| 罗学臣,王婵,李想,等.乳腺癌深吸气屏气放疗中光学表面成像系统纠正摆位误差的适用人群的研究[J].中华放射医学与防护杂志,2026,46(6):581-586.Luo Xuechen,Wang Chan,Li Xiang,et al.Suitable patient populations of optical surface imaging for setup error correction during breast cancer radiotherapy using DIBH[J].Chin J Radiol Med Prot,2026,46(6):581-586 |
| 乳腺癌深吸气屏气放疗中光学表面成像系统纠正摆位误差的适用人群的研究 |
| Suitable patient populations of optical surface imaging for setup error correction during breast cancer radiotherapy using DIBH |
| 投稿时间：2025-08-13 |
| DOI：10.3760/cma.j.cn112271-20250813-00296 |
| 中文关键词: 乳腺癌|深吸气屏气|放疗|摆位误差 |
| 英文关键词:Breast cancer|Deep inspiration breath-hold|Radiotherapy|Setup error |
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| 中文摘要: |
| 目的 明确左乳癌患者深吸气屏气(DIBH)放疗中,应用光学表面成像(OSI)系统纠正摆位误差的适用人群。方法 回顾性选取2023年8月—2025年5月,在北京医院放疗科接受左侧乳腺癌保乳术后DIBH放疗患者53例,中位年龄47岁。按照身体质量指数(BMI)分为3组,其中肥胖组(BMI≥28 kg/m2)15例,超重组(24 kg/m2≤BMI≤27.9 kg/m2)18例,正常组(18.5 kg/m2≤BMI≤23.9 kg/m2)20例。分别记录每位患者锥形束CT(CBCT)及OSI系统测得的摆位误差E1和E2,包括平移误差x(左右)、y(头脚)、z方向(腹背)和分别以x、y、z方向为轴的旋转误差Rx 、Ry、 Rz,OSI测得的误差不用于实际摆位校正。分析CBCT和OSI两套系统摆位误差的相关性,计算平移方向的Er误差,比较每组患者平移方向<E1和Er的差异,进一步将E1和Er分别代入原计划等中心,形成再计划E1和再计划Er,比较3组患者两种再计划靶区(PTV)和重要危及器官的剂量学差异,评价参数包括PTV的V100 %、左肺V5 Gy和V20 Gy、心脏Dmean、冠状动脉左前降支Dmean、Dmax,并利用公式计算出<E1和Er的PTV外放边界(MPTV1和MPTVr)。结果 收集了CBCT和OSI相关数据各284套,3组患者E1和E2的相关性分析结果显示,肥胖组的y、Rx、Ry、Rz方向,表现为低度相关(r=0.46,0.47,0.48,0.41,P＜0.05),其余均表现为中度相关(r=0.52~0.78,P＜0.05)。E1和Er的比较中,超重组在y方向分别为(0.15±4.39)和(1.28±3.19)mm,二者相比差异具有统计学意义(t=-2.00,P＜0.05)。正常组在x方向为(-1.04±2.38)和(-0.14±2.03)mm,在y方向为(-1.68±4.28)和(-0.03±2.89)mm,二者相比差异有统计学意义(t=-3.34,-2.68,P＜0.05)。其余方向误差比较差异无统计学意义(P＞0.05)。3组患者再计划E1和再计划Er的剂量学比较显示,超重组冠状动脉左前降支Dmean为(13.36±4.77)和(10.9±3.83)Gy,Dmax为(33.15±1.43)和(29.10±7.53)Gy,二者相比差异具有统计学意义(t=3.23,2.84,P＜0.05)。正常组冠状动脉左前降支Dmean为(12.58±5.06)和(9.88±3.78)Gy,Dmax为(34.56±8.65)和(28.86±7.52)Gy,二者相比差异具有统计学意义(t=2.89,2.30,P＜0.05),其他剂量比较差异均无统计学意义(P＞0.05)。另外,经计算3组患者的MPTV1和MPTVr结果:肥胖组为5.88、9.45、6.37 mm和5.12、8.92、6.01 mm,超重组为5.23、6.95、5.73 mm和4.57、5.26、5.35 mm,正常组为5.18、6.68、5.75 mm和4.07、5.02、5.41 mm。结论 左乳癌患者接受DIBH放疗,对于体重正常或超重患者(18.5 kg/m2≤BMI≤27.9 kg/m2),OSI系统能够减小摆位误差,更好地保护危及器官,将PTV外放边界缩小至接近5 mm的范围,对于肥胖患者(BMI≥28 kg/m2),OSI系统纠正误差能力减弱,需要增加CBCT扫描频次。 |
| 英文摘要: |
| Objective To determine suitable patient populations with left-sided breast cancer for the application of optical surface imaging (OSI) to setup error correction during radiotherapy using deep inspiration breath-hold (DIBH). Methods A retrospective study was conducted on 53 patients with left-sided breast cancer who received radiotherapy using DIBH after breast-conserving surgery at the Department of Radiation Oncology of Beijing Hospital from August 2023 to May 2025. Based on their body mass index (BMI) values, these patients, with a median age of 47 years, were divided into three groups: obese group (BMI ≥ 28 kg/m2, n = 15), overweight group (24 kg/m2 ≤ BMI ≤ 27.9 kg/m2, n = 18), and normal-weight group (18.5 kg/m2 ≤ BMI ≤ 23.9 kg/m2, n = 20). For each patient, setup errors measured using the cone-beam computed tomography (CBCT) and OSI systems were recorded, denoted as E1 and E2, respectively. These errors included translational errors in the left-right (x), superior-inferior (y), and anterior-posterior (z) directions and rotational errors around the x, y, and z axes (Rx, Ry, Rz). The E2 errors were not applied to