Basic characteristics of tissue-equivalent phantom thermoluminescence slab dosimeter using new TL phosphor Li3B7012:Cu

• TEP-TLSD/SR1 is a high spatial resolution 2D-dosimeter.
• TEP-TLSD/SR1 showed a high tissue equivalence property in OAR and PDD.
• TEP-TLSD/SR1 is a new large area detector and is a tissue equivalent phantom.

Here we investigate the basic characteristics of the tissue-equivalent phantom thermoluminescence slab dosimeter with synthetic resin type 1 (TEP-TLSD/SR1), a two-dimensional TLD based on TL phosphor Li3B7012:Cu developed by the Urushiyama Research Group. Li3B7O12:Cu has a single glow peak at 120 °C at a heating rate of 0.317 °C s−1. The dose response is linear between 0.1 and 10 Gy. The phosphor, when combined with a synthetic resin, can be molded into 200 mm × 200 mm × 2.5 mm slabs. The system has a Charge Coupled Device (CCD) dependent spatial resolution (pixel pitch) of 640 μm and a pixel response standard deviation of 1.33%. Using simple pixel-based noise compensation, we were able to improve the signal-to-noise ratio (SNR) in the final image. In tests as a TEP, this system gives off axis ratio and percentage dose depth results highly correlated with those of an ion chamber suspended in a water phantom. The TEP-TLSD/SR1 produces similar images to Gafchromic film for X-ray imaging. This TEP-TLSD/SR1 is not only larger than the prototype, but also has a better SNR and improved usability. With further improvements in tissue equivalence, we foresee a system where a TEP and dosimeter are combined into a three-dimensional dosimeter.