiopharmaceutical is fluorodeoxyglucose (FDG), which is taken up by metabolically active cells including many cancers.
This document discusses various radiation units used to quantify radiation exposure and its effects. It defines units of radioactivity like curie and becquerel, exposure units like roentgen, absorbed dose units like rad and gray, and equivalent and effective dose units like rem and sievert used to account for radiation type and organ sensitivity. It also discusses concepts like attenuation, kerma, absorbed dose, and weighting factors used to calculate equivalent and effective doses from radiation exposure.
This document discusses image-guided radiation therapy (IGRT) and its evolution and applications. It begins by defining IGRT as external beam radiation therapy using imaging prior to each treatment fraction to verify patient positioning. IGRT allows for reduction of safety margins by compensating for set-up errors and organ motion. The document then reviews the history of IGRT from early portal imaging to modern cone-beam CT and other volumetric imaging techniques. It provides examples of IGRT protocols and clinical outcomes for sites such as prostate, lung, liver, and central nervous system tumors.
QUALITY ASSURANCE IN LINAC AND CYBERKNIFE.pptxSuryaSuganthan2
This document discusses quality assurance procedures for a linear accelerator (linac) and CyberKnife system. It outlines the various QA tools used, including phantoms for checking beam parameters like flatness, symmetry and output. Daily, weekly, monthly and yearly QA tests are described for parameters like lasers, optical distance indicator and radiation output. Tolerance levels are provided. Procedures for specific tests using tools like the Pentaguide and SunNuclear profiler are detailed step-by-step. Results of sample daily output and beam profile measurements are also shown.
The document discusses key concepts in radiobiology relevant for radiotherapy. It defines important treatment volumes including the gross tumour volume (GTV), clinical target volume (CTV), planning target volume (PTV), treated volume (TV), irradiated volume (IV), and organs at risk (OARs). It also describes biological factors that influence radiation effects on tissues, known as the "5 Rs": repair, repopulation, reoxygenation, redistribution, and radiosensitivity. Fractionated radiotherapy takes advantage of these factors to maximize tumor cell kill while minimizing damage to normal tissues.
Beam modification devices are used to alter the spatial distribution of radiation within a patient. The main types are shielding, compensation, wedge filtration, and flattening. Shielding blocks parts of the beam to protect tissues, compensation adjusts for tissue heterogeneity, wedge filtration produces tilted isodose curves, and flattening adjusts the natural beam profile. Materials used for beam modification include lead blocks, Cerrobend custom blocks, wedges, and multileaf collimators. Proper selection and design of these devices is needed to modify the beam as desired while minimizing transmission and penumbra effects.
Brachytherapy involves placing radioactive sources inside or near the target tissue. It began in 1898 with radium and has evolved with different radioactive isotopes and delivery methods. Common isotopes used today include iridium-192, cesium-137, palladium-103, iodine-125, and gold-198, which are used for interstitial, intracavitary, or permanent implantation depending on the clinical application and isotope properties.
Linear Energy Transfer (LET) refers to the energy deposited by ionizing radiation per unit distance traveled through a material. High LET radiation like neutrons and alpha particles deposit energy densely along their tracks, while low LET radiation like x-rays and gamma rays deposit energy sparsely. High LET radiation is more destructive to biological tissue due to localized DNA damage. The relative biological effectiveness (RBE) of radiation, defined as the ratio of doses needed to produce an equal biological effect, increases with LET up to around 100 keV/μm, where DNA damage is maximized. The oxygen enhancement ratio, which quantifies radiation damage under hypoxic versus oxygenated conditions, decreases with increasing LET and reaches unity for LETs over 200 keV
1. Different units are used to measure various properties of ionizing radiation, including the curie, becquerel, roentgen, rad, gray, rem, and sievert.
2. The roentgen measures exposure to gamma or X-rays, while the rad measures absorbed dose, accounting for different materials. The gray is now the SI unit for absorbed dose, replacing the rad.
3. The rem accounts for the different biological effects of various types of ionizing radiation based on their quality factor, and is used to measure equivalent dose. The sievert, replacing the rem, measures stochastic health risks from radiation exposure.
Internal radiation dosimetry describes calculating absorbed doses in organs from internally ingested radionuclides, either from medical procedures or accidents. It involves determining the cumulated activity in each organ from the time-activity curve and residence time of radionuclides, and calculating the absorbed fraction and mean energy released per transition to determine the absorbed dose in each organ from various radiations. The organ receiving the highest absorbed dose is considered the critical organ.
This document discusses radiotherapy (radiation therapy) and its use in treating cancer. It covers the origins and physics of radiotherapy, how radiation affects cells, and methods to improve radiation therapy outcomes. These methods include using radiosensitizers and radioprotectors, hyperbaric oxygen therapy, altered fractionation schedules, and combining radiation with chemotherapy or hyperthermia. The document also addresses complications and dental care considerations related to radiotherapy.
patient dose management in angiography king saud unversity.pdfnaima SENHOU
This document discusses patient dose management in angiography procedures. It defines key radiation terms like exposure, absorbed dose, equivalent dose and effective dose. It explains radiation units like Gray, Sievert and Dose Area Product. Factors influencing patient dose like equipment settings, patient positioning, tube angulation, magnification and collimation are described. Methods to minimize dose like reducing beam-on time, increasing source-to-patient distance and using automatic exposure control are provided. The use of diagnostic reference levels to promote radiation dose optimization is also summarized.
radiation control safety, role of Organization in radiation protection and environmental radiological surveillance.
Factors that affect radiation dose:
Regulations and procedures have been developed and implemented to limit radiation dose by regulating the use, storage, transport, and disposal of radioactive material by controlling time, distance and shielding
Time
The short the time spent near the source, the smaller the dose
Distance
The greater the distance the smaller the dose
Shielding
Use of materials to absorb the radiation dose
Radiation protection and personnel monitoring devicesRubiSapkota
This document discusses radiation protection and personnel monitoring devices. It begins with an introduction to radiation and the electromagnetic spectrum. It then covers the effects of radiation, principles of radiation protection including justification of practice, optimization of protection, and dose limits. The document discusses various personnel monitoring devices including film badges, thermoluminescence dosimeters (TLD), and optically stimulated luminescence dosimeters. It provides details on how each device works and their advantages and disadvantages.
Rp004 r.p. principles & regulatory infrastructure3lanka007
The International Commission on Radiological Protection (ICRP) is an international organization established in 1928 to provide recommendations on radiation protection. The ICRP recommends three fundamental principles of radiation protection: justification of practices, optimization of protection, and dose limitation for individuals. The ICRP does not have regulatory power but its recommendations strongly influence radiation regulations in most countries. National regulatory bodies are responsible for implementing specific codes and regulations based on ICRP guidance.
