Feasibility and limitations of quantitative SPECT for 223Ra
(2020) In Physics in Medicine and Biology 65(8).- Abstract
The aim of this paper is to investigate the feasibility and limitations of activity-concentration estimation for 223Ra using SPECT. Phantom measurements are performed using spheres (volumes 5.5 mL to 26.4 mL, concentrations 1.6 kBq mL-1 to 4.5 kBq mL-1). Furthermore, SPECT projections are simulated using the SIMIND Monte Carlo program for two geometries, one similar to the physical phantom and the other being an anthropomorphic phantom with added lesions (volumes 34 mL to 100 mL, concentrations 0.5 kBq mL-1 to 4 kBq mL-1). Medium-energy and high-energy collimators, 60 projections with 55 s per projection and a 20% energy window at 82 keV are employed. For the Monte Carlo simulated... (More)
The aim of this paper is to investigate the feasibility and limitations of activity-concentration estimation for 223Ra using SPECT. Phantom measurements are performed using spheres (volumes 5.5 mL to 26.4 mL, concentrations 1.6 kBq mL-1 to 4.5 kBq mL-1). Furthermore, SPECT projections are simulated using the SIMIND Monte Carlo program for two geometries, one similar to the physical phantom and the other being an anthropomorphic phantom with added lesions (volumes 34 mL to 100 mL, concentrations 0.5 kBq mL-1 to 4 kBq mL-1). Medium-energy and high-energy collimators, 60 projections with 55 s per projection and a 20% energy window at 82 keV are employed. For the Monte Carlo simulated images, Poisson-distributed noise is added in ten noise realizations. Reconstruction is performed (OS-EM, 40 iterations, 6 subsets) employing compensation for attenuation, scatter, and collimator-detector response. The estimated concentrations in the anthropomorphic phantom are also corrected using recovery coefficients. Errors for the largest sphere in the physical phantom range from -25% to -34% for the medium-energy collimator and larger deviations for smaller spheres. Corresponding results for the high-energy collimator are -15% to -31%. The corresponding Monte Carlo simulations show standard deviations of a few percentage points. For the anthropomorphic phantom, before application of recovery coefficients the bias ranges from -16% to -46% (medium-energy collimator) and -10% to -28% (high-energy collimator), with standard deviations of 2% to 14% and 1% to 16%. After the application of recovery coefficients, the biases range from -3% to -35% (medium energy collimator) and from 0% to -18%. The errors decrease with increasing concentrations. Activity-concentration estimation of 223Ra with SPECT is feasible, but problems with repeatability need to be further studied.
(Less)
- author
- Gustafsson, Johan LU ; Rodeño, Emilia and Mínguez, Pablo
- organization
- publishing date
- 2020-04-21
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Physics in Medicine and Biology
- volume
- 65
- issue
- 8
- article number
- 085012
- publisher
- IOP Publishing
- external identifiers
-
- pmid:32092708
- scopus:85084612656
- ISSN
- 0031-9155
- DOI
- 10.1088/1361-6560/ab7971
- language
- English
- LU publication?
- yes
- id
- 8ddbf92b-37be-441f-9492-0640077c6097
- date added to LUP
- 2020-06-09 16:37:55
- date last changed
- 2024-04-03 08:04:23
@article{8ddbf92b-37be-441f-9492-0640077c6097,
abstract = {{<p>The aim of this paper is to investigate the feasibility and limitations of activity-concentration estimation for <sup>223</sup>Ra using SPECT. Phantom measurements are performed using spheres (volumes 5.5 mL to 26.4 mL, concentrations 1.6 kBq mL<sup>-1</sup> to 4.5 kBq mL<sup>-1</sup>). Furthermore, SPECT projections are simulated using the SIMIND Monte Carlo program for two geometries, one similar to the physical phantom and the other being an anthropomorphic phantom with added lesions (volumes 34 mL to 100 mL, concentrations 0.5 kBq mL<sup>-1</sup> to 4 kBq mL<sup>-1</sup>). Medium-energy and high-energy collimators, 60 projections with 55 s per projection and a 20% energy window at 82 keV are employed. For the Monte Carlo simulated images, Poisson-distributed noise is added in ten noise realizations. Reconstruction is performed (OS-EM, 40 iterations, 6 subsets) employing compensation for attenuation, scatter, and collimator-detector response. The estimated concentrations in the anthropomorphic phantom are also corrected using recovery coefficients. Errors for the largest sphere in the physical phantom range from -25% to -34% for the medium-energy collimator and larger deviations for smaller spheres. Corresponding results for the high-energy collimator are -15% to -31%. The corresponding Monte Carlo simulations show standard deviations of a few percentage points. For the anthropomorphic phantom, before application of recovery coefficients the bias ranges from -16% to -46% (medium-energy collimator) and -10% to -28% (high-energy collimator), with standard deviations of 2% to 14% and 1% to 16%. After the application of recovery coefficients, the biases range from -3% to -35% (medium energy collimator) and from 0% to -18%. The errors decrease with increasing concentrations. Activity-concentration estimation of <sup>223</sup>Ra with SPECT is feasible, but problems with repeatability need to be further studied.</p>}},
author = {{Gustafsson, Johan and Rodeño, Emilia and Mínguez, Pablo}},
issn = {{0031-9155}},
language = {{eng}},
month = {{04}},
number = {{8}},
publisher = {{IOP Publishing}},
series = {{Physics in Medicine and Biology}},
title = {{Feasibility and limitations of quantitative SPECT for <sup>223</sup>Ra}},
url = {{http://dx.doi.org/10.1088/1361-6560/ab7971}},
doi = {{10.1088/1361-6560/ab7971}},
volume = {{65}},
year = {{2020}},
}