Radiology has evolved significantly since its discovery in the late 19th century. Some key developments include:
- 1895 - Wilhelm Roentgen discovers x-rays and takes the first medical x-ray.
- 1950s/60s - Technologies like PET, ultrasound, and angiography are developed, expanding diagnostic abilities.
- 1971 - Godfrey Hounsfield invents CT scanning, revolutionizing cross-sectional imaging.
- 1977 - MRI is developed, providing excellent soft tissue contrast without ionizing radiation.
- Modern advances continue to improve speed, resolution, and functional/molecular imaging capabilities across all modalities. Radiology now plays an essential role in medical diagnosis and treatment planning.
This document provides a history of radiology, beginning with discoveries in electricity, vacuum, and magnetism in the 17th-18th centuries that paved the way for X-rays. It then summarizes key events and discoveries in the late 19th century including Roentgen's discovery of X-rays in 1895 and early uses in medicine. The document also discusses early pioneers in dental radiology in the late 19th century and growth of the field in the 20th century along with important innovations and the realization of radiation hazards.
Computed Radiography and digital radiographyDurga Singh
This document provides an overview of a seminar on Computed Radiography (CR) and Digital Radiography (DR). CR involves capturing x-ray data digitally using an imaging plate, which stores radiation exposure information that is later read out by a laser and processed into an image. DR directly converts x-rays to a digital signal using a detector connected to a computer. The seminar discusses the components, principles, workings, advantages and disadvantages of each technology. It describes how CR imaging plates use photostimulated luminescence and how digital images are produced during plate reading.
This document discusses Computed Radiography (CR) and Digital Radiography (DR), which are two methods for obtaining digital x-rays. CR uses existing x-ray machines and captures images digitally using imaging plates, which store x-ray data that is later extracted digitally. DR uses direct or indirect flat panel detectors in digital x-ray machines to directly or indirectly convert x-rays into electronic signals. Both methods allow for digital image processing and eliminate the need for darkroom film processing.
Wilhelm Roentgen discovered X-rays in 1895 while experimenting with electron beams. He noticed a fluorescent screen glowing near his vacuum tube and saw the silhouette of his wife's bones when she placed her hand in front of the tube. X-rays are produced when electrons collide with metal and knock out inner shell electrons, emitting high energy electromagnetic waves. They can pass through objects at different levels depending on density and are used in medical imaging like radiography.
SPECT involves injecting a radiopharmaceutical that emits gamma rays. Detectors rotate around the body to acquire data from multiple angles and produce 3D images. It allows visualization of organ function. A gamma camera detects gamma rays and includes a collimator, scintillation detector, photomultiplier tubes, and computer. SPECT is used for heart, brain, and tumor imaging. It has lower resolution than PET but is commonly used to detect coronary artery disease.
The document provides information about X-ray tubes, including their history, components, and developments over time. It discusses:
- The key components of an X-ray tube including the cathode, filament, focusing cup, and anode. Electrons are emitted from the filament and accelerated toward the anode to produce X-rays.
- The development of X-ray tubes from the original Crookes tube to modern Coolidge tubes. Coolidge tubes introduced thermionic emission to produce electrons instead of relying on residual gas ionization.
- Advances over time including rotating anodes, improved cooling methods, and different target materials to produce more intense and focused X-rays for various medical and industrial applications
Radiographic contrast refers to the difference in densities between light and dark regions on a radiographic image. It is produced by differences in the attenuation of the x-ray beam as it passes through various tissues. Contrast is influenced by factors related to the subject, x-ray beam, and radiographic film or receptor. High contrast images have greater differences between densities while low contrast images have smaller differences between densities. Contrast can be controlled by adjusting exposure factors like kVp and mAs as well as using techniques to reduce scattered radiation, like grids, that reduce contrast.
Radiation protection methods are necessary to prevent harmful effects of ionizing radiation exposure. The key methods discussed are: 1) increasing distance from the radiation source to reduce exposure, 2) using protective barriers like aprons and gloves between the body and radiation, and 3) employing principles like reducing unnecessary exposures, proper beam filtration, radiation monitoring, and following ALARA to maintain radiation exposures as low as reasonably achievable. Radiation can damage DNA and create free radicals leading to biological effects so proper safety protocols are important.
This document provides a history of radiology, beginning with discoveries in electricity, vacuum, and magnetism in the 17th-18th centuries that paved the way for X-rays. It then summarizes key events and discoveries in the late 19th century including Roentgen's discovery of X-rays in 1895 and early uses in medicine. The document also discusses early pioneers in dental radiology in the late 19th century and growth of the field in the 20th century along with important innovations and the realization of radiation hazards.
Computed Radiography and digital radiographyDurga Singh
This document provides an overview of a seminar on Computed Radiography (CR) and Digital Radiography (DR). CR involves capturing x-ray data digitally using an imaging plate, which stores radiation exposure information that is later read out by a laser and processed into an image. DR directly converts x-rays to a digital signal using a detector connected to a computer. The seminar discusses the components, principles, workings, advantages and disadvantages of each technology. It describes how CR imaging plates use photostimulated luminescence and how digital images are produced during plate reading.
This document discusses Computed Radiography (CR) and Digital Radiography (DR), which are two methods for obtaining digital x-rays. CR uses existing x-ray machines and captures images digitally using imaging plates, which store x-ray data that is later extracted digitally. DR uses direct or indirect flat panel detectors in digital x-ray machines to directly or indirectly convert x-rays into electronic signals. Both methods allow for digital image processing and eliminate the need for darkroom film processing.
Wilhelm Roentgen discovered X-rays in 1895 while experimenting with electron beams. He noticed a fluorescent screen glowing near his vacuum tube and saw the silhouette of his wife's bones when she placed her hand in front of the tube. X-rays are produced when electrons collide with metal and knock out inner shell electrons, emitting high energy electromagnetic waves. They can pass through objects at different levels depending on density and are used in medical imaging like radiography.
SPECT involves injecting a radiopharmaceutical that emits gamma rays. Detectors rotate around the body to acquire data from multiple angles and produce 3D images. It allows visualization of organ function. A gamma camera detects gamma rays and includes a collimator, scintillation detector, photomultiplier tubes, and computer. SPECT is used for heart, brain, and tumor imaging. It has lower resolution than PET but is commonly used to detect coronary artery disease.
The document provides information about X-ray tubes, including their history, components, and developments over time. It discusses:
- The key components of an X-ray tube including the cathode, filament, focusing cup, and anode. Electrons are emitted from the filament and accelerated toward the anode to produce X-rays.
- The development of X-ray tubes from the original Crookes tube to modern Coolidge tubes. Coolidge tubes introduced thermionic emission to produce electrons instead of relying on residual gas ionization.
