This document outlines the key steps and requirements for establishing a 3D conformal radiation therapy (3D-CRT) program. It discusses the clinical evidence supporting 3D-CRT over conventional radiation therapy and lists important milestones that must be achieved before starting a 3D-CRT program, such as ensuring adequate conventional radiation facilities, imaging capabilities, and staff training. The document also details the resources, equipment, processes, and staff training needed for clinical implementation of 3D-CRT planning and treatment.
This document discusses the history and techniques of stereotactic radiosurgery (SRS) and stereotactic body radiation therapy (SBRT). It begins by outlining the early development of SRS by Lars Leksell in the 1950s. It then defines key terms like SRS, SBRT, and fractionated stereotactic radiosurgery. The document goes on to discuss the rationale and advantages of SRS/SBRT, including its ability to deliver high radiation doses with steep dose gradients using multiple beams and image guidance. It also covers topics like tumor oxygenation, cell kill mechanisms, and recent technological advances in the field like VMAT, flattening filter free beams, and 4D
The document discusses the concepts of biological effective dose (BED) and equivalent dose in 2 Gy fractions (EQD2). BED represents the total dose required to achieve a specific biological effect based on the dose per fraction and overall treatment time. EQD2 provides a more practical dose value for clinical use by converting BED to an equivalent total dose given in 2 Gy fractions. The document provides examples of calculating BED and EQD2 for different fractionation schedules and discusses applications in isoeffective dose comparisons and interpreting clinical trial results.
This is a made easy summary of ICRU 89 guidelines for gynecological brachytherapy. Extra practical questions for MD/DNB Radiotherapy exams are also attached.
This document discusses lung stereotactic body radiotherapy (SBRT) for the treatment of early stage non-small cell lung cancer (NSCLC). It covers treatment indications for SBRT, methods used to account for tumor motion including 4DCT planning and respiratory gating, treatment planning guidelines, evidence from studies showing high rates of local control and survival, and results from RTOG trials of SBRT for lung cancer. In particular, it highlights that SBRT achieves local control rates of 85-95% and overall survival rates of 50-95% at 3-5 years for early stage NSCLC.
SBRT is a precise form of radiation therapy that delivers very high ablative doses of radiation to tumors in a small number of fractions. It has become the standard of care for early stage non-small cell lung cancer (NSC LC) that is not surgically resectable. Key aspects of SBRT planning and delivery include delineating targets and organs at risk on imaging, determining appropriate dose and fractionation based on tumor location, using motion management strategies to account for tumor motion, precise daily image guidance, and ensuring dose constraints are met to minimize risks to critical structures like the spinal cord. SBRT provides superior local tumor control compared to conventional fractionation for early stage NSCLC with a favorable toxicity profile.
This document discusses normal tissue tolerance doses from radiation therapy. It describes the formation of a task force to establish tolerance protocols, with an emphasis on partial volume effects. The earliest publication of tolerance doses is cited from 1972. 28 critical organ sites were included and considered in terms of dose, time factors, and partial volumes irradiated. The significance of these parameters and a quantitative model for normal tissue complication probability are provided. Limitations of the available data and ongoing areas of research are also outlined.
The document discusses guidelines from the International Commission on Radiation Units and Measurements (ICRU) for prescribing, recording, and reporting intensity-modulated radiation therapy (IMRT). It describes the different target volumes and organs at risk that must be delineated for treatment planning according to ICRU reports 50, 62, and 83. These include the gross tumor volume, clinical target volume, planning target volume, internal target volume, treated volume, and irradiated volume. Factors such as margins for internal motion and patient setup must be considered when defining volumes. Dose specifications, dose-volume histograms, conformity, and homogeneity are also discussed. Proper delineation of volumes and standardization of dose reporting are emphasized.
This document discusses hemi-body and total body irradiation techniques. Total body irradiation (TBI) delivers a uniform whole body radiation dose and is used as a conditioning regimen before bone marrow transplantation. It was developed in the early 1900s and is now used to treat various cancers and blood disorders. TBI can be delivered using dedicated or modified conventional irradiators. Dosimetry and compensators are used to ensure uniform dose delivery. Adverse effects include nausea, vomiting, pneumonitis and cataracts. Hemi-body irradiation treats only the upper or lower half of the body and has fewer side effects than total body irradiation.
This document discusses the history and techniques of stereotactic radiosurgery (SRS) and stereotactic body radiation therapy (SBRT). It begins by outlining the early development of SRS by Lars Leksell in the 1950s. It then defines key terms like SRS, SBRT, and fractionated stereotactic radiosurgery. The document goes on to discuss the rationale and advantages of SRS/SBRT, including its ability to deliver high radiation doses with steep dose gradients using multiple beams and image guidance. It also covers topics like tumor oxygenation, cell kill mechanisms, and recent technological advances in the field like VMAT, flattening filter free beams, and 4D
The document discusses the concepts of biological effective dose (BED) and equivalent dose in 2 Gy fractions (EQD2). BED represents the total dose required to achieve a specific biological effect based on the dose per fraction and overall treatment time. EQD2 provides a more practical dose value for clinical use by converting BED to an equivalent total dose given in 2 Gy fractions. The document provides examples of calculating BED and EQD2 for different fractionation schedules and discusses applications in isoeffective dose comparisons and interpreting clinical trial results.
This is a made easy summary of ICRU 89 guidelines for gynecological brachytherapy. Extra practical questions for MD/DNB Radiotherapy exams are also attached.
This document discusses lung stereotactic body radiotherapy (SBRT) for the treatment of early stage non-small cell lung cancer (NSCLC). It covers treatment indications for SBRT, methods used to account for tumor motion including 4DCT planning and respiratory gating, treatment planning guidelines, evidence from studies showing high rates of local control and survival, and results from RTOG trials of SBRT for lung cancer. In particular, it highlights that SBRT achieves local control rates of 85-95% and overall survival rates of 50-95% at 3-5 years for early stage NSCLC.
SBRT is a precise form of radiation therapy that delivers very high ablative doses of radiation to tumors in a small number of fractions. It has become the standard of care for early stage non-small cell lung cancer (NSC LC) that is not surgically resectable. Key aspects of SBRT planning and delivery include delineating targets and organs at risk on imaging, determining appropriate dose and fractionation based on tumor location, using motion management strategies to account for tumor motion, precise daily image guidance, and ensuring dose constraints are met to minimize risks to critical structures like the spinal cord. SBRT provides superior local tumor control compared to conventional fractionation for early stage NSCLC with a favorable toxicity profile.
This document discusses normal tissue tolerance doses from radiation therapy. It describes the formation of a task force to establish tolerance protocols, with an emphasis on partial volume effects. The earliest publication of tolerance doses is cited from 1972. 28 critical organ sites were included and considered in terms of dose, time factors, and partial volumes irradiated. The significance of these parameters and a quantitative model for normal tissue complication probability are provided. Limitations of the available data and ongoing areas of research are also outlined.
The document discusses guidelines from the International Commission on Radiation Units and Measurements (ICRU) for prescribing, recording, and reporting intensity-modulated radiation therapy (IMRT). It describes the different target volumes and organs at risk that must be delineated for treatment planning according to ICRU reports 50, 62, and 83. These include the gross tumor volume, clinical target volume, planning target volume, internal target volume, treated volume, and irradiated volume. Factors such as margins for internal motion and patient setup must be considered when defining volumes. Dose specifications, dose-volume histograms, conformity, and homogeneity are also discussed. Proper delineation of volumes and standardization of dose reporting are emphasized.
This document discusses hemi-body and total body irradiation techniques. Total body irradiation (TBI) delivers a uniform whole body radiation dose and is used as a conditioning regimen before bone marrow transplantation. It was developed in the early 1900s and is now used to treat various cancers and blood disorders. TBI can be delivered using dedicated or modified conventional irradiators. Dosimetry and compensators are used to ensure uniform dose delivery. Adverse effects include nausea, vomiting, pneumonitis and cataracts. Hemi-body irradiation treats only the upper or lower half of the body and has fewer side effects than total body irradiation.
