Radiochromic films are useful as dosimeters in high-precision radiotherapy owing to their high spatial resolution. However, when a particle beam is measured using a radiochromic film, the dose cannot be estimated accurately because the film darkness varies with variations in linear energy transfer (LET). This paper proposes a novel method for estimating the LET and the dose based on the film darkness. In this method, after a high-LET particle beam, such as a carbon-ion beam, was incident on the film, the film was digitized and its net optical density was determined. Further, the non-linearity of the film response curve between the dose and the darkness, depending on LET, was used. Then, calibration curves were created using 290 MeV u −1 mono energetic carbon-ion beams. We used LETs of 20, 50, 100, and 150 keV µ m −1 and a physical dose of 2–14 Gy. The calibration curves were approximated for each LET using a quadratic function. The correlations between ...

中文翻译：

---

使用放射致变色膜同时测定碳离子束的剂量和线性能量转移（LET）

放射性变色膜由于其较高的空间分辨率而可用作高精度放射治疗中的剂量计。然而，当使用放射致变色膜测量粒子束时，由于膜的暗度随线性能量转移（LET）的变化而变化，因此无法准确估算剂量。本文提出了一种基于胶片暗度估计LET和剂量的新方法。在这种方法中，在高LET粒子束（例如碳离子束）入射到薄膜上之后，将薄膜数字化并确定其净光密度。此外，使用了取决于LET的剂量和暗度之间的膜响应曲线的非线性。然后，使用290 MeV u -1单能碳离子束创建校准曲线。我们使用了20、50、100和150 keV µm -1的LET，物理剂量为2–14 Gy。使用二次函数为每个LET近似校准曲线。...之间的相关性