Category: Uncategorized

Percent depth dose is dependent on:

The ratio of the dose at depth in tissue to the dose at dmax on the beam axis is known as:

A tumor is treated using an AP field with a high-energy photon beam. The tumor is located at a depth of 6 cm where the percent depth dose is 78.4%. The spinal cord is in the path of the beam and Is located at a depth of 14 cm where the percent depth dose is 35.3%. If 200 cGy is delivered to the tumor, calculate the dose delivered to the spinal cord.

Bragg-Gray cavity theory is used to calculate absorbed dose for any type of radiation. 

Every solid-state system needs to be calibrated in a known radiation field before it can be used for the measurement of absorbed dose. 

The radiation therapy badge that you will wear in clinic uses the principle of:

1 Gy = _____.

A treatment is planned using a single field at a distance of 100 cm and a 6 MV beam (Dmax=1.5 cm). In order to accommodate the target volume, the distance must be extended to 110 cm. The depth of the target is 3 cm. If the original PDD value at depth was 91.4%, what is the PDD value at a distance of 110?

TMR is independent of:

Identify each numbered anatomical structure on the following radiograph.  Each response will be used only once. 004111a.jpg labeled(1).jpg