Reporting of dose–volume specifications for “Martinez Universal Perineal Interstitial Template–based interstitial high-dose-rate brachytherapy for gynecological cancers” according to International Commission on Radiation Units and Measurements 58 with early clinical outcomes

PURPOSE: The study is an audit of reporting dose and volume specifications as per the ICRU 58 for MUPIT-based interstitial brachytherapy in gynecological cancers. Correlation between total reference air kerma (TRAK) and isodose surface was also evaluated to understand the intensity of treatment in interstitial brachytherapy.METHODS AND MATERIALS: Forty-two patients underwent HDR MUPIT-based interstitial brachytherapy 20 Gy in five fractions after EBRT during 2017-2019. Treated volume, high and low-dose regions, mean central dose, Dose Homogeneity Index (DHI), organ at risk doses, and TRAK values were computed.RESULTS: High-dose regions V150 mean was 12.4 cc and V200 was 4.58 cc; and low-dose region was 75.92 cc. The mean treated volume was 59.8 cc. The mean central dose was 3.7 Gy. DHI was 79%. The mean D2cm(3) bladder and rectum were 2.9 Gy and 2.8 Gy. The mean TRAK was 0.16 cGy per fraction per hour at 1 m. TRAK values showed significant correlation with various isodose volumes (TRAK and V100: r = 0.943 p < 0.0005; and TRAK and V50: r = 0.953; p < 0.0005). A positive correlation was observed between TRAK and the number of needles (r = 0.746; p < 0.0005). At a median followup of 16 months, 4 of 42 patients (9.5%) had local recurrences.CONCLUSIONS: Our study shows compliance with ICRU 58 recommendations along with certain deviations. Local recurrence rate is acceptable. TRAK shows correlation with surface isodose in MUPIT-based brachytherapy and should to be evaluated in future studies. (C) 2021 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.