GAMMA SPECTROMETERS IN NUCLEAR MEDICINE

Аннотация

This manuscript discusses the application of radiometry in radiation medicine, focusing on the diverse detectors employed in detecting radiation. The advantages of high- pressure xenon gamma spectrometers developed by MEPhI researchers are highlighted, demonstrating their potential superiority in nuclear medicine applications. Keywords: Gamma spectrometers, radiation medicine, xenon gamma spectrometers, energy resolution. In nuclear medicine, radiometry methods are utilized to measure the intensity of ionizing radiation traversing a patient's body, discern its energy spectrum, and generate a dynamic three- dimensional image. Radionuclide medicine employs radiometry for tasks such as qualitative and quantitative analyses of radionuclides either in a sample (in vitro) or within the patient's body (in vivo). This includes monitoring shifts in the quality and quantity of radiopharmaceuticals during certain medical processes, mapping a three-dimensional radiation field around the patient, and 29 pinpointing the coordinates of radiation sources in the body at specific moments. Such reconstructions aim to base diagnoses on the resultant images. In radiation and nuclear medicine, an array of detectors is utilized for diverse applications. Among these are ionization chambers, proportional counters, Geiger-Muller counters, scintillation counters, Cherenkov counters, and other specialized detectors. Each type of detector is tailored to detect specific radiation types, including α and β particles, X-rays, γ radiation, neutrons, protons, and other forms of radiation, across a wide energy spectrum. The choice of detector depends on factors such as the radiation type, energy range, sensitivity, and spatial resolution required for a particular application. Advancements in detector technology continue to enhance their capabilities and expand their utility in radiation detection and measurement across various fields of science and medicine. Detector requirements encompass particle identification and discernment of its kinematic attributes (like energy and momentum) and its generation rate. Essential detector attributes include efficiency (probability of registering a particle upon impact), temporal resolution (minimum time for distinguishing two particles), and recovery time (duration post-registration when the detector cannot record another particle or has compromised functionality). If the energy and/or coordinates of a particle are determined by the detector, it's further characterized by energy and spatial resolution. Currently, the following detectors are predominantly used for registering gamma radiation in the energy range of (0.01 - 5) MeV: scintillators, HPGe-based semiconductor detectors requiring cooling, semiconductor detectors without cooling, and detectors filled with inert gases. The choice is influenced by the experiment's objective and conditions, considering spectrometer parameters like energy resolution, efficiency, stability, and adaptability to various conditions [2]. The xenon gamma spectrometers developed by the National Research Nuclear University MEPhI. The spectrometer boasts a 1.7 % energy resolution for a 662 keV γ-ray, notably superior to NaI or CsI-based scintillation gamma detectors. This xenon-based spectrometer can measure γ-rays in an energy spectrum from 0.05 to 3 MeV [3]. Scintillation gamma spectrometers are prevalently employed in nuclear medicine, despite their limited energy resolution. Semiconductor gamma spectrometers, while offering better energy resolution, are less convenient due to their cooling requirements. Compressed xenon gamma spectrometers now deliver room-temperature energy resolution far superior to NaI(Tl), and their ionization energy ensures stability across a wide temperature spectrum. These detectors, immune to issues linked with crystallographic defects, including radiation damage, can adopt diverse geometries. The high-pressure xenon gamma spectrometer, developed by MEPhI researchers, outperforms other spectrometers in efficiency and energy resolution and can be custom-sized. In a spectrum of energy resolutions for gamma spectrometers, the high-pressure xenon variant sits between semiconductor and scintillation spectrometers. Conclusion. While scintillation spectrometers have been the standard in nuclear medicine, the xenon gamma spectrometer presents a compelling alternative due to its superior performance characteristics. With higher energy resolution, improved efficiency, and greater reliability, xenon gamma spectrometers offer enhanced capabilities for precise and reliable data collection in various nuclear medicine applications. As technology continues to advance, the adoption of xenon gamma spectrometers is poised to play a significant role in advancing research and clinical practice in nuclear medicine.