- Advances over time including rotating anodes, improved cooling methods, and different target materials to produce more intense and focused X-rays for various medical and industrial applications
Radiographic contrast refers to the difference in densities between light and dark regions on a radiographic image. It is produced by differences in the attenuation of the x-ray beam as it passes through various tissues. Contrast is influenced by factors related to the subject, x-ray beam, and radiographic film or receptor. High contrast images have greater differences between densities while low contrast images have smaller differences between densities. Contrast can be controlled by adjusting exposure factors like kVp and mAs as well as using techniques to reduce scattered radiation, like grids, that reduce contrast.
Radiation protection methods are necessary to prevent harmful effects of ionizing radiation exposure. The key methods discussed are: 1) increasing distance from the radiation source to reduce exposure, 2) using protective barriers like aprons and gloves between the body and radiation, and 3) employing principles like reducing unnecessary exposures, proper beam filtration, radiation monitoring, and following ALARA to maintain radiation exposures as low as reasonably achievable. Radiation can damage DNA and create free radicals leading to biological effects so proper safety protocols are important.
Nuclear medicine is a branch of medicine that uses radioactive tracers and imaging techniques to diagnose and treat diseases. It involves introducing radioactive substances into the patient's body and using a gamma camera to image their distribution and function within organs and tissues. Common nuclear medicine procedures include thyroid scans, bone scans, renal scans, and hepatobiliary scans to evaluate organ function. Positron emission tomography (PET) is an advanced nuclear medicine technique gaining importance in cancer imaging and care.
The document summarizes the process of computed radiography (CR), which uses an imaging plate rather than film. When exposed to X-rays, the phosphor layer in the imaging plate absorbs the radiation and excites electrons. These trapped electrons remain until stimulated by a laser during readout. The plate is scanned by a laser, causing the electrons to release light detected by a photomultiplier tube. This signal is converted to a digital image. After scanning, the plate is erased using light to remove any remaining electrons for future exposures. CR provides benefits over film such as dose reduction and improved image quality.
Mammography is the cornerstone of breast imaging and offers the necessary reliability to diagnose curable breast cancers. It involves using low-dose x-rays of the breast to detect tumors that are too small to feel. Digital mammography offers superior contrast resolution in dense breasts compared to conventional mammography but has lower spatial resolution, potentially missing some lesions. Mammography equipment includes an x-ray tube, compression device, and digital detectors to capture and process images, allowing diagnosis according to the BI-RADS assessment categories.
Artifacts in radiography obscure desired information and are caused by a variety of sources. Screen-film artifacts include exposure artifacts from issues like motion or improper positioning, as well as processing artifacts from problems in the darkroom. Digital artifacts stem from pixel failures, improper settings, or backscatter. Both modalities' artifacts can be reduced by identifying their causes and optimizing technique and quality control procedures.
The document summarizes key aspects of radiographic film, including its composition, construction, types, handling, and the latent image formation process. Radiographic film consists of a base and emulsion layer containing light-sensitive silver halide crystals. X-rays interact with the crystals to form a latent image, which is developed into a visible image. Proper handling and storage of the film is required to avoid artifacts and ensure optimal image quality.
1. Fluoroscopy uses real-time imaging to view internal structures in motion using contrast media and an image intensifier.
2. The image intensifier converts x-rays to visible light images that are hundreds of times brighter, allowing them to be viewed on a monitor or recorded.
3. Quality control measurements are important for fluoroscopy due to the relatively high radiation doses involved.
Exposure factors such as kVp, mA, time, mAs, focal spot size, and distance influence the quality and quantity of the x-ray beam and the resulting radiographic image. KVp controls beam quality and penetration, mA controls quantity of x-rays, and mAs is the product of mA and time determining total exposure. Increasing kVp increases penetration but reduces contrast. Proper selection of these technical factors is needed to produce diagnostic radiographs with minimal radiation exposure.
The document summarizes the components and functioning of a fluoroscope. A fluoroscope uses x-rays to visualize the motion of internal structures in real-time. It consists of an x-ray generator, tube, collimator, filters, table, grid, image intensifier, optical coupling and television system. The image intensifier converts x-rays into light photons, which are converted into an electronic signal via a television camera or CCD and displayed on a monitor. Spot films can also be obtained from fluoroscopy for later examination.
X-ray generators use transformers, rectifiers, and capacitors to convert electrical power into high voltage pulses needed to generate x-rays. There are several types of x-ray generators including single phase generators that produce two pulses, three phase six pulse generators that use three phase power, and three phase twelve pulse generators that add an additional delta connection to produce twelve pulses. High frequency generators use high frequency current to provide a constant voltage to the x-ray tube. Power discharge generators include capacitor discharge generators that use a high voltage capacitor to store and discharge charge, and battery powered generators that use batteries as the power source.
The document discusses digital radiography, including computed radiography (CR) and direct radiography using flat panel detectors. It summarizes the limitations of conventional film-based radiography and then describes the key components and workings of CR and direct digital radiography systems. Some advantages include improved image quality, ability to manipulate images digitally, faster processing, and reduced need for retakes compared to conventional methods.
Factors affecting Quality and Quantity of X-ray beamVinay Desai
The document discusses the components and functioning of an X-ray tube. It describes how X-ray tubes generate X-rays by accelerating electrons using high voltage and directing them at a metal target. It explains how factors like voltage, current, target material, filtration and waveform affect the quality and quantity of the X-ray beam produced. It also discusses X-ray tube ratings and charts that determine safe operational limits for exposures based on combinations of voltage, current and time to prevent overheating.
This document provides an overview of various medical imaging modalities. It defines radiology as the use of radiation for diagnosis and treatment. X-rays are a form of electromagnetic radiation that can pass through objects and are used to view bone structures in the body. The document discusses different imaging modalities including general radiography, fluoroscopy, computed tomography, magnetic resonance imaging, and ultrasound. It also covers related topics such as the units used to measure radiation, basic radiation protection techniques, and the roles of radiologic technologists.
X-ray film was originally recorded on glass plates but nitrocellulose film replaced them during WWI due to its greater feasibility. Double emulsion film was later found to respond faster to x-rays. By 1924, cellulose acetate replaced the flammable nitrocellulose film. Radiographic film consists of a polyester base and emulsion layers containing gelatin and light-sensitive silver halide crystals. Exposure to x-rays or light from intensifying screens causes a latent image in the crystals that is developed to produce the final image. Factors like contrast, speed, and spectral matching must be considered when selecting a film.
Thomas Edison invented fluoroscopy in 1896, which allows radiologists to obtain real-time moving images of internal structures. Fluoroscopy uses low-dose radiation from an x-ray tube and image intensifier to produce dynamic images for guidance during medical procedures. It has many applications including angiography and orthopedic surgery. Modern fluoroscopy equipment includes C-arms and uses automatic brightness control to maintain a constant image brightness during examinations.
This document discusses factors that influence radiographic image quality. It describes three main types of contrast that make up image contrast: subject contrast, radiographic contrast, and subjective contrast. It also discusses factors influencing sharpness and techniques for improving sharpness such as minimizing object-film distance, immobilizing the patient, and using a high mA and short exposure time. Exposure factors like mAs, kVp, and focus-film distance are also covered in regards to their effects on density and contrast.