The document discusses international standards for radiation protection set by organizations like ICRP, IAEA, and ILO. It summarizes ICRP recommendations for occupational exposure limits, public exposure limits, and medical exposure principles. For occupational exposures, ICRP-26 recommended an annual dose limit of 0.5 Sv to all tissues except the lens of the eye and 0.15 Sv to the lens of eye. ICRP-60 introduced the concepts of effective dose and dose constraints and recommended an occupational effective dose limit of 20 mSv per year averaged over 5 years.
The document discusses key concepts in radiation oncology including dose fractionation, tumor lethal dose, normal tissue tolerance, and factors that affect radiosensitivity. Fractionating the total radiation dose into smaller daily doses allows time for repair of sublethal damage in normal tissues, improving the therapeutic ratio by reducing side effects while still effectively treating the tumor.
This document provides information on medical radiation safety. It discusses natural and man-made sources of radiation exposure, units used to measure radiation doses, and key principles of radiation protection including minimizing time, distance, and shielding. The document also covers radiation risks and perceptions, dose limits for occupational exposure, and requirements for radioactive waste management programs.
This document provides an overview of key concepts in radiobiology for radiotherapy. It discusses the biological effects of ionizing radiation, including deterministic effects which have a dose threshold and include tissue injuries, and stochastic effects which have no threshold and include cancer induction. Fractionation of radiation doses is explained, along with the 5 R's that influence radiation response: repair, repopulation, reoxygenation, redistribution, and radiosensitivity. Direct and indirect radiation actions on DNA are also summarized.
This document summarizes key aspects of radiation oncology for head and neck cancers. It discusses the history of radiation therapy, basics of radiation biology, and methods of administering radiation including teletherapy, brachytherapy, and stereotactic radiosurgery. Fractionation is described as reducing normal tissue toxicity while maximizing tumor control. Recent advances in radiation delivery techniques like IMRT allow higher precision in targeting tumors while sparing surrounding tissues. Concurrent chemotherapy with radiation is also shown to improve treatment outcomes for head and neck cancers.
Brachytherapy involves placing radioactive sources inside or next to the tumor to deliver internal radiotherapy. It has advantages like high tumor dose and sparing of normal tissues. There are different types depending on implant duration, source position, loading pattern, and dose rate. Permanent brachytherapy leaves radioactive seeds permanently in the tumor, while temporary brachytherapy removes sources after treatment. Interstitial brachytherapy places sources directly in tissue, while intraluminal brachytherapy inserts sources in body lumens. Remote afterloading automates source insertion compared to manual afterloading.
Radioactivity is the spontaneous disintegration of unstable atomic nuclei. It was discovered in 1896 and results in the emission of radiation. The number of neutrons and protons in a nucleus determines its stability, with heavier elements above atomic number 82 generally being radioactive. Radioactive decay occurs through different types of emission and can be used for medical applications like radiation therapy or diagnostic imaging. Proper patient preparation and safety precautions are important when using radiopharmaceuticals like iodine-131 to optimize treatment and minimize radiation exposure.
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.
Rad safety at hospitals v 0_7 (25-jun-2010) peter+nyanTunoo
The document discusses principles of ionizing radiation safety in a hospital environment. It describes how radiation is used in medical applications like imaging and treatment due to its ability to penetrate tissue. While radiation is useful, it can also cause biological damage. Basic radiation safety principles include justification of use, optimization of doses using ALARA, and limiting exposure. The document outlines various radiation types, interactions with human tissue, monitoring devices, exposure modes in different hospital departments and equipment.
Radiopharmaceuticals are radioactive pharmaceutical agents used for diagnostic or therapeutic procedures. They consist of a carrier molecule and a radionuclide. Common isotopes used include iodine-131, technetium-99m, cobalt-57, cobalt-60, gold-198, and iodine-125. Radiopharmaceuticals allow non-invasive monitoring of biological processes through imaging techniques. They are produced in specialized facilities and handled with precautions due to their radioactivity, requiring shielding and controlled storage conditions. Clinical applications include diagnosis of thyroid function and cancer treatment through targeted radiation exposure.
The document discusses internal radiation dosimetry and methods for calculating radiation doses from radiopharmaceuticals used in nuclear medicine. It covers biokinetic models for radiopharmaceutical uptake and elimination, the MIRD method involving residence time, S-factors, and calculating absorbed dose to target organs. It also addresses models for doses to embryos, fetuses, and infants via breast milk, as well as recommendations and examples of calculating radiation doses. The key aspects covered are biokinetic models, the MIRD methodology, and applications to calculating internal radiation doses, especially for sensitive populations like pregnant patients.
This document discusses various strategies for radiosensitization and radioprotection in radiation oncology. It describes how radiation directly damages DNA and how free radicals generated can be fixed by oxygen, leading to cell death. It then discusses chronic and acute hypoxia in tumors and various mechanisms and agents that can be used for radiosensitization, including hypoxic cell sensitizers like misonidazole and nimorazole, hypoxic cytotoxins like mitomycin C, and strategies like blood transfusion, hyperbaric oxygen, and carbogen inhalation. It also discusses the radioprotector amifostine and its mechanisms of action and administration. Glutamine is mentioned as a potential protector against radiation-induced
The document discusses guidelines for orthodontic radiographs, including the damaging effects of radiation on human tissue and legislation regarding medical radiation exposure in the UK. It covers justifying the need for exposures, optimizing techniques to minimize radiation dose, and estimating effective radiation doses received from common orthodontic radiographs. Guidelines are provided on indication for taking radiographs at different treatment stages and ages based on clinical need. Techniques to reduce patient radiation dose include using faster film/receptors, appropriate collimation and filtration, and digital radiography.
The document discusses the International Commission on Radiation Units and Measurements (ICRU). It summarizes that ICRU defines physical quantities and units related to ionizing radiation. It has published over 85 reports on topics like dose specifications, clinical terms, and recommendations for intensity modulated radiation therapy. ICRU works to establish international standards for radiation quantities, units, and nomenclature used in radiation oncology and other applications of ionizing radiation.
Radiation can have biological effects by directly ionizing DNA or indirectly generating free radicals that cause oxidative damage. The effect depends on linear energy transfer (LET) and relative biological effectiveness (RBE). As LET increases, DNA damage increases until an optimal 100 keV/μm, after which overkill reduces effects. Acute radiation causes early somatic effects like nausea above 1 Gy. Late effects include cancer. Deterministic effects have thresholds while stochastic effects like cancer risk increases linearly with any dose. Radiation affects embryos most pre-implantation and during organogenesis. Occupational and public dose limits aim to prevent deterministic harm and minimize stochastic risk.
