A novel technique for treating deep seated breast cavity boosts.

Breast boost irradiation is an integral component to the standard of care for early staged breast cancer. The use of reduced tangents is common for deep seating tumor bed; however, reduced tangents result in non-conformal plans delivering prescription dose to large volumes of breast tissue. To improve conformity, a novel technique of integrating a single conformal arc with reduced tangents has been developed. With this technique, a conformal arc was placed between a pair of reduced tangents to better conform the prescription dose to the target volume. This new technique improves the conformity but was also shown to potentially increase max dose to nearby critical structures, such as the heart, due to exit dose from the arc. This tangent and arc technique has been implemented at our clinic in cases where the exit dose is not critical to the heart.