Viti V, d'Errico F, Pacilio M, Luciani A M, Palma A, Grande S, Ranghiasci C, Adorante N, Guidoni L, Rosi A, Ranade M, de Pasquale F, Barone P, Sebastiani G
Yale University School of Medicine, New Haven, CT 06510, USA.
Radiat Prot Dosimetry. 2006;120(1-4):148-50. doi: 10.1093/rpd/ncj005. Epub 2006 Apr 13.
Ferrous-sulphate infused gels, or 'Fricke gels', encounter great interest in the field of radiation dosimetry, due to their potential for 3D radiation dose mapping. Typically, magnetic resonance (MR) relaxation rates are determined in these systems in order to derive the absorbed dose. However, when large concentration gradients are present, diffusion effects before and during the MR imaging may not be negligible. In these cases, optical techniques may represent a viable alternative. This paper describes research aimed at measuring 3D dose distributions in a Fricke-xylenol orange gel by measuring optical density with a CCD camera. This method is inexpensive and fast. A series of early experiments is described, in which optical density profiles were measured with a commercial microdensitometer for film dosimetry. The light box of the device was modified to work at 567 nm, close to the maximum absorbance of the ferric ion-xylenol orange complex. Under these conditions, the gel shows linearity with dose and high sensitivity.
硫酸亚铁注入凝胶，即“弗里克凝胶”，因其具有三维辐射剂量映射的潜力，在辐射剂量测定领域引起了极大关注。通常，在这些系统中会测定磁共振（MR）弛豫率以得出吸收剂量。然而，当存在大浓度梯度时，MR成像之前和期间的扩散效应可能不可忽略。在这些情况下，光学技术可能是一种可行的替代方法。本文描述了旨在通过用电荷耦合器件（CCD）相机测量光密度来测量弗里克-二甲酚橙凝胶中三维剂量分布的研究。该方法成本低且速度快。描述了一系列早期实验，其中用用于胶片剂量测定的商用微密度计测量光密度分布。该设备的灯箱经过改装，可在567nm工作，接近铁离子-二甲酚橙络合物的最大吸光度。在这些条件下，凝胶显示出与剂量的线性关系和高灵敏度。
