Universität zu Köln

Dietlein, Felix, Kobe, Carsten, Vazquez, Sergio Munoz, Fischer, Thomas ORCID: 0000-0001-6118-5182, Endepols, Heike, Hohberg, Melanie, Reifegerst, Manuel, Neumaier, Bernd, Schomaecker, Klaus, Drzezga, Alexander E. and Dietlein, Markus (2022). An Zr-89-Labeled PSMA Tracer for PET/CT Imaging of Prostate Cancer Patients. J. Nucl. Med., 63 (4). S. 573 - 584. RESTON: SOC NUCLEAR MEDICINE INC. ISSN 1535-5667

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Abstract

The short half-life of existing prostate-specific membrane antigen (PSMA) tracers limits their time for internalization into tumor cells after injection, which is an essential prerequisite for robust detection of tumor lesions with low PSMA expression on PET/CT scans. Because of its longer half-life, the Zr-89-labeled ligand Zr-89-PSMA-DFO allows acquisition of PET scans up to 6 d after injection, thereby overcoming the above limitation. We investigated whether Zr-89-PSMA-DFO allowed more sensitive detection of weak PSMA-positive prostate cancer lesions. Methods: We selected 14 prostate cancer patients with biochemical recurrence who exhibited no PSMA-positive lesions on a PET scan acquired with existing PSMA tracers (Ga-68-PSMA-11, F-18-JK-PSMA-7). Within 5 wk after the negative scan result, we obtained a second PSMA PET scan using Zr-89-PSMA-DFO (117 +/- 16 MBq, PET acquisition within 6 d of injection). Results: Zr-89-PSMA-DFO detected 15 PSMA-positive lesions in 8 of 14 patients, who had a PET-negative reading of their initial PET scans with existing tracers. In these 8 patients, the new scans revealed localized recurrence of disease (3/8), metastases in lymph nodes (3/8), or lesions at distant sites (2/8). On the basis of these results, patients received lesion-targeted radiotherapies (5/8), androgen deprivation therapies (2/8), or no therapy (1/8). The plausibility of 14 of 15 lesions was supported by histology, clinical follow-up after radiotherapy, or subsequent imaging. Furthermore, comparison of the 15 Zr-89-PSMA-DFO-positive lesions with their correlates on the original PET scan revealed that established tracers exhibited mild accumulation in 7 of 15 lesions; however, con-trast-to-noise ratios were too low for robust detection of these lesions (contrast-to-noise ratios, 2.4 +/- 3.7 for established tracers vs. 10.2 +/- 8.5 for Zr-89-PSMA-DFO, P = 0.0014). The SUVmax of the 15 Zr-89-PSMA-DFO-positive lesions (11.5 +/- 5.8) was significantly higher than the SUVmax on the original PET scans (4.7 +/- 2.8, P = 0.0001). Kidneys were the most exposed organ, with doses of 3.3 +/- 0.7 mGy/MBq. The effective dose was 0.15 +/- 0.04 mSv/MBq. Conclusion: In patients with weak PSMA expression, a longer period of time might be needed for ligand internalization than that offered by existing PSMA tracers to make lesions visible on PET/CT scans. Hence, Zr-89-PSMA-DFO might be of significant benefit to patients in whom the search for weak PSMA-positive lesions is challenging. Radiation exposure should be weighed against the potential benefit of metastasis-directed therapy or salvage radiotherapy, which we initiated in 36% (5/14) of our patients based on their Zr-89-PSMA-DFO PET scans.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Dietlein, Felix UNSPECIFIED UNSPECIFIED UNSPECIFIED Kobe, Carsten UNSPECIFIED UNSPECIFIED UNSPECIFIED Vazquez, Sergio Munoz UNSPECIFIED UNSPECIFIED UNSPECIFIED Fischer, Thomas UNSPECIFIED orcid.org/0000-0001-6118-5182 UNSPECIFIED Endepols, Heike UNSPECIFIED UNSPECIFIED UNSPECIFIED Hohberg, Melanie UNSPECIFIED UNSPECIFIED UNSPECIFIED Reifegerst, Manuel UNSPECIFIED UNSPECIFIED UNSPECIFIED Neumaier, Bernd UNSPECIFIED UNSPECIFIED UNSPECIFIED Schomaecker, Klaus UNSPECIFIED UNSPECIFIED UNSPECIFIED Drzezga, Alexander E. UNSPECIFIED UNSPECIFIED UNSPECIFIED Dietlein, Markus UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-680491
DOI:	10.2967/jnumed.121.262290
Journal or Publication Title:	J. Nucl. Med.
Volume:	63
Number:	4
Page Range:	S. 573 - 584
Date:	2022
Publisher:	SOC NUCLEAR MEDICINE INC
Place of Publication:	RESTON
ISSN:	1535-5667
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language EXPRESSION Multiple languages Radiology, Nuclear Medicine & Medical Imaging Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/68049