Stereotactic body radiotherapy (SBRT) delivers high-dose radiation to tumors in a small number of fractions using high precision. For prostate SBRT, the target and organs at risk are contoured on planning CT. A dose of 35-38Gy in 5 fractions is used as primary treatment for low risk prostate cancer. Rigid image guidance and intrafraction monitoring are important to minimize setup errors. ExacTrac X-ray positioning co-registers X-rays with digitally reconstructed radiographs and corrects for rotational and translational deviations, achieving sub-millimeter accuracy. This allows safe dose escalation for prostate SBRT.
Icru reports in external beam radiotherapyDeepika Malik
The document summarizes key ICRU reports related to external beam radiotherapy, including ICRU Reports 29, 50, and 62. Report 29 established definitions like target volume, treatment volume, and organs at risk. Report 50 refined definitions and introduced clinical target volume, planning target volume, and treated volume. Report 62 further refined margins and introduced internal margin and setup margin. It also defined planning organ at risk volume and conformity index. The reports provide recommendations for dose reporting including minimum, maximum, and reference doses.
Three dimensional conformal radiotherapy - 3D-CRT and IMRT - Intensity modula...Abhishek Soni
Conformal radiation therapy techniques like 3D CRT and IMRT aim to concentrate radiation dose in the tumor while sparing surrounding normal tissues. This is achieved through advances in imaging, treatment planning and delivery. 3D CRT uses geometric field shaping with multiple beams while IMRT further modulates beam intensity across each field. Both require contouring of target and organs at risk on imaging along with inverse or forward treatment planning to optimize dose distribution. Conformal techniques allow higher tumor doses with improved normal tissue sparing compared to conventional radiation therapy.
Accelerated partial breast irradiation (APBI) delivers radiation to only the portion of the breast at highest risk of recurrence rather than the whole breast. This allows radiation to be delivered in a significantly shortened period. Several techniques for APBI exist including brachytherapy using catheters implanted in the breast, balloon brachytherapy, and external beam radiotherapy. Ongoing clinical trials are evaluating outcomes and toxicities of APBI compared to whole breast irradiation in appropriately selected patients with early-stage breast cancer.
ICRU 83 report on dose prescription in IMRTAnagha pachat
this slide is about the report 83 which is published by international commission for units and measurements on the topic dose prescription reporting and recording in intensity modulated radiation therapy . it is useful for personals and students in the field of radiation oncology.
This document discusses the use of stereotactic body radiation therapy (SBRT) for liver tumors. It provides details on common liver tumors including hepatocellular carcinoma and metastases. It describes SBRT as a treatment option for inoperable early stage tumors, as a bridge to transplant, and for intermediate or locally advanced stages. Key factors for patient selection and treatment planning such as tumor size, number and location, as well as liver function are summarized. The document also briefly discusses proton beam therapy and current clinical trials investigating SBRT for liver cancer.
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.
1) The linear-quadratic (LQ) model is commonly used in clinical practice to model cell survival patterns after radiation exposure and calculate biologically equivalent doses.
2) While the LQ model reasonably predicts cell survival up to doses of around 10 Gy per fraction, it may overestimate biological effect at higher doses used in stereotactic radiotherapy.
3) Several modifications have been proposed to the LQ model to address its limitations at high doses, such as accounting for non-DNA targets and cell repopulation, but there is currently no clear alternative model.
This document summarizes the liver stereotactic body radiation therapy (SBRT) techniques used to treat hepatocellular carcinoma (HCC) and liver metastases at Meenakshi Mission Hospital & Research Centre. Key points include:
1) Liver SBRT is used for 3 or fewer lesions 7cm or less in non-cirrhotic or cirrhotic livers, with controlled extrahepatic disease and a treatment history of local/regional/systemic therapies.
2) Treatment plans aim to spare at least 35% of the liver from the high SBRT doses to avoid liver decompensation. Special considerations are made for cirrhotic livers.
3) Treatments utilize respiratory motion management,
The vmat vs other recent radiotherapy techniquesM'dee Phechudi
VMAT is a new type of intensity-modulated radiation therapy (IMRT) treatment technique that uses the same hardware (i.e. a digital linear accelerator) as used for IMRT or conformal treatment, but delivers the radiotherapy treatment using a rotational or arc geometry rather than several static beams.
This technique uses continuous modulation (i.e. moving the collimator leaves) of the multileaf collimator (MLC) fields, continuous change of the fluence rate (the intensity of the X rays) and gantry rotation speed across a single or multiple 360 degree rotations
This document discusses radiotherapy techniques for lymphoma, including:
1. It describes the radiotherapy fields used to treat different lymph node regions, such as cervical, supraclavicular, mediastinal, axillary, abdominal, and inguinal regions.
2. It provides details on the dose of radiotherapy used in combined modality treatment with chemotherapy, ranging from 20-36 Gy depending on disease stage and bulkiness.
3. It outlines both the acute and late side effects of radiotherapy, such as fatigue, dermatitis, hypothyroidism, infertility, and increased risk of secondary cancers. Reducing radiation volumes and doses over time has helped lower long-term risks.
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.
Total skin electron therapy (TSET) is used to treat cutaneous T-cell lymphoma by delivering a uniform dose of radiation to the entire skin surface while sparing underlying organs. It requires large electron fields over the entire body and precise dosimetry. The most common technique uses six electron beams arranged at 60 degree intervals to provide circumferential coverage. Proper field design and calibration are needed to achieve uniform dose across irregular body surfaces and minimize dose from bremsstrahlung x-rays.
This document discusses various methods used to evaluate radiotherapy treatment plans, including physical and biological parameters. Physically, plans are evaluated using isodose curves, dose distribution statistics, differential and cumulative dose-volume histograms (DVHs). Target coverage should be within 95-100% of the prescribed dose. Biologically, tumor control probability (TCP) and normal tissue complication probability (NTCP) models are used. The therapeutic ratio and index compare the dose required for tumor control versus normal tissue complications. NTCP models include Lyman-Kutcher-Burman and critical element/volume models. Plan evaluation ensures target doses are adequate while respecting organ tolerance doses.
Altered fractionation schedules in radiation oncologyAbhishek Soni
Altered fractionation schedules aim to optimize tumor control and normal tissue sparing by manipulating total dose, dose per fraction, time interval between fractions, dose rate, and overall treatment time based on tumor and tissue radiosensitivity and repair characteristics. Hyperfractionation uses a higher total dose with smaller, more frequent fractions to exploit tumor reoxygenation and cell cycle effects while hypofractionation uses fewer, larger fractions which is more effective for tumors with low α/β ratios. Accelerated fractionation decreases treatment time to limit tumor repopulation at the cost of increased acute toxicity. Phase III trials show hyperfractionation and accelerated fractionation improve local control for head and neck cancers with acceptable toxicity.
Mind the Gap: Dealing with Interruptions in Radiotherapy TreatmentVictor Ekpo
A review of guidance on compensatory steps to take due to unscheduled interruptions in patient radiotherapy treatment, due to patient illness, staff illness or machine breakdown.
Interruptions are quite often. Different centres in different literature have quoted from 6 up to 63% of patients experience interruption. To reduce the risk of cancer recurrence, the Medical Physicist needs to calculate and determine compensatory action in dose, number of fraction or other action required.
This document analyzes the rate of normal vs abnormal findings from trauma CT scans performed at AAH over a 4 month period. The study found that 55% of scans were on men under 35, while 8% were on women under 35 and 6.5% were on children. The high percentage of normal findings raises concerns about unnecessary radiation exposure. The document recommends developing trauma CT guidelines to help determine appropriate cases and reduce avoidable scans by 20-40%. It also suggests exploring alternatives like Statscan machines to reduce initial radiation doses.
