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Beta and Alpha Particle Autoradiography
Published in Michael Ljungberg, Handbook of Nuclear Medicine and Molecular Imaging for Physicists, 2022
Anders Örbom, Brian W. Miller, Tom Bäck
The basic principle of scintillation is that ionizing radiation is converted to photons in the visible or at least imageable spectrum. This occurs by electrons in the scintillator material getting excited by interaction with ionizing radiation and, then, when they are de-excited, the excess energy is emitted as photons. The photons can then be imaged with, for example, a charge-coupled device (CCD) allowing for real-time registration and display of the data.
Scintillation Fiber Optic Dosimetry
Published in Arash Darafsheh, Radiation Therapy Dosimetry: A Practical Handbook, 2021
Scintillators are insulators with wide energy gap between their valence and conduction band. Based on their chemical composition, the scintillators can be divided into two broad categories: organic and inorganic. Main advantage of organic scintillators over inorganic scintillators for radiation therapy dosimetry is that the former has almost water equivalent properties that helps avoid complicated dose calibration process during scintillation dosimetry.
Positron Emission Tomography Imaging Systems And Applications
Published in Bhagwat D. Ahluwalia, Tomographic Methods in Nuclear Medicine: Physical Principles, Instruments, and Clinical Applications, 2020
The detectors are the heart of the positron camera system. Various types of scintillator materials are used. A detector assembly consists of scintillator, photomultiplier tube, and amplifier. The scintillator converts the annihilation gamma radiation into light while the photomultiplier tube changes the light energy into electrons. Signal gain is provided in the photomultiplier tube and the amplifier.
Prostate-specific membrane antigen-directed imaging and radioguided surgery with single-photon emission computed tomography: state of the art and future outlook
Published in Expert Review of Medical Devices, 2022
Luca Filippi, Barbara Palumbo, Viviana Frantellizzi, Susanna Nuvoli, Giuseppe De Vincentis, Angela Spanu, Orazio Schillaci
As the present paper is focused on gamma-emitting PSMA-targeting tracers, we briefly describe the main characteristics of the two types of handheld devices employed as gamma-probes: the scintillation and the semiconductor-ionization detectors [28]. Scintillation probes are made up of some components: scintillation crystal – most commonly, thallium-activated sodium iodide/NaI(Tl) -, a light guide, a photomultiplier tube (PMT) and associated electronic: incident photon is absorbed by the scintillator crystal, producing visible light that, in its turn, is converted into electric pulse by the PMT. In the semiconductor-ionization detector-based probes, the main components are: semiconductor crystal, a pre-amplifier and its associated electronic; in this type of gamma-probes, incident photons determine ionization in the semiconductor crystal producing free electrons that are collected as electric pulse. It is still an open debate which type of intraoperative probe (scintillation vs semiconductor ones) performs better: while semiconductor probes, in fact, are generally characterized by higher energy and spatial resolution, scintillation detectors present higher sensitivity, especially for high and medium-energy photons [29,30].
Progress in large field-of-view interventional planar scintigraphy and SPECT imaging
Published in Expert Review of Medical Devices, 2022
Martijn M.A. Dietze, Hugo W.A.M de Jong
There are two disadvantages to the hybrid detector configuration. First, the detection sensitivity for higher energy photons (e.g. those used in therapeutic applications) will be low since the flat panel detector is optimized for x-rays with a mean energy < 100 keV. This challenge may be mitigated to some extent by increasing the thickness of the scintillator material. And second, a normal flat panel detector system will generally not be able to perform photon energy measurements. The lack of energy selection and subsequent inclusion of all scattered photons in the data places additional requirements on the SPECT reconstruction. It may be taken into account in the reconstruction (e.g. by detailed model-based scatter correction) so that quantitative images are still achieved.
Evaluation of species differences in the metabolism of the selective NaV1.7 inhibitor DS-1971a, a mixed substrate of cytochrome P450 and aldehyde oxidase
Published in Xenobiotica, 2021
Daigo Asano, Takahiro Shibayama, Hideyuki Shiozawa, Shin-ichi Inoue, Tsuyoshi Shinozuka, Shinji Murata, Nobuaki Watanabe, Kouichi Yoshinari
Chromatographic separations were performed on Inertsil ODS-3 HP (150 × 4.6 mm I.D., 3 μm; GL Sciences, Inc., Tokyo, Japan) installed on an Ultra Performance LC (UPLC) system (Waters Corporation) or LC-10Avp (Shimadzu Corporation, Kyoto, Japan) equipped with a Radiomatic 625TR radioactivity detector (PerkinElmer). The mobile phase consisted of 0.1% formic acid in purified water (solvent A) and 0.1% formic acid in acetonitrile (solvent B) and the flow rate was 1 mL/min. The elution was conducted using the following gradient: 0–15 min, 15%–20% B; 15–35 min, 20%–50% B; 35–40 min, 50%–95% B; 40–45 min, 95% (constant) B; 45–45.1 min, 95%–15% B; and 45.1–50 min, 15% (constant) B. The column temperature was maintained at 40 °C and an Ultima-Flo M (PerkinElmer) was used as a scintillation cocktail for radioactivity detection. The flow rate of the scintillator for radioactivity detection was set at 3 mL/min.