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Abstract：
OBJECTIVE: To evaluate set-up error for head and neck cancer (HNC) patients according to each neck lymph node (LN) level. And clinical factors affecting set-up error were analyzed.
METHODS: Reference points (RP1, RP2, RP3, and RP4) representing neck LN levels I to IV were designated. These RP were contoured on simulation computed tomography (CT) and cone-beam CT of 89 HNC patients with the same standard. After image registration was performed, movement of each RP was measured. Univariable logistic regression analyses were performed to analyze clinical factors related to measured movements.
RESULTS: The mean value of deviation of all axes was 1.6 mm, 1.3 mm, 1.8 mm, and 1.5 mm for RP1, RP2, RP3, and RP4, respectively. Deviation was over 3 mm in 24 patients. Movement of more than 3 mm was observed only in RP1 and RP3. In RP1, it was related to bite block use. Movement exceeding 3 mm was most frequently observed in RP3. Primary tumor and metastatic LN volume change were clinical factors related to the RP3 movement.
CONCLUSIONS: Planning target volume margin of 4 mm for neck LN level I, 3 mm for neck LN level II, 5 mm for neck LN level III, and 3 mm for neck LN level IV was required to include all movements of each LN level. In patients using bite block, changes in primary tumor volume, and metastatic LN volume were related to significant movement.
METHODS: Reference points (RP1, RP2, RP3, and RP4) representing neck LN levels I to IV were designated. These RP were contoured on simulation computed tomography (CT) and cone-beam CT of 89 HNC patients with the same standard. After image registration was performed, movement of each RP was measured. Univariable logistic regression analyses were performed to analyze clinical factors related to measured movements.
RESULTS: The mean value of deviation of all axes was 1.6 mm, 1.3 mm, 1.8 mm, and 1.5 mm for RP1, RP2, RP3, and RP4, respectively. Deviation was over 3 mm in 24 patients. Movement of more than 3 mm was observed only in RP1 and RP3. In RP1, it was related to bite block use. Movement exceeding 3 mm was most frequently observed in RP3. Primary tumor and metastatic LN volume change were clinical factors related to the RP3 movement.
CONCLUSIONS: Planning target volume margin of 4 mm for neck LN level I, 3 mm for neck LN level II, 5 mm for neck LN level III, and 3 mm for neck LN level IV was required to include all movements of each LN level. In patients using bite block, changes in primary tumor volume, and metastatic LN volume were related to significant movement.
摘要：
目的：根据每个颈部淋巴结（LN）水平评估头颈部癌（HNC）患者的设置误差。并对影响设置误差的临床因素进行分析。
方法:指定代表颈部LN水平I至IV的参考点(RP1、RP2、RP3和RP4)。这些RP在具有相同标准的89例HNC患者的模拟计算机断层扫描（CT）和锥形束CT上进行了轮廓化。进行图像配准后，测量每个RP的运动。进行单变量逻辑回归分析以分析与测量运动相关的临床因素。
结果：所有轴的偏差平均值为1.6mm，1.3mm,1.8mm,RP1、RP2、RP3和RP4分别为1.5mm。24例患者的偏差超过3mm。仅在RP1和RP3中观察到超过3mm的移动。在RP1中，它与咬合块的使用有关。在RP3中最常见的是超过3mm的运动。原发肿瘤和转移性LN体积变更是与RP3运动有关的临床身分。
结论：为I级颈部LN规划4mm的目标体积余量，颈部LNII级为3mm,颈部LNIII级为5mm,对于颈部LNIV级，需要3mm，以包括每个LN级的所有运动。在使用咬合块的患者中，原发性肿瘤体积的变化，转移性LN体积与显著运动有关。
方法:指定代表颈部LN水平I至IV的参考点(RP1、RP2、RP3和RP4)。这些RP在具有相同标准的89例HNC患者的模拟计算机断层扫描（CT）和锥形束CT上进行了轮廓化。进行图像配准后，测量每个RP的运动。进行单变量逻辑回归分析以分析与测量运动相关的临床因素。
结果：所有轴的偏差平均值为1.6mm，1.3mm,1.8mm,RP1、RP2、RP3和RP4分别为1.5mm。24例患者的偏差超过3mm。仅在RP1和RP3中观察到超过3mm的移动。在RP1中，它与咬合块的使用有关。在RP3中最常见的是超过3mm的运动。原发肿瘤和转移性LN体积变更是与RP3运动有关的临床身分。
结论：为I级颈部LN规划4mm的目标体积余量，颈部LNII级为3mm,颈部LNIII级为5mm,对于颈部LNIV级，需要3mm，以包括每个LN级的所有运动。在使用咬合块的患者中，原发性肿瘤体积的变化，转移性LN体积与显著运动有关。
