摘要
目的测量并比较分析鼻咽癌两种固定方式的摆位误差,并确定其计划靶区(planning target volume,PTV)外放边界。方法 73例鼻咽癌患者采用头枕+头颈肩热塑面罩固定35例和发泡胶+头颈肩热塑面罩固定38例均实施调强放射治疗,在治疗摆位纠正前进行锥形束(cone beam computed tomography,CBCT)扫描共429次,其中头枕+头颈肩热塑面罩固定组201次,发泡胶+头颈肩热塑面罩固定组228次。将获得的CBCT图像和计划CT图像匹配,得到X、Y、Z轴方向上的平移及旋转误差,并对摆位误差进行分析。结果头枕+头颈肩热塑面罩固定组在X、Y、Z轴上的平移误差分别为(0.11±0.08)、(0.15±0.12)、(0.12±0.10)cm,旋转角度误差分别为0.59°±0.53°、0.84°±0.62°、0.61°±0.51°,外放边界分别为0.33、0.46、0.37 cm;发泡胶+头颈肩热塑面罩固定组的平移误差分别为(0.09±0.07)、(0.13±0.09)、(0.11±0.10)cm,旋转角度误差分别为0.55°±0.49°、0.69°±0.51°、0.58°±0.46°,外放边界分别为0.28、0.39、0.35 cm。采用发泡胶+头颈肩热塑面罩固定组和头枕+头颈肩热塑面罩固定组在Y轴上的平移及旋转角度误差数据差异均具有统计学意义(P<0.05)。结论采用发泡胶+头颈肩热塑面罩固定鼻咽癌患者,可减小其在Y轴(头脚)方向的平移及旋转误差。CBCT可精确地测量出摆位误差,对外放边界的确定有指导意义。
Objective To measure and evaluate the setup errors in patients with nasopharyngeal carcinoma （NPC） immobilized with two different techniques, and determine the proper margins extended from clinical target volume （CTV） to planning target volume （PTV）. Methods 73 NPC patients treated with intensity-modulated radiotherapy （IMRT） were divided into two groups. All the patients received cone beam computed tomography （CBCT） scan （429 times） and CT image matching before every treatment and correction. 35 patients were immobilized using standard plastics pillow with head-and-neck thermoplastics masks （standard plastics pillow group） and received 201 CBCT scans, 38 patients were immobilized using polyurethane foam sealing agent pillow with head-and-neck thermoplastics masks （ polyurethane foam sealing agent group） received 228 CBCT scans. The shift and rotation setup errors in fight-left （X） , superior-inferior （Y） and anterior-posterior （Z） directions were recorded and analyzed. Results In the standard plastics pillow group, the shift errors inX,Y and Z axes were （0. 11 ±0.08）cm, （0. 15 ±0. 12）cm and （0. 12 ±0. 10） em respectively, the corresponding rotation errors were 0.59° ±0.53°, 0.84° ±0.62°and 0.61°±0.51°, and the margins from CTV to PTV were 0.33 cm, 0.46 cm and 0.37 cm. In the polyurethane foam sealing agent pillow group, the shift errors in X,Y and Z axes were （0.09 ± 0.08 ）em, （0.13 ±0.09 ）cm and （0. 11 ± 0. 10 ）cm respectively, the corresponding rotation errors were 0.55° ±0.49°, 0.69° ±0.51°and 0.58° ±0.47°, and the margins from CTV to PTV were 0.28 cm, 0.39 cm andO. 35 cm. The differences of shift and rotation errors in Y axis between the two groups were statistically significant （ both P 〈0.05）. Conclusions The shift and rotation errors in Y axis can be obviously decreased by immobilization with polyurethane foam sealing agent pillow plus head-and-neck thermoplastics masks during IMRT of NPC patients. CBCT can be used in the precise measure of setup errors, which is instructive to determine the margins from CTV to PTV.
出处
《中国耳鼻咽喉颅底外科杂志》
CAS
2017年第6期550-554,共5页
Chinese Journal of Otorhinolaryngology-skull Base Surgery
关键词
鼻咽癌
发泡胶
头颈肩热塑面罩
摆位误差
外放边界
Nasopharyngeal neoplasm
Polyurethane foam
Head-and-neck thermoplastics mask
Setup error
Margin
