Page 24 - ARNM-2-4

Advances in Radiotherapy
& Nuclear Medicine 68 Ga-PSMA PET CT/MRI in prostate cancer

68 Ga-PSMA-PET/CT. 11,23 A comprehensive review of 18 particularly in cases classified as PI-RADS 3, while
diagnostic test accuracy trials evaluating Ga-PSMA-PET established SUV cutoff values aid in discriminating
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for primary lymph node staging in PCa reported superior csPCa, thereby reducing the need for unnecessary
sensitivity (59%) and specificity (93%) compared to biopsies. 26 68 Ga-PSMA-PET/MRI demonstrates superior
conventional CT and MRI. Despite variations in diagnostic accuracy in detecting primary PCa compared to mpMRI
accuracy attributed to factors such as research design and alone, with a pooled sensitivity of 94.9%. However, the
technical aspects, these findings underscore the potential lack of standardized SUV cutoff values for PSMA-
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of Ga-PSMA-PET as a valuable imaging tool for primary PET analysis presents a challenge in clinical practice,
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staging. 27 68 Ga-PSMA-PET imaging, especially Ga-PSMA- highlighting the need for further research to optimize
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PET/CT, exhibits heightened sensitivity and specificity biopsy guidance and PCa detection strategies. 19
in detecting LNM compared to conventional methods, In a review by Dhar et al. , Area Under the Receiver
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highlighting its potential utility in primary staging. 19,28 Operating Characteristic Curve values indicated very good
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68 Ga-PSMA-PET imaging outperforms conventional diagnostic accuracy for mpMRI, Ga-PSMA-PET, and
imaging in N and M staging for high-risk PCa patients, their combination (0.852, 0.889, and 0.796, respectively).
offering superior sensitivity and accuracy in detecting However, the limited studies using both modalities
lymph nodes and distant metastases. 26 68 Ga-PSMA-PET resulted in wider confidence intervals. 68 Ga-PSMA-
imaging demonstrates superior sensitivity and specificity PET/CT independently predicts treatment response for
compared to conventional imaging techniques such as salvage radiation, while 68 Ga-PSMA-PET/MRI shows
bone scans, detecting additional metastases, including notable accuracy in staging primary PCa and is potentially
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those missed by bone scans, with an additional 17.6% superior to mpMRI in a review by Zhao et al. Combining
involvement of bone regions. In intermediate to high-risk 68 Ga-PSMA-PET/CT with MRI enhances sensitivity
PCa patients, Ga-PSMA-PET reveals LNM in extrapelvic for detecting csPCa, necessitating further large-scale
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sites (M1a) in up to 36.0% of cases, highlighting its efficacy prospective studies for validation, while Ga-PSMA-PET/
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in identifying distant metastases, particularly in high-risk MRI demonstrates higher accuracy in detecting primary
populations. In a review by Jiao et al. , it was noted that PCa compared to mpMRI alone, with established SUV
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68 Ga-PSMA-PET/CT also demonstrates the same result cutoff values supporting biopsy-free diagnosis. 14
stated above when compared to conventional imaging
in detecting metastases with sensitivity of 96.2% and 4. Discussion
specificity of 99.1%. In addition, Ga-PSMA-PET/CT can So far, the majority of clinical evidence for Ga-PSMA-
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detect more undetected metastases, especially extrapelvic PET has supported its use in staging PCa. Only in
lesions, highlighting its utility in the M staging of PCa. 19 recent years has considerable attention been given to the
potential benefits of PSMA-PET in diagnosing suspected
3.4. Comparison with MRI and Ga-PSMA-PET/MRI
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PCa. Ga-68-PSMA-11, marketed under the trade names
®
®
MRI, a commonly used imaging modality in PCa staging, Locametz and Illuccix , has been used globally in a
is limited by its reliance on morphological information large number of patients, showing its profound clinical
and lymph node size criteria, resulting in low sensitivity impact. This PET method has replaced some conventional
in detecting LNM, thus necessitating more accurate imaging techniques, such as bone scintigraphy. The shift
alternatives. Arising as a comprehensive imaging solution, toward PET imaging has led to significant changes in
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68 Ga-PSMA-PET/MRI combines precise visualization of clinical management, as evidenced in numerous analyses,
local tumors through MRI with the sensitive detection of including our own, highlighting its transformative role in
LNM and distant metastases through Ga-PSMA-PET, diagnostic imaging.
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although at a higher cost and requiring more intricate The use of Ga-PSMA-PET in the initial detection
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image analysis compared to PET/CT. 23 68 Ga-PSMA-PET/ of PCa has shown promising results, with variability in
MRI shows superior detection and accuracy in diagnosing specificity highlights challenges in achieving consistent
recurrent PCa compared to Ga-PSMA-PET/CT, offering diagnostic accuracy. Despite these limitations, Ga-PSMA-
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clearer findings and improved localization of primary PCa PET’s ability to correlate with GS and PSA levels supports
compared to mpMRI and standalone PET. its utility in risk evaluation and management planning.
68 Ga-PSMA-PET/MRI demonstrates higher accuracy The integration of PET/MRI offers a comprehensive
than mpMRI alone in detecting primary PCa, offering approach by combining the anatomical detail of MRI with
improved sensitivity and specificity. In addition, combining the functional imaging capabilities of PET, thus improving
68 Ga-PSMA-PET/MRI enhances lesion detection rates, the accuracy of initial diagnoses and reducing the need

Volume 2 Issue 4 (2024) 5 doi: 10.36922/arnm.4590