quiz questions

protons are ____ charged particles located in the nucleus of an atom

positively

calculate the inverse square factor that would be used in a MU calc for a 10MV isocentric beam given that the unit is calibrated at Dmax

1.05 [(SCD/(SSD + d)²]

what is the therapeutic range (depth of 90% isodose line) of a 12MeV electron beam?

3.75 cm (MeV/3.2)

formula for practical range

MeV/2

TD5/5 for the heart

40 Gy

the method of treatment planning, generally used with IMRT< which begins with the end in mind is termed “inverse planning”

true

level of the umbilicus

L3-4

Dmax for a 4MV beam

1 cm

a wedge transmission factor for a 45 degree wedge is .775. What is the percentage of the beam is being absorbed by the wedge

22.5% (100-transmission factor)

a patient receiving a total dose of 4000cGy was incorrectly treated through the entire course of treatment because 95cm SSD was used instead of the correct SSD of 90cm. What total dose did the patient receive if this error occurred throughout the length of the treatment course

3590cGy [(correct SSD/incorrect SSD)² x dose ]

T/F instructions for patients receiving irradiation to the head/scalp: shampoo frequently to minimize residue buildup

false

T/F instructions for patients receiving irradiation to the head/scalp: use mild shampoo

true

T/F instructions for patients receiving irradiation to the head/scalp: avoid frequent brushing

true