Measurement and analysis of out-of-field tissue dose under typical accelerator radiotherapy conditions

Abstract

Abstract:

Objective To investigate the dose of out-of-field tissues under typical linear accelerator radiotherapy conditions，and to provide experimental evidence for optimizing patient protection strategies and refining treatment planning. Methods A Varian TrueBeam 6 MV linear accelerator served as the radiation source，and an adult female anthropomorphic phantom RANDO 110 manufactured by Phantom Laboratory was used to simulate the patient in this study. A 10 cm×10 cm standard field was applied to the abdomen below navel with SSD of 100 cm，delivering a total dose of 600 cGy. LiF（Mg，Cu，P） thermoluminescent detectors were used to measure the absorbed doses in critical out-of-field tissues，including the breast，liver，stomach，bladder and gonads. A database was established using Excel 2019，and SPSS 21.0 software was utilized for statistical analysis. The Mann-Whitney test（U test） was employed to compare the longitudinal dose levels from the chest to the pelvis in the human torso on both the left and right sides of the radiation field. Results The highest out-of-field doses were observed in organs adjacent to the radiation field. The mean doses to the left and right gonads were 723.00 mGy（12.05% of the target dose），and the mean bladder dose was 409.00 mGy（6.82%）. The liver received a dose of 46.40 mGy（0.77%）. In contrast，doses to remote organs were considerably lower than that of above，with mean left and right breast doses of 10.20 mGy（0.17%） and 11.01 mGy（0.18%），respectively. There was no statistically significant difference in the distribution between the left and right sides dose（Z=1.132，P>0.05）. Conclusion Radiation exposure of out-of-field tissues during radiotherapy is inevitable and non-negligible. Doses to organs close to the target-field may approach thresholds for radiation-induced damage. Therefore，individualized protection strategies should be implemented in clinical practice to minimize out-of-field exposure and associated radiation risks.

Key words: Radiotherapy, Out-of-field tissues, Patient absorbed dose, Radiation protection, Anthropomorphic phantom, Linear accelerator

CLC Number:

R148

JIANG Wenwen, GU Haoyan, YU Runqiu, FENG Zechen, WANG Hongfang, MA Yongzhong. Measurement and analysis of out-of-field tissue dose under typical accelerator radiotherapy conditions. [J]OCCUPATION AND HEALTH, 2026, 42(1): 17-21.

Figures/Tables 6

References 25

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序号	编号	模体TLD探测位置与照射野边缘水平距离（cm）	模体TLD探测位置对应的体表位置	吸收剂量（mGy）	关注点剂量与照射野中心剂量的比率（%）
1	R-01	20	右乳腺外侧	10.15	0.17
2	R-02	20	右乳腺下缘	10.76	0.18
3	R-03	20	右乳腺内侧	12.11	0.20
4	L-03	20	左乳腺外侧	9.57	0.16
5	L-02	20	左乳腺下缘	9.84	0.16
6	L-01	20	左乳腺内侧	11.20	0.19
7	2301	7	肝脏	46.40	0.77
8	2302	7	胃与肠道	33.83	0.56
9	2303	7	胃与肠道	41.43	0.69
10	2304	7	腹部浅层组织右侧	44.16	0.74
11	2305	7	腹部浅层组织中央	44.21	0.74
12	2306	7	腹部浅层组织左侧	40.08	0.67
13	3201	1	右侧性腺	803.10	13.39
14	3202	1	子宫	628.38	10.47
15	3203	1	左侧性腺	642.06	10.70
16	3204	1	膀胱右侧	427.80	7.13
17	3205	1	膀胱中部	474.96	7.92
18	3206	1	膀胱左侧	323.28	5.39

序号	编号	模体TLD探测位置与照射野边缘水平距离（cm）	模体TLD探测位置对应的体表位置	吸收剂量（mGy）	关注点剂量与照射野中心剂量的比率（%）
1	R-01	20	右乳腺外侧	10.15	0.17
2	R-02	20	右乳腺下缘	10.76	0.18
3	R-03	20	右乳腺内侧	12.11	0.20
4	L-03	20	左乳腺外侧	9.57	0.16
5	L-02	20	左乳腺下缘	9.84	0.16
6	L-01	20	左乳腺内侧	11.20	0.19
7	2301	7	肝脏	46.40	0.77
8	2302	7	胃与肠道	33.83	0.56
9	2303	7	胃与肠道	41.43	0.69
10	2304	7	腹部浅层组织右侧	44.16	0.74
11	2305	7	腹部浅层组织中央	44.21	0.74
12	2306	7	腹部浅层组织左侧	40.08	0.67
13	3201	1	右侧性腺	803.10	13.39
14	3202	1	子宫	628.38	10.47
15	3203	1	左侧性腺	642.06	10.70
16	3204	1	膀胱右侧	427.80	7.13
17	3205	1	膀胱中部	474.96	7.92
18	3206	1	膀胱左侧	323.28	5.39