Dosimetry of anal radiation in high-dose-rate brachytherapy for prostate cancer.
OBJECTIVE
The objective of this study is to determine the radiation dose to the anus during brachytherapy using high-dose-rate Ir-192 sources.


METHODS
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 0.85 Gy (range, 0.48-1.37 Gy) per treatment. The transport dose using 15 and 19 needles in the prostate phantom was 0.07 and 0.08 Gy, 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.
Kälkner
Karl Mikael
KM
Department of Oncology, Radiumhemmet, Karolinska University Hospital, Stockholm, Sweden. karl.kalkner@karolinska.se
Bengtsson
Emil
E
Eriksson
Simone
S
Holmberg
Carina
C
Nilsson
Sten
S
Levitt
Seymour
S
Lundell
Marie
M
D000368:Aged; D000369:Aged, 80 and over; D001003:Anal Canal; D001918:Brachytherapy / Q000009:adverse effects / Q000379:methods; D006801:Humans; D008297:Male; D008875:Middle Aged; D019047:Phantoms, Imaging; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D011879:Radiotherapy Dosage; D013819:Thermoluminescent Dosimetry