Berger Thomas, Hajek Michael, Fugger Mamfred, Vana Norbert
Atomic Institute of the Austrian Universities (ATI), Stadionallee 2, 1020 Vienna, Austria.
Radiat Prot Dosimetry. 2006;120(1-4):361-4. doi: 10.1093/rpd/nci581. Epub 2006 May 18.
One of the most essential difficulties in heavy-ion dosimetry by means of thermoluminescence dosemeters (TLDs)--often seen as a serious disadvantage of TLD utilisation--regards the changing TL-efficiency with increasing linear energy transfer (LET) of the particle. This behaviour leads to a falsification of absorbed dose that can be significant for many applications, e.g. in space or radiotherapeutic dosimetry. The high-temperature TL emission of LiF:Mg,Ti TL detectors can be exploited to obtain information about the LET of the heavy-ion radiation field under study. The high-temperature ratio (HTR) is used as a parameter to determine average LET. To correct the absorbed dose according to the TL-efficiency, the detailed dependence of HTR- and TL-efficiency on LET was recorded. These investigations were accomplished at the Heavy Ion Medical Accelerator (HIMAC) in Chiba, Japan, with a variety of high-energy ion beams (helium, carbon, neon, silicon and iron) ranging in LET from 2.2 to 393 keV microm(-1). The obtained relationships HTR vs. LET and TL-efficiency vs. LET were combined into a TL efficieny vs. HTR relationship. This enables correction of the absorbed dose (HTR-B method). The methodology is demonstrated by means of TLD 700 ((7)LiF:Mg,Ti) measurements in carbon beams of 290 and 400 MeV n(-1) available from HIMAC.
利用热释光剂量计（TLD）进行重离子剂量测定时，最基本的困难之一——这通常被视为使用TLD的一个严重缺点——是随着粒子线能量转移（LET）的增加，热释光效率会发生变化。这种行为会导致吸收剂量的错误，这在许多应用中可能很显著，例如在空间或放射治疗剂量测定中。LiF:Mg,Ti热释光探测器的高温热释光发射可用于获取有关所研究重离子辐射场LET的信息。高温比（HTR）用作确定平均LET的参数。为了根据热释光效率校正吸收剂量，记录了HTR和热释光效率对LET的详细依赖性。这些研究是在日本千叶的重离子医学加速器（HIMAC）上完成的，使用了各种高能离子束（氦、碳、氖、硅和铁），LET范围为2.2至393 keV·μm⁻¹。将获得的HTR与LET以及热释光效率与LET的关系合并为热释光效率与HTR的关系。这使得能够校正吸收剂量（HTR - B方法）。通过在HIMAC提供的290和400 MeV·n⁻¹碳束中使用TLD 700（⁷LiF:Mg,Ti）进行测量，展示了该方法。
