Development of a new dosimetry technique

Abstract: In order to minimize the damage inflicted in healthy tissue during radiotherapy, it is vital to verify the dose absorbed by the patient. A common approach is the use of dosimetry gels in which local radiolysis processes are induced through radiation. As the subsequent read-out using Magnetic Resonance Imaging techniques is time-consuming, the here presented thesis investigates a new approach based on light scattering to determine the absorbed dose. More precisely, a laser sheet with sinusoidal intensity modulation is employed to scan the dosimetry gel slice-wise and scattered light is detected at a 90 degree angle which allows the determination of the local extinction coefficient in the sample. The idea is to relate the local extinction coefficient to the absorbed dose. In order to achieve this task, a setup for the data acquisition is built and the algorithm necessary for the calculation is written. Based upon first measurements investigating the applicability of the new approach, one can state that the new technique is of great potential as it allows the visualization of the irradiation structures with high resolution.