Quantitative imaging with commercial SPECT

Abstract

With the introduction of the Computed Tomography (CT) into the SPECT technology, SPECT-CT is now capable to quantify the uptake to the organ by the introduction of Activity Calibration Factor (ACF). We implemented three different phantoms geometry to obtain the ACF. First acquisition done with uniform cylinder phantom from Data Spectrum, followed with uniform NEMA IEC Body and uniform glass bottle allows the simulation of different type of clinical imaging study. Acquisitions were performed on a Brightview XCT (Philip) gamma camera. All acquisition and reconstruction protocol according to the clinical practice setting with different voxel volume sizes of 0.811 cm3, 0.104 cm3 and 0.012 cm3 to demonstrate the different values of ACFs. The ACFs for Tc-99m, I-131 and Lu-177 calculated from 3D segmentation of SPECT-CT images for scaling three different matrix sizes. The results obtained in this study demonstrated that SPECT-CT is able to quantify uptake at the organ, and it has high possibility to be used as quantitative SPECT in clinical practice in the future.

Validation Calibration Factor of Single Photon Emission Computed Tomography for Iodine-131 using Non-Spherical Targeted Volume

“…Remarkably, the result is in concordance with [20], who stated that the best radionuclide for SPECT quantification is Technitium-99m (Tc-99m), followed by Lutetium-177 (Lu-177) and 131 I. This is because Tc-99m emitted a gamma energy of 140 keV, and the scintillation detector is technically suitable for 140 keV gamma rays.…”

“…According to Figure 1, the VOI was scaled to the physical sphere's inner diameter. A 1000-litre glass bottle containing 212 Megabecquerel Iodine-131 (MBq 131 I) will be used as the activity concentration sphere [20]. For the first scan, the activity concentration was 0.212 MBqml -1 (Table 1 followed until the fourth scan, as reported in Table 1).…”