Accelerated Low-Dose Total Skin Electron Beam Therapy Using the Modified Stanford Technique: An In Vivo Dosimetry Confirmation Study.

Purpose Low-dose total skin electron beam therapy (LD-TSEBT) has recently gained popularity in treating mycosis fungoides (MF) due to its reduced toxicity and favorable response rates. Combining accelerated LD-TSEBT with the modified Stanford technique (mST), a condensed cycling approach, offers a promising and convenient option. However, in vivo dosimetry data confirming the effectiveness of this approach is limited. We retrospectively analyzed in vivo data from patients who received accelerated LD-TSEBT using the mST for MF. Methods Patients treated with accelerated LD-TSEBT using the mST for MF were identified. Optically stimulated radiation dosimeters (OSLDs) were used to measure doses at 10 anatomical sites: vertex, larynx, right shoulder, right forearm, right hip, umbilicus, left medial thigh, right knee, left dorsal foot, and left dorsal hand. Measurements were aggregated and compared to the prescribed dose, using the European Organisation For Research And Treatment Of Cancer (EORTC) homogeneity tolerance criteria, which account for the American Association of Physicians in Medicine (AAPM) TG023 setup variability: ±20% of the prescribed dose. Patient characteristics, demographics, and disease details were also collected. Descriptive statistics were performed to evaluate clinical and dosimetric characteristics. Results Thirty-six patients were identified, and 360 OSLD measurements were recorded. The median of all OSLD measurements relative to the prescribed dose at all sites was 97.4%. The highest median delivered dose was recorded at the umbilicus (106%) and the lowest at the left dorsal hand (79%). After accounting for deviation at the left dorsal hand, 85.8% of all OSLD measurements met the homogeneity criteria at the other anatomic sites. Other patient metrics, such as height and BMI, did not impact the median delivered OSLD dose or number of anatomical sites per patient meeting the EORTC tolerance criteria. Conclusion Accelerated LD-TSEBT using the mST delivers accurate doses, with most subjects meeting the EORTC tolerance criteria. This study supports the use of OSLDs for in vivo dosimetry in patients undergoing this regimen, ensuring adequate dosing despite the truncated cycling approach.