Introduction:
Total skin electron therapy (TSET) is an effective treatment for cutaneous T-cell lymphomas (CTCL). However, the nuances of patient setup and treatment delivery present challenges for treatment verification.
Objectives:
To report on the utility of Cherenkov imaging, a novel modality that allows for visualization of radiotherapy beams on patients, to verify patient positioning and block placement during TSET.
Methods:
Cherenkov imaging combined with on-patient dosimetry was used to image and measure dose during TSET for 4 patients with CTCL. Dose measurements were made at the umbilicus, extremities, and left chest. Cumulative Cherenkov intensity was obtained from regions adjacent to dosimeters, and a correlation between intensity and dose was made. Cherenkov images from each treatment delivery were reviewed.
Results:
For 3 patients, measured dose at the umbilicus varied among patients and positions, ranging from 27–42 cGy for oblique and 40–60 cGy for anterior positions. Measured doses across body regions varied within patients, for example one patient received 40 cGy to the arm and 60 cGy to the chest. Cherenkov intensity-to-dose ratios varied according to patient and anatomic location. Review of Cherenkov images revealed non-ideal position of a facial block, which was corrected in subsequent treatment deliveries. Cherenkov imaging was compatible with additional treatment modifications made to accommodate a patient unable to stand for standard Stanford poses.
Conclusions:
Cherenkov imaging combined with on-patient dosimetry is a versatile and effective methodology for verifying TSET delivery and identifying treatment improvement opportunities. Future work will focus on improving Cherenkov-to-dose relationships, which could provide key information for dose quantification among TSET patients.
