Petrović Nina, Krestić-Vesović Jelena, Stojanović Darko, Ciraj-Bjelac Olivera, Lazarević Dorde, Kovacević Milojko
Clinical Center Kragujevac, Kragujevac, Serbia.
Radiat Prot Dosimetry. 2011 Jan;143(1):109-12. doi: 10.1093/rpd/ncq290. Epub 2010 Oct 14.
When high-energy photon beams are used for irradiation in radiotherapy, neutrons that are the result of photonuclear reactions create activation products that affect the occupational dose of radiotherapy staff. For the assessment of activation products in situ gamma spectroscopy was performed parallel to dose-rate measurements following irradiation, by using a high-energy photon beam from a linear accelerator Elekta Precise (Elekta, Stockholm, Sweden) used in radiotherapy. The major identified activation products were the following radioisotopes: (28)Al, (24)Na, (56)Mn, (54)Mn, (187)W, (64)Cu and (62)Cu. Based on the typical workload and dose-rate measurement, the assessed additional annual occupational dose ranged from 1.7 to 0.25 mSv. As the measured dose rate arising from the activation products rapidly decreases as a function of time, the assessed additional dose is negligible after 10 min following irradiation. To keep the occupational dose as low as reasonably achievable, it is recommended to delay entrance to the therapy room at least 2-4 min, when high-energy photons are used. This would reduce the effective dose by 30%.
在放射治疗中使用高能光子束进行照射时，光核反应产生的中子会生成活化产物，影响放射治疗工作人员的职业剂量。为了评估活化产物，在使用放射治疗中线性加速器Elekta Precise（瑞典斯德哥尔摩的Elekta公司）产生的高能光子束照射后，与剂量率测量同时进行了原位伽马能谱分析。识别出的主要活化产物是以下放射性同位素：铝-28、钠-24、锰-56、锰-54、钨-187、铜-64和铜-62。根据典型工作量和剂量率测量结果，评估出的额外年职业剂量范围为1.7至0.25毫希沃特。由于活化产物产生的测量剂量率会随时间迅速下降，照射后10分钟后评估出的额外剂量可忽略不计。为了将职业剂量保持在合理可行的最低水平，建议在使用高能光子时，至少延迟2至4分钟进入治疗室。这将使有效剂量降低30%。
