Objective To discuss the shielding calculation method for proton therapy room, and to provide a scientific basis for shielding design of proton therapy room and improvement of existing national standards. Methods Using the calculation formula and key characteristic parameters from national standards and Chinese and foreign literature, combining with the FLUKA Monte Carlo method, empirical formula calculation and Monte Carlo simulation were conducted for the neutron ambient dose equivalent rates of the focuses outside the shielding of proton therapy room. The estimation results of the two methods were analyzed. Results Relative to the calculation results of the single exponential formula in the two directions of 0° and 50° in the beam loss point of divergence slit (0.13 and 12.4), the calculation results of the double exponential formula (0.40 and 17.9) were more consistent with the Monte Carlo simulation results (0.32 ± 0.19 and 18.2 ± 4.98). The Monte Carlo simulation results of copper target and nickel target were similar, suggesting that the key characteristic parameters of concrete shielding for copper target could be well applied to the calculation of nickel target, but the neutron ambient dose equivalent rates were underestimated when applied to tantalum target, with a difference of 5.7 times and 1.3 times in the two directions of 0° and 40°, respectively. Conclusion The dose rate estimates based on the calculation formula and key characteristic parameters from Chinese and foreign literature are consistent with FLUKA simulation results, and this method can be used in the shielding design of proton therapy room as a supplement and improvement to the existing national standards.

Objective To compare H_p(3) calibration with a homemade (A) thermoluminescent dosimeter (TLD) and an imported (B) TLD in a standard X-ray RQR radiation field, to explore the different responses of A and B, and to provide foundation for the calibration of H_p(3). Methods A column mode was selected. H_p(3) calibration was performed using A and B in a standard X-ray RQR radiation field in the Secondary Standard Dosimetry Laboratory, National Institute for Radiological Protection, China Center for Disease Control and Prevention. Angle response, energy response, and linear response were calibrated with RQR4 (60 kV), RQR7 (90 kV), and RQR9 (120 kV), respectively. Results In terms of angle response, the calibration results of A were relatively high, while the calibration results of B were relatively low. In terms of energy response, the calibration results showed a similar pattern to angle response. In terms of linear response, the calibration results of both A and B were satisfactory. Conclusion Both A and B can be used for normal calibration of H_p(3) in a standard X-ray RQR radiation field. However, in actual monitoring, attention should be paid to the energy and angle response values of TLDs.