This document discusses patient radiation dose management in medical imaging. It describes how patient dose is estimated using entrance skin exposure, bone marrow dose, and gonadal dose. Factors that influence patient dose include equipment design and operator technique. Unnecessary dose should be avoided by restricting unnecessary exams, repeats, and optimizing techniques like collimation and shielding. Special considerations are discussed for mammography, CT imaging, and protecting dose to pregnant patients.
The document summarizes key aspects of radiographic grids used to reduce scatter radiation in x-ray imaging. It describes the components and invention of grids, different grid patterns like linear and focused grids, as well as factors that affect grid performance such as grid ratio and lines per inch. Methods for evaluating grids like primary transmission, Bucky factor and contrast improvement are also outlined. Potential issues with grid use involving cutoff and decentering are discussed.
This document discusses the proper construction, equipment, and safety procedures for a radiology dark room. It outlines important considerations for the location, size, ventilation, lighting, entrance types, and hazards associated with a dark room. Key pieces of equipment like cassettes, film hangers, and processing chemicals and their uses are described. Common problems that can occur with screen film radiography like crossover exposure, cassette artifacts, and dirty/damaged screens are also reviewed.
The document discusses important figures and discoveries in the fields of electricity, vacuums, x-rays, and image recording materials. Some of the key people mentioned include Archimedes, Democritus, Thales, Pierre and Marie Curie, Evangelista Torricelli, Otto van Guericke, William Gilbert, Isaac Newton, Charles Dufay, Wilhelm Röntgen, and J.H. Scholtz. Röntgen accidentally discovered x-rays in 1895, while Scholtz produced the first photographic copy of written material, laying foundations for further developments in imaging technologies.
Wilhelm Röntgen discovered X-rays in 1895 while experimenting with cathode ray tubes. He found that X-rays could pass through human tissue but not bones, allowing him to see inside the body. Henri Becquerel discovered radioactivity in uranium in 1896 by accident. The Curies isolated radioactive elements radium and polonium between 1898-1902 through long purification processes which unfortunately led to their early deaths from radiation exposure. Rutherford discovered three types of radiation emitted from atoms - alpha, beta, and gamma rays - in the late 1890s. These early pioneers in the late 19th century laid the foundations for understanding radiation and nuclear physics.
Nuclear medicine is a branch of medicine that uses radioactive tracers and imaging techniques to diagnose and treat diseases. It involves introducing radioactive substances into the patient's body and using a gamma camera to image their distribution and function within organs and tissues. Common nuclear medicine procedures include thyroid scans, bone scans, renal scans, and hepatobiliary scans to evaluate organ function. Positron emission tomography (PET) is an advanced nuclear medicine technique gaining importance in cancer imaging and care.
The document summarizes the process of computed radiography (CR), which uses an imaging plate rather than film. When exposed to X-rays, the phosphor layer in the imaging plate absorbs the radiation and excites electrons. These trapped electrons remain until stimulated by a laser during readout. The plate is scanned by a laser, causing the electrons to release light detected by a photomultiplier tube. This signal is converted to a digital image. After scanning, the plate is erased using light to remove any remaining electrons for future exposures. CR provides benefits over film such as dose reduction and improved image quality.
Mammography is the cornerstone of breast imaging and offers the necessary reliability to diagnose curable breast cancers. It involves using low-dose x-rays of the breast to detect tumors that are too small to feel. Digital mammography offers superior contrast resolution in dense breasts compared to conventional mammography but has lower spatial resolution, potentially missing some lesions. Mammography equipment includes an x-ray tube, compression device, and digital detectors to capture and process images, allowing diagnosis according to the BI-RADS assessment categories.
Artifacts in radiography obscure desired information and are caused by a variety of sources. Screen-film artifacts include exposure artifacts from issues like motion or improper positioning, as well as processing artifacts from problems in the darkroom. Digital artifacts stem from pixel failures, improper settings, or backscatter. Both modalities' artifacts can be reduced by identifying their causes and optimizing technique and quality control procedures.
The document summarizes key aspects of radiographic film, including its composition, construction, types, handling, and the latent image formation process. Radiographic film consists of a base and emulsion layer containing light-sensitive silver halide crystals. X-rays interact with the crystals to form a latent image, which is developed into a visible image. Proper handling and storage of the film is required to avoid artifacts and ensure optimal image quality.
1. Fluoroscopy uses real-time imaging to view internal structures in motion using contrast media and an image intensifier.
2. The image intensifier converts x-rays to visible light images that are hundreds of times brighter, allowing them to be viewed on a monitor or recorded.
3. Quality control measurements are important for fluoroscopy due to the relatively high radiation doses involved.
Exposure factors such as kVp, mA, time, mAs, focal spot size, and distance influence the quality and quantity of the x-ray beam and the resulting radiographic image. KVp controls beam quality and penetration, mA controls quantity of x-rays, and mAs is the product of mA and time determining total exposure. Increasing kVp increases penetration but reduces contrast. Proper selection of these technical factors is needed to produce diagnostic radiographs with minimal radiation exposure.
The document summarizes the components and functioning of a fluoroscope. A fluoroscope uses x-rays to visualize the motion of internal structures in real-time. It consists of an x-ray generator, tube, collimator, filters, table, grid, image intensifier, optical coupling and television system. The image intensifier converts x-rays into light photons, which are converted into an electronic signal via a television camera or CCD and displayed on a monitor. Spot films can also be obtained from fluoroscopy for later examination.
X-ray generators use transformers, rectifiers, and capacitors to convert electrical power into high voltage pulses needed to generate x-rays. There are several types of x-ray generators including single phase generators that produce two pulses, three phase six pulse generators that use three phase power, and three phase twelve pulse generators that add an additional delta connection to produce twelve pulses. High frequency generators use high frequency current to provide a constant voltage to the x-ray tube. Power discharge generators include capacitor discharge generators that use a high voltage capacitor to store and discharge charge, and battery powered generators that use batteries as the power source.
The document discusses digital radiography, including computed radiography (CR) and direct radiography using flat panel detectors. It summarizes the limitations of conventional film-based radiography and then describes the key components and workings of CR and direct digital radiography systems. Some advantages include improved image quality, ability to manipulate images digitally, faster processing, and reduced need for retakes compared to conventional methods.
Factors affecting Quality and Quantity of X-ray beamVinay Desai
The document discusses the components and functioning of an X-ray tube. It describes how X-ray tubes generate X-rays by accelerating electrons using high voltage and directing them at a metal target. It explains how factors like voltage, current, target material, filtration and waveform affect the quality and quantity of the X-ray beam produced. It also discusses X-ray tube ratings and charts that determine safe operational limits for exposures based on combinations of voltage, current and time to prevent overheating.
This document provides an overview of various medical imaging modalities. It defines radiology as the use of radiation for diagnosis and treatment. X-rays are a form of electromagnetic radiation that can pass through objects and are used to view bone structures in the body. The document discusses different imaging modalities including general radiography, fluoroscopy, computed tomography, magnetic resonance imaging, and ultrasound. It also covers related topics such as the units used to measure radiation, basic radiation protection techniques, and the roles of radiologic technologists.
