AR and posterior cortical atrophy: Therefore, alternative radiotracers are under investigation, such as bombesin (BBN) analogs, that reached a detection rate of 71.8% in patients with conventional negative imaging [15]; androgen receptor (AR) imaging with [18F]FDHT, which might be useful to assess the feasibility and efficacy of AR-directed pharmaceuticals [16]; and [18F]NaF for the assessment of PCa bone metastases [17].