The document discusses the safe transport of radioactive material. It outlines the various national and international regulations that govern the transport of radioactive material via different modes such as road, rail, air, sea, and post. The key principles of transport include keeping doses received by persons and the number of exposed persons as low as reasonably achievable. The document then defines various terms related to transport such as types of packages (exempted, industrial, type A, B, C), activity limits, and contamination limits. It describes the different tests and requirements for each package type to ensure containment of radioactive materials during normal and accident conditions of transport.
The document discusses various considerations for magna field irradiation (TBI) including:
1) Biological factors like repair, repopulation and fractionation that are important for TBI. Fractionation increases lung tolerance up to 175%.
2) Physical factors that must be addressed like dose calibration, scatter corrections, and ensuring dose uniformity throughout the body.
3) Methods for calculating and prescribing dose including using average or single point doses. Most protocols prescribe to the umbilicus midpoint.
4) Techniques used to achieve homogeneity like bolus, compensators and beam energies. Homogeneity of ±10% is typically achieved.
5) Determining lung dose accurately through methods like CT-based calculations or
This document discusses brachytherapy dosimetry using the TG-43 formulation. It begins by introducing brachytherapy and the sources commonly used, such as iridium-192 and iodine-125. It then covers how sources are specified and calibrated, including using exposure rate constants, air kerma rate constants, and apparent activity. Methods for source calibration include air ionization chambers, well chambers, and solid phantoms. Dose distribution around sources is also discussed, including using the Sievert integral for line sources. The TG-43 formalism provides a standardized method for calculating dose around brachytherapy sources.
The document summarizes the history and technology of computed tomography (CT) scanners. It describes how CT was developed in the 1970s by Godfrey Hounsfield and Alan Cormack, who were later awarded the Nobel Prize. It outlines the key innovations in each generation of CT scanners, from the first generation's pencil beam geometry to later generations' use of detector arrays and helical scanning, which reduced scan times. The document also discusses the components of a CT scanner, including the x-ray tube, detectors, and techniques for image reconstruction and calibration.
Charged particle interaction with matterSabari Kumar
This document discusses charged particle interactions with matter. It begins by outlining the topics to be covered, including interactions of heavy charged particles like protons, electrons, and light ions. It then explains that charged particle interactions are mediated by Coulomb forces and may involve ionization or excitation of orbital electrons or interactions with atomic nuclei. Different types of interactions like elastic and inelastic collisions are described. Equations for energy loss by heavy charged particles during collisions are shown. The interactions of protons, electrons, neutrons, and light and heavy ions are then discussed in more detail.
The document discusses the interaction of radiation with matter. It describes different types of interactions including the photoelectric effect, Compton scattering, and pair production. These interactions vary based on the photon energy and atomic number of the absorbing material. The photoelectric effect is more likely for low energy photons and high atomic number materials. Compton scattering does not depend on atomic number. Pair production requires the highest minimum photon energy and is more likely for high atomic number materials. The document also discusses attenuation coefficients and how they relate to the probability of each interaction type.
ESR spectroscopy in liquid food and beverages.pptxPRIYANKA PATEL
With increasing population, people need to rely on packaged food stuffs. Packaging of food materials requires the preservation of food. There are various methods for the treatment of food to preserve them and irradiation treatment of food is one of them. It is the most common and the most harmless method for the food preservation as it does not alter the necessary micronutrients of food materials. Although irradiated food doesn’t cause any harm to the human health but still the quality assessment of food is required to provide consumers with necessary information about the food. ESR spectroscopy is the most sophisticated way to investigate the quality of the food and the free radicals induced during the processing of the food. ESR spin trapping technique is useful for the detection of highly unstable radicals in the food. The antioxidant capability of liquid food and beverages in mainly performed by spin trapping technique.
The use of Nauplii and metanauplii artemia in aquaculture (brine shrimp).pptxMAGOTI ERNEST
Although Artemia has been known to man for centuries, its use as a food for the culture of larval organisms apparently began only in the 1930s, when several investigators found that it made an excellent food for newly hatched fish larvae (Litvinenko et al., 2023). As aquaculture developed in the 1960s and ‘70s, the use of Artemia also became more widespread, due both to its convenience and to its nutritional value for larval organisms (Arenas-Pardo et al., 2024). The fact that Artemia dormant cysts can be stored for long periods in cans, and then used as an off-the-shelf food requiring only 24 h of incubation makes them the most convenient, least labor-intensive, live food available for aquaculture (Sorgeloos & Roubach, 2021). The nutritional value of Artemia, especially for marine organisms, is not constant, but varies both geographically and temporally. During the last decade, however, both the causes of Artemia nutritional variability and methods to improve poorquality Artemia have been identified (Loufi et al., 2024).
Brine shrimp (Artemia spp.) are used in marine aquaculture worldwide. Annually, more than 2,000 metric tons of dry cysts are used for cultivation of fish, crustacean, and shellfish larva. Brine shrimp are important to aquaculture because newly hatched brine shrimp nauplii (larvae) provide a food source for many fish fry (Mozanzadeh et al., 2021). Culture and harvesting of brine shrimp eggs represents another aspect of the aquaculture industry. Nauplii and metanauplii of Artemia, commonly known as brine shrimp, play a crucial role in aquaculture due to their nutritional value and suitability as live feed for many aquatic species, particularly in larval stages (Sorgeloos & Roubach, 2021).
Deep Behavioral Phenotyping in Systems Neuroscience for Functional Atlasing a...Ana Luísa Pinho
Functional Magnetic Resonance Imaging (fMRI) provides means to characterize brain activations in response to behavior. However, cognitive neuroscience has been limited to group-level effects referring to the performance of specific tasks. To obtain the functional profile of elementary cognitive mechanisms, the combination of brain responses to many tasks is required. Yet, to date, both structural atlases and parcellation-based activations do not fully account for cognitive function and still present several limitations. Further, they do not adapt overall to individual characteristics. In this talk, I will give an account of deep-behavioral phenotyping strategies, namely data-driven methods in large task-fMRI datasets, to optimize functional brain-data collection and improve inference of effects-of-interest related to mental processes. Key to this approach is the employment of fast multi-functional paradigms rich on features that can be well parametrized and, consequently, facilitate the creation of psycho-physiological constructs to be modelled with imaging data. Particular emphasis will be given to music stimuli when studying high-order cognitive mechanisms, due to their ecological nature and quality to enable complex behavior compounded by discrete entities. I will also discuss how deep-behavioral phenotyping and individualized models applied to neuroimaging data can better account for the subject-specific organization of domain-general cognitive systems in the human brain. Finally, the accumulation of functional brain signatures brings the possibility to clarify relationships among tasks and create a univocal link between brain systems and mental functions through: (1) the development of ontologies proposing an organization of cognitive processes; and (2) brain-network taxonomies describing functional specialization. To this end, tools to improve commensurability in cognitive science are necessary, such as public repositories, ontology-based platforms and automated meta-analysis tools. I will thus discuss some brain-atlasing resources currently under development, and their applicability in cognitive as well as clinical neuroscience.
