Dosimetric properties of TL foils based on LiF:Mg,Cu,P (MCP-N) phosphors for clinical applications

• Published in: Radiation measurements 2010-03, Vol.45 (3), p.716-718
• Main Authors: Kisielewicz, K., Świebocka, J., Czopyk, Ł., Kłosowski, M., Lesiak, J., Byrski, E., Kabat, D., Wawrzak, M., Śladowska, A., Dziecichowicz, A., Olko, P., Waligórski, M.P.R.
• Format: Article
• Language: English
• Subjects: 2-D TL dosimetry; Earth sciences; Earth, ocean, space; Exact sciences and technology; Geochronology; IMRT; Isotope geochemistry. Geochronology; QA in radiotherapy; Stereotactic radiosurgery; TL foils
• ISSN: 1350-4487; 1879-0925
• DOI: 10.1016/j.radmeas.2009.12.002

Two prototype 2-D thermoluminescence (TL) readers: a laboratory reader equipped with a sensitive 640 × 480 pixel CCD camera and a heater planchet of 7.2 cm diameter, and a clinical reader with a 14-bit CCD PCO camera of 1024 × 1024 pixel resolution and a 20 × 20 cm 2 heater, were developed at the Institute of Nuclear Physics (IFJ PAN) in Kraków, Poland. These readers are able to produce digital images of 2-D dose distributions from exposed TL foils of sizes up to 20 × 20 cm 2, composed of ETFE (ethylene tetrafluoroethylene) and LiF:Mg,Cu,P (MCP-N) powder, also developed and manufactured at IFJ PAN in Krakow. The clinical 2-D TL system is being developed specifically for clinical measurements of 2-D dose distributions in external photon or electron radiotherapy beams and around small sources applied in brachytherapy. We report results of our tests of basic dosimetric properties (repeatability, linearity vs. absorbed dose, signal-to-noise ratio and energy dependence) of the 2-D TL foil-reader systems using MCP-N based foils and megavolt X-ray radiotherapy beams, over a range of dose relevant to clinical radiotherapy. We conclude that the clinical 2-D TL system may be useful in clinical dosimetry of external radiotherapy beams and photon-emitting brachytherapy sources. As examples of such applications, we show verification of computer therapy planning system calculations of fields produced by multileaf collimators or stereotactic radiosurgery systems, performed as part of the quality assurance procedure in radiotherapy.