Partial Volume Effect (PVE) Correction in Single Photon Emission Computed Tomography (SPECT) Imaging
Koffi N’guessan Placide Gabin Allangba,
Annick Kouame Koutouan,
Alessia Giuliano,
Zié Traoré,
Antonio Traino
Issue:
Volume 9, Issue 3, September 2023
Pages:
26-35
Received:
5 August 2023
Accepted:
23 August 2023
Published:
6 September 2023
Abstract: Quantitative analyses in Nuclear Medicine are essential, hence growing interest in algorithms that make nuclear medical data more reliable and accurate. The Partial Volume Effect (PVE) is the most important factor of loss of quantification in Nuclear Medicine, particularly for evaluation in regions of interest (ROIs) smaller than the Full Width at Half Maximum (FWHM) of the Point Spread Function (PSF) of the imaging system. This study is focused on applying a post-reconstruction correction algorithm of PVE at regional level in SPECT imaging. After a quantitative evaluation of the sigma of the PSF of the SPECT imaging system, several experimental situations have been studied using the standard IEC NEMA Body phantom, which contains six spherical inserts that mimic lesions with diameters of 10 mm, 13 mm, 17 mm, 22 mm, 28 mm, and 37 mm. They were filled with 99mTc mixed with distilled water using a sphere-to-background activity concentration ratio of 10: 1. The experimental measurements were carried out with two activity concentrations of 99mTc: 170.2 KBq/mL and 451.0 KBq/mL. The PVE correction approach has been employed in this paper to correct PVE on spherical volumes of interest (VOIs) of different sizes and to evaluate the recovery of quantitative data. Images were reconstructed using Ordered-Subset Expectation Maximization (OSEM) algorithm, applying scatter and attenuation corrections of photons, both with and without the application of the Butterworth filter. In the end, a post-reconstruction algorithm implemented with MATLAB was used. The mean difference rate between the corrected image and the raw image of the medium-sized spheres (13mm, 17mm, and 22mm) gives an improvement rate of about 70% of the PVE correction for unfiltered images at 170.2 KBq/mL. This work showed that the application of the PVE correction method recovers lost activity concentration with accuracy.
Abstract: Quantitative analyses in Nuclear Medicine are essential, hence growing interest in algorithms that make nuclear medical data more reliable and accurate. The Partial Volume Effect (PVE) is the most important factor of loss of quantification in Nuclear Medicine, particularly for evaluation in regions of interest (ROIs) smaller than the Full Width at ...
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Research Article
Assessment of Radiological Hazards in Drinking Water (Mineral Water) Consumed by the Malian Population Using Gamma Spectrometry
Adama Coulibaly*
,
Aly Ag Mohamed Dicko,
Oumou Camara
Issue:
Volume 9, Issue 3, September 2023
Pages:
36-40
Received:
3 October 2023
Accepted:
23 October 2023
Published:
9 November 2023
DOI:
10.11648/j.rst.20230903.12
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Views:
Abstract: Background: Qualitatively risk to human health is the product of the probability that contaminated water or food will be ingested and the radiological consequence or damage due to the intake. The human being activities can increase the deposition and transportation of naturally occurring radioactive materials (NORM) in the groundwater and surface water bodies. The determination of radionuclide concentration in twelve (12) drinking water in Mali, the calculation of annual effective dose due to their ingestion, the calculation of risk assessment, etc. will permit to the AMARAP to avoid any over exposition (determinist effects) and minimize as well the associated risk due to low doses (stochastic effects). Materials and Methods: The health impact due to ingestion of radionuclides from these drinking waters was evaluated by the determination of activity concentration of radionuclides U-238, Th-232 and K-40 using gamma spectrometry analysis. The concentration of gross alpha/beta counting was also evaluated and the radiological hazards were calculated in in these drinking waters. Results: The range of activity concentrations for U-238 vary from 0.24 ±0.02 to 9.42 ± 0.8 Bq/l, for Th-232 from 0.28 ± 0.02 to 5.54 ± 0.28 Bq/l and for K-40 from 0.44 ± 0.03 to 4.23± 0.23 Bq/l. The highest value of activity concentration for gross αβ radionuclides was reported in samples Emin05 (CRISTALINE) 2,4 Bq/l. The mean values of radiological hazard such as risk assessment (RA) and annual committed effective dose (AED) from this work were within the dose criteria limits given by international organizations (ICRP and UNSCEAR) and national standards. Conclusion: Based on the obtained results in this study, these drinking waters are safe for human consumption even if the risk (stochastic effect) associated with internal exposure due to low dose intakes exists. Based on obtained values, the probability of someone dying of cancer due to the ingestion of these drinking waters is less than 10-5 in the Malian population.
Abstract: Background: Qualitatively risk to human health is the product of the probability that contaminated water or food will be ingested and the radiological consequence or damage due to the intake. The human being activities can increase the deposition and transportation of naturally occurring radioactive materials (NORM) in the groundwater and surface w...
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