KLK3 and posterior cortical atrophy: Similarly, for staging of patients with suspected bone metastases, the NCCN PCa guideline recommends a bone scan in clinical tumour stage T1 patients when prostatic specific antigen value (PSA) is >20 ng/ml or if clinical tumour stage is T2 when PSA is >10 ng/ml or if clinical tumour stage is T3 or T4 or if Gleason score is ≥8 or if patients are symptomatic.2