Ahmad Denil, Nurnadiah (2021) The Value Of Delayed Imaging In Detection Of Recurrent Prostate Cancer Using Gallium-68 Prostate Specific Membrane Antigen (Psma) Positron Emission Tomography/computed Tomography (Pet/CT). Masters thesis, Universiti Sains Malaysia.
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Abstract
PURPOSE: Prostate specific antigen (PSA) levels and imaging modalities serve as a tool to detect recurrent prostate cancer after radical prostatectomy or radiation treatment for localized prostate cancer. Gallium-68 (Ga-68) prostate specific membrane antigen (PSMA) positron-emission tomography/computed tomography (PET/CT) has shown high detection rate in primary staging and recurrent prostate cancer with significant clinical impact on treatment allocation. However, Ga-68 PSMA PET/CT has shown limitation in delineating benign and malignant prostatic tissue due to physiological variability, tracer accumulation and post treatment changes within the pelvic region. The aim of this study is to evaluate the value of delayed imaging in Ga-68 PSMA PET/CT to detect prostate cancer lesion in biochemically recurrent patients. METHODS: This retrospective analysis included 87 biochemical recurrent prostate cancer patients with detectable or rising PSA level after radical prostatectomy or radiation therapy. Imaging consisted of whole-body PET/CT at 1 hour post injection (1 h p.i) and 3 hour post injection (3 h p.i). The early 1 h p.i and 3 h p.i Ga-68 PSMA PET/CT images were analyzed visually and semi quantitatively. The number of detected lesions maximum standardized uptake value (SUVmax) were recorded for analysis. RESULTS: Ga-68 PSMA PET/CT showed overall high detection rate of 84%. A total of 158 PSMA positive lesions were identified in 73 out of 87 patients. The standard 1 h p.i. scan can detect majority of lesions with sufficient tracer uptake and optimum target to background contrast for qualitative assessment of malignant lesions. No additional lesion was detected at 3 h p.i. The mean PSA of the positive scans was higher than that of negative scans (mean PSA 5.11 ng/mL vs 2.82 ng/mL) however was not statistically significant (p = 0.17 by Mann-Whitney U-test). Our data demonstrated a statistically significant higher SUVmax in most pathologic lesions between 1 h p.i. and 3 h p.i. scans (p < 0.001 by Wilcoxon Signed Ranks Test in local recurrence, pelvic and extra pelvic nodes and bones) except for soft tissue organ metastasis (p = 0.110 by Wilcoxon Signed Ranks Test). Only 46% of patients with PSA level < 3.0ng/m had PSMA positive scans. There was a weak correlation observed between the PSA level and the SUVmax of the PSMA avid lesions between early and delayed imaging. CONCLUSION: Ga-68 PSMA PET/CT showed high detection rates in biochemical recurrent prostate cancer. The value of routine whole body delayed Ga-68 PSMA PET/CT in detection of lesion in biochemical recurrent prostate cancer is limited in terms of detecting higher number of PSMA lesions. However, the overall increased in the SUVmax in the delayed imaging than 1 hour p.i imaging. for majority of tumor localization is still helpful to clarify equivocal lesions seen at standard 1 hour imaging based on the SUVmax.
| 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: | 13 May 2026 01:39 |
| Last Modified: | 13 May 2026 01:39 |
| URI: | http://eprints.usm.my/id/eprint/64174 |
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