Phantom and clinical evaluation of combined image reconstruction parameters of Philips Gemini TF 64 PET/CT imaging system

• Main Authors: Arzabal, Delmar R., Bernhard, Egwolf, Ariel, Moleno
• Format: text
• Published: Animo Repository 2018
• Subjects: Tomography, Emission; Image reconstruction; Health Information Technology
• Online Access: https://animorepository.dlsu.edu.ph/faculty_research/11232
• Institution: De La Salle University

PURPOSE: Positron emission tomography-computed tomograhy imaging provides information on glucose metabolism uptake of the FDG. This may also indicate the functional status of cancer lesions. Erroneous image details may lead to false results. Reconstruction is used to enhance the data by minimizing the noise, adjusting the contrast, and modifying the features of the image mathematically. METHODS: The study used the NEMA phantom for quantitative analysis and retrospective data for clinical evaluation. The data were reconstructed using defined Time-of-Flight (ToF) protocols ofvarying relaxation parameter, iteration subsetsand kernelwidth. For the phantom study, the data were analyzed to determine the percent contrast (PC), background variability (BV), and contrast­ to-noise ratio (CNR) for each reconstruction protocol. Two experienced nuclear medicine physicians, who were blinded by the reconstruction methods used, evaluated the retrospective data. The reconstructed images are rated on a scale of 1-4 and scored by rank according to 6 parameters. RESULTS: In the quantitative analysis, the smallest radioactive sphere obtained the highest PC of 18.3% on Protocol 5, while the largest radioactive sphere had the highest value of 55.1% on Protocol 6. The BV was least at 4.37% for the smallest radioactive sphere, and at 5.55% for the largest radioactive sphere, both on Protocol 1. The CNR was highest on Protocol 1 across all sphere sizes. The clinical evaluation of the retrospective data subjectively preferred Protocol 1 and Protocol 5. CONCLUSION: The findings showed that lower values of image reconstruction parameters produced improved CNR and were more favored by nuclear medicine physicians.