Study of clinical application of a novel immobilization system in total marrow irradiation

Objective: To evaluate the clinical application value of a novel immobilization system in total marrow irradiation (TMI) with MVCT image. Methods: From 2016 to 2017, a retrospective analysis of the setup errors of 22 patients receiving TMI in two groups (twelve patients were immobilized with the novel immobilization system in group 1, ten patients were immobilized with the combinatorial immobilization devices in group 2) was performed in this study on Zhongnan Hospital of Wuhan University. Two-sample t-test was used to analyze the differences of setup errors and the consistency of setup between two groups. Results: In group 1, the setup errors on left-right, superior-inferior, anterior-posterior and rotation directions were (1.06 ± 0.79), (1.34 ± 0.66), (2.45 ± 1.48) mm and (0.63° ± 0.65°) for the head and neck position, (1.58 ± 1.13), (2.38 ± 1.99), (2.05 ± 1.68) mm and (0.31° ± 0.32°) for the chest position, (1.67 ± 1.24), (3.88 ± 2.20), (1.96 ± 1.32) mm and (0.48° ± 0.53°) for the pelvis position, and (0.95 ± 0.73), (1.99 ± 1.35), (3.66 ± 2.13) mm and (0.24° ± 0.31°) for the lower limb, respectively. In group 2, the setup errors were (2.59 ± 2.58), (3.28 ± 1.85), (3.71 ± 2.43) mm and (1.15° ± 1.18°) for the head and neck position, (4.38 ± 3.69), (5.64 ± 3.78), (2.72 ± 1.91) mm and (1.55° ± 0.86°) for the chest position, (4.14 ± 2.97), (6.97 ± 3.68), (2.21 ± 2.26) mm and (1.23° ± 0.74°) for the pelvis position, (2.28 ± 1.15), (5.97 ± 3.00), (3.44 ± 1.93) mm and (1.09° ± 0.94°) for the lower limb, respectively. The setup errors significantly differed between two groups on the left-right, superior-inferior and rotation directions for all positions (all P < 0.05). The setup consistency significantly differed between two groups on the left-right, superior-inferior and rotation directions for the chest and pelvis positions (all P < 0.05). Conclusion: The novel immobilization system can significantly improve the setup accuracy and setup consistency, and enhance the precision of treatment for patients. (authors)