Zaragoza Francisco J, Eichmann Marion, Flühs Dirk, Sauerwein Wolfgang, Brualla Lorenzo
NCTeam, Strahlenklinik, Universitätsklinikum Essen, Essen, Germany.
Fakultät Physik, Technische Universität Dortmund, Dortmund, Germany.
Ocul Oncol Pathol. 2017 Sep;3(3):204-209. doi: 10.1159/000456717. Epub 2017 Feb 23.
The distribution of the emitter substance in Ru eye plaques is usually assumed to be homogeneous for treatment planning purposes. However, this distribution is never homogeneous, and it widely differs from plaque to plaque due to manufacturing factors.
By Monte Carlo simulation of radiation transport, we study the absorbed dose distribution obtained from the specific CCA1364 and CCB1256 Ru plaques, whose actual emitter distributions were measured. The idealized, homogeneous CCA and CCB plaques are also simulated.
The largest discrepancy in depth dose distribution observed between the heterogeneous and the homogeneous plaques was 7.9 and 23.7% for the CCA and CCB plaques, respectively. In terms of isodose lines, the line referring to 100% of the reference dose penetrates 0.2 and 1.8 mm deeper in the case of heterogeneous CCA and CCB plaques, respectively, with respect to the homogeneous counterpart.
The observed differences in absorbed dose distributions obtained from heterogeneous and homogeneous plaques are clinically irrelevant if the plaques are used with a lateral safety margin of at least 2 mm. However, these differences may be relevant if the plaques are used in eccentric positioning.
出于治疗计划的目的，通常假定钌眼贴片中发射体物质的分布是均匀的。然而，这种分布并非均匀，并且由于制造因素，不同贴片之间差异很大。
通过辐射传输的蒙特卡罗模拟，我们研究了从特定的CCA1364和CCB1256钌贴片中获得的吸收剂量分布，这些贴片的实际发射体分布已被测量。还模拟了理想化的均匀CCA和CCB贴片。
对于CCA和CCB贴片，非均匀贴片和均匀贴片之间观察到的深度剂量分布的最大差异分别为7.9%和23.7%。就等剂量线而言，相对于均匀贴片，在非均匀CCA和CCB贴片的情况下，代表参考剂量100%的等剂量线分别深入0.2毫米和1.8毫米。
如果贴片使用至少2毫米的侧向安全裕度，则从非均匀贴片和均匀贴片中获得的吸收剂量分布的观察差异在临床上无关紧要。然而，如果贴片用于偏心定位，这些差异可能是相关的。
