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Dose distributions for 90 Y intravascular brachytherapy sources used with balloon catheters
Author(s) -
Piessens Marleen,
Reynaert Nick,
Potempa Jaroslaw,
Thierens Hubert,
Wijns William,
Verbeke Luc
Publication year - 2002
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.1488604
Subject(s) - scintillator , imaging phantom , calibration , brachytherapy , thermoluminescent dosimeter , materials science , monte carlo method , nuclear medicine , dosimetry , detector , dose profile , balloon , physics , optics , dosimeter , medicine , radiology , mathematics , statistics , quantum mechanics , radiation therapy , cardiology
The dose distribution around an intravascular brachytherapy90 Y line source with centering balloon catheters was measured with a plastic scintillator, TLD and radiochromic film. The absolute dose rates measured with the three detectors in a solid water phantom at 1, 2 and 3 mm distance from the centering balloon surfaces are in agreement within 3.5%, when the detectors are calibrated with the same90 Sr / 90 Y source. The dose rates measured with the plastic scintillator in the solid water phantom are in agreement with those directly measured in water. The measured relative dose distributions can be reproduced by Monte Carlo calculations. Also, the influence of the balloon diameter on the dose rate can be reproduced by the calculations. The dose rate calibration routinely performed with the plastic scintillator was checked for fifty‐one sources with a well chamber and with another dedicated dose rate checking device. These measurements show that the consistency of the calibration of these sources was better than 10%. In a previous paper absolute dose rates for five other90 Y sources measured with TLD and radiochromic film in a solid water phantom were compared with those obtained with the plastic scintillator in water [Piessens and Reynaert, “Verification of absolute dose rates for intravascular beta sources,” Phys. Med. Biol. 45 , 2219–2231 (2000)]. Differences of 25 to 41%, depending on the balloon diameter, were reported. In this paper we show the evidence for three main reasons for these previously observed discrepancies: an inconsistency between a detector calibration performed with a 6 MeV electron beam and with a calibrated90 Sr / 90 Y source from NIST (16%), inaccuracies of the measuring distances in the solid water phantom (maximum 7.5%) and a time instability of the plastic scintillator, probably due to radiation damage (6%).