The document summarizes recommendations from the GYN GEC-ESTRO Working Group regarding MRI use for image-based adaptive brachytherapy in cervical cancer treatment. It recommends performing pelvic MRI before radiotherapy (pre-RT) and at the time of brachytherapy (BT MRI) using the same MRI machine. T2-weighted multiplanar MRI with a pelvic surface coil provides optimal visualization of the tumor and organs at risk. Patient preparation and MRI protocols should be tailored to the needs of BT. Following these recommendations can help optimize target definition and dose distribution during treatment.
Stereotactic body radiotherapy (SBRT) delivers high-dose radiation to tumors in a small number of fractions using high precision. For prostate SBRT, the target and organs at risk are contoured on planning CT. A dose of 35-38Gy in 5 fractions is used as primary treatment for low risk prostate cancer. Rigid image guidance and intrafraction monitoring are important to minimize setup errors. ExacTrac X-ray positioning co-registers X-rays with digitally reconstructed radiographs and corrects for rotational and translational deviations, achieving sub-millimeter accuracy. This allows safe dose escalation for prostate SBRT.
Icru reports in external beam radiotherapyDeepika Malik
The document summarizes key ICRU reports related to external beam radiotherapy, including ICRU Reports 29, 50, and 62. Report 29 established definitions like target volume, treatment volume, and organs at risk. Report 50 refined definitions and introduced clinical target volume, planning target volume, and treated volume. Report 62 further refined margins and introduced internal margin and setup margin. It also defined planning organ at risk volume and conformity index. The reports provide recommendations for dose reporting including minimum, maximum, and reference doses.
Three dimensional conformal radiotherapy - 3D-CRT and IMRT - Intensity modula...Abhishek Soni
Conformal radiation therapy techniques like 3D CRT and IMRT aim to concentrate radiation dose in the tumor while sparing surrounding normal tissues. This is achieved through advances in imaging, treatment planning and delivery. 3D CRT uses geometric field shaping with multiple beams while IMRT further modulates beam intensity across each field. Both require contouring of target and organs at risk on imaging along with inverse or forward treatment planning to optimize dose distribution. Conformal techniques allow higher tumor doses with improved normal tissue sparing compared to conventional radiation therapy.
Accelerated partial breast irradiation (APBI) delivers radiation to only the portion of the breast at highest risk of recurrence rather than the whole breast. This allows radiation to be delivered in a significantly shortened period. Several techniques for APBI exist including brachytherapy using catheters implanted in the breast, balloon brachytherapy, and external beam radiotherapy. Ongoing clinical trials are evaluating outcomes and toxicities of APBI compared to whole breast irradiation in appropriately selected patients with early-stage breast cancer.
ICRU 83 report on dose prescription in IMRTAnagha pachat
this slide is about the report 83 which is published by international commission for units and measurements on the topic dose prescription reporting and recording in intensity modulated radiation therapy . it is useful for personals and students in the field of radiation oncology.
This document discusses the use of stereotactic body radiation therapy (SBRT) for liver tumors. It provides details on common liver tumors including hepatocellular carcinoma and metastases. It describes SBRT as a treatment option for inoperable early stage tumors, as a bridge to transplant, and for intermediate or locally advanced stages. Key factors for patient selection and treatment planning such as tumor size, number and location, as well as liver function are summarized. The document also briefly discusses proton beam therapy and current clinical trials investigating SBRT for liver cancer.
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.
1) The linear-quadratic (LQ) model is commonly used in clinical practice to model cell survival patterns after radiation exposure and calculate biologically equivalent doses.
2) While the LQ model reasonably predicts cell survival up to doses of around 10 Gy per fraction, it may overestimate biological effect at higher doses used in stereotactic radiotherapy.
3) Several modifications have been proposed to the LQ model to address its limitations at high doses, such as accounting for non-DNA targets and cell repopulation, but there is currently no clear alternative model.
This document summarizes the liver stereotactic body radiation therapy (SBRT) techniques used to treat hepatocellular carcinoma (HCC) and liver metastases at Meenakshi Mission Hospital & Research Centre. Key points include:
1) Liver SBRT is used for 3 or fewer lesions 7cm or less in non-cirrhotic or cirrhotic livers, with controlled extrahepatic disease and a treatment history of local/regional/systemic therapies.
2) Treatment plans aim to spare at least 35% of the liver from the high SBRT doses to avoid liver decompensation. Special considerations are made for cirrhotic livers.
3) Treatments utilize respiratory motion management,
The vmat vs other recent radiotherapy techniquesM'dee Phechudi
VMAT is a new type of intensity-modulated radiation therapy (IMRT) treatment technique that uses the same hardware (i.e. a digital linear accelerator) as used for IMRT or conformal treatment, but delivers the radiotherapy treatment using a rotational or arc geometry rather than several static beams.
This technique uses continuous modulation (i.e. moving the collimator leaves) of the multileaf collimator (MLC) fields, continuous change of the fluence rate (the intensity of the X rays) and gantry rotation speed across a single or multiple 360 degree rotations
This document discusses radiotherapy techniques for lymphoma, including:
1. It describes the radiotherapy fields used to treat different lymph node regions, such as cervical, supraclavicular, mediastinal, axillary, abdominal, and inguinal regions.
2. It provides details on the dose of radiotherapy used in combined modality treatment with chemotherapy, ranging from 20-36 Gy depending on disease stage and bulkiness.
3. It outlines both the acute and late side effects of radiotherapy, such as fatigue, dermatitis, hypothyroidism, infertility, and increased risk of secondary cancers. Reducing radiation volumes and doses over time has helped lower long-term risks.
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.
Total skin electron therapy (TSET) is used to treat cutaneous T-cell lymphoma by delivering a uniform dose of radiation to the entire skin surface while sparing underlying organs. It requires large electron fields over the entire body and precise dosimetry. The most common technique uses six electron beams arranged at 60 degree intervals to provide circumferential coverage. Proper field design and calibration are needed to achieve uniform dose across irregular body surfaces and minimize dose from bremsstrahlung x-rays.
This document discusses various methods used to evaluate radiotherapy treatment plans, including physical and biological parameters. Physically, plans are evaluated using isodose curves, dose distribution statistics, differential and cumulative dose-volume histograms (DVHs). Target coverage should be within 95-100% of the prescribed dose. Biologically, tumor control probability (TCP) and normal tissue complication probability (NTCP) models are used. The therapeutic ratio and index compare the dose required for tumor control versus normal tissue complications. NTCP models include Lyman-Kutcher-Burman and critical element/volume models. Plan evaluation ensures target doses are adequate while respecting organ tolerance doses.
Altered fractionation schedules in radiation oncologyAbhishek Soni
Altered fractionation schedules aim to optimize tumor control and normal tissue sparing by manipulating total dose, dose per fraction, time interval between fractions, dose rate, and overall treatment time based on tumor and tissue radiosensitivity and repair characteristics. Hyperfractionation uses a higher total dose with smaller, more frequent fractions to exploit tumor reoxygenation and cell cycle effects while hypofractionation uses fewer, larger fractions which is more effective for tumors with low α/β ratios. Accelerated fractionation decreases treatment time to limit tumor repopulation at the cost of increased acute toxicity. Phase III trials show hyperfractionation and accelerated fractionation improve local control for head and neck cancers with acceptable toxicity.
Mind the Gap: Dealing with Interruptions in Radiotherapy TreatmentVictor Ekpo
A review of guidance on compensatory steps to take due to unscheduled interruptions in patient radiotherapy treatment, due to patient illness, staff illness or machine breakdown.
Interruptions are quite often. Different centres in different literature have quoted from 6 up to 63% of patients experience interruption. To reduce the risk of cancer recurrence, the Medical Physicist needs to calculate and determine compensatory action in dose, number of fraction or other action required.
This document analyzes the rate of normal vs abnormal findings from trauma CT scans performed at AAH over a 4 month period. The study found that 55% of scans were on men under 35, while 8% were on women under 35 and 6.5% were on children. The high percentage of normal findings raises concerns about unnecessary radiation exposure. The document recommends developing trauma CT guidelines to help determine appropriate cases and reduce avoidable scans by 20-40%. It also suggests exploring alternatives like Statscan machines to reduce initial radiation doses.
