Basic Radiation physics


Sashisaroj T Tiwari


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Subject Code: BSRT1104

Subject Type: 3+1+0

Credit: 4


Course Objectives

  • To understand the importance of the X – rays in medical field
  • To study the applications of radiotherapy sources.
  • To develop an understanding of radiation measurements.
  • To understand how to follow radiation protection rules
  • To study the physical properties and applications of x- ray machine techniques

Learning Outcomes

  • Know what it takes to have a career in physics in x-ray techniques
  • Understand the need to increase Physics in radiology
  • Know the radiation protection rules and measurements
  • Know the application of physical parts in x-ray machines


Modern Atomic Physics : Constituents of matters & atomic structure, orbits and orbital, binding energy and mass defect, isotopes, isotones and isobars, electromagnetic and particle radiations Radioactivity: Radioactivity decay, half-life & mean-life, decay series, modes of decay: alpha, beta and gamma radiation, electron capture, internal conversion, isomeric transition, production of radioisotopes.

Production of X-Rays : Discovery and origin of X-rays, Production of X-rays, Nature and properties of X-rays, Energy spectrum, characteristic radiations, Absorption, scattering and quality of X-rays, HVT and TVT, Angular distribution.



Unit 2

X-ray tube and Generators : Features of X-ray tube, anode, cathode and filament, characteristics of target materials, cooling system, insulation and tube housing, filters, rating of tubes, faults of X-ray tubes; Gas tube, Hot cathode tube, fixed anode and rotating anode tube, line-focus tube, dual focus tube, Mammography X-ray tube; X-ray generators, power supply : transformers, Half-wave and full- wave rectifications, timer.

Physical Principles of X-ray Diagnosis: Radiological images: Photon fluence, Unsharpness, resolution, Contrast, scattered radiation, grids, Radiographic film processing : Film, Density of films, Characteristic curves, gamma factor, film processing, Intensifying screens, speed, fluoroscopy.



Heat Definition of heat, temperature, Heat capacity, specific heat capacity, Heat transferconduction, convection, radiation, thermal conductivity, equation for thermal conductivity (k), the value of k of various material of interest in radiology, thermal expansion, Newton’s law of cooling, Heat radiation, perfect black body, Stefan law, application in Diagnostic Radiology (Heat dissipation in both stationary and rotating X-ray tubes).

Suggested Reading

  1. Textbook of Radiological Safety by Thalayan, Publisher Jaypee brothers
  2. Advance Medical Physic by Rehani, Publisher Jaypee brothers
  3. Basic of Radiological Physics by Thalayan,Publisher Jaypee brothers


Session Plan

Session 1

Effects of variation of tube voltage current, filtration, III waveform


Session 2

Target material on X-ray production


Session 3

Laws of radioactivity

Session 4

Different schemes of alpha, Beta and gamma ray decay

Session 5

Megnetron and position emitters as used in medicine especially in radiotherapy

Session 6

Explain the Artificial radionuclides

Session 7

Artificial radionuclide generators employed in medicine in general.

Session 8

Discussing about radiotherapy sources in particulars.

Session 9

Explaining Physical requirements of beam defining devices i.e cones, diaphram and collimator

Session 10

Units of radiation measurement

Session 11

Measurements of specification of quality and half-wave thickness

Session 12

Discussed about the filters and filtration

Session 13

Measurement of radiation and dosimetric procedures

Session 14

Demonstrate the principles and working of radiation detectors.

Session 15

Explain the Bragg peak, percentage depth dose, peak scatter factor,tissue air – ratio, tissue maximum ratio and scatter air ratio.

Session 16

Draw the isodose curves

Session 17

Demonstrate the radiation penumbra of different beams

Session 18

Demonstrate the Wedge filters and wedge angle and hinge angle

Session 19

Explaining the working of Compensator beams flattering filters and scattering foils

Session 20

Explain the physical properties of phantom materials

Session 21

Explain bolus and substitutes, the factors used for treatment dose calculations

Session 22

Demonstrate the daily treatment time and monitor units calculation method aspects of electron and neutron therapy.

Session 23

Demonstrate the radiation hazards.

Session 24

Explaining the annual limit of intake (ALI) permissible dose levels on and around sealed source housing

Session 25

Explain the installation principles of radiation protection.

Session 26

Explain MPD(maximum permissible dose), Different ICRP rules

Session 27

Explain Stochastic and nonstochatic effects

Session 28

Demonstrate the  Importance of ALRA principle

Session 29

Explain physical principles of design and planning of installation safe work practice in teletherapy

Session 30

Explain physical principles of design and planning of installation safe work practice in brachytherapy

Session 31

Explaining the shielding materials and radiation survey.

Session 32

Explain the film badges

Session 33

Explain TLD badges and comparison

Our Main Teachers

Sashisaroj T Tiwari

Assistant Professor, Department of Radiology,  SoPAHS