X-ray film was originally recorded on glass plates but nitrocellulose film replaced them during WWI due to its greater feasibility. Double emulsion film was later found to respond faster to x-rays. By 1924, cellulose acetate replaced the flammable nitrocellulose film. Radiographic film consists of a polyester base and emulsion layers containing gelatin and light-sensitive silver halide crystals. Exposure to x-rays or light from intensifying screens causes a latent image in the crystals that is developed to produce the final image. Factors like contrast, speed, and spectral matching must be considered when selecting a film.
Thomas Edison invented fluoroscopy in 1896, which allows radiologists to obtain real-time moving images of internal structures. Fluoroscopy uses low-dose radiation from an x-ray tube and image intensifier to produce dynamic images for guidance during medical procedures. It has many applications including angiography and orthopedic surgery. Modern fluoroscopy equipment includes C-arms and uses automatic brightness control to maintain a constant image brightness during examinations.
This document discusses factors that influence radiographic image quality. It describes three main types of contrast that make up image contrast: subject contrast, radiographic contrast, and subjective contrast. It also discusses factors influencing sharpness and techniques for improving sharpness such as minimizing object-film distance, immobilizing the patient, and using a high mA and short exposure time. Exposure factors like mAs, kVp, and focus-film distance are also covered in regards to their effects on density and contrast.
This document discusses patient radiation dose management in medical imaging. It describes how patient dose is estimated using entrance skin exposure, bone marrow dose, and gonadal dose. Factors that influence patient dose include equipment design and operator technique. Unnecessary dose should be avoided by restricting unnecessary exams, repeats, and optimizing techniques like collimation and shielding. Special considerations are discussed for mammography, CT imaging, and protecting dose to pregnant patients.
The document summarizes key aspects of radiographic grids used to reduce scatter radiation in x-ray imaging. It describes the components and invention of grids, different grid patterns like linear and focused grids, as well as factors that affect grid performance such as grid ratio and lines per inch. Methods for evaluating grids like primary transmission, Bucky factor and contrast improvement are also outlined. Potential issues with grid use involving cutoff and decentering are discussed.
This document discusses the proper construction, equipment, and safety procedures for a radiology dark room. It outlines important considerations for the location, size, ventilation, lighting, entrance types, and hazards associated with a dark room. Key pieces of equipment like cassettes, film hangers, and processing chemicals and their uses are described. Common problems that can occur with screen film radiography like crossover exposure, cassette artifacts, and dirty/damaged screens are also reviewed.
The document discusses important figures and discoveries in the fields of electricity, vacuums, x-rays, and image recording materials. Some of the key people mentioned include Archimedes, Democritus, Thales, Pierre and Marie Curie, Evangelista Torricelli, Otto van Guericke, William Gilbert, Isaac Newton, Charles Dufay, Wilhelm Röntgen, and J.H. Scholtz. Röntgen accidentally discovered x-rays in 1895, while Scholtz produced the first photographic copy of written material, laying foundations for further developments in imaging technologies.
Wilhelm Röntgen discovered X-rays in 1895 while experimenting with cathode ray tubes. He found that X-rays could pass through human tissue but not bones, allowing him to see inside the body. Henri Becquerel discovered radioactivity in uranium in 1896 by accident. The Curies isolated radioactive elements radium and polonium between 1898-1902 through long purification processes which unfortunately led to their early deaths from radiation exposure. Rutherford discovered three types of radiation emitted from atoms - alpha, beta, and gamma rays - in the late 1890s. These early pioneers in the late 19th century laid the foundations for understanding radiation and nuclear physics.
Radioactivity is the spontaneous emission of particles or energy from unstable atomic nuclei to become more stable. It was discovered in 1896 by Henri Becquerel when studying uranium salts that emitted rays and could burn skin. Later, Marie and Pierre Curie isolated the radioactive elements radium and polonium, and defined their property of half-life. There are three main types of radioactive emissions - alpha, beta, and gamma rays - which were categorized by their ability to ionize atoms as either ionizing or non-ionizing radiation.
The document provides an overview of the history of radiation, including key discoveries and events. It describes Wilhelm Roentgen's discovery of X-rays in 1895, Henri Becquerel's accidental discovery of radioactivity in uranium in 1896, and Marie and Pierre Curie's isolation of the radioactive elements polonium and radium in 1898. It also discusses the radium dial painters who suffered health impacts from radium exposure in the early 20th century. Finally, it outlines the 1986 Chernobyl disaster, considered the worst nuclear power plant accident, which occurred at a reactor in Ukraine and spread radioactive debris over parts of Europe.
The document provides instructions for an assignment on medical device pioneers. Students are to choose a pioneer from a list, research the medical device they developed or advanced, and create a PowerPoint presentation with details on who they were, what they invented, when and where. They will post their presentation to the instructor's blog and comment on a classmate's post. The document lists helpful resources and questions students should answer in their presentation.
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.
Digital radiography involves using digital x-ray sensors instead of film to capture x-ray images. There are two main types: computed radiography, which uses phosphor plates that store x-ray data that is later scanned, and direct digital radiography, where x-ray data is captured directly by a sensor and displayed immediately. The key components required are sensors or phosphor plates, imaging software for viewing, storing and managing images, and a computer system. Digital radiography provides advantages over traditional film such as faster imaging and the ability to digitally enhance images.
Radiography uses x-rays to generate images of the internal structures of objects. X-rays are generated using an x-ray tube, which accelerates electrons toward a metal target. When the electrons collide with the target, x-rays are produced. These x-rays are used to expose radiographic film, creating a latent image. The film is then developed using chemical processes similar to photographic film development, making the latent image visible. The visible image reveals the internal structures and densities of the object in a manner similar to shadows.
This document discusses diagnostic radiology and x-rays. It begins by outlining the learning outcomes which include defining x-rays, comparing invasive and noninvasive procedures, and the medical assistant's role in radiology. It then provides a brief history of x-rays and their diagnostic and therapeutic uses. The document outlines the medical assistant's role in preparing patients, assisting with procedures, and filing/maintaining records. It describes various diagnostic radiology tests and therapeutic uses of radiation. Throughout, it emphasizes the importance of safety precautions for patients and medical personnel.
This document provides an agenda for a lesson on atoms and radiation. It includes:
- A review of exam questions and mind maps from the previous lesson on the plum pudding model, Rutherford scattering experiment, and basic atomic structure.
- An overview of topics that should now be covered, including ions, isotopes, radioactive decay, and different types of radiation (alpha, beta, gamma).
- Details on properties of each type of radiation, their uses and dangers, and how they behave in magnetic fields.
- Information on alpha decay and beta decay, including examples and nuclear equations.
- A note that past exam questions will also be reviewed.
This document discusses the structure of atoms, radioactivity, and uses evidence about radiation and the universe to support the Big Bang theory. It describes:
1) The basic structure of atoms including protons, neutrons, electrons, isotopes, and radioisotopes.
