TY - JOUR T1 - Multiphasic <sup>68</sup>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 JF - Journal of Nuclear Medicine JO - J Nucl Med SP - 1484 LP - 1490 DO - 10.2967/jnumed.119.238071 VL - 61 IS - 10 AU - Mohsen Beheshti AU - Reyhaneh Manafi-Farid AU - Hans Geinitz AU - Reza Vali AU - Wolfgang Loidl AU - Felix M. Mottaghy AU - Werner Langsteger Y1 - 2020/10/01 UR - http://jnm.snmjournals.org/content/61/10/1484.abstract N2 - The main objective of this prospective study was to determine the impact of multiphasic acquisition of 68Ga-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, 68Ga-PSMA PET/CT positivity was correlated with clinical parameters for the assessment of predictive markers. Methods: 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. 68Ga-prostate-specific membrane antigen (PSMA) PET/CT positivity was also correlated with primary clinical findings. Results: 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 &lt; 0.2 ng/mL, 0.2 ≤ PSA &lt; 0.5, and 0.5 ≤ PSA &lt; 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. Conclusion: 68Ga-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 68Ga-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. ER -