The document summarizes recommendations from the GYN GEC-ESTRO Working Group regarding MRI use for image-based adaptive brachytherapy in cervical cancer treatment. It recommends performing pelvic MRI before radiotherapy (pre-RT) and at the time of brachytherapy (BT MRI) using the same MRI machine. T2-weighted multiplanar MRI with a pelvic surface coil provides optimal visualization of the tumor and organs at risk. Patient preparation and MRI protocols should be tailored to the needs of BT. Following these recommendations can help optimize target definition and dose distribution during treatment.
The EMBRACE protocol involves a prospective multicenter study evaluating image-guided radiotherapy for cervical cancer, with a focus on improving outcomes. Key aspects of the protocol include:
1. Retrospective studies identified the benefits of MRI-based adaptive brachytherapy and established guidelines for parameters to evaluate.
2. The prospective EMBRACE I study involved over 1400 patients treated with chemoradiation followed by MRI-guided brachytherapy at 23 centers. Early results showed high local control rates and the benefits of combined intracavitary/interstitial brachytherapy in reducing morbidity.
3. The ongoing EMBRACE II study aims to further improve outcomes through
IRJET- Computer Aided Detection Scheme to Improve the Prognosis Assessment of...IRJET Journal
This document describes a computer-aided detection scheme to predict the risk of cancer recurrence in early-stage lung cancer patients after surgery. The scheme uses chest CT images taken before surgery to automatically segment lung tumors and extract morphological and texture-based image features. A naive Bayesian classifier is trained on six image features to predict recurrence risk. A separate artificial neural network classifier is trained on two genomic biomarkers to predict risk. The results from the two classifiers are then combined using a fusion method to produce the overall risk prediction. The goal is to more accurately assess prognosis and help doctors better manage early-stage non-small cell lung cancer patients after surgery.
Nasopharyngeal carcinoma is typically treated with radiation therapy. Concurrent chemotherapy and radiation is the standard for locally advanced disease and improves survival compared to radiation alone. Intensity-modulated radiation therapy provides better tumor coverage and reduces side effects. Surgery has a limited role except for biopsy or salvaging recurrent tumors. Temporal lobe necrosis is a serious potential complication, so fractional doses above 2Gy should be avoided. Close follow-up is needed due to risk of recurrence or late effects.
Radiobiological aspects of radiotherapy precisionAmin Amin
This document discusses the required accuracy and uncertainties in radiotherapy. It begins by introducing improvements in radiotherapy technologies that allow more precise dose delivery to tumors. It then discusses various modern radiotherapy modalities and the need for precision radiotherapy given technical and scientific advances. While survival improvements have not been conclusively shown, strategies to widen the therapeutic window include improved treatment conformity and personalized biological treatments. Accuracy requirements in radiotherapy are clinically driven and depend on dose-response curves for tumors and normal tissues. Overall uncertainties of 3% or less are recommended to minimize changes to tumor control or normal tissue complications. The document examines sources of uncertainty and accuracy achievable with techniques like 3D conformal radiotherapy and intensity-modulated radiotherapy.
3DCRT. radiation oncology conference in Tanzaniareuben mringo
This document discusses 3D conformal radiotherapy (3D CRT) and the process used in Tanzania. 3D CRT allows for radiation treatment plans to be customized for each patient's tumor and organs at risk by shaping the radiation fields based on 3D imaging. The process involves patient immobilization and simulation with CT imaging, tumor and organ contouring, beam placement and dose calculation, plan evaluation, data transfer to the treatment system, treatment delivery and verification, and patient follow up. Accurate imaging, planning and delivery are essential for 3D CRT to achieve dose escalation for tumor control while sparing healthy tissues and reducing side effects.
1. The document provides guidance from the ICRP on the radiological protection of patients and workers during the use of cone beam computed tomography (CBCT).
2. It notes that CBCT is being used in new medical specialties by practitioners without traditional CT training, so optimized protection principles are needed.
3. The document makes recommendations to justify CBCT use, optimize protocols to reduce dose, and properly record and report patient radiation exposure for management.
1. The document discusses various aspects of intensity-modulated radiation therapy (IMRT) planning and delivery, including the use of inverse planning, optimization objectives and constraints, and different delivery methods like static field, dynamic field, tomotherapy, and VMAT.
2. It also discusses treatment volumes defined in ICRU 83 like gross tumor volume, clinical target volume, planning target volume, and organ-at-risk volumes. The document emphasizes using dose-volume histograms to specify dose rather than a single point.
3. Challenges with overlapping treatment volumes and the importance of evaluating the remaining volume at risk are also covered.
Intensity modulated radiotherapy (IMRT) uses computer-optimized radiation beam intensities to conform the high dose region to the tumor target while reducing exposure to surrounding normal tissues. Key aspects of IMRT planning include tumor and organ contouring, beam arrangement optimization to meet dose constraints, and quality assurance of treatment delivery. IMRT offers advantages over conventional radiotherapy such as superior dose distribution, better normal tissue sparing, and potential for dose escalation through its ability to sculpt high dose regions closely to irregularly shaped tumor volumes.
1. ICRU Report 83 provides guidelines for prescribing, recording, and reporting intensity-modulated radiation therapy (IMRT). It emphasizes using dose-volume histograms and statistics like median dose to describe dose distributions.
2. The report outlines three levels of prescribing and reporting with increasing complexity. Level 1 involves basic 2D dose distributions while Level 3 incorporates more advanced metrics like tumor control probability.
3. Key volumes discussed include gross tumor volume, clinical target volume, planning target volume, and organs at risk. The report standardized how to account for uncertainties and patient motion when defining these volumes.
SOP CONFERENCE PROTOCOLS FOR BEGINNERSKanhu Charan
This document provides guidelines and standard operating procedures for stereotaxy radiosurgery and stereotactic body radiation therapy. It discusses patient selection criteria and protocols, simulation, treatment planning, quality assurance procedures, responsibilities of clinical team members, and patient follow-up. Standardized checklists and protocols are recommended to ensure safety and accuracy in patient localization, treatment planning and delivery for different anatomical sites. Strict quality assurance of equipment, imaging, treatment planning systems and patient-specific validation tests are essential parts of the procedures.
Cancerous lung nodule detection in computed tomography imagesTELKOMNIKA JOURNAL
Diagnosis the computed tomography images (CT-images) is one of the images that may take a lot of time in diagnosis by the radiologist and may miss some of cancerous nodules in these images. Therefore, in this paper a new novel enhancement and detection cancerous nodule algorithm is proposed to diagnose a CT-images. The novel algorithm is divided into three main stages. In first stage, suspicious regions are enhanced using modified LoG algorithm. Then in stage two, a potential cancerous nodule was detected based on visual appearance in lung. Finally, five texture features analysis algorithm is implemented to reduce number of detected FP regions. This algorithm is evaluated using 60 cases (normal and cancerous cases), and it shows a high sensitivity in detecting the cancerous lung nodules with TP ration 97% and with FP ratio 25 cluster/image.
This document discusses intensity-modulated radiation therapy (IMRT) planning. It describes how IMRT allows for more conformal radiation dose distributions compared to 3D conformal radiation therapy by modulating the fluence or intensity of the radiation beams. This capability of IMRT is particularly advantageous for sites with concave target volumes or where sensitive structures are located very close to the target, like for prostate cancer treatment. The document covers the historical development and technical aspects of IMRT planning and optimization methods as well as examples of clinical applications.
This document summarizes key concepts from ICRU report 83 regarding intensity modulated radiation therapy (IMRT) planning and dose reporting recommendations. Some of the main points include:
1) IMRT uses mathematical objective functions and dose-volume constraints in optimization, compared to traditional planning which iteratively modifies beam parameters.
2) ICRU 83 provides guidelines for standardizing IMRT techniques and procedures such as defining treatment volumes, dose prescription, and reporting levels.
