PURPOSE: Postoperative intravaginal brachytherapy for endometrial carcinoma is usually performed with (192)Ir high-dose rate (HDR) afterloading. A potential alternative is treatment with a broadband 50kV X-ray point source, the advantage being its low energy and the consequential steep dose gradient. The aim of this study was to create and evaluate a homogeneous cylindrical energy deposition around a newly designed vaginal applicator. METHODS AND MATERIALS: To create constant isodose layers along the cylindrical plastic vaginal applicator, the source (INTRABEAM system) was moved in steps of 17-19.5 mm outward from the tip of the applicator. Irradiation for a predetermined time was performed at each position. The axial shift was established by a stepping mechanism that was mounted on a table support. The total dose/dose distribution was determined using film dosimetry (Gafchromic EBT) in a "solid water" phantom. The films were evaluated with Mathematica 5.2 and OmniPro-I'mRT 1.6. The results (dose D0/D5/D10 in 0/5/10 mm tissue depth) were compared with an (192)Ir HDR afterloading plan for multiple sampling points around the applicator. RESULTS: Three different dose distributions with lengths of 3.9-7.3 cm were created. The irradiation time based on the delivery of 5/7 Gy to a 5 mm tissue depth was 19/26 min to 27/38 min. D0/D5/D10 was 150%/100%/67% for electronic brachytherapy and 140%/100%/74% for the afterloading technique. The deviation for repeated measurements in the phantom was <7%. CONCLUSIONS: It is possible to create a homogeneous cylindrical dose distribution, similar to (192)Ir HDR afterloading, through the superimposition of multiple spherical dose distributions by stepping a kilovolt point source.
PURPOSE: Postoperative intravaginal brachytherapy for endometrial carcinoma is usually performed with (192)Ir high-dose rate (HDR) afterloading. A potential alternative is treatment with a broadband 50kV X-ray point source, the advantage being its low energy and the consequential steep dose gradient. The aim of this study was to create and evaluate a homogeneous cylindrical energy deposition around a newly designed vaginal applicator. METHODS AND MATERIALS: To create constant isodose layers along the cylindrical plastic vaginal applicator, the source (INTRABEAM system) was moved in steps of 17-19.5 mm outward from the tip of the applicator. Irradiation for a predetermined time was performed at each position. The axial shift was established by a stepping mechanism that was mounted on a table support. The total dose/dose distribution was determined using film dosimetry (Gafchromic EBT) in a "solid water" phantom. The films were evaluated with Mathematica 5.2 and OmniPro-I'mRT 1.6. The results (dose D0/D5/D10 in 0/5/10 mm tissue depth) were compared with an (192)Ir HDR afterloading plan for multiple sampling points around the applicator. RESULTS: Three different dose distributions with lengths of 3.9-7.3 cm were created. The irradiation time based on the delivery of 5/7 Gy to a 5 mm tissue depth was 19/26 min to 27/38 min. D0/D5/D10 was 150%/100%/67% for electronic brachytherapy and 140%/100%/74% for the afterloading technique. The deviation for repeated measurements in the phantom was <7%. CONCLUSIONS: It is possible to create a homogeneous cylindrical dose distribution, similar to (192)Ir HDR afterloading, through the superimposition of multiple spherical dose distributions by stepping a kilovolt point source.
Authors: Arne Mathias Ruder; Laurens Inghelram; Frank Schneider; Gustavo R Sarria; Jürgen Hesser; Frederic Bludau; Udo Obertacke; Frederik Wenz; Yasser Abo-Madyan; Frank A Giordano Journal: J Contemp Brachytherapy Date: 2020-10-30
Authors: Carsten Herskind; Lin Ma; Qi Liu; Bo Zhang; Frank Schneider; Marlon R Veldwijk; Frederik Wenz Journal: Radiat Oncol Date: 2017-01-19 Impact factor: 3.481
Authors: Frank Schneider; Sven Clausen; Johannes Thölking; Frederik Wenz; Yasser Abo-Madyan Journal: J Appl Clin Med Phys Date: 2014-01-06 Impact factor: 2.102