Imprimir Resumo


Teste
Abstract: 84-1

84-1

First Prototype of a 3D-Printed Zoomorphic Mouse Model for Small Animal PET Scanner Sensitivity Calibration

Authors:
Ester Maria Rodrigues de Andrade (CDTN - Centro de Desenvolvimento da Tecnologia Nuclear) ; Lucas Paixao (IMA/UFMG - Departamento de Anatomia e Imagem, Universidade Federal de Minas Gerais) ; Andrea Vidal Ferreira (CDTN - Centro de Desenvolvimento da Tecnologia Nuclear) ; Telma Cristina Ferreira Fonseca (DEN/UFMG - Departamento de Engenharia Nuclear, Universidade Federal de Minas Gerais) ; Bruno Melo Mendes (CDTN - Centro de Desenvolvimento da Tecnologia Nuclear)

Abstract:

The use of small animal positron emission tomography (PET) is crucial for developing radiopharmaceuticals for diagnosis and therapy. Precise calibration is essential for accurate imaging. Routine quality control tests ensure equipment safety, performance, and adherence to standards, indicating maintenance needs. Quality assurance programs for PET scanners are important for accurate image interpretation [1,2]. Similarly, SPECT in nuclear medicine depends on careful quality control to ensure imaging accuracy and efficacy [3]. Both, PET and SPECT, rely on rigorous calibration and quality control, involving multiple steps, materials, and suitable phantoms. The aim of this study was to develop a 3D-printed mouse phantom based on the DM_BRA voxel mouse phantom [4] and demonstrate its applicability for the sensibility test in a small animal’s PET scanner and in a SPECT equipment. The physical mouse phantom consists of the 3D printing of a minimum 2 mm thick with an empty internal cavity corresponding to the real dimensions of the DM_BRA voxel phantom. The model was waterproofed with epoxy resin to prevent leakage. A sensibility test was conducted using the small animal’s PET scanner (LabPET4 Solo, GE Healthcare Technologies) at the Radiopharmaceuticals Research and Production Unit (UPPR/CDTN/CNEN) in Brazil. Approximately 22 ml of an 18F-FDG solution with a known activity was added to the model cavity. The model was positioned at the small animal PET scanner and measurements were made with different 18F-FDG activities. The suitability of the 3D-printed model for SPECT was tested in a (human) GE Healthcare Infinia Hawkeye 4 camera. To simulate a standard cylindrical phantom employed in small animal testing, a fully filled 5 mL syringe was utilized. The mouse phantom and the standard were filled with a known activity of 99mTc. A counting efficiency curve as a function of activity was plotted for both small animal PET scanner and SPECT. The preliminary results shows that the zoomorphic phantom may present a 30% higher sensitivity than the reference cylindrical phantom. However, sensitivity results may also vary due to electronic fluctuations in the equipment. The results obtained with the sensitivity test in SPECT could not be compared due to the activity inserted in the phantoms apparently being in the saturation zone of the curve. This precludes an evaluation of the linearity aspects, as is possible in PET. In conclusion, a prototype based on the DM_BRA voxel phantom was modeled and 3D printed. Sensitivity tests demonstrated greater sensitivity than the reference cylindrical phantom for PET. The SPECT tests were inconclusive, requiring further adjustments. It is expected that the model development, printing and characterization techniques should be improved in the next steps, including specific organs in new prototypes.

 

Acknowledgments

We are thankful to Hospital das Clínicas of Universidade Federal de Minas Gerais (HC UFMG/EBSERH) and the Nuclear Medicine team, especially S. S. Freitas, S. S. Nunes, L. G. Mota, and S. M. D. Sanches, for providing the SPECT equipment and the  99mTc source. We also thanks the financial support provided by FAPEMIG (Project APQ-03582-18). This work is part of the Brazilian Institute of Science and Technology for Nuclear Instrumentation and Applications to Industry and Health (INCT/INAIS), CNPq project 406303/2022-3.

Keywords:
 3D-print, Mouse Phantom, Small Animals PET scanner, Calibration Phantom