2) Different types of radiation including alpha, beta, and gamma rays and how they are produced and can be blocked.
3) How radioisotopes are used in medical tracers and carbon dating to measure material ages based on half-life decay.
4) Evidence from light spectroscopy showing redshift of spectra from distant galaxies, which suggests everything is moving away from a single point supporting the Big Bang theory of an expanding universe.
This document discusses different types of radiation sources. It describes natural sources like cosmic rays, terrestrial radiation from rocks and soil, and internal sources in the human body. It also covers artificial sources like medical procedures, nuclear power plants, nuclear weapons, and consumer products. The document defines ionizing radiation as high energy waves or particles that can strip electrons from atoms, and non-ionizing radiation as lower energy waves that can excite but not ionize electrons. It provides examples of different radioactive decays and how to balance nuclear equations.
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.for more details please visit
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This document discusses various topics related to radiation and its units of measurement. It defines (1) radiation oncology as the field concerned with treating cancer and other diseases using ionizing radiation, (2) the two main types of radiation as ionizing and non-ionizing, and (3) some key units used to measure radiation exposure and its effects on living tissue, including the becquerel, curie, gray, sievert, and rem. It also provides background on the scientists who discovered various types of radiation and developed these units, such as Becquerel, Curie, Roentgen, and Gray.
Current applications of interventional radiology 97Arun Jagannathan
Interventional radiologists are physicians who specialize in minimally invasive targeted treatments using image guidance. They undergo 4 years of undergraduate education, 4 years of medical school, 5 years of residency training, and 1 year of fellowship training. Interventional radiology pioneered modern medicine by inventing angioplasty and stenting to treat blocked arteries. Some key milestones include the first angioplasty in 1964, development of embolization therapy in the 1960s, and invention of the catheter-delivered stent in the late 1960s and early 1970s. Interventional radiologists now perform a variety of minimally invasive procedures to treat cancer, vascular diseases, trauma, and other conditions.
Wilhelm Roentgen discovered x-rays in 1895 when he observed that a fluorescent screen glowed near a cathode ray tube. He found that x-rays are produced when electrons collide with a metal target in a vacuum tube. There are two types of x-ray spectra produced: continuous spectra which has a range of wavelengths, and characteristic spectra which consists of peaks produced by electronic transitions within atoms. X-rays can diffract when they interact with the periodic planes of atoms in a crystal according to Bragg's law. The wavelength is determined by the spacing between planes and the diffraction angle. Moseley's law describes the relationship between an element's atomic number and the wavelength of its spectral lines.
A linha do tempo descreve eventos históricos do Brasil entre 1896 e 1917, incluindo a Guerra de Canudos, a Revolta da Vacina no Rio de Janeiro e a Greve Geral de 1917 em São Paulo.
1) Radiation is energy transmitted through space or matter in the form of waves or particles. It is classified as ionizing or non-ionizing.
2) X-rays are a type of ionizing electromagnetic radiation that was discovered in 1895 by Wilhelm Röntgen. They are produced within diagnostic X-ray tubes and are widely used in medical imaging due to their ability to pass through objects.
3) Diagnostic X-rays are the largest man-made source of radiation exposure to the general population. While they provide medical benefits, high doses can cause radiation sickness or increase cancer risk. Risk is kept as low as reasonably achievable.
The document discusses concepts related to x-ray attenuation including:
1. Attenuation is the reduction in intensity of an x-ray beam as it passes through matter by absorption or deflection of photons.
2. Exponential attenuation occurs when the number of photons decrease by the same percentage with each increment of absorber thickness, as seen with monochromatic radiation.
3. The half value layer is the thickness of absorber needed to reduce the intensity of an x-ray beam by half.
Ultrasonography - History, evolution and principlesaparna666
This document provides an overview of ultrasound imaging and its applications in head and neck imaging. It discusses the history and evolution of ultrasound from its origins in sonar to modern medical applications. The basic physics of ultrasound such as piezoelectricity and acoustic impedance are explained. The document outlines the components of an ultrasound machine and different imaging modes. Finally, it demonstrates how ultrasound can be used to visualize normal head and neck anatomy and diagnose various pathologies.
Radiography, also known as X-ray imaging, is a medical imaging technique that uses X-rays to produce images of the internal structures of the body. It has various applications in diagnostic imaging and therapeutic procedures. Some key applications discussed in the document are mammography, which uses low-dose X-rays to screen and detect breast cancer, and fluoroscopy, which produces a continuous X-ray image on a monitor. The document provides historical context on the discovery of X-rays and development of various radiography techniques over time.
Radiography, also known as X-ray imaging, is a medical imaging technique that uses X-rays to produce images of the internal structures of the body. It has a variety of medical uses including diagnostic imaging to detect fractures or tumors, as well as therapeutic applications in areas like radiation therapy for cancer treatment. Key developments in radiography over time include the introduction of digital X-ray systems and newer modalities like computed tomography (CT), which can generate cross-sectional slices of the body, and mammography for breast imaging.
Basics of imaging by mohamed abou el gharFarragBahbah
This document provides an overview of various medical imaging modalities including X-rays, computed tomography (CT), ultrasonography, magnetic resonance imaging (MRI), and nuclear medicine. It describes some key details about each technique such as how images are produced, advantages, and disadvantages. For example, it states that CT uses X-rays and computers to produce high quality images while MRI utilizes strong magnetic fields and hydrogen atom energy to generate tissue-specific images without ionizing radiation. Nuclear medicine is described as using radioactive tracers and gamma cameras to image body tissues.
This document provides an overview of computed tomography (CT) scanning. It discusses the history and invention of CT, its common uses in medicine, working principles including components like the gantry and detectors, generations of CT technology, and the mathematical principles behind image reconstruction. CT scanning uses X-rays and computers to produce cross-sectional images of the body and has become an important medical imaging tool since its invention in the 1970s.
This document provides an overview of various imaging techniques used in orthopaedics, including their history, uses, and classifications. It discusses techniques such as x-rays, CT, MRI, ultrasound, bone scans, and DEXA scans. For each technique, it covers the basic principles, advantages, disadvantages, and applications in orthopaedics such as diagnosis, surgical planning, and monitoring treatment.
Ultrasound uses sound waves to visualize soft tissue structures in the body. It was developed from discoveries in acoustics and piezoelectricity in the late 19th/early 20th centuries. Uses of ultrasound include imaging organs, tissues, and blood flow. It has evolved from 1D to 2D to 3D imaging with advances in transducer technology, computer processing, and the introduction of Doppler and contrast agents. Today ultrasound provides real-time diagnostic imaging across many medical specialties.
The document summarizes the history and development of computed tomography (CT) scanning technology. It describes the key events and innovations such as the development of the first CT scanner by Godfrey Hounsfield in 1972 (1), the introduction of whole body scanning in 1975 (2), and Hounsfield and Cormack being awarded the Nobel Prize in 1979 (3). Subsequent generations of CT scanners incorporated improvements like faster scanning speeds, multiple detectors, and eliminating moving parts to enable ultra-fast scanning.
