What is the dose area product (DAP) if the entrance skin exposure is 70 mGy and the collimated area is 6 cm by 8 cm?

To determine the dose area product (DAP), you multiply the entrance skin exposure (in mGy) by the area of the radiation field (in cm²). In this scenario, the entrance skin exposure is 70 mGy, and the dimensions of the collimated radiation area are 6 cm by 8 cm.

First, calculate the area of the collimated field by multiplying the dimensions:

Area = length × width = 6 cm × 8 cm = 48 cm².

Next, to find the DAP, multiply the entrance skin exposure by this area:

DAP = entrance skin exposure × area = 70 mGy × 48 cm².

Calculating that gives:

DAP = 70 × 48 = 3,360 mGy-cm².

This value represents the total dose received by the area of tissue irradiated. The DAP is important in radiology as it takes into account both the exposure and the area being exposed, providing a useful measure for evaluating patient radiation exposure.