3) It recommends dose-volume histogram reporting for target volumes and organs at risk, using metrics like D98%, D2%, Dmean rather than a single point dose. A homogeneity index is also defined.
TexRAD is software that analyzes textures in existing medical scans to provide prognostic information and risk stratification to clinicians. It does this by measuring fine, medium, and coarse textures in scans of tumors like those in the liver, lungs, and other organs. This additional texture information can help predict factors like cancer stage, metastasis risk, and prognosis. TexRAD requires no new scanning procedures and can analyze routine clinical images, providing more information to clinicians to guide patient care decisions.
This document outlines guidelines for target volume delineation for pelvic radiotherapy in cervical cancer. It summarizes recommendations from studies by Lim et al. and Taylor et al. regarding clinical target volume (CTV) contours for the cervix, uterus, parametria, vagina, and pelvic lymph nodes. For lymph nodes, a 7mm margin around blood vessels was found to provide 99% coverage while minimizing normal tissue irradiation. Non-uniform margins are recommended for certain nodal groups. Daily image-guided verification is important with IMRT to prevent geographic misses of the CTV.
Updates on Electron Beam Therapy
I) Introduction
II) Central Axis Depth dose distribution
III) Dosimetric parametrics of electron beam
IV) Clinical Considerations of Electron beam therapy
This phase 3 trial investigated adding abemaciclib to standard adjuvant endocrine therapy in patients with hormone receptor-positive, HER2-negative, lymph node-positive, high-risk early breast cancer. At the interim analysis, the addition of abemaciclib resulted in a statistically significant improvement in invasive disease-free survival compared to endocrine therapy alone. The most common adverse events with abemaciclib were diarrhea, neutropenia, and fatigue. Additional follow-up is still needed to determine if the benefit persists for later recurrences and overall survival.
This document discusses radiotherapy planning for vulvar cancer. It begins with an introduction that notes vulvar cancer is rare but usually presents as early stage squamous cell carcinoma in elderly women. It then covers anatomy, lymphatic spread, investigations, staging, indications for radiotherapy, patient positioning and immobilization, target volumes, field arrangements, doses, and toxicities. The target volumes include the vulvar tumor bed, inguinal lymph nodes, and sometimes pelvic lymph nodes. Doses depend on whether radiotherapy is adjuvant or definitive and if there is gross disease or positive margins. Toxicities are a concern especially for organs at risk like the bowels and bladder.
1) The document outlines various treatments for superior vena cava syndrome (SVCS) including radiation therapy (RT), chemotherapy, stenting, and surgery.
2) RT is effective at relieving symptoms in 80% of cases and works rapidly with initial high doses, while chemotherapy can also effectively palliate SVCS in lung cancers and lymphomas.
3) Stenting provides rapid and effective relief in 95% of cases and should be considered for life-threatening presentations or where other treatments are limited. Surgery has a limited role and is mainly used for refractory cases or certain malignancies.
This document outlines the key aspects of radiotherapy treatment planning for rectal cancer, including:
1) The epidemiology of rectal cancer, stages of disease, and patient positioning and immobilization techniques.
2) How to define the target volumes including the gross tumor, clinical target volume, and planning target volume based on disease stage and risk of lymph node involvement.
3) Typical three-field beam arrangements and doses of 45-50.4 Gy given in 1.8 Gy fractions for preoperative or postoperative radiotherapy, with additional boost doses sometimes used.
4) The acute and chronic complications of radiotherapy and dose constraints for organs at risk like the small bowel and bladder.
This document outlines a case presentation on testicular seminoma cancers. It discusses the case presentation, investigations including imaging, tumor markers, biopsy, and staging. It then covers prognosis factors, management strategies for different stages including surveillance, chemotherapy regimens, radiotherapy fields and doses. It also discusses complications, follow up, residual disease, and special considerations for patients with conditions like horseshoe kidney.
This document presents a case study on metastatic melanoma. It outlines the investigations performed which included a full-thickness biopsy with margins, pathology report including Breslow thickness and ulceration status, sentinel lymph node biopsy using blue dye and radiocolloid, and imaging for staging. Management options discussed include surgery, immunotherapy like CTLA-4 and PD-1 inhibitors, targeted therapy for BRAF/KIT mutations, and clinical trials. Clinical trials showed improved overall survival with combinations of nivolumab and ipilimumab compared to monotherapies.
This document presents a case presentation on salivary gland tumors. It outlines the investigations, staging, management, and prognosis of salivary gland tumors. The key investigations discussed are history and physical exam, ultrasound with fine needle aspiration, MRI, and histological diagnosis. Surgical management is the primary treatment and may include parotidectomy or neck dissection. Adjuvant radiation therapy can improve outcomes for high-grade or advanced tumors. Definitive radiation is an option for unresectable tumors. Prognosis depends on factors like tumor site, grade, and stage. Sequelae of treatment include facial nerve damage and xerostomia.
This document presents a case of oropharyngeal cancer and outlines its investigation, staging, management, and follow up. Investigations included imaging of the head and neck as well as biopsy of the primary tumor and lymph nodes. Staging involved assessing the extent of the primary tumor and evaluating for metastases. Management involved a multidisciplinary approach, with the main options being surgery followed by adjuvant radiation/chemoradiation or definitive chemoradiation. Follow up after curative treatment involved regular exams to monitor for recurrence. Key considerations in management included organ preservation and minimizing treatment-related toxicities such as dysphagia.
This document presents a case of non-metastatic colonic cancer. Investigations included bloodwork, colonoscopy, CT/MRI scans of the abdomen and chest. Pathologic staging evaluated tumor grade, depth of invasion, lymph node involvement and margins. For stage I-III disease, treatment involved surgery with the type depending on tumor location, followed by adjuvant chemotherapy with FOLFOX or CapeOx depending on risk level. Adjuvant chemotherapy duration was typically 6 months but 3 months was found non-inferior for some regimens and stages. Follow up involved CT scans and colonoscopies to monitor for recurrence.
Breast cancer can be locally advanced. The document discusses the anatomy, vasculature, lymphatics, and nerves of the breast. It then covers the pathology, epidemiology, genetics, classification, clinical features, and risk factors of breast cancer. Locally advanced breast cancer is discussed in terms of ductal carcinoma in situ (DCIS), lobular carcinoma in situ (LCIS), invasive ductal carcinoma (IDC), and invasive lobular carcinoma (ILC). Grading, genetic predisposition, male breast cancer, and phyllodes tumors are also summarized.
This document discusses cancer cachexia, beginning with an introduction that notes weight loss in cancer patients is associated with poor quality of life and increased morbidity. It then defines cachexia as a complex metabolic syndrome characterized by loss of muscle and fat mass. The pathophysiology section explains cachexia is multifactorial, involving anorexia, abnormal metabolism, and cytokine changes. Management involves treating the underlying cancer, nutritional intervention such as supplements by various routes, and pharmacological treatments including progestational agents, corticosteroids, and cytokine inhibitors, with some promising animal research on combinations. The document concludes by recommending various steps to address cachexia in clinical practice.
This document provides an overview of neuroendocrine tumors (NETs) that originate in the gastrointestinal tract (GIT). It discusses the classification, grading, epidemiology, pathophysiology, clinical features, and molecular biology of GIT-NETs. Some key points include:
- GIT-NETs are classified as well-differentiated or poorly-differentiated and further graded based on proliferation rate.
- The ileum is a common primary site. Symptoms vary depending on secretion of hormones.
- Carcinoid syndrome results from secretion of substances like serotonin that cause flushing, diarrhea, and heart disease.
- Molecular drivers include growth factors but causes are still not fully understood. Prognosis depends on
Cervical cancer arises from the transformation zone of the cervix. Risk factors include HPV infection, early age of first intercourse, multiple sexual partners, and smoking. It typically spreads locally first through direct extension, then can metastasize via lymph nodes or hematogenously to distant sites like lungs and liver. Screening via Pap smears can detect pre-cancerous changes and has reduced cervical cancer rates in developed nations by 75% over 50 years. Vaccination against HPV also prevents infection and future cancer development. Treatment and prognosis depends on the stage, with early localized disease having the best outcomes.