This document provides an overview of computed tomography (CT) and magnetic resonance imaging (MRI). It discusses the history and development of CT from the early 1970s to present day, including the evolution from first to fifth generation CT scanners. Key aspects of CT technology covered include the basic principles, components like the x-ray tube and detectors, and types of scans like conventional tomography and cone beam CT. The document also briefly introduces magnetic resonance imaging.
CT or computed tomography is a medical imaging technique that uses x-rays and computer processing to create cross-sectional images of the body. The first CT scan took 9 days to produce a single image in 1971, while modern CT scanners can produce multiple slices in under 1 second. A CT scan uses an x-ray tube and detectors mounted on a rotating gantry to measure the attenuation of x-rays through tissue from different angles, and computers process this data to reconstruct cross-sectional images. CT has advanced from early generations with single detectors to current multi-detector arrays that allow faster whole-organ or whole-body imaging.
The document provides a historical overview of computed tomography (CT) scanning. It describes how CT scanning was developed in the 1970s by Godfrey Hounsfield and Allan Cormack, who were later awarded the Nobel Prize. It outlines the key events in the development of CT technology, from the early prototype scanners to modern multi-detector CT machines. The document also discusses the impact of CT scanning in medical imaging and different scan types like spiral CT.
The document provides a historical overview of computed tomography (CT) scanning. It describes how CT scanning was developed in the 1970s by Godfrey Hounsfield and Allan Cormack, who were later awarded the Nobel Prize. It outlines the key events in the development of CT technology, including the creation of the first CT scanner by Hounsfield in 1971 and its introduction to medical use. It also summarizes the different generations of CT scanners and how they have improved imaging capabilities over time.
The document provides a historical overview of computed tomography (CT) scanning. It describes how CT scanning was developed in the 1970s by Godfrey Hounsfield and Allan Cormack, who were later awarded the Nobel Prize. It outlines the key events in the development of CT technology, including the creation of the first CT scanner by Hounsfield in 1971 and the introduction of multi-detector CT scanners. The document also discusses the impact of CT scanning in medical imaging and different types of CT scans.
1. X-rays were discovered in 1895 by Wilhelm Röntgen, a German physicist, while experimenting with cathode ray tubes. He noticed that materials near the tube would glow, even when shielded from known radiation sources, and concluded he had discovered a new type of radiation which he named X-rays.
2. X-rays are produced when high-energy electrons collide with a metal target, causing the electrons to lose energy which is released as X-ray photons. Modern X-ray tubes contain a tungsten target and operate by accelerating electrons toward the target with a high voltage.
3. X-rays have wavelengths between 10 picometers to 10 nanometers, shorter than visible light.
Computed tomography (CT) uses X-rays and computer processing to create cross-sectional images of the body. It was developed in the 1970s based on earlier work using X-rays and mathematical theories. CT provides detailed internal images without invasive surgery. It has become a standard medical imaging technique due to its high-resolution views of internal structures.
CT scanning uses X-rays and digital processing to create cross-sectional images of the body. It has become an important medical imaging tool since its invention in the 1970s. A CT scan produces detailed images of tissues and organs to help diagnose medical conditions and guide treatment. The document discusses the history, generations, and clinical applications of CT scanning as well as how to interpret CT images.
X-ray Production A Journey Through History and the X-ray Tube.pptxDr. Dheeraj Kumar
Welcome to our presentation on X-ray Production and its significance in Medical Imaging.
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General x-ray machine and fluoroscopy
the presentation to medical workers
contain simple explanation about radiation protection in the radiology department
Computed tomography (CT) uses X-rays and digital image processing to generate cross-sectional images of the body. It has undergone several generations of technological advancement, increasing scanning speed and image quality. Modern multi-detector CT can acquire multiple slices simultaneously in a few seconds, and its 3D imaging capabilities are useful for medical diagnosis and guiding procedures. However, the increased use of CT has also led to higher population radiation exposure from medical imaging.
Computed tomography (CT) uses X-rays and digital image processing to generate cross-sectional images of the body. It has undergone several generations of technological advancement, increasing scanning speed and image quality. Modern multi-detector CT can acquire multiple slices simultaneously in a few seconds, and its 3D imaging capabilities are useful for medical diagnosis and guiding procedures. However, the increased use of CT has also led to higher population radiation exposure from medical imaging.
Similar to historical perspective of radiology (20)
LAND USE LAND COVER AND NDVI OF MIRZAPUR DISTRICT, UPRAHUL
This Dissertation explores the particular circumstances of Mirzapur, a region located in the
core of India. Mirzapur, with its varied terrains and abundant biodiversity, offers an optimal
environment for investigating the changes in vegetation cover dynamics. Our study utilizes
advanced technologies such as GIS (Geographic Information Systems) and Remote sensing to
analyze the transformations that have taken place over the course of a decade.
The complex relationship between human activities and the environment has been the focus
of extensive research and worry. As the global community grapples with swift urbanization,
population expansion, and economic progress, the effects on natural ecosystems are becoming
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significant role in maintaining the ecological equilibrium of our planet.Land serves as the foundation for all human activities and provides the necessary materials for
these activities. As the most crucial natural resource, its utilization by humans results in different
'Land uses,' which are determined by both human activities and the physical characteristics of the
land.
The utilization of land is impacted by human needs and environmental factors. In countries
like India, rapid population growth and the emphasis on extensive resource exploitation can lead
to significant land degradation, adversely affecting the region's land cover.
Therefore, human intervention has significantly influenced land use patterns over many
centuries, evolving its structure over time and space. In the present era, these changes have
accelerated due to factors such as agriculture and urbanization. Information regarding land use and
cover is essential for various planning and management tasks related to the Earth's surface,
providing crucial environmental data for scientific, resource management, policy purposes, and
diverse human activities.
Accurate understanding of land use and cover is imperative for the development planning
of any area. Consequently, a wide range of professionals, including earth system scientists, land
and water managers, and urban planners, are interested in obtaining data on land use and cover
changes, conversion trends, and other related patterns. The spatial dimensions of land use and
cover support policymakers and scientists in making well-informed decisions, as alterations in
these patterns indicate shifts in economic and social conditions. Monitoring such changes with the
help of Advanced technologies like Remote Sensing and Geographic Information Systems is
crucial for coordinated efforts across different administrative levels. Advanced technologies like
Remote Sensing and Geographic Information Systems
9
Changes in vegetation cover refer to variations in the distribution, composition, and overall
structure of plant communities across different temporal and spatial scales. These changes can
occur natural.
How to Make a Field Mandatory in Odoo 17Celine George
In Odoo, making a field required can be done through both Python code and XML views. When you set the required attribute to True in Python code, it makes the field required across all views where it's used. Conversely, when you set the required attribute in XML views, it makes the field required only in the context of that particular view.