Unlocking the mysteries of reproduction: Exploring fecundity and gonadosomati...AbdullaAlAsif1
The pygmy halfbeak Dermogenys colletei, is known for its viviparous nature, this presents an intriguing case of relatively low fecundity, raising questions about potential compensatory reproductive strategies employed by this species. Our study delves into the examination of fecundity and the Gonadosomatic Index (GSI) in the Pygmy Halfbeak, D. colletei (Meisner, 2001), an intriguing viviparous fish indigenous to Sarawak, Borneo. We hypothesize that the Pygmy halfbeak, D. colletei, may exhibit unique reproductive adaptations to offset its low fecundity, thus enhancing its survival and fitness. To address this, we conducted a comprehensive study utilizing 28 mature female specimens of D. colletei, carefully measuring fecundity and GSI to shed light on the reproductive adaptations of this species. Our findings reveal that D. colletei indeed exhibits low fecundity, with a mean of 16.76 ± 2.01, and a mean GSI of 12.83 ± 1.27, providing crucial insights into the reproductive mechanisms at play in this species. These results underscore the existence of unique reproductive strategies in D. colletei, enabling its adaptation and persistence in Borneo's diverse aquatic ecosystems, and call for further ecological research to elucidate these mechanisms. This study lends to a better understanding of viviparous fish in Borneo and contributes to the broader field of aquatic ecology, enhancing our knowledge of species adaptations to unique ecological challenges.
EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...Sérgio Sacani
Context. With a mass exceeding several 104 M⊙ and a rich and dense population of massive stars, supermassive young star clusters
represent the most massive star-forming environment that is dominated by the feedback from massive stars and gravitational interactions
among stars.
Aims. In this paper we present the Extended Westerlund 1 and 2 Open Clusters Survey (EWOCS) project, which aims to investigate
the influence of the starburst environment on the formation of stars and planets, and on the evolution of both low and high mass stars.
The primary targets of this project are Westerlund 1 and 2, the closest supermassive star clusters to the Sun.
Methods. The project is based primarily on recent observations conducted with the Chandra and JWST observatories. Specifically,
the Chandra survey of Westerlund 1 consists of 36 new ACIS-I observations, nearly co-pointed, for a total exposure time of 1 Msec.
Additionally, we included 8 archival Chandra/ACIS-S observations. This paper presents the resulting catalog of X-ray sources within
and around Westerlund 1. Sources were detected by combining various existing methods, and photon extraction and source validation
were carried out using the ACIS-Extract software.
Results. The EWOCS X-ray catalog comprises 5963 validated sources out of the 9420 initially provided to ACIS-Extract, reaching a
photon flux threshold of approximately 2 × 10−8 photons cm−2
s
−1
. The X-ray sources exhibit a highly concentrated spatial distribution,
with 1075 sources located within the central 1 arcmin. We have successfully detected X-ray emissions from 126 out of the 166 known
massive stars of the cluster, and we have collected over 71 000 photons from the magnetar CXO J164710.20-455217.
Comparing Evolved Extractive Text Summary Scores of Bidirectional Encoder Rep...University of Maribor
Slides from:
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Track: Artificial Intelligence
https://www.etran.rs/2024/en/home-english/
The debris of the ‘last major merger’ is dynamically youngSérgio Sacani
The Milky Way’s (MW) inner stellar halo contains an [Fe/H]-rich component with highly eccentric orbits, often referred to as the
‘last major merger.’ Hypotheses for the origin of this component include Gaia-Sausage/Enceladus (GSE), where the progenitor
collided with the MW proto-disc 8–11 Gyr ago, and the Virgo Radial Merger (VRM), where the progenitor collided with the
MW disc within the last 3 Gyr. These two scenarios make different predictions about observable structure in local phase space,
because the morphology of debris depends on how long it has had to phase mix. The recently identified phase-space folds in Gaia
DR3 have positive caustic velocities, making them fundamentally different than the phase-mixed chevrons found in simulations
at late times. Roughly 20 per cent of the stars in the prograde local stellar halo are associated with the observed caustics. Based
on a simple phase-mixing model, the observed number of caustics are consistent with a merger that occurred 1–2 Gyr ago.
We also compare the observed phase-space distribution to FIRE-2 Latte simulations of GSE-like mergers, using a quantitative
measurement of phase mixing (2D causticality). The observed local phase-space distribution best matches the simulated data
1–2 Gyr after collision, and certainly not later than 3 Gyr. This is further evidence that the progenitor of the ‘last major merger’
did not collide with the MW proto-disc at early times, as is thought for the GSE, but instead collided with the MW disc within
the last few Gyr, consistent with the body of work surrounding the VRM.
The ability to recreate computational results with minimal effort and actionable metrics provides a solid foundation for scientific research and software development. When people can replicate an analysis at the touch of a button using open-source software, open data, and methods to assess and compare proposals, it significantly eases verification of results, engagement with a diverse range of contributors, and progress. However, we have yet to fully achieve this; there are still many sociotechnical frictions.
Inspired by David Donoho's vision, this talk aims to revisit the three crucial pillars of frictionless reproducibility (data sharing, code sharing, and competitive challenges) with the perspective of deep software variability.
Our observation is that multiple layers — hardware, operating systems, third-party libraries, software versions, input data, compile-time options, and parameters — are subject to variability that exacerbates frictions but is also essential for achieving robust, generalizable results and fostering innovation. I will first review the literature, providing evidence of how the complex variability interactions across these layers affect qualitative and quantitative software properties, thereby complicating the reproduction and replication of scientific studies in various fields.
I will then present some software engineering and AI techniques that can support the strategic exploration of variability spaces. These include the use of abstractions and models (e.g., feature models), sampling strategies (e.g., uniform, random), cost-effective measurements (e.g., incremental build of software configurations), and dimensionality reduction methods (e.g., transfer learning, feature selection, software debloating).
I will finally argue that deep variability is both the problem and solution of frictionless reproducibility, calling the software science community to develop new methods and tools to manage variability and foster reproducibility in software systems.
Exposé invité Journées Nationales du GDR GPL 2024
Or: Beyond linear.
Abstract: Equivariant neural networks are neural networks that incorporate symmetries. The nonlinear activation functions in these networks result in interesting nonlinear equivariant maps between simple representations, and motivate the key player of this talk: piecewise linear representation theory.
