Author: Xiu tong Lin, Tao Sun 👨🔬
Affiliation: Department of Radiation physics and technology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Department of Radiation physics and technology, Shandong Second Provincial General Hospital 🌍
Purpose: To compare the positioning accuracy and time efficiency of "Sphere-Mask" Optical Positioning System (OPS) and traditional laser light positioning method in breast cancer radiotherapy, and to provide more reliable basis for clinical practice.
Methods: In this study, three breast cancer patients receiving radiotherapy were monitored for a total of 30 treatment sessions. An "Sphere-Mask" Optical Positioning System (OPS) with automatic correction function was used for real-time patient positioning monitoring. Manual positioning utilizes traditional laser lights to mark a cross on the front and sides of the body for alignment, serving as the matched group. The positioning error index (PEI) in three directions (left-right, anterior-posterior, and up-down) were calculated and analyzed using the error formula. The average positioning time of the two positioning methods were recorded and compared.
Results: The error ranges of the OPS positioning system in the left-right, anterior-posterior, and up-down directions are 1.2-3.5 mm, 1.8-4.0 mm, 1.5-3.0 mm, respectively, with the upper quartile values of 2.7 mm, 3 mm, 2.5 mm, respectively. The PEI for OPS in the three directions were 2.2mm, 2.7mm, 2.3mm respectively, with average errors all less than those of manual positioning (2.5mm, 4.8mm, 3.2mm in the three directions). The differences were statistically significant. OPS also demonstrated a significant advantage in positioning time, with a mean of 2.5 minutes compared to the mean of 4.5 minutes for manual laser positioning (P<0.01).
Conclusion: OPS shows significantly higher positioning accuracy than traditional manual laser positioning methods in radiotherapy for breast cancer patients. Additionally, the significant reduction in positioning time with OPS indicates its efficiency in clinical applications. The real-time monitoring ability, non-radiation characteristic and individual adaptability of OPS make it have certain application potential in breast cancer radiotherapy.