Fifty-seventh annual meeting of the American association of physicists in medicine
SU-E-I-82: PET Radiopharmaceuticals for Prostate Cancer Imaging: A Review
The aim of this work was to review new and clinical practice PET radiopharmaceuticals for prostate cancer imaging. Methods: PET radiopharmaceuticals were reviewed on the main databases. Availability, dosimetry, accuracy and limitations were considered. Results: The following radioisotopes with respective physical half-life and mean positron energy were found: 18F (109,7 min, 249,8 keV), 89Zr (78,4 hs, 395,5 keV), 11C (20,4 min, 385,7 keV) and 68Ga (67,8 min, 836 keV). 68Ga was the only one not produced by cyclotron. Radiopharmaceuticals uptake by glucose metabolism (18F-FDG), lipogenesis (11C-Choline and 11C-Acetate), amino acid transport (Anti-18F-FACBC), bone matrix (18F-NaF), prostatespecific membrane antigen (68Ga-PSMA and 89Zr-J591), CXCR receptors (89Ga-Pentixafor), adrenal receptors (18F-FDHT) and gastrin release peptide receptor (bombesin analogue). Most of radiopharmaceuticals are urinary excretion, so bladder is the critical organ. 11C-choline (pancreas), Anti-18FFACBC (liver) and 18F-FBDC (stomach wall) are the exception. Higher effective dose was seen 18F-NaF (27 μSv/MBq) while the lowest was 11CAcetate (3,5 μSv/MBq).
Even though 18F-FDG has a large availability its high urinary excretion and poor uptake to slow growing disease offers weak results for prostate cancer. Better accuracy is obtained when 18F-NaF is used for bone metastatic investigation although physicians tend to choose bone scintigraphy probably due to its cost and practice. Many guidelines in oncology consider 11C or 18F labeled with Choline the gold standard for biochemical relapse after radical treatment. Local, lymph node and distant metastatic relapse can be evaluated at same time with this radiopharmaceutical. There is no consensus over bigger urinary excretion for 18F labeling. Anti-18F-FACBC, 68Ga-PSMA and 68Ga-Pentixafor are demonstrating good results but more researches are needed. While PSMA imaging seems to be independent of PSA level, one choline limitation, anti-18F-FACBC adds value because imaging any disease stage. 68Ga-Petixafor is being tested as theranostics marker integrating molecular image and therapy.