Disclaimer: No one is perfect, so please mind that there might be mistakes and typos.
dtubbenhauer@gmail.com
Corrected slides: dtubbenhauer.com/talks.html
2. Introduction
Isotopes used in Therapy
Administration Procedures
Internal Dosimetry
Designing a Nuclear Medicine Dept.
Radiation Protection
OUTLINE
3. Introduction
Radionuclides are being extensively used for treatment of
various benign and malignant conditions like hyperthyroidism,
thyroid carcinoma, painful bone metastases, arthritis etc.,
It is a rapidly expanding cancer treatment modality
Unsealed radioisotopes are directly administrated to the
patient in this treatment modality.
Radiation protection in radionuclide therapy requires control
of both external exposure and contamination of the medical
staff, laboratory personnel, family members, visitors and general
public
4. Biological Half life:
Biological Half life is defined as the exponential removal of radio
activity from the organs as well as from the whole body
This help us understand the dynamics of radio nuclide retention
times, internal dosimetry, and risks of radiation injury
Effective Half Life:
The time in which half of the radio activity is
removed from the organ or from the whole
body by the combined processes of radioactive
decay and biological excretion.
Element Whole Body Tb Organ Organ Tb
Iodine 138d Thyroid 138d
Calcium 4.5y Bone 4.9y
Cesium 70d Whole Body 70d
Sodium 11d Whole Body 11d
bp
bp
e
TT
TT
T
5. Annual Limit on Take: (ALI)
The amount of radioactive material allowed to be taken into the
body of an adult worker as a result of inhalation or ingestion in a
year
e – Effective dose co-efficient is a measure of damage done by
ionizing radiation associated with radioactivity of an isotope (units:
Sv/Bq).
It accounts WR & WT , metabolic & biokinetic information
Factors affecting the calculation of the ALI are:
Chemical form,
retention time in the body,
for inhalation – the aerosol activity median
aerodynamic diameter
)50(e
Sv02.0
tcoefficien.dose.effective.committed
equivalent.dose.effective.committed
ALI
6. Derived Air Concentrations:
It is calculated by dividing the limit on intake by the volume of
air breathed over the working period.
If a reference person inhales 20lt of air/min then,
DAC = ALI Inhale (Bq)/2400 x 103 lt/year
Ex: 137Cs has an ALI Inhale of 3 x 106 Bq/year
DAC = 3 x 106 Bq/year /2400 x 103 lt/year = 1.25 Bq/lt
Derived Water Concentration:
It is calculated by dividing the limit on take by the volume of
water intake over the working period.
If a reference person water intake is 2.5 lt/day then,
DWC = ALI ingest (Bq)/ 912.5lt/year
7. Committed Dose:
The total dose delivered during the period of time when radio
nuclide is administrated into the body is referred to as Committed
dose and is calculated as a specified time integral of the rate of
receipt of the dose
Where
t0 - time of intake
τ – Integration Time
For adults τ is taken as 50 years and for children it will be 70 years
Committed Effective Dose:
Committed effective dose is measure of radio-toxicity (the dose
received by a population ingesting all the radio active material
present at a given time)
Radio toxicity = E(τ) . A
0
0
t
t
TT dt).t(H)(H
T
TT )(H.W)(E
8. Isotopes used in Therapy – NM
Beta or Alpha emitting radio isotopes are used in mostly. But
presence of gamma is helpful in imaging & studying of bio-
distribution of radio nuclide
Physical & Biological half lives should be paired to the drug
half life in the body.
Simple, stable radio-labeling to biological compounds is one of
the most important quality for an ideal therapeutic isotope
Binding efficiency & stability of a radio labeled compound
results in optimal delivery of radiation in vivo
There should not be any significant radiolysis of the compound
after labeling, during storage and shipment
9. Isotopes used in Therapy – NM
Radioisotopes used in therapy are largely divided into two
types : Radio-metals and Radio-halogens
Radio-metals have long been attractive options and have gained
widespread popularity for many clinical uses
Radio-halogens have maintained their popularity because of
their relatively simpler radio-labelling characteristics.
Radionuclide
Beta Emax
(MeV)
Max Range
(mm)
Mean
Range (mm)
Gamma energy
(KeV)
Half life
(hr)
32P 1.71 8.7 1.985 - 342
131I 0.61 2.4 0.4 364 193
89Sr 1.46 8.0 - - 1212
211At+ 5.9 (Alpha) - 0.06 670 7.2
212Bi 1.36 (beta)
6.1 (alpha)
- 0.09
0.06
727 1.0
10. Isotopes used in Therapy – NM
131 I
Normal physiological uptake of iodide in functioning Thyroid
tissue is the primary reason for its role in treating several thyroid
disorders & malignancies.
Nuclear Fission (235U) product
Half life : 8.1 days
Beta Energy (max) : 600 KeV
Gamma Energy : 364 KeV
Administration in the form of liquid Sodium Iodide
11. Isotopes used in Therapy – NM
32 P
31P (n,γ)32P
The ratio of phosphorus uptake in tumorous bone relative to
normal bone is about 2:1
Reactor Produced and Pure beta emitter
Half Life : 14.3 days
Energy (average) : 694.7KeV
Average range of beta rays in water :0.198cm
Used for Polycythemia Vera treatment
Administration in the form as Sodium Phosphate
12. Isotopes used in Therapy – NM
89Sr
Fission product and Pure beta emitter
Half Life : 50.5 days
Energy (max) : 1.46MeV
It is handled by body in the same manner as calcium
Used for Bone Metastases
13. Administration Procedure
131 I Administration:
The most common form of Hyper-thyroidism is Grave’s disease
and 131 I is the treatment choice for this.
Also beneficial of metastatic thyroid cancer treatment
Treatment doses of 200-400 MBq (5 – 10 mCi) administrated to
reduce the incidence of Hypo-Thyroidism.
Patient should discontinue anti-thyroid medication prior to
therapy for 2 – 8 days
Female patients should be advised to not conceive for at least
six months following therapy
No intravenous contrast should be administrated for at least two
months prior to therapy
14. Administration Procedure
131 I Administration:
Patient should be encouraged to reduce iodine content in diet to
optimize uptake of 131I by thyroid tissue
Patient should be empty stomach at least 1 to 2 hrs before and
after therapy to reduce the volume of vomits
A tracer study may be carried out prior to administration of 131I,
to ensure 131I uptake in thyroid tissue and/or in metastatically
diseased tissue
131I is given orally; neck uptake and imaging is carried out
between 24 and 72 hrs after administration
Whole body imaging at 72hrs should also be carried out,
especially when results of neck imaging are negative
15. Administration Procedure
32P Administration:
Polycythemia Rubra Vera is a chronic hameotological disorder
characterized by increased proliferative activity of the erythroid,
myeloid and fibroblast cell lines.