Nasopharyngeal cancer is a type of head and neck cancer that originates in the nasopharynx. The nasopharynx is located behind the nose and above the soft palate. This document discusses the anatomy, pathology, risk factors, epidemiology, clinical features, and spread of nasopharyngeal cancer. It notes that nasopharyngeal cancer is most commonly associated with Epstein-Barr virus infection and is more prevalent in certain parts of Asia and Africa. Local spread of the cancer typically occurs to nearby structures like the nasal cavity, skull base, and cranial nerves, while lymphatic and hematogenous spread can occur to cervical lymph nodes and distant organs.
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Recomendações da OMS sobre cuidados maternos e neonatais para uma experiência pós-natal positiva.
Em consonância com os ODS – Objetivos do Desenvolvimento Sustentável e a Estratégia Global para a Saúde das Mulheres, Crianças e Adolescentes, e aplicando uma abordagem baseada nos direitos humanos, os esforços de cuidados pós-natais devem expandir-se para além da cobertura e da simples sobrevivência, de modo a incluir cuidados de qualidade.
Estas diretrizes visam melhorar a qualidade dos cuidados pós-natais essenciais e de rotina prestados às mulheres e aos recém-nascidos, com o objetivo final de melhorar a saúde e o bem-estar materno e neonatal.
Uma “experiência pós-natal positiva” é um resultado importante para todas as mulheres que dão à luz e para os seus recém-nascidos, estabelecendo as bases para a melhoria da saúde e do bem-estar a curto e longo prazo. Uma experiência pós-natal positiva é definida como aquela em que as mulheres, pessoas que gestam, os recém-nascidos, os casais, os pais, os cuidadores e as famílias recebem informação consistente, garantia e apoio de profissionais de saúde motivados; e onde um sistema de saúde flexível e com recursos reconheça as necessidades das mulheres e dos bebês e respeite o seu contexto cultural.
Estas diretrizes consolidadas apresentam algumas recomendações novas e já bem fundamentadas sobre cuidados pós-natais de rotina para mulheres e neonatos que recebem cuidados no pós-parto em unidades de saúde ou na comunidade, independentemente dos recursos disponíveis.
É fornecido um conjunto abrangente de recomendações para cuidados durante o período puerperal, com ênfase nos cuidados essenciais que todas as mulheres e recém-nascidos devem receber, e com a devida atenção à qualidade dos cuidados; isto é, a entrega e a experiência do cuidado recebido. Estas diretrizes atualizam e ampliam as recomendações da OMS de 2014 sobre cuidados pós-natais da mãe e do recém-nascido e complementam as atuais diretrizes da OMS sobre a gestão de complicações pós-natais.
O estabelecimento da amamentação e o manejo das principais intercorrências é contemplada.
Recomendamos muito.
Vamos discutir essas recomendações no nosso curso de pós-graduação em Aleitamento no Instituto Ciclos.
Esta publicação só está disponível em inglês até o momento.
Prof. Marcus Renato de Carvalho
www.agostodourado.com
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Radiotheray transition from 2D to 3D Conformal radiotherapy(3D-CRT)
1.
2. • ‘’It must be emphasized that the development of
radiotherapy facilities should be regarded as a
stepwise process’’
3. Out lines of presentation
• Introduction
• Clinical Evidences for 3D-CRT
• Milestones for 3D CRT
• Approaches to 3D-CRT
• Resources required to establish 3D-CRT
• Clinical Implementation of 3-D CRT
• Education & training Requirement
• Quality assurance and Quality control in 3D CRT
• References
4. Introduction
• The term cancer (Greek "karkinos") was
proposed for the first time by Hippocrates, who
argued the roots of this disease resided in a
humoral imbalance.
• Radiation oncology is that discipline of human
medicine concerned with the generation,
conservation, and dissemination of knowledge
concerning the causes, prevention, and treatment
of cancer and other diseases involving special
expertise in the therapeutic applications of
ionizing radiation.
5. Introduction
• There are three key milestones in the history of
radiotherapy
I) Discovery of X-rays- by Wilhelm Rőntgen, in
1895
II) Discovery of natural radioactivity- by Marie
Curie in 1898
III) Production of artificial radioactive elements
6.
7. Introduction
• In 1897, Leopold Freund & Eduard Schiff proposed
X-rays to treat some diseases.
• In 1899, Tage Sjögren became the first person to
successfully treat a person with cancer through X-
rays
• In1900, Thor Stenbeck cured a skin cancer patient
with small doses of radiation
• In the 1980s the quadratic linear model was
proposed to describe the effects of radiation on
irradiated tissues
8. Introduction
• Between 1950 & early 1980s, the field of
radiotherapy began to use cobalt therapy
machines that allow the treatment of deeper and
“difficult” cancers,
• while X-rays only allow the treatment of
superficial tumors
• Subsequently, the linear particle accelerators
have begun to replace the cobalt units
9. Introduction
• When a physician decided administering RT to a
pt, six fundamental questions that must be
answered are:
1. Indication for RT?
2. Goal of radiation therapy?
3. Treatment volume?
4. Treatment technique
5. Treatment dose and fractionation?
6. Radiation tolerance of surrounding normal
tissues?
10. Introduction
• In technical terms, there are three main types of
radiotherapy
Radiation through external therapy (teletherapy)
Radiation through internal therapy (brachytherapy) and
Systemic therapy with radioisotopes
• There are seven main types of teletherapy
1. Conventional external radiation therapy or 2-D
2. Conformational radiation therapy or 3-D
3. Stereotactic (precision) radiation therapy
4. Radiation beam intensity modulation or IMRT
5. Image-guided radiation therapy or IGRT
6. Volumetric modulation arc therapy or VMAT
7. Particle therapy
11. Introduction
• The European Dynarad consortium has proposed
that the complexity of RT planning & treatment
methodologies can be captured in 04 levels
• Level 0 -represents basic RT where no attempt is
made to shape the treatment fields & as such
can’t be described as conformal
• Level 2 conformal RT requires a full 3-D data set,
usually of CT images, on which the tumor volume
is defined
12.
13.
14.
15. Conventional (2D) radiation therapy
-Old techniques of radiotherapy
-Treatments planned with limited number of
beams
- Boundaries delineated on orthogonal x-rays of
the patient
16. 3D conformal radiation therapy (3D-CRT
• Main distinction between treatment planning
of 3-D CRT and conventional radiation therapy
is
• it requires 3-D anatomic information &
treatment-planning system that allows
optimization of dose distribution which meets
the clinical objectives.
17. 3D conformal radiation therapy (3D-CRT)
• 3-D CRT-term to describe the design &
delivery of RT treatment plans based on 3-D
image data.
• Organ at risk also delineated &reduce
treatment side effects.
• RT planning software is used to design
complicated beam arrangements & to assess
DVH.
18. 3D conformal radiation therapy (3D-CRT
• If the adverse effects of treatment can be
reduced in this way, the dose of the target
volume can be increased with the expectation
of improving survival
• Its principal benefit therefore is to patients who
are to be given potentially curative radiotherapy
19. 3D conformal radiation therapy (3D-CRT
• The incremental benefits in the transition from
conventional RT to 3-D CRT are substantially
greater than those achieved in the transition from
3-D CRT to IMRT.
• It is therefore recommended that the
implementation of 3-D CRT should be given
priority over the implementation of IMRT
20. 3D conformal radiation therapy (3D-CRT)
• While 2-D RT can be applied with simple
equipment, infrastructure & training, transfer to
3-D CRT requires more resources in technology,
equipment, staff & training.
• A novel radiation treatment approach using
IMRT demands even more:
Sophisticated equipment
More teamwork
Consequentially more resources, advanced
training & more time for treatment planning &
verification of dose delivery than 3-D CRT.
