Mohd Yahya, Mohd Hizwan (2021) Accuracy Of 131i Activity Quantification And Dosimetry In Thyroid Phantom Using 3d-image Based Spect/CT. Masters thesis, Universiti Sains Malaysia.
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Abstract
Quantitative imaging gives a better understanding of the distribution of radioactivity that can be used in the estimation of absorbed dose in the specific target organ. The goal of this study was to obtain the accuracy of 131I activity quantification and dosimetry in thyroid uptake phantom using 3-dimensional (3D) SPECT/CT imaging. In this study, a series of SPECT/CT acquisitions of the thyroid uptake was performed. Images of different voxel sizes 64, 128, and 256 with several iterations numbers were reconstructed using ordered-subsets expectation maximization (OSEM). The quantification of the activity in the phantom was determined using a Medical Image Data Examiner (AMIDE) software based on the mean, maximum, 0.7 maximum and 0.6 maximum value. The cumulated activity in the phantom was determined by the calculating area under the curve (AUC) in the time-activity curve. The results showed that the mean value of 128 and 256 voxel show a better result with the error obtained between 4.1% and 18.2% whereas for the maximum value, it gives an overestimate count with the error up to 78%. The cumulated activity derived from SPECT/CT showed an error margin of 15%. The dosimetry result of organ absorbed dose using 3D imaged based dosimetry was approximately 16.1% lower than the absorbed dose measure using Optical Stimulated Luminescence (OSL) dosimeter. This research shows that the 3D image based SPECT/CT with good quantification accuracy capable of estimating organ absorbed dose in131I therapy.
| Item Type: | Thesis (Masters) |
|---|---|
| Subjects: | R Medicine |
| Divisions: | Institut Perubatan & Pergigian Termaju (Advanced Medical & Dental Institute (AMDI)) > Thesis |
| Depositing User: | NOR HASHIMY BIN ABDULLAH |
| Date Deposited: | 22 Apr 2026 01:55 |
| Last Modified: | 22 Apr 2026 01:55 |
| URI: | http://eprints.usm.my/id/eprint/63947 |
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