Week2 D1. Ch 4&7

Question 1

FILTRATION
Inherent Filtration

Answer 1

INHERENT FILTRATION
• Takes place when the primary beam passes through the glass window, oil bath and tube head seal of the x-ray unit
• 0.5 to 1.0 mm aluminum

Question 2

Collimator& Cone

Answer 2

COLLIMATOR
s Restricts the size and shape of x-ray beam thus reducing patient exposure
§ Circular collimation produces a beam that is 2.75 inches in diameter
POSITION INDICATING DEVICE (PID) / CONE so Today, short (8”) or long (16”) rectangular and round cones are used not pointed plastic cones
s Long, rectangular PID_ is recommended since less divergence of x-ray beam thus most effective in reducing client exposure

Question 3

Collimator

Answer 3

Rectangle less radiation

Question 4

MAXIMUM PERMISSIBLE DOSE (MPD)

Answer 4

§ Maximum dose equivalent that a body is permitted to receive in a
specific period of time

Dose of radiation that the body can endure with little or no injury
& Rem = unit of radiation dosage
s Sv = unit of ionizing radiation dosage

Question 5

Maxim Accumulated Dose (MAD)

Answer 5

§ Occupationally exposed workers must not exceed an
accumulated lifetime radiation dose s MAD is determined by the person’s AGE
5 The mathematical formula is as follows:
5 MAD = (N - 18) X 5 rem / year
so MAD = (N - 18) X 0.05 Sv / year
so N = individual’s age in years

Question 6

ALARA

Answer 6

ALARA is an acronym for “As Low As Reasonably Achievable”