A Visual Guide to 1 Samuel | A Tale of Two HeartsSteve Thomason
These slides walk through the story of 1 Samuel. Samuel is the last judge of Israel. The people reject God and want a king. Saul is anointed as the first king, but he is not a good king. David, the shepherd boy is anointed and Saul is envious of him. David shows honor while Saul continues to self destruct.
Walmart Business+ and Spark Good for Nonprofits.pdfTechSoup
"Learn about all the ways Walmart supports nonprofit organizations.
You will hear from Liz Willett, the Head of Nonprofits, and hear about what Walmart is doing to help nonprofits, including Walmart Business and Spark Good. Walmart Business+ is a new offer for nonprofits that offers discounts and also streamlines nonprofits order and expense tracking, saving time and money.
The webinar may also give some examples on how nonprofits can best leverage Walmart Business+.
The event will cover the following::
Walmart Business + (https://business.walmart.com/plus) is a new shopping experience for nonprofits, schools, and local business customers that connects an exclusive online shopping experience to stores. Benefits include free delivery and shipping, a 'Spend Analytics” feature, special discounts, deals and tax-exempt shopping.
Special TechSoup offer for a free 180 days membership, and up to $150 in discounts on eligible orders.
Spark Good (walmart.com/sparkgood) is a charitable platform that enables nonprofits to receive donations directly from customers and associates.
Answers about how you can do more with Walmart!"
Beyond Degrees - Empowering the Workforce in the Context of Skills-First.pptxEduSkills OECD
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2. History of radiology
1895 – Wilhelm Conrad Roentgen detects x rays & take first x
ray
1896 – Antoine Henri Becquerel discovers radioactivity
1896 – Thomas Alva Edison invents first commercially
available fluoroscope
1913 – Albert Salmon – mammography
1927 – Egas Moniz – cerebral angiography
1950 – David e.kuhl invents PET
3. • 1953 – Sven Ivar Seldinger – seldinger technique
• 1957 – Ian Donald – ultrasound
• 1964 – Charles Dotter – image guided intervention
• 1972 – Godfrey Hounsfield & Allan m.Conmarck – CT
• 1977 – Raymond Vahan Damadian – mri scanner
4. History of X rays
Discovery of x rays was the beginning
of revolutionary change
German physicist WILHELM CONRAD
RONTGEN discovers x rays – 1895
Nobel prize in physics in 1901
In 2004, international union of pure
and applied chemistry named element
111 as ROENTGENIUM(radio active
element)
5. • In early november he was investigating external effects of
various vacuum tubes.
• While doing experiments with vacuum tubes,he added
aluminium window to permit cathode rays to exit & a
cardboard covering added to protect aluminium from
damage by electrostatic field that is necessary to produce
cathode rays
• Roentgen observed invisible rays caused fluorescent
effect on carboard screen painted with barium
platinocyanide
6. • He investigated various properties of rays
which he called ‘X RAYS’
• He took the very first picture using x rays
of his wife Anna berthas’s hand
7. X RAYS
part of electromagnetic spectrum
Wide range of Wavelength
Deeply penetrating,highly destructive shorter wavelength – HARD X RAYS
Longer wavelength,lesser penetrating power – SOFT X RAYS
Soft xrays – used in medical & dental diagnosis
Ionising radiation
Carries high energy & deposits a part of it within the body it passes
Cause biological effects
8. X ray tubes
Crookes tube
-invented by william crookes
-first used x ray tubes
-used untill 1920
-generate electrons by ionization
of residual air in the tube
-used an aluminium cathode,
platinum anode
-unreliable as residual air in tube
absorbed by walls
9. Coolidge tube
• Improved by william coolidge 1913
• Most widely used
• Electrons produced by thermionic effect
• Tungsten filament(cathode) heated by electric current
• High voltage potential between cathode & anode
• Electrons accelerated hit anode
11. X rays produced due to sudden deceleration of fast moving electrons when they
collide & interact with target anode
99% electron energy converted to heat and 1% into x ray production
Cathode(tungsten filament) is the negative terminal of x ray tube
When current is flowing through it filament gets heated and start emitting electrons by
process called thermionic emission
High voltage applied between cathode and anode
Anode(tungsten disc) is the positive terminal.fast moving electron interact with anode
in 3 ways
1)Interaction with K-shell electron – charecteristic x rays
2)Interaction with nucleus – bremsstrahlung radiation
3)Interaction with outer shell electron – line spectrum
12. In early 1896 in the wave of excitement following
Roentgen’s discovery of x rays, Antoine Henri
Becquerel ,french physicist thought that
phosphorescent materials such as Uranium salts emit
penetrating x ray like radiation when illuminated by
sunlight
Discoverer of radioactivity
1903 – received nobel prize in physics along with
Marie Curie & Pierre Curie
13. Fluoroscopy
• First crude fluoroscope created within
months after x ray discovery
• Use of x rays to produce a moving
image of internal structure of patient
• Fluoroscopy uses continuous x ray
beam that is passed over area of
interest
• Frequently used to evaluate GI
tract,kidney function etc
14. Computerised radiography
• Similar to conventional radiography except that in
place of the flim to create the image,an imaging
plate made of photostimulable phosphor used
• Imaging plate is housed in a special cassette and
placed under the object and xray exposure made
• Imaging plate is run through a special laser
scanner that reads the image
15. Digital x ray
• X ray sensors(digital image capture device)are used
instead of traditional photographic film
• Time efficiency
• Ability to digitally transfer & enhances image
• Less radiation
• Immediate image preview & availability
• Eliminates costly film processing
16.
