Cros Maria, Joemai Raoul M S, Geleijns Jacob, Molina Diego, Salvadó Marçal
Faculty of Medicine and Health Sciences, Universitat Rovira i Virgili, C/Sant Llorenç 21, 43201 Reus, Spain.
Phys Med Biol. 2017 Jul 17;62(15):6304-6321. doi: 10.1088/1361-6560/aa77ea.
This study aims to develop and test software for assessing and reporting doses for standard patients undergoing computed tomography (CT) examinations in a 320 detector-row cone-beam scanner. The software, called SimDoseCT, is based on the Monte Carlo (MC) simulation code, which was developed to calculate organ doses and effective doses in ICRP anthropomorphic adult reference computational phantoms for acquisitions with the Aquilion ONE CT scanner (Toshiba). MC simulation was validated by comparing CTDI measurements within standard CT dose phantoms with results from simulation under the same conditions. SimDoseCT consists of a graphical user interface connected to a MySQL database, which contains the look-up-tables that were generated with MC simulations for volumetric acquisitions at different scan positions along the phantom using any tube voltage, bow tie filter, focal spot and nine different beam widths. Two different methods were developed to estimate organ doses and effective doses from acquisitions using other available beam widths in the scanner. A correction factor was used to estimate doses in helical acquisitions. Hence, the user can select any available protocol in the Aquilion ONE scanner for a standard adult male or female and obtain the dose results through the software interface. Agreement within 9% between CTDI measurements and simulations allowed the validation of the MC program. Additionally, the algorithm for dose reporting in SimDoseCT was validated by comparing dose results from this tool with those obtained from MC simulations for three volumetric acquisitions (head, thorax and abdomen). The comparison was repeated using eight different collimations and also for another collimation in a helical abdomen examination. The results showed differences of 0.1 mSv or less for absolute dose in most organs and also in the effective dose calculation. The software provides a suitable tool for dose assessment in standard adult patients undergoing CT examinations in a 320 detector-row cone-beam scanner.
本研究旨在开发并测试一款软件，用于评估和报告在320排探测器锥形束扫描仪中接受计算机断层扫描（CT）检查的标准患者的剂量。这款名为SimDoseCT的软件基于蒙特卡罗（MC）模拟代码，该代码是为在使用Aquilion ONE CT扫描仪（东芝）进行采集时，计算国际辐射防护委员会（ICRP）成人参考计算体模中的器官剂量和有效剂量而开发的。通过将标准CT剂量体模内的CTDI测量值与相同条件下的模拟结果进行比较，对MC模拟进行了验证。SimDoseCT由一个连接到MySQL数据库的图形用户界面组成，该数据库包含通过MC模拟生成的查找表，这些查找表用于在体模上沿不同扫描位置进行容积采集时，使用任何管电压、蝴蝶结滤波器、焦点和九种不同束宽的情况。开发了两种不同的方法，用于根据扫描仪中其他可用束宽的采集来估计器官剂量和有效剂量。使用校正因子来估计螺旋扫描中的剂量。因此，用户可以为标准成年男性或女性选择Aquilion ONE扫描仪中的任何可用协议，并通过软件界面获得剂量结果。CTDI测量值与模拟值之间9%以内的一致性允许对MC程序进行验证。此外，通过将该工具的剂量结果与MC模拟针对三次容积采集（头部、胸部和腹部）获得的结果进行比较，对SimDoseCT中的剂量报告算法进行了验证。使用八种不同的准直进行了比较，并且在螺旋腹部检查中针对另一种准直也进行了比较。结果表明大多数器官的绝对剂量以及有效剂量计算中的差异在0.1 mSv或更小。该软件为在320排探测器锥形束扫描仪中接受CT检查的标准成年患者提供了一种合适的剂量评估工具。
