Analysis of dosimetric characteristics of proton radiotherapy in 1 case of whole central nervous system tumor

Journal of International Oncology››2025,Vol. 52››Issue (7): 434-440.doi:10.3760/cma.j.cn371439-20250217-00076

• Dosimetric characteristics of proton radiotherapy •Previous Articles Next Articles

Analysis of dosimetric characteristics of proton radiotherapy in 1 case of whole central nervous system tumor

Wu Shizhang¹^,², Hu Man³, Dai Tianyuan¹^,², Li Chengqiang¹^,², Tao Cheng¹^,², Duan Jinghao¹^,², Chen Jinhu¹^,², Bai Tong¹^,², Kong Tian⁴, Zhu Jian¹^,²()

¹Department of Radiation Oncology Physics，Shandong Cancer Hospital and Institute，Shandong First Medical University and Shandong Academy of Medical Sciences，Jinan 250117，China
²Shandong Provincial Key Medical and Health Laboratory of Pediatric Cancer Precision Radiotherapy （Shandong Cancer Hospital），Jinan 250117，China
³Department of Head and Neck Radiotherapy，Unit 1，Shandong Cancer Hospital and Institute，Shandong First Medical University and Shandong Academy of Medical Sciences，Jinan 250117，China
⁴Disease Control and Prevention Institute of China Railway Jinan Bureau Group Co.，Ltd.，Jinan 250031，China

Received:2025-02-17Revised:2025-03-27Online:2025-07-08Published:2025-07-23
Contact:Zhu Jian E-mail:zhujian@sdfmu.edu.cn
Supported by:
National Science and Technology Major Project of China(2024ZD0519901);National Natural Science Foundation of China(12105160);National Natural Science Foundation of China(82172072);Key R&D Program of Shandong Province，China(2024CXPT084);Natural Science Foundation of Shandong Province of China(ZR2021QA099);Natural Science Foundation of Shandong Province of China(ZR2022QH188);Youth Innovation Team Development Plan of Shandong Universities(2024KJJ013);Shandong Provincial Young Science and Technology Talent Support Project(SDAST2024QTB034)

Abstract

Abstract:

ObjectiveTo explore the dosimetric characteristics of intensity modulated proton therapy （IMPT），intensity modulated radiation therapy （IMRT） and tomotherapy （TOMO） techniques applied in the irradiation of pediatric whole central nervous system tumors.MethodsTaking the target area of a 14-year-old pediatric patient clinically diagnosed with atypical teratoid/rhabdomyoid tumor，meningeal metastasis by Shandong Cancer Hospital and Institute，and undergoing craniospinal irradiation （CSI） as an example，IMPT，IMRT and TOMO plans were designed respectively based on the clinical prescription of the target area and the limit requirements of organs at risk （OARs）. The conformal index （CI），homogeneity index （HI） and gradient index （GI） of each planning target volume，as well as the dose volume index of normal tissues，were evaluated to compare the dosimetric characteristics of the three types of plans.ResultsThe CI （0.71），HI （0.05） and GI （3.13） of the IMPT plan were comparable to those of IMRT plan （0.80，0.08，3.14）. The HI （0.03） and GI （2.54） of the TOMO plan were excellent，which were all within the clinically acceptable range. The irradiation dose to parallel organs in the IMPT plan was lower than that in the IMRT and TOMO plan. In the IMPT plan，V₅of lungs was 2.9%，IMRT plan was 37.6%，and TOMO plan was 43.5%. The D_meanof liver in the IMPT plan was 0.01 Gy（RBE），IMRT plan was 6.12 Gy，and TOMO plan was 6.39 Gy. In the IMPT plan，none of the bladder，rectum，and femoral head received the dose，while there was low-dose radiation in both IMRT and TOMO plan. For serial organs adjacent to and within the target area，the D_maxof spinal cord and brainstem in IMPT plan was 39.89 and 39.88 Gy（RBE），respectively； in IMRT plan，they were 39.43 and 38.59 Gy，respectively； and in TOMO plan，they were 38.41 and 37.69 Gy，respectively. The low-dose area in the IMPT plan was significantly better than the photon radiotherapy plans. Among them，the absolute volume IMPT plan occupied by 10% of the prescribed dose area in the patient's body was reduced by 70.10% compared with IMRT plan and 76.96% compared with TOMO plan； the 30% prescribed dose volume IMPT plan was reduced by 53.49% compared with IMRT plan and 62.51% compared with TOMO plan； the 50% prescribed dose volume IMPT plan was reduced by 39.06% compared with IMRT plan and 42.23% compared with TOMO plan.ConclusionsThe IMPT plan demonstrated significantly reduced low-dose exposure and lower doses to parallel OARs compared to both IMRT and TOMO plans in pediatric CSI. The CI，HI and GI of the three plans can all meet the clinical requirements. However，for serial organs adjacent to and within the target area，the D_maxof the IMPT plan may be higher than that of IMRT and TOMO plans.

Key words:Central nervous system neoplasms,Radiotherapy,Proton therapy,Radiotherapy dosage

Wu Shizhang, Hu Man, Dai Tianyuan, Li Chengqiang, Tao Cheng, Duan Jinghao, Chen Jinhu, Bai Tong, Kong Tian, Zhu Jian. Analysis of dosimetric characteristics of proton radiotherapy in 1 case of whole central nervous system tumor[J]. Journal of International Oncology, 2025, 52(7): 434-440.

Figures/Tables7

参数	IMPT	IMRT	TOMO	参数	IMPT	IMRT	TOMO
CI	0.71	0.80	0.71	眼球（右）D_mean	10.90	15.80	16.18
HI	0.05	0.08	0.03	腮腺（左）D_mean	5.54	8.75	12.66
GI	3.13	3.14	2.54	腮腺（右）D_mean	3.28	8.46	10.76
正常组织[质子Gy（RBE）；光子Gy]				心脏D_mean	0.01	2.74	10.03
晶体（左）D_max	2.10	5.66	5.05	肝脏D_mean	0.01	6.12	6.39
晶体（右）D_max	2.47	5.48	5.34	肾（左）D_mean	0.09	2.98	6.13
视神经（左）D_max	39.37	38.49	37.70	肾（右）D_mean	0.04	2.65	5.36
视神经（右）D_max	39.33	38.21	37.90	膀胱D_mean	0.00	2.72	2.21
视交叉D_max	39.22	38.44	37.68	直肠D_mean	0.00	1.23	1.81
脑干D_max	39.88	38.59	37.69	股骨头（左）D_mean	0.00	0.54	0.57
脊髓D_max	39.89	39.43	38.41	股骨头（右）D_mean	0.00	0.50	0.64
双肺V₅	2.9%	37.6%	43.5%	body（cm³）
双肺V₂₀	0.1%	1.5%	3.4%	10%D_处方剂量	6 179	20 652	26 817
双肺D_mean	0.40	4.82	6.56	30%D_处方剂量	5 169	11 114	13 786
眼球（左）D_mean	10.55	19.39	15.87	50%D_处方剂量	4 487	7 363	7 767

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