17. Mammogram
1949 – Raul Leborgne,radiologists
introduced compression technique
Late 50’s –Robert L.Egan,radiologists introduces
a new technique using fine-grain intensifying
screen & industrial film for clearer images
MID 60’s – gain acceptance as screening
tool
german surgeon Albert Salmon attempts to visualize
cancer of breast through radiograph
1913
1949
Late 50’s
MID 60’s
18. – modern day film mammogram invented1969
1993
2000
2011
– mammogram recommended as screening tool by
American Cancer Society
– FDA approves first digital
mammography system
– FDA approves Hologic’s 3D mammography
technology(breast tomosynthesis),proven
clinically superior to digital mammography
19. Ultrasonogram
• Ian Donald – first diagnostic application of usg –
1956,one dimentional A mod (amplitude mode)
• 1963 – B mode(brightness mode)two dimentional
devices constructed
• Turning point in application of ultrasound in medicine
• In mid seventies (kossoff garrett)introduction of real
time ultrasound scanner
• Decade later,doppler effect enabled visualization of
blood circulation
20. • Ultrasound refers to sound waves with frequency too high
for humans to hear
• Images made by sending a pulse of ultrasound into tissue
using ultrasound transducer
• Sound reflected fron parts of tissue recorded as image
21. Modes
A-MODE :
-simplest type
-single transducer scans a line through the body
with echoes plotted on screens function of depth
-therapeutic ultrasound for tumor or calculus for
pinpoint focus of destructive wave energy
B MODE :
Linear array of transducers scan a plane that viewed
as two – dimentional image on screen
22. M – MODE :
M for motion
rapid sequence of B mode scans images
follow each other in sequences ,enable
see & measure range of motion
commonly used to measure cardiac
dimensions & ejection fraction
DOPPLER MODE :
In measuring & visualizing blood flow
23. Doppler effect
• Christian Andreas Doppler(1803-1853),austrian
physicist & mathemetician formulated his theory in
1842
• Observed change in the
frequency of transmitted
waves when relative motion
exists between the source
of wave & an observer
24. • First medical applications of
doppler sonography initiated
during late 1950’s
• First pulsed-wave doppler
equipment developed by
Donald Baker,Dennis Watkins
& John Reid worked on this
project in 1966 produced one
of first pulsed Doppler devices
25. Convex 3.5 MHz
For abdominal and
OB/GYN studies
Micro-convex: 6.5MHz
For transvaginal and
transrectal studies
Ultrasound
machine
Ultrasound
examination
26. 3D USG
Sound waves sent at different angles
Returning echoes processed by sophisticated
computer resulting in three dimentional volume
image of fetus’s surface
First developed by Olaf Von Ramm 1987
OBS - Timing of 3d scan between 26 to 30wks
27. 4D USG
• Similar to 3D usg with the
difference associated with
time
4D allows 3 dimentional
picture in real time
it is reffered to 4D when
baby is moving in 3D
28. Elastography
Maps the elastic properties of soft tissue
Gives diagnostic information about disease
by saying whether tissue is hard or soft
Offers very high contrast between masses
and host tissues
The acoustic radiation force moves the
tissue and detect distorsion by speckle
tracking
Results are quantitative
Found applications in breast,liver
prostate,thyroid
29. Ultrasound therapy
Role in tissue ablation therapy in the form of high intensity focused
ultrasound
Exploits thermal effects of high power ultrasound beams focused on
very small target tissue
Use frequency 0.7 to 3.3 mhz
More precise, easy to handle compared to radiotherapy
In ligament sprains,lithotripsy,cataract,acoustic targeted drug
delivery,cancer therapy,thrombolysis etc
30. Computerized Tomography
Also known as computerized axial tomography[CAT]
Imaging of a cross sectional slice of the body using X-
rays.
Invented by Dr. G. N. Housfield in 1971. Received the
Nobel prize in medicine in 1979.
The method is constructing images from large number of
measurements of x-ray transmission through the patient.
The resulting images are tomographic maps of the X-ray
linear attenuation coefficient.
31. • Hounsfield built a prototype head scanner & tested it on a
preserved human brain later on himself
• In 1971 CT scanning introduced into medical practice with a
successful scan on cerebral cyst patient at Atkinson Morley’s
hospital London
• In 1975 he built a whole body scanner
• In early experiments he used gamma source & it took 9 days to
acquire image data & 2 ½ hrs to reconstruct image
• He replaced gamma source with x ray tube, scan time reduced to 9
hrs
32. ALLAN M.CORMACK
• 1979 – nobel prize shared with
DR.Hounsfield developed
solutions to mathematical
problems in CT
33. • Principle - The density of the tissue passed by x ray
beam can be measured from calculation of the
attenuation coeffient
• Two processes of absorption
photoelectric effect
compton effect
Measure transmission of thin beam of x rays through full
scan of body
Image of that section taken from different angles,allows to
retrieve information on the depth
Consists of square matrix of elements(pixel) & volume
34. CT-First generation
• Single x ray source
• Beam – pencil beam
• Detector rotate slightly
• Translate/rotate scanner
• Duration of time 25 to 30 mins
• Resolution very poor
35. Second generation
• Design – multiple detectors upto 30
• X rays beam – fan shaped
• Translate – rotate
• Duration of scan - <90 secs
36. Third generation
• Design – larger array of detectors
• 300-700 detectors ,circular
• Beam – fan shaped x ray beam
• Tube and detector arrays rotate
around patient
• Rotate rotate scanner
• Duration of scan – 5sec
37. Fourth generation
• Detector – multiple >2000 arranged in outer ring fixed
• Beam – fan shaped
• Rotate – fixed scanner
• Duration of scan few seconds
38.
39. Fifth generation
• X ray tube is a large ring that circles
patient
• Use – cardiac tomography imaging “cine
CT”
• Stationary/stationary geometry
40. Spiral/helical ct
• Design – x ray tube rotates as patient moved smoothly
into x ray scan field
• Source rotation,table translation,data acquition
• Advantages
speed-30 sec for abdomen,chest
improved detections
improved contrast
improved reconstruction
improved 3D images
41. Seventh generation
• Design – multiple detector array
• Turbo charged spiral
• Upto 8 rows of detectors
• Improvement in details
• Cone beam and multiple parallel rows
of detectors
• Reducing scan time,increase z
resolution
44. 1946 - NMR Discovered by two physicists Felix Bloch &Edward Mills Purcell
1952 - They received nobel prize in physics
1971 - Use of NMR to produce 2D images made by Paul Lauterbur
1976 - First clinical human MRI
2003 - Nobel prize for Lauterbur & Mansfield
Uses strong magnetic fields and radiowaves to form image of the body
Used for medical diagnosis,staging of disease,follow up without exposure to
radiation
45. How it works
First – mri creates steady state of magnetism within human body by
placing the body in a steady magnetic field
Second – mri stimulates body with radiowaves to change the steady
state orientation of protons
Third – mri machine stops the radiowaves & register the body’s
electromagnetic transmission
Fourth – transmitted signal used to construct internal images of body
51. PET
• Concept of emission and transmission tomography
introduced by David E.Kuhl in late 1950s
• In 1961 James Robertson built the first single plane
PET Scan,nick named “head-shrinker”
• Development of labeled 2FDG was a major factor in
expanding in the scope of PET imaging
• The compound was first administered to two
volunteers in aug 1976,at university of pennsylvania
52. •Modern non invasive imaging technique for quantification of radioactivity in
vivo
•Involves use of radiopharmaceutical injected into body & its accumulation in
body detected,quantified & interpreted
Concept
• radiolabelled biocompound 2-fluoro-2-deoxy-D-glucose injected iv
• uptake of compound followed by breakdown occurs in cells
• tumors have high metabolic rate hence this compound metabolised by
• tumor cells
• FDG metabolised to FDG 6 phosphate
• further not metabolised by tumor cells hence accumulates
• accumulation is quantified
56. Radionuclide (isotope) scan
• Radionuclide is a chemical which emits a type of
radioactivity called gamma rays
• Tiny amount of radionuclide put into body
• Cells which are more active will take up more of
radionuclide & emits more gamma rays
• Detected by gamma camera,converted into
electrical signal & sent to computer
• Computers builds into different colours/shades of
grey
58. • Tomographic slice is reconstructed from
photons emitted by the radio isotope in a
nuclear medicine study
• SPECT is 3D Tomographic technique that
uses Gamma Camera data from many
projections and reconstructed in different
planes