Validation of [Formula: see text]Tc and [Formula: see text]Lu quantification parameters for a Monte Carlo modelled gamma camera

Giovanni Di Domenico; Simona Di Biaso; Lorenzo Longo; Alessandro Turra; Eugenia Tonini; MariaConcetta Longo; Licia Uccelli; Mirco Bartolomei

doi:10.1186/s40658-023-00547-6

Validation of [Formula: see text]Tc and [Formula: see text]Lu quantification parameters for a Monte Carlo modelled gamma camera

EJNMMI Phys. 2023 Apr 8;10(1):27. doi: 10.1186/s40658-023-00547-6.

Authors

Giovanni Di Domenico¹, Simona Di Biaso¹, Lorenzo Longo¹, Alessandro Turra², Eugenia Tonini², MariaConcetta Longo³, Licia Uccelli^{4

5}, Mirco Bartolomei⁴

Affiliations

¹ Department of Physics and Earth Science, University of Ferrara, via Saragat 1, 44122 Ferrara, IT Italy.
² Medical Physics Unit, University Hospital, 44124 Ferrara, IT Italy.
³ San Bortolo Hospital, 44124 Vicenza, IT Italy.
⁴ Nuclear Medicine Unit, University Hospital, 44124 Ferrara, IT Italy.
⁵ Department of Translational Medicine, University of Ferrara, via Fossato di Mortara, 70 c/o viale Eliporto, 44124 Ferrara, IT Italy.

Abstract

Purpose: Monte Carlo (MC) simulation in Nuclear Medicine is a powerful tool for modeling many physical phenomena which are difficult to track or measure directly. MC simulation in SPECT/CT imaging is particularly suitable for optimizing the quantification of activity in a patient, and, consequently, the absorbed dose to each organ. To do so, validating MC results with real data acquired with gamma camera is mandatory. The aim of this study was the validation of the calibration factor (CF) and the recovery coefficient (RC) obtained with SIMIND Monte Carlo code for modeling a Siemens Symbia Intevo Excel SPECT-CT gamma camera to ensure optimal [Formula: see text]Tc and [Formula: see text]Lu SPECT quantification.

Methods: Phantom experiments using [Formula: see text]Tc and [Formula: see text]Lu have been performed to measure spatial resolution and sensitivity, as well as to evaluate the CF and RC from acquired data. The geometries used for 2D planar imaging were (1) Petri dish and (2) capillary source while for 3D volumetric imaging were (3) a uniform filled cylinder phantom and (4) a Jaszczack phantom with spheres of different volumes. The experimental results have been compared with the results obtained from Monte Carlo simulations performed in the same geometries.

Results: Comparison shows good accordance between simulated and experimental data. The measured planar spatial resolution was 8.3[Formula: see text] mm for [Formula: see text]Tc and 11.8±0.6 mm for [Formula: see text]Lu. The corresponding data obtained by SIMIND for [Formula: see text]Tc was 7.8±0.1 mm, while for [Formula: see text]Lu was 12.4±0.4 mm. The CF was 110.1±5.5 cps/MBq for Technetium and 18.3±1.0 cps/MBq for Lutetium. The corresponding CF obtained by SIMIND for [Formula: see text]Tc was 107.3±0.3 cps/MBq, while for [Formula: see text]Lu 20.4±0.7 cps/MBq. Moreover, a complete curve RCs vs Volume (ml) both for Technetium and Lutetium was determined to correct the PVE for all volumes of clinical interest. In none of the cases, a RC coefficient equal to 100 was found.

Conclusions: The validation of quantification parameters shows that SIMIND can be used for simulating both gamma camera planar and SPECT images of Siemens Symbia Intevo using [Formula: see text]Tc and [Formula: see text]Lu radionuclides for different medical purposes and treatments.

Keywords: Molecular radiotherapy; Quantitative activity estimation; Quantitative imaging; SIMIND Monte Carlo code.