Comparing 3-D Printed vs Standard Bolus for Breast Cancer Chest Wall Radiotherapy

This is a cohort study of 16 women undergoing post-mastectomy chest wall radiotherapy for breast cancer comparing two ways of modifying the radiation beam with bolus (a 5mm rubber substance placed on the skin to modify the radiation beam). The hypothesis is that 3D printed bolus will conform more closely to the chest wall than standard 5mm-thick standard bolus and thus lead to less chance of underdose or overdose of the skin. Each patient will receive the standard dose of radiotherapy, but half the treatments will use standard bolus and half the treatments will 3D printed bolus (ie each patient will act as is their own control). The primary outcome is the comparison of the amount of air under the bolus for each technique. Secondary outcome is the amount of time it takes to set up the patient for radiotherapy.