actual error correction. The correlation between the E1 and E2 errors was analyzed, followed by the calculation of their differences (Er = E1-E2) in translational directions. Differences between E1 and Er errors in translational directions were then compared for each group. Subsequently, E1 and Er were separately substituted into the isocenters of the original plans, generating re-planned E1 and Er. Dosimetric differences of planning target volumes (PTVs) and key organs at risk (OARs) between re-planned E1 and Er were compared across the three groups. The evaluation parameters included the V100 % of PTVs, the V5 Gy and V20 Gy of the left lung, the mean dose (Dmean) to the heart, and the Dmean and maximum dose (Dmax) to the left anterior descending (LAD) artery. Finally, using a margin formula, the PTV margins were calculated based on E1 and Er errors, denoted as MPTV1 and MPTVr, respectively. Results A total of 284 datasets of setup errors measured using CBCT and OSI each were collected. The correlations between E1 and E2 errors reveal that the obese group exhibited low correlations in the y, Rx, Ry, and Rz directions (r = 0.46, 0.47, 0.48, 0.41, P < 0.05), while other groups exhibited moderate correlations in other directions (r = 0.52-0.78, P < 0.05). The comparison between E1 and Er errors indicated that the overweight group showed statistically significant differences in the y direction ［(0.15 ±4.39)mm vs. (1.28 ±3.19) mm, t = -2.00, P < 0.05］; the normal-weight group exhibited statistically significant differences in both the x direction ［(-1.04 ±2.38)mm vs. (-0.14 ±2.03) mm, t = -3.34, P< 0.05］ and the y direction ［(-1.68 ±4.28) mm vs. (-0.03 ±2.89) mm, t = -2.68, P< 0.05), while minimal statistically significant differences were observed in other directions (P > 0.05). Dosimetric comparison between re-planned E1 and Er indicated that the overweight group displayed significant differences in both Dmean ［(13.36 ±4.77)Gy vs. (10.9 ±3.83) Gy］ and Dmax ［(33.15±1.43)Gy vs. (29.10±7.53) Gy］ to the LAD artery (t = 3.23, 2.48, P < 0.05). The normal-weight group showed statistically significant differences in both Dmean ［(12.58 ±5.06)Gy vs. (9.88 ±3.78) Gy］ and Dmax ［(34.56 ±8.65)Gy vs. (28.86 ±7.52) Gy］ to the LAD artery (t = 2.89, 2.30, P < 0.05), while no statistically significant differences were observed in other dosimetric parameters (P > 0.05). Additiontionally, the calculated MPTV1 and MPTVr in x, y, and z directions of the obsess group were 5.88, 9.45, 6.37 mm and 5.12, 8.92, 6.01 mm, respectively. While those of the overweight group were 5.23, 6.95, 5.73 mm and 4.57, 5.26, 5.35 mm, respectively, and those of the normal-weight group were 5.18, 6.68, 5.75 mm and 4.07, 5.02, 5.41 mm, respectively. Conclusions Among the left-sided breast cancer patients treated with radiotherapy using DIBH, those with normal weight or overweight (18.5 kg/m2 ≤ BMI ≤ 27.9 kg/m2) are suitable populations for OSI. For these patients, OSI can reduce their setup errors, effectively protect their OARs, and reduce PTV margins to approximately 5 mm. In contrast, for obese patients (BMI ≥ 28 kg/m2), OSI exhibits a diminished capacity for setup error correction, necessitating an increased frequency of CBCT scans. |
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