open access

Vol 13, No 1 (2008)
Untitled
Published online: 2008-01-01
Submitted: 2007-07-09
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Optimization in high dose rate vaginal cylinder for vaginal cuff irradiation

Somangili Sathyamoorthy Sivakumar, Johnson Gilbert Solomon, Sanjay Sudhakar Supe, Bejadi Manjunath Vadhiraja, Kilari Koteshwer Rao, Mamidipudi Srinivasa Vidyasagar
DOI: 10.1016/S1507-1367(10)60080-6
·
Rep Pract Oncol Radiother 2008;13(1):35-48.

open access

Vol 13, No 1 (2008)
Untitled
Published online: 2008-01-01
Submitted: 2007-07-09

Abstract

Aim

The aim of this study is to evaluate the influence of high dose rate (HDR) brach-ytherapy source step size, source dwell position, dose prescription depth, dose specification points and optimization technique on dose distribution around Microselectron HDR brachytherapy vaginal cylinders and to evaluate the influence of distal dwell position and optimization technique on rectal and bladder dose of patients treated for vaginal cuff irradiation.

Materials/Methods

Orthogonal radiographs of vaginal cylinders of diameter 2.0, 2.5, 3.0 and 3.5cm form the basis of the study. Dose distribution using the PLATO brachytherapy treatment planning system (version 14.1) was generated. Two different HDR cylinder models, namely the non-curved dome model (NCDM) and curved dome model (CDM), were studied. To evaluate bladder and rectum dose in the patients NCDM was used.

Results

CDM gives more uniform dose distribution around the cylinder than NCDM. Dose prescription at 5mm depth from the surface results in very high dose to apex and dome as compared with the surface dose prescription. Dose prescription depth and dwell positions influence the length of prescription isodose. Optimization method and dwell positions affect the bladder and rectal dose of the studied patients.

Conclusions

Uniform dose distribution can be obtained for HDR vaginal cylinders by appropriately selecting dose specification points and optimization method. Dose distribution can be configured to provide a uniform dose on the surface, if the apex and curved surface of the cylinder are considered for dose specification and optimization. Appropriate HDR parameters are identified to minimize the dose to the apex of the vaginal cylinder, essential to reduce the dose to overlying small bowel and reduce the dose to rectum and bladder.

Abstract

Aim

The aim of this study is to evaluate the influence of high dose rate (HDR) brach-ytherapy source step size, source dwell position, dose prescription depth, dose specification points and optimization technique on dose distribution around Microselectron HDR brachytherapy vaginal cylinders and to evaluate the influence of distal dwell position and optimization technique on rectal and bladder dose of patients treated for vaginal cuff irradiation.

Materials/Methods

Orthogonal radiographs of vaginal cylinders of diameter 2.0, 2.5, 3.0 and 3.5cm form the basis of the study. Dose distribution using the PLATO brachytherapy treatment planning system (version 14.1) was generated. Two different HDR cylinder models, namely the non-curved dome model (NCDM) and curved dome model (CDM), were studied. To evaluate bladder and rectum dose in the patients NCDM was used.

Results

CDM gives more uniform dose distribution around the cylinder than NCDM. Dose prescription at 5mm depth from the surface results in very high dose to apex and dome as compared with the surface dose prescription. Dose prescription depth and dwell positions influence the length of prescription isodose. Optimization method and dwell positions affect the bladder and rectal dose of the studied patients.

Conclusions

Uniform dose distribution can be obtained for HDR vaginal cylinders by appropriately selecting dose specification points and optimization method. Dose distribution can be configured to provide a uniform dose on the surface, if the apex and curved surface of the cylinder are considered for dose specification and optimization. Appropriate HDR parameters are identified to minimize the dose to the apex of the vaginal cylinder, essential to reduce the dose to overlying small bowel and reduce the dose to rectum and bladder.

Get Citation

Keywords

optimization; Dwell position; Curved Dome Model; Non-Curved Dome Model

About this article
Title

Optimization in high dose rate vaginal cylinder for vaginal cuff irradiation

Journal

Reports of Practical Oncology and Radiotherapy

Issue

Vol 13, No 1 (2008)

Pages

35-48

Published online

2008-01-01

DOI

10.1016/S1507-1367(10)60080-6

Bibliographic record

Rep Pract Oncol Radiother 2008;13(1):35-48.

Keywords

optimization
Dwell position
Curved Dome Model
Non-Curved Dome Model

Authors

Somangili Sathyamoorthy Sivakumar
Johnson Gilbert Solomon
Sanjay Sudhakar Supe
Bejadi Manjunath Vadhiraja
Kilari Koteshwer Rao
Mamidipudi Srinivasa Vidyasagar

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