21. 3D conformal radiation therapy (3D-CRT
• The design & delivery of a 3-D CRT treatment
requires a chain of procedures all of which must
be in place if the treatment is to be safe &
accurate.
• A chain is as strong as its weakest link.
• If any of the links of a chain are weaker than the
others the chain will break at that point.
• It is therefore essential that all the links have been
established before starting pt therapy.
22. 3D conformal radiation therapy (3D-CRT
• The links in this chain are:
1. Precise immobilization of pts throughout the
whole process
2. Use of high quality 3-D medical imaging to
determine GTV, CTV, PTV &PRV
3. Use of 3-D planning systems to choose beam
orientations & to display BEVs
4. computation of 3-D dose to the PTV & PRV
5. Evaluation of the dose plan effect using
-dose volume histograms (DVH)
-tumor control probability (TCP)
-normal tissue complication probability (NTCP)
23. 3D conformal radiation therapy (3D-CRT
• The links in this chain are…
6. Transfer of these planning data to the delivery
machine
7. Verification of pt position, beam placement &
dosimetry
8. Measurement of outcome
24. Clinical Evidence for 3D
• When the appropriate technology to deliver 3-D CRT,
such as
CT simulators,
Radiation treatment planning systems (RTPS) capable
of performing 3D dose calculations, producing DRRs
and DVHs,
Beam shaping devices like MLCs became available,
• This way of planning & delivering RT soon gained
popularity.
• 3D CRT now become standard practice in the
developed world to treat many types of tumors with
curative intent.
25. Clinical Evidence for 3D…
• The largest body of available evidence in support
of 3-D CRT is in the treatment of prostate & lung
cancers.
• By conforming the dose to the target volume, a
reduction in the treated volume of about 30% to
50% can be achieved using 3-D CRT.
26. Clinical Evidence for 3D…
• Local control can therefore be improved by ↑ the
dose to the tumor, without unacceptable toxicity.
• Evidence exists of a dose-response relationship in
many tumors
• This possibility of escalating doses, thus increasing
local control & potentially improving survival,
help to change the treatment from palliative to
curative
27. Milestones for 3D CRT
• A conformal radiotherapy program should be built
on a firm foundation of expertise in conventional
radiotherapy, and should not be started until
certain basic milestones have been met.
28. Milestones for 3D CRT
• Milestones that must be achieved before
resources are committed to the establishment of
3-D CRT
Facilities are in place for the provision of
conventional RT
Adequate Dxtic imaging facilities are in place for
Dx & staging
ƒAdequate imaging facilities are in place for
planning CT scans
ƒThere is an intention to deliver curative RT
29. Milestones for 3D CRT
• Milestones in the process once the project has started:
Appointment of sufficient staff that the existing program of
conventional therapy will not be compromised
ƒAcademic training of staff (radiation oncologist & medical
physicist)
ƒSpecification & purchase of necessary additional
equipment
ƒPractical training of radiation oncologist & medical
physicist
Practical training of other staff (treatment planners & RTTs)
ƒExtension of QA program to cover 3-D CRT
ƒEstablishment of clinical treatment protocols
30. APPROACHES TO CONFORMAL RADIOTHERAPY
• Starting a conformal radiotherapy program requires
considerable planning.
• To establish 3-D CRT in an institution the following steps
should be taken:
define the scope of the program
develop staffing needs for the program
ƒidentify necessary space and equipment
develop a program budget
ƒprepare space and purchase equipment
ƒhire new staff
ƒtrain all personnel to be involved with the program
ƒacceptance & commissioning test of the new equipment
develop necessary policies and procedures
develop & implement a comprehensive QA program
31. APPROACHES TO CONFORMAL RADIOTHERAPY
• It is important to allow sufficient time for physics
staff training prior to the arrival of the equipment
so that trained staff are in place to carry out
acceptance testing & commissioning.
• A complete understanding of all these steps is
necessary before one can successfully begin a
new program in 3-D CRT
32. Resources required to establish 3D-CRT
• Imaging equipment:
• All radiation therapy centers require Dxtic imaging
for optimum imaging of each tumor site.
• Ideally, each cancer centre will have a CT
simulator housed in the RT department.
• If this is not possible, RT departments must have
access to a CT scanner for planning conformal RT
33. Resources required to establish 3D-CRT
• Dedicated CT simulators are based on
Dxtic CT scanners, with a few
modifications:
I. Laser alignment system as a
reference for pt positioning,
II. 3-D imaging workstation for image
visualization & manipulation
III. Larger bore size to accommodate pt
immobilization devices
IV. Flat tabletop to replicate the
radiotherapy treatment unit couch
V. Modern CT simulators are also
capable of acquiring 4-D data
34. Resources required to establish 3D-CRT…
• Imaging equipment:
• Other imaging modalities that are useful (but not
essential) in the delineation of target volume are:
• MRI
• US
• various functional imaging modalities(PET, SPECT,
functional MRI, MR spectroscopic & molecular
imaging.
37. Resources required to establish 3D-CRT…
• Imaging equipment:
• The incorporation of information from multiple
imaging modalities has proven useful, but is not
an essential prerequisite.
• So it is useful to be able to co-register the data
from other imaging modalities with the planning
CT data
38. Resources required to establish 3D-CRT…
• Immobilization:
• Reproducible immobilization techniques are
essential to safely use this treatment technique.
• Examples include thermoplastic masks with bite
block fixation, alpha cradle etc.
39. Resources required to establish 3D-CRT…
• Treatment machine:
• A linear accelerator fitted with a MLC is ideal for
the delivery of planned conformal radiation
therapy.
• Ideally, the accelerator will also be fitted with
EPID that used for verification of pt setup &
geometric verification of beam portals.
• If an accelerator is not fitted with an EPID,
conventional port films can be used for the
verification of pt setup & beam portals.
40. Resources required to establish 3D-CRT…
• Record and verification system and networking:
• When a MLC is used, a record and verification
(R&V) system is needed to ensure planned
conformal radiation therapy is delivered as per
prescription.
• Care must be taken to ensure that errors do not
occur during transfer of data between simulator
,RTPS & treatment machine.
41. Resources required to establish 3D-CRT…
• Record and verification system and networking:
• An electronic network system for data transfer
from imaging facilities to the RTPS and then to the
delivery systems is desirable and this should
comply with DICOM (Digital Imaging and
Communications in Medicine) DICOM-RT
protocols.
• If networking capabilities are not available, an
alternative means of data transfer, like CD-ROM,
should be developed to ensure accurate transfer
of digital data from scanning facilities to RTPS &
from the RTPS to delivery systems
42. Resources required to establish 3D-CRT…
• Staffing and training:
• Dose planning in CRT is accomplished by
optimizing the weights of strategically placed
radiation portals that conform to the target
volume.
• Treatment of pts using 3-D CRT is a significant
departure from treating pts with conventional 2-D
RT.
• Therefore, there is a significant sub optimal
potential of pts if members of the treatment team
lack the necessary training in the 3-D CRT process.
43. Resources required to establish 3D-CRT…
• Staffing and training:
• Thus, it is essential that the treatment team,
consisting of :
Radiation oncologists
Medical physicists
Dosimetrists
RTT
• are well-trained in image guided treatment
planning & delivery with good understanding of
the uncertainties involved in these technique
44. Clinical Implementation of 3-D CRT
• There are many steps that are required to
implement 3D-CRT in the clinic.
47. Clinical Implementation of 3-D CRT…
• Patient assessment and decision to treat with
radiation:
• The first step in the process is patient assessment and
deciding how the pt should be treated.
• During assessment various Dxtic procedures are
undertaken to define the state of the disease.
• This involves :
imaging
biochemical testing
review of pathologic information to identify the type,
stage and grade of the cancer.
• The decision to treat the patient with radiation
should be made by a team of clinicians.
48. Clinical Implementation of 3-D CRT…
• Immobilization and patient positioning:
• An immobilization device is any device that helps
to establish & maintain the pt in a fixed, well-
defined position from treatment to treatment -
reproduce the treatment everyday
• It is often more practical and accurate to have
minimal immobilization aids accurately placed by
a skilled teams, than an over-complex system.
