F-rhPSMA-7 PET for the Detection of Biochemical Recurrence of Prostate Cancer After Radical Prostatectomy. Eiber Matthias,Kroenke Markus,Wurzer Alexander,Ulbrich Lena,Jooß Lena,Maurer Tobias,Horn Thomas,Schiller Kilian,Langbein Thomas,Buschner Gabriel,Wester Hans-Jürgen,Weber Wolfgang Journal of nuclear medicine : official publication, Society of Nuclear Medicine F-labeled prostate-specific membrane antigen (PSMA) PET tracers are increasingly used in preference to Ga-PSMA-11 for restaging biochemical recurrence (BCR) of prostate cancer. They are associated with longer half-lives, larger-scale production, and lower positron range than their Ga-labeled counterparts. Here, we describe the efficacy of an F-labeled radiohybrid PSMA, rhPSMA-7, a novel theranostic PSMA-targeting agent for imaging BCR of prostate cancer. Datasets from 261 consecutive patients with noncastrate BCR after radical prostatectomy who underwent F-rhPSMA-7 PET/CT at our institution between June 2017 and March 2018 were reviewed retrospectively. All lesions suspected of being recurrent prostate cancer were recorded. The detection rate for sites of presumed recurrence was correlated with patients' prostate-specific antigen (PSA) level, primary Gleason score, and prior therapy (androgen deprivation therapy and external-beam radiation therapy). The 261 patients had a median PSA level of 0.96 ng/mL (range, 0.01-400 ng/mL). The median injected activity of F-rhPSMA-7 was 336 MBq, with a median uptake time of 76 min. In total, 211 patients (81%) showed pathologic findings on F-rhPSMA-7 PET/CT. The detection rates were 71% (42/59), 86% (44/51), 86% (42/49), and 95% (76/80) at PSA levels of 0.2 to <0.5 ng/mL, 0.5 to <1 ng/mL, 1 to <2 ng/mL, and ≥2 ng/mL, respectively. In 32% patients (7/22) with a PSA of less than 0.2 ng/mL, suggestive lesions were present. F-rhPSMA-7 PET/CT revealed local recurrence in 43% of patients (113). Lymph node metastases were present in the pelvis in 42% of patients (110), in the retroperitoneum in 17% (45), and in a supradiaphragmatic location in 8.0% (21). Bone and visceral metastases were detected in 21% (54) and 3.8% (10), respectively. Detection efficacy was not influenced by prior external-beam radiation therapy (79.1% vs. 82.1%, = 0.55), androgen deprivation therapy within the 6 mo preceding imaging (80.6% vs. 80.9%, = 0.54), or primary Gleason score (77.9% for ≤7 vs. 82.6% for ≥8, = 0.38). F-rhPSMA-7 PET/CT offers high detection rates in early BCR after radical prostatectomy, especially among patients with low PSA values. 10.2967/jnumed.119.234914

(68)Ga-PSMA-11 dynamic PET/CT imaging in biochemical relapse of prostate cancer. Sachpekidis C,Eder M,Kopka K,Mier W,Hadaschik B A,Haberkorn U,Dimitrakopoulou-Strauss A European journal of nuclear medicine and molecular imaging OBJECTIVES:We aim to investigate the pharmacokinetics and distribution of the recently clinically introduced radioligand (68)Ga-PSMA-11 in men with recurrent prostate cancer (PC) by means of dynamic and whole-body PET/CT. The correlation between PSA levels and (68)Ga-PSMA-11 PET parameters is also investigated. METHODS:31 patients with biochemical failure after primary PC treatment with curative intent (median age 71.0 years) were enrolled in the analysis. The median PSA value was 2.0 ng/mL (range = 0.1 - 130.0 ng/mL) and the median Gleason score was 7 (range = 5 - 9). 8/31 (25.8 %) of the included patients had a PSA value < 0.5 ng/ml. All patients underwent dynamic PET/CT (dPET/CT) scanning (60 min) of the pelvis and lower abdomen as well as whole-body PET/CT with (68)Ga-PSMA-11. dPET/CT assessment was based on qualitative evaluation, SUV calculation, and quantitative analysis based on a two-tissue compartment model and a non-compartmental approach leading to the extraction of fractal dimension (FD). RESULTS:22/31 patients (71.0 %) were (68)Ga-PSMA-11-positive, while 9/31 (29.0 %) patients were (68)Ga-PSMA-11-negative. The median PSA value in the (68)Ga-PSMA-11-positive group was significantly higher (median = 2.35 ng/mL; range = 0.19 - 130.0 