Courses in Diagnostic Imaging – Physics

Course Outline
Physics of Radiology and Nuclear Medicine, Andrew Karellas, Ph.D. Associate Professor, Radiology, University of Massachusetts

• Modern Physics concepts: Quantum nature of radiation, electromagnetic spectrum, units of measurement, nature and origin of electromagnetic radiation with emphasis on visible, UV, gamma-ray and x-ray part of the spectrum.

• Production of ionizing radiation, x-ray tubes and circuits. X-ray generators (single phase, 3-phase, high frequency). X-ray beam filtration, X-ray spectra and energy. X-ray tube power ratings and practical limitations. X-ray focal spots and how they affect tube loading and geometric unsharpness. Extrafocal radiation (origin and effects). Beam restriction and collimation.

• Interactions of radiation and matter (photoelectric, Compton, coherent scattering), exponential law of attenuation.

• The radiographic image (concepts of contrast and resolution) Modulation Transfer Function (MTF), Wiener spectrum and noise. Some applications of Fourier analysis to radiographic systems. Geometry of radiographic image. Origin and nature of x-ray scatter. Effect of scatter on subject contrast. Antiscatter mechanisms, grids and air gaps, automatic exposure control devices. Radiation quantity and quality, radiation detectors.

• Image receptors: Radiographic screens, radioluminescent materials, physical and photographic characteristics of x-ray film, photostimulable phosphor technology for digital radiography.

• Image recording techniques (laser printing methods, physical requirements).

• Fluoroscopy: Image intensification techniques (concepts, units and noise concerns). The physics and engineering of modern image intensifiers, video cameras and charge-coupled devices. Cineangiography, image viewing and recording. Bandwidth limitations. Television techniques and electronic x-ray imaging. Digital subtraction angiography.

• Conventional tomography. Magnification radiography (advantages and limitations).

• Mammography: Mamrnographic equipment and image receptors. Quantitative aspects of the mammography image. Future outlook of digital mammography.

• Computed tomography: mechanisms of contrast, reconstruction, equipment requirements, spiral scanning techniques.

• Computers and Teleradiology: Image data communication, archiving and display requirements and digital radiography.

• Nuclear Medicine Imaging: Nuclear emissions and their applications, nuclear counting statistics. Gas, scintillation and solid state detectors, nuclear spectroscopy and gamma camera imaging spectroscopy, radionuclide generators, concepts of Single Photon Emission Tomography (SPECT) and Positron Emission Tomography (PET). Medical Internal Radiation Dosimetry (MID) calculations.

• Radiation effects and radiation protection: Basic radiobiological aspects, Radiation protection measures, and practices, regulatory aspects. Radiation dose precautions in fluoroscopy. The concept of effective dose.

• Ultrasound: Basic interactions, transducers and image acquisition techniques. Doppler effect, applications and imaging.

• Basic principles of MRI and imaging techniques.