Patient and personnel dosimetry in endovascular radiotherapy with 90Sr/90Y sources

Abstract

Endovascular brachytherapy (EVBT) is an established treatment to reduce the probability of restenosis after a percutaneous coronary intervention. The purpose of this study was to assess (1) the manufacturer's stated dosimetric data for (90)Sr/(90)Y source trains to be used in EVBT and (2) the procedure-related radiation burden. The radiation fields in water around six (90)Sr/(90)Y source trains were studied using phantoms made of 'solid water' and MD55-2 radiochromic films. The water equivalence of the phantom material was tested by applying quantitative computed tomography. Thermoluminescence dosemeters were used to assess personal radiation burden and crosscheck the dose distribution along the source trains. Technical failure was observed in one source train and this train was excluded from analysis. The measured dose rate in water at 2 mm radial distance was on average 8% higher than the manufacture's stated value (range of measured to stated values 1.05--1.15). The dose rate decreased exponentially with radial distance between 2 and 6 mm. The dose rate in contact with the source viewing window of the delivery devices ranged between 0.5 and 7.5 mGy h(-1). Low-energy photons were the main contributors to personal dose.

Verification and uniformity control of doses for 90 Sr/ 90 Y intravascular brachytherapy sources using radiochromic film dosimetry

“…Several studies[26–33] have been performed for the verification of the dose rates of the 90 Sr/ 90 Y source trains, produced by the Novoste Corporation, using radiochromic film dosimetry [Table 2]. One of them is the study of Duggan et al,[26] where four 90 Sr/ 90 Y source trains (5.0 F-30 mm) and an HD-810–type radiochromic film were used.…”

“…Most recently, Kalef-Ezra et al . [33] have studied the dosimetry of five 90 Sr/ 90 Y source trains (3.5 F–40-60 mm and 5.0 F–40-60 mm) using MD55-2–type radiochromic film, and they reported that the average of the measured dose rate was 8% higher than the manufacture's stated value. Although the results of these studies are close to certificate values, major differences (exceeding 10%) have also been reported in the study by Piessens and Reynaert.…”

“…Although well-type ionization chambers are well suited to measure the dose rate of sources of these types, radiochromic films can be used as a tool to determine the dose distributions rather than point doses. Already, some studies have shown that radiochromic film dosimetry is suitable to be performed with some type of phantoms specially designed to work with IVBT sources[26–33] and with conventional brachytherapy sources[3435] because it is nearly tissue equivalent and has a linear optical density–dose response.…”

Induced Radioactivity in Medical Accelerators

“…These measurements were combined with long-term environmental and personnel dose measurements. Among others, personnel badges containing LiF:Mg,Ti,… thermoluminescent dosimeters (TLDs) measured by either the Greek Atomic Energy Commission (GAEC) or the University of Ioannina Medical Physics Laboratory (UIMPL) [8] were used to monitor occupational and environmental radiological burden during the study period. The adequacy of the room shielding was tested my multiple dose rate measurements carried out at various locations around the treatment using various β, γ and neutron detectors.…”

Radiochromic film dosimetry: Reflection vs transmission scanning

“…According to the standard protocol applied in our laboratory, 6,8 the films are read four days postirradiation. To investigate the long-term stability, films were irradiated at doses between 7 and 20 Gy, kept at room temperature, and read twice, 4 and 30 days postirradiation using either the transmission ͑60 films͒ or the reflection ͑40 films͒ mode.…”