The impact of NaI(Tl) crystal hydration on gamma camera spectral response and image uniformity.
Gespeichert in:
| Titel: | The impact of NaI(Tl) crystal hydration on gamma camera spectral response and image uniformity. |
|---|---|
| Autoren: | Eliason G; Department of Radiology, University of Colorado School of Medicine, Aurora, Colarado, USA., Silosky MS; Department of Radiology, University of Colorado School of Medicine, Aurora, Colarado, USA. |
| Quelle: | Journal of applied clinical medical physics [J Appl Clin Med Phys] 2025 Sep; Vol. 26 (9), pp. e70218. |
| Publikationsart: | Journal Article |
| Sprache: | English |
| Info zur Zeitschrift: | Publisher: Wiley on behalf of American Association of Physicists in Medicine Country of Publication: United States NLM ID: 101089176 Publication Model: Print Cited Medium: Internet ISSN: 1526-9914 (Electronic) Linking ISSN: 15269914 NLM ISO Abbreviation: J Appl Clin Med Phys Subsets: MEDLINE |
| Imprint Name(s): | Publication: 2017- : Malden, MA : Wiley on behalf of American Association of Physicists in Medicine Original Publication: Reston, VA : American College of Medical Physics, c2000- |
| MeSH-Schlagworte: | Gamma Cameras* , Sodium Iodide*/chemistry , Thallium*/chemistry , Water*/chemistry , Image Processing, Computer-Assisted*/methods , Phantoms, Imaging* , Radionuclide Imaging*/methods , Radionuclide Imaging*/instrumentation, Humans ; Iodides ; Sodium |
| Abstract: | Background: NaI(Tl) scintillators used in most gamma cameras are hermetically sealed to prevent the absorption of water molecules from the surrounding environment. If this seal is compromised, crystal hydration, a localized defect resulting in non-uniform attenuation of scintillation photons, may occur. Purpose: The purpose of this study was to evaluate the effects of crystal hydration across multiple radionuclides, characterizing the impact on spectral response and image uniformity. Methods: Hydration was assessed using on-peak and off-peak imaging for several radionuclides. The progression of hydration was assessed by calculating the contrast-to-noise ratio in hydrated regions on monthly uniformity maps. Spectra were captured for both hydrated and non-hydrated regions of the detector to determine photopeak energy and energy resolution. Results: The visual appearance of the hydration effect in off-peak images was greatest for 133 Xe. The effect was more substantial in the 10% low off-peak image than in the 10% high off-peak image. Hydration was not observed in on-peak images for either 133 Xe or 99m Tc and was only barely visible for 131 I. CNR measurements show a slow but notable progression of hydration in uniformity maps over time. The measured photopeak in hydrated regions was lower than that of non-hydrated regions. Hydration also resulted in a degradation in energy resolution with the effect being more significant at lower energies. Conclusions: Hydrated regions of the detector demonstrated an energy-dependent degradation in energy resolution which corresponded to an energy dependence in the detectability of hydration in off-peak images. Monthly updates to the uniformity correction maps were able to adequately account for hydration. When hydration has been identified, routine evaluation of its impact on uniformity maps may provide a convenient method of tracking progression. (© 2025 The Author(s). Journal of Applied Clinical Medical Physics published by Wiley Periodicals, LLC on behalf of The American Association of Physicists in Medicine.) |
| References: | Radiology. 1986 Mar;158(3):823-6. (PMID: 3945758) J Appl Clin Med Phys. 2025 Sep;26(9):e70218. (PMID: 40841187) |
| Contributed Indexing: | Keywords: NaI(Tl); QC; gamma camera; hydration; nuclear medicine |
| Substance Nomenclature: | F5WR8N145C (Sodium Iodide) AD84R52XLF (Thallium) 059QF0KO0R (Water) 0 (thallium-doped sodium iodide) 0 (Iodides) 9NEZ333N27 (Sodium) |
| Entry Date(s): | Date Created: 20250821 Date Completed: 20250821 Latest Revision: 20250825 |
| Update Code: | 20250903 |
| PubMed Central ID: | PMC12370380 |
| DOI: | 10.1002/acm2.70218 |
| PMID: | 40841187 |
| Datenbank: | MEDLINE |
Full Text 
Full Text Finder 
Nájsť tento článok vo Web of Science | Abstract: | Background: NaI(Tl) scintillators used in most gamma cameras are hermetically sealed to prevent the absorption of water molecules from the surrounding environment. If this seal is compromised, crystal hydration, a localized defect resulting in non-uniform attenuation of scintillation photons, may occur.<br />Purpose: The purpose of this study was to evaluate the effects of crystal hydration across multiple radionuclides, characterizing the impact on spectral response and image uniformity.<br />Methods: Hydration was assessed using on-peak and off-peak imaging for several radionuclides. The progression of hydration was assessed by calculating the contrast-to-noise ratio in hydrated regions on monthly uniformity maps. Spectra were captured for both hydrated and non-hydrated regions of the detector to determine photopeak energy and energy resolution.<br />Results: The visual appearance of the hydration effect in off-peak images was greatest for <sup>133</sup> Xe. The effect was more substantial in the 10% low off-peak image than in the 10% high off-peak image. Hydration was not observed in on-peak images for either <sup>133</sup> Xe or <sup>99m</sup> Tc and was only barely visible for <sup>131</sup> I. CNR measurements show a slow but notable progression of hydration in uniformity maps over time. The measured photopeak in hydrated regions was lower than that of non-hydrated regions. Hydration also resulted in a degradation in energy resolution with the effect being more significant at lower energies.<br />Conclusions: Hydrated regions of the detector demonstrated an energy-dependent degradation in energy resolution which corresponded to an energy dependence in the detectability of hydration in off-peak images. Monthly updates to the uniformity correction maps were able to adequately account for hydration. When hydration has been identified, routine evaluation of its impact on uniformity maps may provide a convenient method of tracking progression.<br /> (© 2025 The Author(s). Journal of Applied Clinical Medical Physics published by Wiley Periodicals, LLC on behalf of The American Association of Physicists in Medicine.) |
|---|---|
| ISSN: | 1526-9914 |
| DOI: | 10.1002/acm2.70218 |