Cherenkov imaging for total skin electron therapy (TSET)

Abstract

Background Total Skin Electron Therapy (TSET) utilizes high‐energy electrons to treat malignancies on the entire body surface. The otherwise invisible radiation beam can be observed via the optical Cherenkov photons emitted from interactions between the high‐energy electron beam and tissue. Methods & Materials With a time‐gated intensified camera‐system, the Cherenkov emission can be used to evaluate the dose uniformity on the surface of the patient in real‐time. Fifteen patients undergoing TSET in various conditions (whole body and half body) were imaged and analyzed. Each patient was monitored during TSET via in‐vivo detectors (IVD) in nine locations. For accurate Cherenkov imaging, a comparison between IVD and Cherenkov profiles were conducted using a PVC board to establish the perspective corrections. Results & Discussion With proper corrections developed in this study including the perspective and inverse square corrections, the Cherenkov imaging provided 2‐dimensional maps proportional to dose and projected on patient skin. The results of ratio between chest and umbilicus points were in good agreement with in‐vivo point dose measurements, with a standard deviation of 2.4% compared to OSLD measurements. Conclusion Cherenkov imaging is a viable tool for validating patient specific dose distributions during TSET.