Eisenlohr H H, Jayaraman S
Phys Med Biol. 1977 Jan;22(1):18-28. doi: 10.1088/0031-9155/22/1/003.
The IAEA-WHO postal dose comparison service for cobalt-60 teletherapy dosimetry is an ongoing programme aimed at improving dosimetric accuracy in IAEA-WHO Member States. LiF dosemeters were irradiated under specified conditions in a water phantom at the participating radiotherapy centres and returned to the IAEA's Dosimetry Labotatory for evaluation. The participants filled in a data sheet giving numerical values of physical factors (such as per cent depth dose, tissue-air ratio, etc.) that they employed. Nearly 65% of the comparisons showed deviations within +/- 5%, a figure which is believed to represent the overall uncertainty of the method itself. Almost 10% of the measurements deviated more than +/- 15%. It appears that participants applying 'in phantom' output measurements have better control over the dose they administer. Many of the errors observed are due to the use of faulty values for the various physical factors employed, and to the fact that often a check of the output just before the irradiation of the LiF dosemeters was not carried out.
国际原子能机构-世界卫生组织关于钴-60远距离治疗剂量测定的邮政剂量比较服务是一项正在进行的计划，旨在提高国际原子能机构-世界卫生组织成员国的剂量测定准确性。氟化锂剂量计在参与的放射治疗中心的水模体中按照特定条件进行照射，然后送回国际原子能机构剂量测定实验室进行评估。参与者填写一份数据表，给出他们所采用的物理因素（如百分深度剂量、组织空气比等）的数值。近65%的比较显示偏差在±5%以内，这个数字被认为代表了该方法本身的总体不确定性。近10%的测量偏差超过±15%。似乎采用“模体内”输出测量的参与者对他们给予的剂量有更好的控制。观察到的许多误差是由于对所采用的各种物理因素使用了错误的值，以及在照射氟化锂剂量计之前经常没有对输出进行检查。
