Development of Scintillators in Nuclear Medicine

Abstract

High-quality image is necessary for accurate diagnosis in nuclear medicine. There are many factors in creating a good image and detector is the most important one. In recent years, several detectors are studied to get a better picture. The aim of this paper is comparison of some type of these detectors such as thallium activated sodium iodide bismuth germinate cesium activated yttrium aluminum garnet (YAG: Ce) YAP: Ce “lutetium aluminum garnet activated by cerium” CRY018 “CRY019” lanthanum bromide and cadmium zinc telluride. We studied different properties of these crystals including density, energy resolution and decay times that are more important factors affecting the image quality.

Cadmium telluride semiconductor detector for improved spatial and energy resolution radioisotopic imaging

“…Commonly, the attenuation is indicated by the mass attenuation coefficient, μ/ρ, wherein ρ is the density of the substrate (g/cm 3 ). [ 5 19 ] Figure 1 shows the linear attenuation coefficients as a function of photon energy for CdTe, NaI(Tl), Ge, and Si detector materials. [ 11 ] To obtain excellent detection efficiency with a partly thin crystal, the attenuation coefficient must be sufficient.…”

“…In the detectors, gamma-ray photons caused electron-hole pairs and electrical charge drift to opposite directions using an electric field, then induce signals on electrodes, and directly create electrical current. [ 1 4 5 6 ] On the other hand, ionization detectors and ionization chambers use gas as the interested medium. Gas detectors convert absorbed photon energy into electron-ion pairs that move toward electrodes.…”

“…Furthermore, it is responsible for absorbing and detecting the high-energy photons emitted from the patient and also providing the location of the photon interaction for the photomultiplier tube (PMT) circuit. [ 1 5 ]…”

“…[ 1 5 9 ] However, it has some limitations such as low-energy resolution, low intrinsic spatial resolution, and hygroscopic. [ 5 10 11 ] The low intrinsic spatial resolution is confined by its low density (3.76 g/cm 3 )[ 10 12 13 14 ] and low-energy resolution related to the abundant PMTs needed for the positioning circuit. Due to the large and massive scheme of the conventional camera, it is generally difficult to position it as near the organ and to obtain the appropriate view.…”

Radio-adaptive response in myocardial perfusion imaging induced by technetium-99m

“…Nuclear medicine includes both therapeutic and diagnostic modalities, and it provides physiological and functional information to assess therapeutic response and to determine the drug dosage in the body. [ 1 ] One of the applications of nuclear medicine is in the cardiovascular system. Myocardial perfusion imaging (MPI) is a noninvasive diagnostic procedure for coronary artery disease assessment.…”