Feasibility study of entrance in vivo dose measurements with mailed thermoluminescence detectors
| Autor: | Ans Swinnen, Dominique Huyskens, Jan Verstraete |
|---|---|
| Rok vydání: | 2003 |
| Předmět: |
Dosimeter
business.industry Phantoms Imaging Detector Dose profile Hematology Thermoluminescence Imaging phantom Oncology In vivo Calibration Medicine Feasibility Studies Humans Radiology Nuclear Medicine and imaging Thermoluminescent Dosimetry Thermoluminescent dosimeter Postal Service Radiation treatment planning Nuclear medicine business |
| Zdroj: | Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology. 73(1) |
| ISSN: | 0167-8140 |
| Popis: | Background and purpose The aim of this work is to set-up mailed entrance in vivo dosimetry by means of thermoluminescence dosimeters (TLDs) in the form of LiF powder in order to assess the overall accuracy of patient treatment delivery by comparing the doses delivered to patients with the doses calculated by the treatment planning system (TPS) in different institutions. Patients and methods Two millimeter thick copper (for 6MV photon beams) and 1.3mm thick aluminium (for 60 Co gamma beams) build-up caps are developed. The characteristics of these build-up caps are tested by phantom measurements: the response of the TLD inside the build-up cap is compared to the ionisation chamber (IC) signal in the same irradiation conditions. A pilot study using the copper build-up cap is performed on 8 patients, treated with a 6MV photon beam at the radiotherapy department of the University Hospital of Leuven. Additionally, a first run of mailed entrance in vivo dosimetry is performed by 18 radiotherapy centres in Europe. Results For 80 different phantom set-ups using copper and aluminium build-up caps, the mean TLD dose compared to the IC dose is 0.993±0.015 (1SD). Regarding the patient measurements in the radiotherapy department of the University Hospital of Leuven, the mean ratio of the measured entrance dose (TLD) to the entrance dose calculated by the TPS, is equal to 0.986±0.017 (1SD) ( N =8), after correction of an error detected in one of the patient treatments. For the 18 radiotherapy centres participating in the mailed in vivo TLD study, the mean measured versus stated entrance dose for patients treated in a 60 Co and 6 MV photon beam is 1.004±0.021 (1SD) ( N =143). Conclusions From the results, it can be deduced that the build-up caps and the proposed calibration methodology allow the use of TLD in the form of powder to be applied in large scale in vivo dose audits. |
| Databáze: | OpenAIRE |
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