Sodium 32P is used for treatment of PRV; supplied as
orthophospate
32P is administered by intravenous injection using canella; care
must be taken to avoid extravasations
The biological half life of the radio pharmaceutical in Bone
Marrow is 7 to 9 days
16. Administration Procedure
32P Administration:
Two treatment approaches are used:
Fixed Approach
Sliding Approach
In fixed one, 74 – 111 MBq (2 – 3 mCi)/m2 body surface area is
administrated with an upper limit of 185MBq (5mCi). This may
be repeated at three monthly intervals
In sliding scale, a fixed dose of 111MBq (3mCi) is first
administrated. If there is no response a second treatment may be
given after three months with a 25% increment in dose.
Treatment may be repeated with continuing dose increments until
an adequate response is obtained the upper limit for a single
treatment is 7mCi.
17. Internal Dosimetry
Absorbed Dose depends on :
The amount of radioactivity administrated
The physical and biological half lives of the radio nuclide
The fraction of abundance of the radiation in question from
the radionuclide
The bio distribution of radio activity in the body
The fraction energy released from the source organ that is
absorbed in the target volume, which is related to the shape,
composition and location of the target
18. Internal Dosimetry
The energy absorbed per hour by the target, due to ith radiation is:
Total Dose becomes,
Where,
A0 = Initial Activity of Radio Nuclide
m = mass of target v = volume of target
f = fraction of activity localized in organ
i = Equilibrium Dose constant (g.rad/μCi.hr)
= 2.13Ni.Ei
Te = Effective Half Life of radio nuclide
Φi(v ← r) = Absorbed fraction
)rv(.T.).f.
m
A
(44.1)hr/rad(R iei
0
i
n
1i
iie
0
)rv(..T).f.
m
A
(44.1D
19. Internal Dosimetry
Φi – Absorbed Fraction is defined as ratio of energy absorbed by
target to energy emitted by source
Φi depends on the type & energy of radiation, shape & size of
source and volume, shape composition & distance from the source.
For β-particles, α-particles, X-rays and γ-rays less than 11KeV
and target volume larger than 1cm then φi = 0 unless in case of
source & target are same, φi = 1
For remaining all situations, φi lies between 0 to 1
It is difficult to evaluate these values. Thus Monte Carlo methods
are used and tabulated by Society of Nuclear Medicine.
20. Internal Dosimetry
A unified approach to internal dosimetry was published by the
MIRD Committee in 1968, as MIRD Pamphlet No. 1, which
was updated several times thereafter.
The latest publication on the formalism was published in 2009
in MIRD pamphlet No.21, which provides a notation meant to
bridge the differences in the formalism used by the MIRD
Committee and the ICRP.
The MIRD formalism gives a framework for the calculation of
the absorbed dose to a target region from activity in a source
region is
Where
à = Cumulative Activity (μCi.hr)
S = Mean Absorbed dose/Cumulative activity (rad/μCi.hr)
S.A
~
Drad
21. Internal Dosimetry
The Cumulative Activity (Ã) is represented by the area under the time
activity curve (or) The time integrated activity equals the no. of
decays that take place in a certain source region.
à = 1.44 A0.Te.f
Where,
A0 = Initial Activity before administration
Te = Effective Half Life
f = fraction of activity localized in organ
Models of Cumulative Activity:
Uptake of source is instantaneous with no biologic excretion
Uptake by organ is instantaneous with elimination by biologic
excretion only
Uptake by organ is instantaneous with removal by both
physical decay and biological excretion
Uptake by organ is not instantaneous
22. Internal Dosimetry
The Residence time (or) Time Integrated Activity co-efficient is
defined as the time-integrated activity divided by the administrated
activity
In other way, the area under the curve describing the activity as a
function of time equals the area for the rectangle.
ã = Ã/A0
ã = 1.44 A0.Te.f /A0
ã = 1.44 Te. f (total activity located at source t=0)
This can be described as an
average time that the activity
spends in source region
23. Internal Dosimetry
S - Mean Absorbed dose/Cumulative activity is defined as the ratio
of product of equilibrium dose constant & absorption fraction to
target mass
S value for a certain radionuclide and source-target combination is
generated from Monte Carlo simulations in a computer model of
the anatomy.
Earlier, in coordinate system simple geometrical shapes such as
spheres or cylinders were placed to represent important structures
of the anatomy for S value calculations
Next, voxel based phantoms from tomo-graphic image data, used
for the calculation of S values.
The phantom , created using non-uniform rational B-spline
(NURBS) is used to represent surfaces, is used for S values
m
)rv(
S
n
1i
ii
24. Pediatric Doses:
The metabolisms, bio-
distribution and excretion of
drugs are different in children
from in adults, thus dosages
for children must be adjusted
Several methods &
formulas have been reported
on pediatric dosage
calculations based on body
weight, body surface area,
combination
Weight in
kg (lb)
Fraction
Weight in
kg (lb)
Fraction
3(6.6) 0.1 28(61.6) 0.58
4(8.8) 0.14 30(66.0) 0.62
8(17.6) 0.23 32(70.4) 0.65
10(22.0) 0.27 34(47.8) 0.68
12(26.4) 0.32 36(79.2) 0.71
14(30.8) 0.36 38(83.6) 0.73
16(35.2) 0.4 40(88.0) 0.76
18(39.6) 0.44 42(92.4) 0.78
20(44.0) 0.46 44(96.8) 0.8
22(48.4) 05 46(101.2) 0.83
24(52.8) 0.53 48(105.6) 0.85
26(57.2) 0.56 50(110.0) 0.88
Internal Dosimetry
25. Internal Dosimetry
Assumptions & Limitations of MIRD formula:
Assumptions are made that
The activity distribution in the source region is assumed to
be uniform
The mean absorbed dose to the target region is calculated
MIRD formalism dose not set any restrictions on either
volume or shape of the source or target as long as uniformity
can be assumed
MIRD implementation is simple and ease of use
Major limitation is that the absorbed dose may vary throughout
the region
26. Internal Dosimetry
Assumptions & Limitations of MIRD formula:
The Activity distribution is seldom completely uniform over
the whole tissue.
The non-uniformity in the activity distribution can be overcome
by redefining the source region into a smaller volume.
MIRD formalism utilizes the concept of cumulated activity,
defined as the total number of decays during the time of
integration.
For practical application, heterogeneities or source distribution
within organs are neglected.