ng/mL) than in the (68)Ga-PSMA-11-negative group (median value: 0.34 ng/mL; range = 0.10 - 4.20 ng/mL). A total of 76 lesions were semi-quantitatively evaluated. PC recurrence-associated lesions demonstrated a mean SUVaverage = 12.4 (median = 9.0; range = 2.2 - 84.5) and mean SUVmax = 18.8 (median = 14.1; range = 3.1 - 120.3). Dynamic PET/CT studies of the pelvis revealed the following mean values for the PC recurrence-suspicious lesions: K1 = 0.26, k3 = 0.30, influx = 0.14 and FD = 1.24. Time-activity curves derived from PC-recurrence indicative lesions revealed an increasing (68)Ga-PSMA-11 accumulation during dynamic PET acquisition. Correlation analysis revealed a moderate, but significant, correlation between PSA levels and the number of lesions detected on (68)Ga-PSMA-11 PET/CT (r = 0.54) and between PSA levels and SUVaverage (r = 0.48) or SUVmax (r = 0.44). CONCLUSIONS:Ga-PSMA-11 PET/CT demonstrated an overall detection rate of 71.0 % 60 min p.i. of the radiotracer in a mixed patient population with respect to PSA levels and including patients with very low PSA values. Higher PSA values were associated with a higher detection rate. The tracer uptake in PC-recurrence-indicative lesions is increasing during the 60 minutes of dynamic PET acquisition. 10.1007/s00259-015-3302-4

Multiphasic Ga-PSMA PET/CT in the Detection of Early Recurrence in Prostate Cancer Patients with a PSA Level of Less Than 1 ng/mL: A Prospective Study of 135 Patients. Beheshti Mohsen,Manafi-Farid Reyhaneh,Geinitz Hans,Vali Reza,Loidl Wolfgang,Mottaghy Felix M,Langsteger Werner Journal of nuclear medicine : official publication, Society of Nuclear Medicine The main objective of this prospective study was to determine the impact of multiphasic acquisition of Ga-PSMA PET/CT in the detection of recurrent prostate cancer in the early stage of biochemical recurrence with a prostate-specific antigen (PSA) level of less than 1 ng/mL. Also, Ga-PSMA PET/CT positivity was correlated with clinical parameters for the assessment of predictive markers. A prospective monocentric study was conducted on 135 prostate cancer patients with biochemical recurrence and a PSA level of less than 1 ng/mL. All patients had undergone initial prostatectomy, with additional radiation therapy in 19.3% of patients and androgen-deprivation therapy in 7.4%. The patients underwent dynamic acquisitions from the prostate bed (1-8 min after injection), standard whole-body acquisitions (60 min after injection), and limited-bed-position delayed acquisitions (120-150 min after injection). The studies were reviewed by 2 board-certified nuclear medicine specialists, independently. A combination of visual and semiquantitative analyses and correlation with morphologic (e.g., MRI) or clinical follow-up findings was used for the final interpretation of lesions as benign or malignant. Ga-prostate-specific membrane antigen (PSMA) PET/CT positivity was also correlated with primary clinical findings. Incorporating the information from all phases, we were able to detect 116 lesions in 49.6% of patients (22 local recurrences, 63 lymph nodes, and 31 distant metastases). The detection rates were 31.8%, 44.9%, and 71.4% for PSA < 0.2 ng/mL, 0.2 ≤ PSA < 0.5, and 0.5 ≤ PSA < 1, respectively. Additional dynamic or delayed phases resulted in better determination of equivocal lesions and a higher diagnostic performance in 25.9% of patients. Stand-alone dynamic and delayed images led to better interpretation of equivocal findings in the prostate bed (31.4%) and in other lesions (lymph node or bone) (20%), respectively. Ga-PSMA PET/CT showed promise for early detection of recurrent disease in patients with a PSA level of 0.5-1.0 ng/mL. However, it showed limited value in patients with a PSA level of less than 0.5 ng/mL. Multiphasic Ga-PSMA PET/CT led to a better determination of equivocal findings. Although dynamic images may provide helpful information for assessment of the prostate bed, delayed acquisitions seem to have a greater impact in clarifying equivocal findings. 10.2967/jnumed.119.238071