Technical note: Evaluation of the dose enhancement effect for a novel transmission-type x-ray tube using the Monte Carlo method

Purpose: Transmission-target x-ray tubes generate more x-rays than reflection thick-target x-ray tubes. A transmission x-ray tube combined with radiosensitizers has a better radiation enhancement effect. This study investigated the feasibility of using a transmission x-ray tube with radiosensitizers in clinical radiotherapy and its effect on radiation dose enhancement. Methods: This study used MCNP6.2 to simulate the model of a transmission x-ray tube and Co-60 beam. The radiation enhancement effect of radiosensitizers was examined with iodine-127 (I-127), radioiodinated iododeoxyuridine (IUdR), and gold nanoparticles (GNPs). Results: The study results showed that the dose enhancement factor (DEF) of the transmission x-ray tube with GNPs was 10.27, which was higher than that of I-127 (6.46) and IUdR (3.08). The DEF of the Co-60 beam with GNPs, I-127, and IUdR was 1.23, 1.19, and 1.2, respectively. The Auger electron flux of the transmission x-ray tube with GNPs was 1.19E+05 particles/cm². Conclusions: This study found that a transmission x-ray tube with appropriate radiosensitizers could produce a high rate of Auger electrons to fulfill the radiation enhancement effect, and this procedure has the potential to become a radiotherapy modality.