Medical Physics Graduate Program, Duke University, Durham, NC 27705, USA.
Health Phys. 2012 Feb;102 Suppl 1(Suppl 1):S8-12. doi: 10.1097/HP.0b013e31823c9671.
To enable accurate and reproducible dosimetry for biological sample irradiation in a 137Cs irradiator, routine quality assurance of the dose rate and isodose distributions should be considered. Our previous work demonstrated a means for accurate dose rate quality assurance and for quality assurance of isodose distributions of non-rotational samples. This work presents a means to accurately and cost effectively measure dose distributions within a 137Cs irradiator using rotational geometry, which geometry represent a more typical use of these irradiators. A simple apparatus was developed to hold radiochromic film and was constructed of polymethyl methacrylate. The rotational quality assurance device allowed the comparison of measured radiochromic film vs. manufacturer provided isodose distributions. A good agreement was discovered between the two data sets along the central vertical axis of rotation in the 137Cs irradiator, but a 40-50% smaller 100% isodose region in the horizontal direction. These findings may lead to limiting the overall size of a sample capable of being uniformly irradiated by the 137Cs irradiator at this research institution. The authors propose the construction and use of a simple rotational quality assurance device for routine quality assurance of 137Cs irradiators.
为了在 137Cs 辐照器中实现对生物样本照射的准确和可重复剂量测定，应考虑对剂量率和等剂量分布进行常规质量保证。我们之前的工作展示了一种用于准确剂量率质量保证和非旋转样本等剂量分布质量保证的方法。本工作提出了一种使用旋转几何形状在 137Cs 辐照器内准确且具有成本效益地测量剂量分布的方法，这种几何形状代表了这些辐照器的更典型用途。开发了一种简单的装置来固定辐射色迹胶片，并由聚甲基丙烯酸甲酯制成。旋转质量保证装置允许比较测量的辐射色迹胶片与制造商提供的等剂量分布。在 137Cs 辐照器的中心垂直旋转轴上，两个数据集之间发现了很好的一致性，但在水平方向上，100%等剂量区域小了 40-50%。这些发现可能会导致限制本研究机构中能够被 137Cs 辐照器均匀照射的样本的总体尺寸。作者提出构建和使用简单的旋转质量保证装置，以对 137Cs 辐照器进行常规质量保证。
