TABLE 1.

Summary of PSMA-RADS Version 1.0 for Reporting Findings on PSMA-Targeted PET Imaging

Category	Findings
PSMA-RADS-1 (benign)
PSMA-RADS-1A	Benign lesion characterized by biopsy or pathognomonic finding on anatomic imaging and without abnormal uptake (Fig. 1).
PSMA-RADS-1B	Benign lesion characterized by biopsy or pathognomonic finding on anatomic imaging and with focal radiotracer uptake (Fig. 2).
PSMA-RADS-2 (likely benign)	Equivocal (focal, but low level such as blood pool) uptake in soft-tissue site atypical of PCa involvement (e.g., axillary or hilar lymph nodes) (Fig. 3); equivocal uptake in bone lesion atypical of PCa involvement (e.g., uptake fused to bone lesion and strongly suspected of being degenerative or another benign etiology) (Fig. 4).
PSMA-RADS-3 (equivocal*)
PSMA-RADS-3A	Equivocal uptake in soft-tissue site typical of PCa involvement (e.g., pelvic or retroperitoneal lymph nodes). If targetable for biopsy (up to and including excision), biopsy may help confirm diagnosis. Alternatively, follow-up imaging (either anatomic or PSMA-targeted PET/CT) showing progression can confirm diagnosis. We recommend initial follow-up period of 3–6 mo (Fig. 5).
PSMA-RADS-3B	Equivocal uptake in bone lesion not definitive but also not atypical of PCa on anatomic imaging (i.e., pure marrow-based lesion with little if any surrounding bony reaction, lytic or infiltrative lesion, or classic osteoblastic lesion [Fig. 6]). Comparison to bone scan, Na18F PET, or tumor-protocol MR images may be helpful, and bone biopsy may have a role. Alternatively, follow-up imaging (either anatomic or PSMA-targeted PET/CT) with evidence of progression may confirm diagnosis. We recommend initial follow-up period of 3–6 mo.
PSMA-RADS-3C	Intense uptake in site highly atypical of all but advanced stages of PCa. Likelihood of nonprostatic malignancy or other benign tumor is high (Fig. 7). Biopsy to confirm diagnosis histologically is often preferred, although organ-specific follow-up imaging may be done (e.g., liver-protocol MRI to evaluate possible primary hepatocellular carcinoma).
PSMA-RADS-3D	Lesion suggestive of malignancy on anatomic imaging but lacking uptake (Fig. 8). Differential considerations include nonprostatic malignancy, neuroendocrine PCa, and an uncommon case of prostate adenocarcinoma that fails to express PSMA. Biopsy to confirm diagnosis histologically is often preferred, although organ-specific follow-up imaging may be done.
PSMA-RADS-4 (PCa highly likely)	Intense uptake in site typical of PCa but lacking definitive findings on conventional imaging (Fig. 9). Given the high specificity of PSMA agents in all reported series, it is unlikely that biopsy confirmation will be needed, although obtaining tissue for genomic analysis or other purposes may be useful.
PSMA-RADS-5 (PCa almost certainly present)	Intense uptake in site typical of PCa and having corresponding findings on conventional imaging (Fig. 10). Given the high specificity of PSMA agents in all reported series, it is unlikely that biopsy confirmation will be needed, although obtaining tissue for genomic analysis or other purposes may be useful.

^*Further work-up can be considered.