Dosimetry of anal radiation in high-dose-rate brachytherapy for prostate cancer

Kälkner, Karl Mikael; Bengtsson, Emil; Eriksson, Simone; Holmberg, Carina; Nilsson, Sten; Levitt, Seymour; Lundell, Marie

doi:10.1016/j.brachy.2006.08.008

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Volume 6, Issue 1 , Pages 49-52, January 2007

Dosimetry of anal radiation in high-dose-rate brachytherapy for prostate cancer

Karl Mikael Kälkner
- Department of Oncology, Radiumhemmet, Karolinska University Hospital, Stockholm, Sweden
- Corresponding author. Department of Oncology, Radiumhemmet, Karolinska University Hospital, SE-171 76 Stockholm, Sweden. Tel.: +46-8-517-79927.
Emil Bengtsson
- Department of Medical Physics, Radiumhemmet, Karolinska University Hospital, Stockholm, Sweden
Simone Eriksson
- Department of Medical Physics, Radiumhemmet, Karolinska University Hospital, Stockholm, Sweden
Carina Holmberg
- Department of Oncology, Radiumhemmet, Karolinska University Hospital, Stockholm, Sweden
Sten Nilsson
- Department of Oncology, Radiumhemmet, Karolinska University Hospital, Stockholm, Sweden
Seymour Levitt
- Department of Oncology, Radiumhemmet, Karolinska University Hospital, Stockholm, Sweden
- Department of Therapeutic Radiology, University of Minnesota, Minneapolis, MN
Marie Lundell
- Department of Medical Physics, Radiumhemmet, Karolinska University Hospital, Stockholm, Sweden

Received 30 June 2006; received in revised form 21 August 2006; accepted 24 August 2006. published online 11 December 2006.

Abstract

Purpose

The objective of this study is to determine the radiation dose to the anus during brachytherapy using high-dose-rate Ir-192 sources.

Methods and materials

Thermoluminescence dosimeters were used for measuring the dose to the distal part of the anus in 10 patients, and in a prostate phantom to measure the radiation dose during the transport of the radiation source.

Results

The measured dose to the anus in vivo was on average 0.85Gy (range, 0.48–1.37Gy) per treatment. The transport dose using 15 and 19 needles in the prostate phantom was 0.07 and 0.08Gy, respectively.

Conclusions

The dose delivered to the anus using high-dose-rate brachytherapy with Ir-192 sources is quite low. There is a contribution to the anal radiation dose during the transport of the Ir-192 source into the needles. However, in clinical practice when using 15–20 needles, the dose from transporting the Ir-192 source can be ignored.

Keywords: Prostate cancer, Dosimetry, High-dose-rate brachytherapy, Thermoluminescence dosimeters