Quantitative Dual-Isotope Planar Imaging of Thorium-227 and Radium-223 Using Defined Energy Windows.
Cancer Biother Radiopharm
; 35(7): 530-539, 2020 Sep.
Article
en En
| MEDLINE
| ID: mdl-32429699
ABSTRACT
Introduction:
Thorium-227 is an alpha-emitting radioisotope with potential therapeutic applications in targeted alpha therapy. Thorium-227 decays to Radium-223, which may have an independent biodistribution to that of the parent Thorium-227 radiopharmaceutical. Quantitative in vivo imaging with sodium iodide (NaI) detectors is challenging due to cross-talk between neighboring γ-photopeaks as well as scattered γ-photons. The aim of this work was to validate the use of a spectral analysis technique to estimate the activity of each isotope within a region of interest applied to a pair of conjugate view planar acquisitions, acquired at multiple energy windows.Methods:
Energy spectra per unit activity arising from unscattered Thorium-227 photons and Radium-223 photons as well as from scattered photons were modeled. These spectra were scaled until the combination of these component spectra resulted in the closest match to the measured data in four energy windows.Results:
Measured estimates of activity followed the known decay curves in phantoms representative of a human torso. The mean errors in estimating Thorium-227 and Radium-223 were 5.1% (range -8.0% to 40.0%) and 3.4% (range -50.0% to 48.7%), respectively. The differences between the integrals of the theoretical and estimated time activity curve were <10% for both Thorium-227 and Radium-223.Conclusion:
γ-camera quantification of Thorium-227 and Radium-223 can be achieved by using multiple energy window acquisitions.Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Radio (Elemento)
/
Torio
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Radiofármacos
/
Modelos Teóricos
Límite:
Humans
Idioma:
En
Revista:
Cancer Biother Radiopharm
Asunto de la revista:
FARMACIA
/
FARMACOLOGIA
/
NEOPLASIAS
/
TERAPEUTICA
Año:
2020
Tipo del documento:
Article
País de afiliación:
Reino Unido