Chapter 9 study guide

basic radiation protection and radiobiology

photo-electric absorption

incoming x-ray photon strikes inner shell electron and ejects it from it’s orbit around nucleus creating atom pair. atom, having lost an electron, is positively charged, and the released electron, referred to as the ——-, continues to travel until it combines with other matter. As outer shell electrons transition to fill vacancies in inner shells, they release excess energy in the form of x-rays. X-rays originating within the body as a result of the —— are collectively known as characteristic radiation and are the source of secondary radiation.

Compton absorption

incoming x-ray photon strikes a target atom and uses a portion of its energy to eject an outer shell electron. The remainder of the photon’s energy proceeds in a direction different from that of the incoming photon. results in a —— recoil electron ejected from the outer shell, which travels until it combines with matter, and a photon of less energy that can react with the patient through further——, or that can exit the patient and reach imaging equipment or the occupational worker.

center for devices and radiological health

regulates standards for equipment

nuclear regulatory commission

enforcement and pregnancy regulations

what does alara stand for

as low as reasonably achievable

occupational worker annual dose limit

50 mSv

occupational worker cumulative dose limit

10 mSv x age

occupational worker eye dose limit

150 mSv

occupational worker skin dose limit

500 mSv

general population frequent exposure dose limit

1 mSv

general population infrequent exposure dose limit

5 mSv

general population eye dose limit

15 mSv

general population skin dose limit

50 mSv

embryo 1 month dose limit

.5 mSv

embryo total dose limit

5 mSv

educational & training effective dose limit

1 mSv

educational & training eye dose limit

15 mSv

educational & training skin dose limit

50 mSv

ARS

acute radiation syndrome

early effects

mins hours days :

prodromal - nausea , vomiting , diarrheas

latent period - feel ok then biological changes

manifest stage - you feel it , infection , anemia , coma ,

late effects

1-30 years :

somatic - in you (cancer )

genetic - in offspring (DNA muatation)

Cardinal rules of rad protection

time -- minimize time in the room during exposures

distance - maximize distance between you & Xray source

shielding - shield yourself whenever you have to be in the room

who is required to wear dosimeters?

every occupational worker that is regularly exposed