Zulkarnain, Aina Nadhirah (2025) Tomographic sensitivity analysis of spect/ct detectors equipped with low energy high resolution collimators at different tc-99m activity levels. Other thesis, Universiti Sains Malaysia.
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Abstract
Single Photon Emission Computed Tomography/Computed Tomography (SPECT/CT) is a key hybrid imaging technique in nuclear medicine, combining functional and anatomical data for improved disease detection and management. While planar sensitivity is well-studied, the tomographic sensitivity of SPECT/CT detectors with low energy high resolution (LEHR) collimators at varying Tc-99m activity levels remains underexplored. This study examines the effects of Tc-99m activities and LEHR collimator characteristics on tomographic sensitivity, spatial resolution, image contrast, and quantification accuracy. A Jaszczak phantom was scanned using a SPECT/CT system with LEHR collimators at Tc-99m activity levels of 7 mCi, 10 mCi, and 12 mCi. Standard acquisition and reconstruction protocols were used. Tomographic sensitivity was measured in counts per second per millicurie (cps/mCi), spatial resolution was assessed via phantom rod visualisation, and image contrast and relative error were calculated from defined regions of interest. Results show increasing Tc-99m activity enhances tomographic sensitivity which was 176.49 cps/mCi at 7 mCi to 209.45 cps/mCi at 12 mCi, spatial resolution (smaller rods visible at 12 mCi), and contrast the larger spheres showed more negative contrast (e.g., −47% for 31.8 mm at 7 mCi), which improved with higher activity. Smaller spheres exhibited greater variability and higher relative errors. In summary, Tc-99m activity and LEHR collimator design significantly influence tomographic sensitivity, spatial resolution, and image contrast in SPECT/CT imaging. Optimising activity levels and system parameters is vital for enhanced image quality and reducing radiation dose, providing critical insights for clinical protocol improvement in nuclear medicine.
| Item Type: | Thesis (Other) |
|---|---|
| Uncontrolled Keywords: | Tomographic |
| Subjects: | R Medicine R Medicine > RC Internal medicine > RC71-78.7 Examination. Diagnosis Including raiography |
| Divisions: | Kampus Kesihatan (Health Campus) > Pusat Pengajian Sains Perubatan (School of Medical Sciences) > Thesis |
| Depositing User: | MUHAMMAD AKIF AIMAN AB SHUKOR |
| Date Deposited: | 13 Oct 2025 08:15 |
| Last Modified: | 04 Nov 2025 07:53 |
| URI: | http://eprints.usm.my/id/eprint/62949 |
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