MDCB test Questions and Answers 100%
Solved
When an enface electron beam is used for chest wall irradiation, which of the following
describes the dose at the interface between the chest wall and lung? decreased due to
reduced scatter from the lung
An averaged ionization chamber reading for a 10 cm x 10 cm electron applicator is 98.5 and an
averaged ionization chamber reading for an electron cut-out in a 6 cm x 10 cm applicator is 92.4.
What is the monitor unit setting if 200 cGy is prescribed to 90% and the 6 cm x 10 cm cut-out is
utilized? (The output factor for 10 cm x 10 cm is 1 cGy/MU.) 237 MU
Parent and daughter radioactive isotopes are said to be in secular equilibrium when they:
have a constant ratio of activity.
To make inhomogeneity corrections in treatment plans based on CT derived anatomical
information, the TPS: determines electron densities.
, When opposing lateral fields to the pharynx are abutted at midline to an anterior field to the
supraclavicular fossae, overdose in the cord may be avoided by: a small block over the
cord in the inferior posterior corner of both lateral fields.
According to the NCRP guidelines #116, the annual equivalent dose limit for the hands of an
occupational worker in 1 year is: 500 mSv (50.0 rem).
In photoelectric interactions: the entire energy of the incident photon is absorbed by the
resulting electron
Film badges used for personnel monitoring contain filters that are used to: provide
information concerning beam quality.
The most important prognostic factor in breast cancer is the: status of the axillary nodes.
A dose of 30 Gy in 10 fractions to a depth of 7 cm from a 6 MV single posterior field using an
isocentric technique at 100 cm source-to-axis distance (SAD). The patient was incorrectly treated
five times at 100 cm source-to-surface distance (SSD). The approximate dose at 7 cm after five
fractions is: 13.1 Gy.
Solved
When an enface electron beam is used for chest wall irradiation, which of the following
describes the dose at the interface between the chest wall and lung? decreased due to
reduced scatter from the lung
An averaged ionization chamber reading for a 10 cm x 10 cm electron applicator is 98.5 and an
averaged ionization chamber reading for an electron cut-out in a 6 cm x 10 cm applicator is 92.4.
What is the monitor unit setting if 200 cGy is prescribed to 90% and the 6 cm x 10 cm cut-out is
utilized? (The output factor for 10 cm x 10 cm is 1 cGy/MU.) 237 MU
Parent and daughter radioactive isotopes are said to be in secular equilibrium when they:
have a constant ratio of activity.
To make inhomogeneity corrections in treatment plans based on CT derived anatomical
information, the TPS: determines electron densities.
, When opposing lateral fields to the pharynx are abutted at midline to an anterior field to the
supraclavicular fossae, overdose in the cord may be avoided by: a small block over the
cord in the inferior posterior corner of both lateral fields.
According to the NCRP guidelines #116, the annual equivalent dose limit for the hands of an
occupational worker in 1 year is: 500 mSv (50.0 rem).
In photoelectric interactions: the entire energy of the incident photon is absorbed by the
resulting electron
Film badges used for personnel monitoring contain filters that are used to: provide
information concerning beam quality.
The most important prognostic factor in breast cancer is the: status of the axillary nodes.
A dose of 30 Gy in 10 fractions to a depth of 7 cm from a 6 MV single posterior field using an
isocentric technique at 100 cm source-to-axis distance (SAD). The patient was incorrectly treated
five times at 100 cm source-to-surface distance (SSD). The approximate dose at 7 cm after five
fractions is: 13.1 Gy.
