Simulation based conceptual design development and optimization for intraoperative gamma probe

Gamma radiation-detecting probes are portable radiation detectors used in nuclear medicine to perform radioactivity counts over the patient during surgery, aiming to locate tissues showing excessive radioactivity uptake. There are many studies in the literature about the performance parameters of gamma probes, and studies on these detection systems remain up-to-date. In cases of gamma probe usage, gamma rays emitted by the respective radioisotopes that attach to the relevant tissue/organ are counted, and different radioisotopes emit gamma rays at different energy levels. Although the performance parameters of these probes vary for different energies, gamma probes optimized for a certain energy range provide advantages in terms of counting efficiency. Due to different system components and costs, simulation methods are used for conceptual design and optimizations in both commercial and research studies. In this thesis study, optimized conceptual designs for different gamma energies were made for the gamma probe used in surgery by using Monte Carlo-based OpenGATE simulation. For this, first a standard gamma probe containing a scintillation crystal (HiSens gamma probe used at KTU Farabi hospital) was sampled. The consistency of the simulations was verified by comparing the sensitivity, angular sensitivity, lateral deviation sensitivity, energy resolution and spatial resolution parameters at 140 keV (for 99mTc) and 511 keV (for 18F) energies according to crystal sizes and comparing them with sample probe catalog data. After this verification, the optimized conceptual design in terms of probe technical parameters for different crystal depths at high gamma (511 keV) energy was revealed. Additionally, the effectiveness of this gamma probe design, designed for high energy, in the low gamma energy region was also investigated. As a result, the crystal depth of the gamma probe, which is not produced in our country but has an important role in the surgical field, was evaluated in terms of device performance parameters and the most effective gamma probe crystal depths were determined according to different radionuclide usage conditions.