49. Clinical Implementation of 3-D CRT…
• Immobilization and patient positioning:
• Before starting to develop the treatment plan the
team needs to decide on the position required for
the pt treatment & immobilization needed.
• The use of 3-D CRT is usually associated with a ↓
in the margins around the CTV, but this is only
safe if random & systematic errors can be ↓.
• The key to satisfactory positioning of the pt is to
ensure that they are as comfortable and relaxed
as possible!!
50.
51. Clinical Implementation of 3-D CRT…
• Image acquisition and target Localization :
• Every RT department should develop protocols for
image acquisition for various body sites.
• These protocols will define the requirements for
the most common treatment sites.
• Where a protocol is not available a discussion
should take place among :
Treating radiation oncologist
Medical physicist
Dosimetrist
CT technologist on the goal of therapy
52. Clinical Implementation of 3-D CRT…
• Image acquisition and target Localization :
• CT imaging
• For many tumor sites CT scanning provides the optimal
method of tumor localization.
• All CT planning must be carried out under conditions as
nearly identical as possible to those in the treatment room,
including the:
pt support system (couch top),
laser positioning lights
any patient positioning aids.
• For conformal therapy a slice separation and thickness of
between 3 mm and 5 mm is recommended for CT scanning.
• For head & neck and CNS-between 2 -3 mm
53. Clinical Implementation of 3-D CRT…
• Image acquisition and target Localization :
• CT imaging
• To define anatomy adequately & generate DRRs of
high quality use closer CT slices than of the rest
of the volume, provided that the RTPS can cope
with different slice spacing.
• Using radio-opaque markers lateral and anterior
reference points should be established on the
patient or the immobilization device.
54. Clinical Implementation of 3-D CRT…
• Image acquisition and target Localization :
• MR and other imaging modalities
• In radiation therapy, the main application of MRI
involves mapping of anatomical data across to a
planning CT study (co-registration).
• This process retains the benefits of :
CT scan- study for dose calculation & treatment
verification
MRI- improved tumor visualization particularly in
the CNS & prostate
55. Clinical Implementation of 3-D CRT…
• Image acquisition and target Localization :
• MR and other imaging modalities
• direct use of MRI for radiotherapy planning
purposes suffers from the following
disadvantages:ƒ
Geometric distortion of the image;
Absence of tissue density information
ƒPoor definition of bone
ƒDRRs cannot be created
ƒDisease visualization is strongly dependent upon
the scan settings
56.
57. Clinical Implementation of 3-D CRT…
• Image acquisition and target Localization :
• To ensure the state-of-the-art Dxtic imaging
information (CT, MRI, PET, SPECT) is used to
provide an accurate GTV on a CT-based TPS,
→these images need to be registered at a single
workstation
58.
59. Clinical Implementation of 3-D CRT…
• Segmentation of structures:
• 3D-CRT treatment planning is dependent on an
image based simulation approach for accurately
delineating tumor & OAR volumes for an
individual pt.
• These volumes are drawn on a slice-by-slice basis
on a CT data set.
• Target volumes are contoured manually or
automatically
60. Clinical Implementation of 3-D CRT…
• Target volume delineation:
• Volume definition is a prerequisite for meaningful
3-D treatment planning & for accurate dose
reporting.
• ICRU Reports No. 50 and 62 define and describe
several target & critical structure volumes that aid
in the treatment planning process & provide a
basis for comparison of treatment outcomes
63. Clinical Implementation of 3-D CRT…
• Target volume delineation:
• GTV-
• Gross palpable/visible/demonstrable extent of
location of malignant growth.
• Usually based on information obtained from:
Physical examination
Results from imaging modalities (CT, MR, PET…)
Other diagnostic modalities (pathologic)
64. Clinical Implementation of 3-D CRT…
• Target volume delineation:
• CTV
• is the tissue volume that contains a demonstrable
GTV and/or sub-clinical microscopic malignant
disease, which has to be eliminated.
• This volume has to be treated adequately in
order to achieve the aim of therapy ( cure or
palliation)
65. Clinical Implementation of 3-D CRT…
• Target volume delineation:
• ITV
• is a new concept introduced in ICRU Report 62
• To compensate for variations in size, shape and
location of the CTV relative to the patient’s reference
frame (i.e. bony landmarks), ITV is added to CTV .
• ITV can be small (brain) or large (physiological
movements such as respiration, bladder and rectal
filling etc…)
• When defining the ITV it is important to account for
the asymmetric nature of the organ motion.
66. Clinical Implementation of 3-D CRT…
• Target volume delineation:
• PTV
• is a geometrical concept
• Used to select appropriate beam arrangement in
order to ensure the prescribed dose is actually
absorbed in the CTV.
67. Clinical Implementation of 3-D CRT…
• Target volume delineation:
• PTV
• In order to achieve the prescribed dose to the CTV
throughout the course of irradiation, margins
need to be added to the ITV to account for
uncertainties in patient positioning and alignment
of treatment beams throughout a fractionated
course of radiotherapy (set-up margin)
68.
69. Clinical Implementation of 3-D CRT…
• Target volume delineation:
• Organ at risk volumes
• ICRU Report 62 recognizes that normal tissue
structures are subject to the same movement
uncertainties as the target volumes.
• So the concept of Planning Risk Volume (PRV)
was introduced which is the volume of an organ
at risk with an appropriate margin for the
uncertainty in its position
70. Clinical Implementation of 3-D CRT…
• The treatment planning process:
• Once the target volume, organs at risk, and the
required doses have been defined, the treatment
plan will be produced by a person trained in 3-D
planning.
• The aim of the treatment planning process is to
achieve the dose objectives to the target and
critical structures and to produce a dose
distribution that is “optimal’’.
71. Clinical Implementation of 3-D CRT…
• The treatment planning process:
• TPS provides tools for
– Image registration
– Image segmentation or contouring
– Dose calculations
– Plan Evaluation
– Data Storage and transmission to console
– Treatment verification
72.
73. Clinical Implementation of 3-D CRT…
• The treatment planning process:
• Tools used in the evaluation of the planned dose
distribution:
Isodose lines
Color wash
DVH
• The ICRU report 50 recommends a target dose uniformity
within +7 % and -5 %.
• 95% of the PTV should received 95% the prescribed dose
74. Clinical Implementation of 3-D CRT…
• Data transfer for treatment delivery:
• Once the treatment plan has been designed and
approved by the radiation oncologist the details
need to be transferred to the treatment unit.
• If possible, a R&V system should be used to
control the treatment unit and data transfer
carried out electronically.
• Treatment errors are reduced by electronic data
transfer.
• If custom blocks are being used it may be
acceptable to use manual systems
75. Clinical Implementation of 3-D CRT…
• Data transfer for treatment delivery:
• A printout of the field shape is a useful method to
allow comparison of the treatment planning with
the field shape on the treatment machine.
• Safeguards must be put in place to prevent data
corruption due to infection by computer viruses,
etc
76. Clinical Implementation of 3-D CRT…
• Position verification and treatment delivery:
• Conformal radiotherapy by its nature requires
good geometrical accuracy in order for it to be
successful.
• It is normally the intention of conformal therapy
to reduce the volume of normal tissue included
within the treated volume.
77. EDUCATION AND TRAINING REQUIREMENTS
• There are significant differences between
conventional 2-D RT and 3-D CRT.
• Making a transition from one to the other is a
substantial undertaking.
• Experience gained by carrying out conventional
2D RT is essential; however, additional skill sets
are necessary to make the transition to 3-D CRT
• Each member of the team involved in the
planning & delivery of 3-D CRT understands
his/her role well for safe & effective of 3D-CRT
78. Quality assurance and Quality control in 3D CRT
• For the safe practice of 3-D CRT it is essential that
there is a QA program covering the whole process
from CT scanning through to treatment delivery