Non-invasive PET imaging of fPSA expression in PCa lesions has been proven to be a potential route toward monitoring treatment response in patients treated with frontline AR inhibitors.30–32 However, a current limitation in utilising non-invasive detection of PSA as a companion diagnostic is that very few drugs33–35 or radiotacers31,32 have been developed to target PSA with high affinity and specificity. The gene discussed is KLK3; the disease is posterior cortical atrophy.