28. Internal Dosimetry
Therapy Agent Organ rad/mCi mSv/MBq
32 P – Phosphate Bone Marrow 37.0 10
Red Bone
Marrow
28.1 7.6
89 Sr – Chloride Bone Surface 63.0 17.0
Red Bone
Marrow
40.7 11.0
LLI 17.4 4.7
Bladder 4.8 1.3
Kidneys 3.0 0.8
153 Sm – EDTMP Bone Surface 25.0 6.8
Red Bone
Marrow
5.7 1.5
Bladder Wall 3.6 1.0
29. Dose Calibration
It is important to measure the activity to be administrated to the
patient in prior to achieve therapeutic effect without excessive
radiation burden
Dose calibrators are used in Nuclear Medicine dept which
indicates the activity to be administrated to the patient
Before dose measuring, it is mandatory to check for
contamination of the chamber
Background radiation adjustments should perform
To check changes in calibration or malfunction of the dose
calibrator, a source of known activity (137Cs) is measured to
compare measured & calculated activity (5% difference is
acceptable)
30. Designing a Nuclear Medicine Dept
An approved nuclear medicine department, a qualified nuclear
medicine physician and a RSO are the prerequisites for any
radionuclide therapy program
The administration of therapeutic doses of radio nuclides must be
under the responsibility of a Physician who is licensed under
national regulations
While designing therapy room, the factors to be considered are:
Type of radionuclide is used and its energy
potential for contamination and degree of hazards
Type of waste generated and the way they should be handled
Requirements:
Patients must be housed in isolated room with dedicated
washroom
Access to the treatment room must be controllable
31. Designing a Nuclear Medicine Dept
Any required shielding must be designed for proposed floor plan
A non-porous, easily decontaminated floor and wall surfaces with
coved junctions to make cleaning easier
A minimum projections to prevent dust collection
A dedicated shower & toilet, draining directly to the main sewer
or delay tank depending on local regulatory requirements
A physical barrier to entry
Moveable lead shields to minimize nursing exposures
Possible installation of remote patient monitoring system
Door signs prohibiting entry to pregnant women, children and
other persons without permission, limiting visiting hours
32. Radiation Protection
Radio Nuclides must be used in strict accordance with safety
measures and any special instructions and all precautions must be
taken to avoid un-necessary exposure to radiation
Use of disposable gloves, gowns etc.,
While discharge of patient, patient belongings must be surveyed
for contamination
The patient must aware of information related to radio-nuclide
administration prior to treatment
131I therapy doses usually given in liquid or capsule form. The
patient is required to swallow the capsule without chewing
followed by a drink of water
A prophylactic anti-emetic should be given prior to or
immediately after the dose is administrated to avoid vomiting
33. Radiation Protection
A decontamination kit should always be available in the
treatment room in order to deal with the spillage.
Beta emitters such as 89Sr and 32P, generally require consideration
only at the time of administration
Following administration the injection site must be checked for
spilt or leaked radio nuclide by swabbing and checking the swab
with a beta detector
Most of the excretion occurs in the urine, significant
contamination in saliva, less in sweat etc.,
To stimulate the excretion, patients should be advised to drink
freely and void frequently
Patients should be advised to flush the toilet twice after voiding
The precautions may usually be discontinued after 72 hrs
34. Radiation Protection
The rooms where work with unsealed sources are taken places
should be under negative pressure to minimize the risk of air-borne
radio nuclide to be spread
Always open vials in fume hood. Avoid direct handling of vials.
Use forceps with rubber grips
Cap tightly vials when not in use
Movement of radio nuclide must be minimized
Effective dose to patient’s comforter shall not normally exceed
5mSv during the period of patients treatment
After discharge, family members dose other than comforter does
not exceed 1mSv/Year (estimated)
35. Radiation Protection
Spillage Management:
Radio active spills should not be treated as events completely
without hazard even though those are not life threatening
Spillage occurs in radio active solutions can spill in transit, inside
containers, during preparations, QA, while loading syringes or
while injecting patients etc.,
Two types of spills:
Major Spills
Minor Spills
There is no definitive distinction exists between these two spills
36. Radiation Protection
Spillage Management:
Minor spills represent the release of several micro curies (over
100 kBq) of radio activity
The person involved
Warns other workers
wearing gloves, proceeds to decontaminate the area
immediately
Inform RSO
RSO has to prepare an incident report for the files
37. Radiation Protection
Spillage Management:
Major spills involve the release of several milli Curies (over
100MBq) of radio activity
The person involved:
Warns other workers
Closes the area to traffic
Summons the RSO who immediately assesses the situation
and gives direction for decontamination
An assessment of the quality & quantity of radioactive spilled
is made
The area covered by spill is recognized by monitoring. If any
worker is injured, medical assistance is requested immediately.
38. Radiation Protection
Spillage Management: Major Spills
Wearing protective clothing, the worker proceeds to pick up
most of spilled solution with absorbent paper towels held with
18 inch forceps.
Pick up procedure: spiral in technique. Wipe with paper
towels starting at the periphery and in a circular motion toward
the center of the area.
Heavy duty plastic bags use to sent to decay in storage
Cleaning solutions are then used to decontaminate the area
Monitoring of the area with a surface monitor will confirm
complete decontamination less than 2mR/hr (0.2 μSv/hr)
RSO prepares incident reports to the radiation safety
committee and makes recommendations to prevent future spills.
39. Radiation Protection
Waste Management:
Each type of waste should be kept in separate containers that are
properly labeled
Waste should be properly packed in order to avoid leakage during
storage
The final disposal of the radio active waste produced in the NM
facility includes:
Storage for decay (applicable only for radionuclides with less
than 120 days half life, until decay to 10 half lives of activity and
monitor before disposal)
Disposal as cleared waste into the sewage system,
transfer to authorized recipient
Other disposal methods approved by the NRC (incineration of
solid waste and atmospheric release of radioactive gases)
40. Radiation Protection
Emergency Management:
Medical event occurs when a dose exceeds 5rem (0.05Sv)
effective dose equivalent, or 50rem (0.5Sv) to an organ or tissue or
skin from any of the following situations.
Total dose delivered differs from prescribed dose by 20% or
more
Total dosage delivered differs from the prescribed dosage by
20% or more, or falls outside the prescribed dosage range
Administration of a wrong radioactive drug containing by-
product
Administration by wrong route
Administration to a wrong individual
41. Radiation Protection
Emergency Management:
The licensee must notify by phone to competent authority no
later 24 hrs after the discovery
Written report to the competent authority within 15 days which
includes brief description of the event, cause of the event, effect of
the event, corrective action taken if any, and whether the affected
individual or his or her relative or guardian has been notified etc.,
An emergency preparedness program should be available in the
institute to handle above mentioned situations
42. Radiation Protection
Surface contamination with radioactivity could lead to
contamination of a radiation worker and/or external irradiation of
the skin of the worker.
