ABR Radiation Dosimetry Flashcards
6 cards from real ABR practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 ABR Radiation Dosimetry flashcards as text
What is the SI unit of absorbed dose used in radiation dosimetry?
Answer: Gray (Gy)
The Gray (Gy) is the SI unit of absorbed dose, defined as 1 joule of energy deposited per kilogram of tissue.
Which type of ionization chamber is the recommended reference dosimeter for photon beam calibration per AAPM TG-51?
Answer: Farmer-type cylindrical chamber
The Farmer-type cylindrical ionization chamber is the standard reference dosimeter for photon beam calibration per the AAPM TG-51 protocol.
In TG-51 dosimetry protocol, what reference depth is used for photon beam calibration?
Answer: 10 cm
TG-51 specifies beam calibration at a reference depth of 10 cm in a water phantom for photon beams.
What is the purpose of the kQ factor in the TG-51 calibration protocol?
Answer: Corrects for beam quality differences from the calibration standard
The kQ factor corrects the chamber's calibration coefficient from the reference 60Co beam quality to the clinical beam quality being measured.
Which dosimetry formalism does AAPM TG-51 replace for clinical photon and electron beam calibration in the US?
Answer: TG-21
TG-51 replaced the older TG-21 protocol, transitioning from exposure-based to absorbed dose-to-water calibrations.
What correction factor accounts for the incomplete collection of ions in a dosimetry chamber?
Answer: Ion recombination correction (Pion)
The ion recombination correction factor (Pion) accounts for ions that recombine before reaching the collecting electrode, especially at high dose rates.