Wieland, M. (2010). Magnetic resonance based polymer gel dosimetry [Diploma Thesis, Technische Universität Wien]. reposiTUm. https://resolver.obvsg.at/urn:nbn:at:at-ubtuw:1-30381
This work deals with normoxic polymer gels used as dosimetric verification tool in radiotherapy. Magnetic resonance imaging is used as read-out technique to generate 2D and 3D images of complex dose distributions. The intention of this work was to investigate properties of MAGIC (Methacrylic and Ascorbic Acid in Gelatin initiated by Copper) polymer gels crucial to radiotherapy dosimetry. These properties are precision, accuracy, dependence on radiation quality, dose rate, storage and handling conditions. The results showed that the dose response is independent of radiation quality and independent of dose rate up to 2.5 Gy/min in the investigated range. It was discovered that non-linearity in dose response can be avoided with extended storage time between production and irradiation of the gels. The work also includes the first investigation of the influence of systematic constituent variation on the limits of spatial resolution and edge enhancement at sub-millimeter scale. The gathered data verified the assumption that the edge enhancement effect can be reduced with increased gelatin concentration.<br />The final part of the work is the verification of an IMRT treatment plan with polymer gel dosimetry and a head phantom.