Thermoluminescence of 7LiF in therapeutic high linear energy transfer (LET) charged-particle beams.

The thermoluminescence of the 200 and 260 degrees C peaks of 7LiF has been measured and compared with off-axis dose and depth-dose distributions for three therapeutic high-LET beams: negative pions, helium ions and neon ions. The methods of analysis consisted of both a single-peak analysis and the dual-peak analysis methods of Hogstrom and Irifune and Hoffmann et al. The results indicate that 7LiF, analysed by the dual-peak analysis methods, is potentially useful for extracting total dose, high-LET dose, and beam quality of helium-ion and negative-pion beams. For the higher-LET neon beam, differences in sensitivity between the 200 and 260 degrees C peaks of 7LiF were found to be independent of variations in LET within the beam; consequently, only the single-peak analysis method is applicable in which case the dosemeter at best can only estimate total dose.