Does the Lead Apron Protect the Mammary Gland During CBCT?

Objectives: Currently, it is not mandatory to wear a lead apron during CBCT, in contradiction to the ALARA principle, assuming a significant amount of dose can be reduced. The aim of this study is to measure the relative dose reduction by using a lead apron to shield the mammary gland, which is considered highly radiosensitive.
Methods: The female Alderson Rando Phantom is used as a scattering body. As a measuring device, the TOL-F dosimeter is selected. Its construction resembles an ionization chamber filled with a gas corresponding to air and includes a gas amplification in the low-dose range. To determine the relative dose reduction by using a conventional lead apron, the surface dose is measured at the level of both left and right mamilla.
Three devices and seven different radiation modes are used in this study. Preliminary tests evaluating the selection of dosimeter, positioning, and reproducibility of the experimental set-up are taken and the outcome is statistically analyzed. In addition, experiments were conducted to evaluate the penetrating ability of radiation and the scattered radiation source. The interpretation and weighting of the results are founded physically.
Results: The relative dose reduction using the lead apron averaged 86.63% in the OP 3D Vision, 94.16% in the 3D Accuitomo, and 94.58% in the Orthophos SL. The COV of the reproduction tests varies between 0.33% and 1.77%. An absolute dose reduction of 106.7 µSv was measured during standard exposure.
Conclusions: This study demonstrates a significant reduction in surface dose at the female breast level when wearing a lead apron. The Compton effect is superior in radiology, thus proving that the average loss of energy is limited to about 5%. This leads to the assumption that scattered radiation is equally high-energized and high-penetrating as the primary ray. The highly dense mandibula might emit most of the scattered radiation striking the female breast.