Pappas E, Angelopoulos A, Kipouros P, Vlachos L, Xenofos S, Seimenis I
Nuclear and Particle Physics Section, Physics Department, University of Athens, Panepistimioupolis, Ilisia, 157 71 Athens, Greece.
Phys Med Biol. 2003 Mar 7;48(5):N65-73. doi: 10.1088/0031-9155/48/5/401.
The aim of this investigation was the evaluation of the usefulness of N-vinyl pyrrolidone argon (VIPAR) polymer gel dosimetry for relative dose measurements using the majority of types and energies of radiation beams used in clinical practice. For this reason, VIPAR polymer gels were irradiated with the following beams: 6 and 23 MV photons (maximum dose: 15 Gy) and 6, 9, 12, 15, 18 and 21 MeV electrons (90% dose: 15 Gy). Using 6 MV x-rays, a linear gel dose response was verified for doses up to 20 Gy. Assuming linearity of response for the rest of the photon and electron beams used in this study, percentage depth dose measurements were derived. For all beams used and the range of relative doses studied, a satisfying agreement was observed between percentage depth dose measurements performed using the VIPAR gel-MRI method and an ion chamber, validating the assumption that a linear gel dose response holds for all photon and electron beams studied. VIPAR gels, therefore, can be used for relative dose distribution measurements using photons or electrons of any typical energy used in external radiotherapy applications. It is also demonstrated that two-dimensional dose distribution measurements through an irradiated (9 MeV electrons, 3 cm x 3 cm cone) VIPAR gel volume can be easily obtained.
本研究的目的是评估N-乙烯基吡咯烷酮氩（VIPAR）聚合物凝胶剂量测定法在使用临床实践中大多数类型和能量的辐射束进行相对剂量测量时的实用性。因此，用以下射线束对VIPAR聚合物凝胶进行照射：6和23兆伏光子（最大剂量：15戈瑞）以及6、9、12、15、18和21兆电子伏电子（90%剂量：15戈瑞）。使用6兆伏X射线，验证了剂量高达20戈瑞时凝胶剂量响应呈线性。假设本研究中使用的其余光子束和电子束的响应呈线性，得出了百分深度剂量测量值。对于所使用的所有射线束以及所研究的相对剂量范围，观察到使用VIPAR凝胶-MRI方法和电离室进行的百分深度剂量测量之间具有令人满意的一致性，这验证了对于所有所研究的光子束和电子束凝胶剂量响应呈线性的假设。因此，VIPAR凝胶可用于使用外部放射治疗应用中任何典型能量的光子或电子进行相对剂量分布测量。还证明了通过照射的（9兆电子伏电子，3厘米×3厘米射野）VIPAR凝胶体积可以轻松获得二维剂量分布测量结果。
