Publication

Determination of the source dwell position of an afterloading device with a detector array

Journal Paper/Review - Sep 6, 2011

Units
Keywords
high dose rate brachytherapy, afterloading, dwell position, calibration, measurement, 2D detector array
Doi
Contact

Citation
Breithuth F, Schiefer J, Arn M, Peters S, Seelentag W. Determination of the source dwell position of an afterloading device with a detector array. J Radiat Oncol Inform 2011;3:1:12-24 2011
Type
Journal Paper/Review (English)
Journal
J Radiat Oncol Inform 2011;3:1:12-24 2011
Publication Date
Sep 6, 2011
Issn Electronic
1663-618X
Publisher
SROI
Brief description/objective

It was the aim to develop and test a measurement technique for the source position of an afterloading system using an electronic two-dimensional detector array (2D array). A "GammaMed plus IX" high dose rate afterloading device (Varian Medical Systems, Palo Alto, USA), and a Seven29 2D detector array (PTW Freiburg GmbH, Freiburg, Germany) have been used. A hollow needle has been connected to the afterloading device. Its outer diameter is 3.0 mm and its length about 220 mm. A 14 mm thick Perspex slab was fixed in a reproducible position on the 2D array. Above the 14th detector row, a groove was cut in the slab which accommodates the hollow needle in a fixed position relative to the 2D array. In order to define the position of the source, the signals of the detectors in the 14th detector row have been evaluated. A theoretical curve depending on the source position and strength, has been fitted to the acquired detector signals. It has been shown that the reproducibility of the measurement technique - including the reproducibility of the source placement - was within 0.15 mm. This method can not only replace film measurements, it is also more exact and less time consuming.