Roesink Judith M, Moerland Marinus A, Hoekstra Anne, Van Rijk Peter P, Terhaard Chris H J
Department of Radiotherapy, University Hospital Utrecht, University Medical Centre Utrecht, Utrecht, The Netherlands.
Int J Radiat Oncol Biol Phys. 2004 Apr 1;58(5):1451-60. doi: 10.1016/j.ijrobp.2003.09.021.
To investigate the value of scintigraphy as an indirect measurement of parotid function after radiotherapy (RT).
Ninety-six patients with primary or postoperative RT for various malignancies in the head-and-neck region were prospectively evaluated. Parotid gland scintigraphy was performed before RT and 6 weeks and 1 year after RT. The uptake, excretion fraction of the saliva from the parotid gland to the oral cavity (SEF), and the ratios of uptake and SEF after and before treatment were calculated. CT-based treatment planning was used to derive dose-volume histograms of the parotid glands. To establish the effects of both the radiation dose and the volume of the parotid gland irradiated, the normal tissue complication probability model proposed by Lyman was fit to the data.
The mean maximal uptake of 192 parotid glands decreased significantly from 3329 counts (ct)-/s before RT to 3084 ct/s and 3005 ct/s at 6 weeks and 1 year after RT. The SEF before treatment was 44.7%. The SEF decreased to 18.7% at 6 weeks after RT, but recovered to a SEF of 32.4% at 1 year after RT. A significant correlation was found between the uptake 1 year after RT and the mean parotid dose. The reduction in post-RT SEF correlated significantly with the mean parotid gland dose. The normal tissue complication probability model parameter TD50 was found to be 29 and 43 Gy at 6 weeks and 1 year after RT, respectively, when a complication was defined as a posttreatment SEF parotid ratio of <45%.
The effects of radiation on parotid gland function using scintigraphy could be well established. A statistically significant correlation between the SEF ratio and the mean parotid dose was shown, with some recovery of function at 1 year after RT, comparable with the flow results. When direct flow measurements are not feasible, parotid scintigraphy appears to be a good indicator of gland function.
探讨闪烁扫描术作为放疗（RT）后腮腺功能间接测量方法的价值。
对96例因头颈部各种恶性肿瘤接受原发或术后放疗的患者进行前瞻性评估。在放疗前、放疗后6周和1年进行腮腺闪烁扫描。计算摄取量、腮腺唾液向口腔的排泄分数（SEF）以及治疗前后摄取量和SEF的比值。采用基于CT的治疗计划得出腮腺的剂量体积直方图。为确定辐射剂量和受照射腮腺体积的影响，将Lyman提出的正常组织并发症概率模型与数据进行拟合。
192个腮腺的平均最大摄取量从放疗前的3329计数（ct）/秒显著下降至放疗后6周的3084 ct/秒和1年后的3005 ct/秒。治疗前的SEF为44.7%。放疗后6周SEF降至18.7%，但放疗后1年恢复至32.4%的SEF。放疗后1年的摄取量与腮腺平均剂量之间存在显著相关性。放疗后SEF的降低与腮腺平均剂量显著相关。当将并发症定义为治疗后腮腺SEF比值<45%时，正常组织并发症概率模型参数TD50在放疗后6周和1年分别为29 Gy和43 Gy。
利用闪烁扫描术可很好地确定辐射对腮腺功能的影响。SEF比值与腮腺平均剂量之间显示出统计学上的显著相关性，放疗后1年功能有一定恢复，与流量结果相当。当直接流量测量不可行时，腮腺闪烁扫描似乎是腺体功能的良好指标。
