Objective:In Shanghai Advanced Proton Therapy Facility (SAPT) of Ruijin Hospital Proton Therapy Center, the calculation accuracy of the commercial proton treatment planning system RayStation (V10), especially the accuracy of the proton range calculation, was measured and verified, aiming to provide reference for the clinical application of the treatment planning system.Methods:A head phantom was used to verify the calculation accuracy of RayStation. The phantom CT was imported into treatment planning system (TPS). The phantom was followed closely by a water tank with a one-liter cubic target. A single field verification plan with the prescribed dose of 200 cGy (relative biological effectiveness) was designed and implemented. Then, the measured distribution results were compared with the calculation results.Results:When the verification plan of the phantom was designed with the default settings of RayStation, the measured longitudinal dose distribution was approximately 4 mm deeper than that of TPS, indicating that RayStation overestimated the water equivalent thickness (WET) of the tissue substitute materials in the phantom. To study the range error, the actual beam was used to measure the WET of the soft tissue substitute material. The default setting of RayStation was fine-tuned according to the measured results. It was found that the error between the measured SOBP and TPS calculations was reduced to only 2 mm.Conclusions:Using the default setting of RayStation to calculate the stopping power of the phantom may cause a large range error. A method that combines tissue segmentation with the measured WET of the tissue substitute material is proposed to improve the range calculation accuracy of the TPS. The results show that the proposed method can improve the dose and range accuracy of the commercial TPS including RayStation for tissue substitute materials.

Objective:To investigate the initial effectiveness of manual techniques versus navigation positioning system-assisted reconstruction for anterior cruciate ligament (ACL) injuries in children and adolescent populations.Methods:A retrospective analysis was conducted on 28 patients with ACL rupture who underwent primary total epiphyseal ACL reconstruction in the Sports Medicine Treatment Center of Honghui Hospital Affiliated to Xi'an Jiaotong University from January 2019 to October 2022. Patients were categorized into two groups based on the method of guide needle insertion: the manual group (guide needle insertion relying on the operator's expertise) and the robot-assisted group (guide needle insertion assisted by the Tianji robot navigation and positioning system). The manual group comprised 14 cases (9 males, 5 females) with an average age of 13.59±1.59 years, while the robot-assisted group included 14 patients (10 males, 4 females) with an average age of 13.27±1.66 years. The operation time, intraoperative fluoroscopy times, guide needle placement times, the distance between the central point of the internal articular opening of the tibial and femoral bone tunnel and the ideal point, the rate of epiphyseal inflammation, and the International Knee Documentation Committee (IKDC) subjective score, Lysholm score, KT-2000 ligament relaxation, lower limb force line were compared between the two groups.Results:The follow-up duration was 19.9±6.3 months for the manual group and 18.8±4.9 months for the robot group ( t=0.546, P=0.589). The manual group's operation duration was 123.0±12.6 min, significantly longer than the robot group's 96.4±12.9 min ( t=5.502, P<0.001). Intraoperative fluoroscopy was performed 11.8±3.1 times in the manual group, markedly more than the robot group's 3.7±0.8 times ( t=9.434, P<0.001). The robot group required only one guide needle placement for both femur and tibia, while the manual group had 5.7±1.2 placements on the femur side and 4.6±1.8 on the tibia side. The distance between the femoral joint's central point and the ideal point was 0.87±0.20 mm in the robot group, superior to the manual group's 1.92±0.64 mm ( t=5.816, P<0.001). Similarly, the distance between the central point and the ideal point was 1.15±0.34 mm for the robot group, better than the manual group's 1.94±0.55 mm ( t=4.582, P<0.001). No cases of epiphyseal irritation were observed in the robot group, while 21% (3/14) of the manual group experienced tibial or femoral epiphyseal plate involvement. At 3 months post-surgery, the robot group exhibited higher IKDC subjective scores (90.57±8.46) and Lysholm scores (86.29±5.09) compared to the manual group (83.50±6.19 and 80.93±5.93), respectively ( P<0.05). However, at the final follow-up, there were no significant differences in IKDC subjective scores, Lysholm scores, or KT-2000 ligament relaxation between the two groups ( P>0.05). Both groups showed normal lower limb force alignment and no abnormal growth or development. Conclusion:Tianji robot navigation and positioning system-assisted ACL reconstruction in children and adolescents offer advantages such as precise positioning, shorter operation times, reduced intraoperative fluoroscopy, faster recovery, and enhanced epiphyseal protection compared to manual methods.