1. The document discusses the interactions of different types of radiation with matter, including alpha particles, beta particles, gamma rays, and their interactions through processes like the photoelectric effect, Compton scattering, and pair production. 2. It provides information on dose measures like RAD, REM, and RBE, which depend on factors like linear energy transfer and radiation quality factors related to biological effectiveness. 3. Safety rules of thumb are given for penetration depths of different radiations in air, skin, and tissue based on their energy levels.

1. RADIOBIOLOGY Prof.Dr.Tarek Elnimr L 8 Presented to the Biology Departments in Faculty of Sciences on February 15 , 2009

2. Interactions of radiation with Matter

3. Interaction with beta Electrons excited or kicked off. ionization Energy dissipated as heat. As Z of material increases, so does bremsstrahlung. Note that range is different from path .

4. Interaction with gamma Photon travels until it hits something, either an electron or a nucleus. Several types of interactions have been observed.

8. Pair production and annihilation Two gamma collide, convert to a positron and a negatron. Complete energy to matter conversion These two betas collide, converting to 2 gammas with equal energy of 511 kev. Complete matter to energy conversion. www.mhhe.com/.../fix/ student/images/26f14.jpg

14. More on calculating REM LET (keV per µm) Q example 3.5 and less 1 X-rays, β ,  7 2 neutrons 23 5 53 10 175 and over 20 alpha

15. Comparing old, SI units Rad = 100 ergs/gram; Rem = rad x Q; 1 Gray = 100 Rads, 1 j/kg; 1 Sievert = 100 rem; Old SI Radioactive material curies becquerels Deposited energy Rads Grays Dose to humans Rems Sieverts Units of energy in air Roentgens none