The surface contamination limits were derived based on a
committed effective dose limit of 20 mSv/year.
Contamination should check with contamination monitor with
appropriate probe detector.
Nuclide Surfaces in designated
areas (including protective
clothing ) (Bq/cm2)
Interiors of glove
boxes and fume
cupboards (Bq/cm2)
Non Designated areas
including personal
clothing (Bq/cm2)
131I 100 1000 5
89Sr 100 1000 5
32P 100 1000 5
99mTc 1000 10000 50
43. Radiation Protection
If any difficulty found while measuring low beta emitter present
in area, wipe test should be used
100cm2 should be wiped and activity on the wipe assessed.
Usually do dry wipe which will remove 1/10th of contamination
where as wet wipe removes 1/5th of the contamination
A ring monitor at the base of the middle is used to assess the
finger doses
The detector element positioned on palm side estimated dose to
the tip. If detector is worn facing towards the back of the hand, a
factor of 6 should be applied
44. Radiation Protection
Classification of Hazards:
This is done based on calculation of a weighted activity using
weighting factors according to radio nuclide and type of operation
performed
According to sources:
Class A sources : 131 I, 125 I, 89 Sr, 75 Se ==> weighting factor : 100
Class B sources: 99m Tc ==> Weighting factor : 1.00
Class C sources: 3H, 14C ==> Weighting factor : 0.01
According to type of work:
Storage ==> weighting factor : 0.01
Waste handling, imaging room, patient bed ==> Weighting Factor : 0.1
Radionuclide Administration ==> Weighting Factor : 1
Complex Preparation ==> Weighting Factor : 10
45. Radiation Protection
Classification of Hazards:
Ex: Administration of 400MBq 131I
Weighting factor of administration : 1
Weighting factor of 131 I : 100
Source activity : 400MBq
Weighted Activity : 1 x 100 x 400 = 40000MBq
==> Medium Hazard
Weighted Activity Category
< 50MBq (1.35mCi) Low Hazard
50 to 50000MBq (up to 1.35Ci) Medium Hazard
>50000MBq (>1.35Ci) High Hazard
46. Radiation Protection
Monitoring after Receiving of Radionuclide:
Monitoring of packages is required to check if the packages are
damaged or leaking
Monitoring must be done as soon as possible after receipt but not later
than 3 hr after delivery.
Two types of monitoring : survey for external exposure and wipe test
for contamination on the surface of the package
The survey reading of external exposure should not exceed
200mrem/hr (2mSv/hr) on the surface of the container or 10mrem/h
(100μSv/hr) at 1 meter from the surface of the container
The wipe test is performed by swabbing an area of 300cm2 of the
package and should not exceed of 6600dpm or 111MBq/300cm2.
All surveys are data must be logged in includes the date of receipt, the
manufacture, the lot number, name and quantity of the product, date and
time of calibration and survey data etc.,
47. Radiation Protection
Precautions following death of a therapy patient:
The procedures like labeling, contamination avoidance and
notification of the staff who may have to handle the body, should
be put in place
The procedures will depend on the radio nuclide involved, the
dose and time since administration etc.,
The sheet in which the body is wrapped should be clearly visible
to all those handling the body
During cremation, prior authorization and specific safety
precautions to be followed must be obtained from RSO.
The RSO shall recommend methods on dose reduction to the
personnel involved.
48. Radiation Protection
If a corpus contains less than
150MBq (4mCi) of colloidal 90Y
300MBq (8mCi) of 32P
450MBq (12mCi) of 131I
Normal procedures are adequate for examination
If a corpus contains radioactivity in excess of above mentioned
levels, the pathologist should be informed of the radiation levels
likely to be encountered and of the hazards involved.
In such cases, precautions need to be taken
No special precautions are necessary for the cremation of corpus
containing not more than 1000MBq (30mCi) of 90Y, 89Sr and 131I
(or) 400MBq (10mCi) of 32P
49. Radiation Protection
Prevention of Internal Contamination:
Internal contamination is possible by ingestion, inhalation,
percutaneous absorption or by accidental injection
There should be no eating, drinking, or using cosmetics in the
working areas of the NM dept
Any kind of radio active things should not brought into the
lounge room, waiting room etc.,
Some volatile radio activities (131I and 125I) could be released
accidentally.
All preparations are to be done in a properly operating fume hood
or glove box. The exhaust must be equipped with sodium
hydroxide solution traps to catch any volatile radio-iodine. Any
liquid waste must be dumped in a container with some strong
NaOH solution and kept covered
50. Radiation Protection
Prevention of Internal Contamination:
To avoid percutaneous absorption, long-sleeved coats, gloves,
masking tapes around the wrists to seal the gap between the gloves
and the lab coat sleeves, transparent plastic shields in front of the
face, and lead glass glasses are recommended when handling these
nuclides in liquid form.
If the contamination of the skin does occur accidentally, the
contaminated clothing must be removed immediately, and
decontamination of the skin with soap and water must follow. This
is followed by proper monitoring to ensure successful
decontamination
51. Radiation Protection
Bio-Assay of Radioactivity: For Occupational worker
Radio-bioassays are laboratory tests that quantify the accidental
intake of radioactivity in the body of radiation workers
In this method samples are collected from person and analyzed to
measure the contamination
Regulations require that the person intake of radioactivity and
assess the committed effective dose likely to receive more than
10% of the ALI
Nuclide ALI (Ingestion)
(μCi)
ALI (Inhalation)
(μCi)
DAC (inhalation)
(μCi/ml)
125I 4 x 101 6 x 101 3 x 10-6
32P 6 x 103 3 x 103 1 x 10-6
131I 9 x 101 5 x 101 2 x 10-8
52. Radiation Protection
Patient discharge:
Patients may be discharged only when the remaining activity is
less than that prescribed by the local regulatory authority
(555MBq/15mCi)
Patient monitoring should be done with survey meter at 1meter
distance from the patient
On discharge patients must be given instructions such as maintain
distance from others, sleep alone, do not travel by airplane or mass
or mass transportation, regarding contact with children and adults,
breast feeding and toilet use etc.,
Radionuclide Activity remaining
(GBq (mCi))
Dose rate at 1m
(μSv/hr) (mR/hr)
I – 131 1.1 (30) 50 - 60 (5 - 6)
P – 32 No practical limit Not applicable
Sr – 89 No practical limit Not applicable
53. Conclusion
In any radionuclide therapy program, proper implementation
of radiation safety measures and the cardinal principles of
Time, Distance & Shielding can kept exposure to patient,
nuclear medicine physician, nurses, staff and public
As
Low
As
Reasonably
Achievable