Anam Choirul, Sutanto Heri, Amilia Riska, Marini Rini, Barokah Sinta Nur, Osman Noor Diyana, Dougherty Geoff
Department of Physics, Faculty of Sciences and Mathematics, Diponegoro University, Central Java, Jl. Prof Soedarto, SH Tembalang, Tembalang, Semarang, 50275, Indonesia.
Regional Public Hospital of Karawang, Jl. Galuh Mas Raya No.1, Sukaharja, Telukjambe Timur, Kabupaten Karawang 41361, West Java, Indonesia.
Phys Eng Sci Med. 2024 Dec;47(4):1525-1535. doi: 10.1007/s13246-024-01465-2. Epub 2024 Jul 31.
The aim of this study was to evaluate the point doses using a distribution of the size-specific dose estimate (SSDE) from axial CT images of in-house phantoms having diameters from 8 to 40 cm. In-house phantoms made of polyester-resin (PESR) mixed with methyl ethyl ketone peroxide (MEKP) were used. The phantoms were built with different diameter sizes of 8, 16, 24, 32, and 40 cm. The phantoms were scanned by Siemens a SOMATOM Perspective-128 slice CT scanner with constant input parameters. The point doses were interpolated from the central SSDE (SSDEc) and the peripheral SSDE (SSDEp). The SSDEc and SSDEp were calculated from the SSDE with h- and k-factors. The point doses were compared to the direct measurements using the nanoDot™ optically-stimulated luminescence dosimeter (OSLD) in dedicated holes on the phantoms. It was found that the point dose decreases as the phantom diameter increased. The doses obtained using two approaches differed by 11% on average. The highest difference was 40% and the lowest difference was < 1%. It was found that dose based on the SSDE concept tended to be higher compared to the measured dose by OSLD. Point dose estimation using the concept of SSDE distribution can be considered an alternative for accurate and simple estimation. This approach still requires improvements to increase its accuracy and its application to estimate the organ dose needs further investigation.
本研究的目的是利用直径为8至40厘米的内部体模轴向CT图像的尺寸特异性剂量估计（SSDE）分布来评估点剂量。使用了由聚酯树脂（PESR）与过氧化甲乙酮（MEKP）混合制成的内部体模。这些体模构建有8、16、24、32和40厘米的不同直径尺寸。使用西门子SOMATOM Perspective - 128层CT扫描仪以恒定输入参数对体模进行扫描。点剂量通过中央SSDE（SSDEc）和外周SSDE（SSDEp）进行插值。SSDEc和SSDEp是根据具有h因子和k因子的SSDE计算得出的。将点剂量与在体模上专门的孔中使用nanoDot™光激发发光剂量计（OSLD）进行的直接测量结果进行比较。结果发现，随着体模直径的增加，点剂量降低。两种方法获得的剂量平均相差11%。最高差值为40%，最低差值<1%。结果发现，基于SSDE概念的剂量往往高于OSLD测量的剂量。使用SSDE分布概念进行点剂量估计可被视为一种准确且简单估计的替代方法。这种方法仍需改进以提高其准确性，并且其在估计器官剂量方面的应用需要进一步研究。
