ABSTRACT
AIM: This study focuses on the potential role of [11C]choline positron emission tomography (PET) for the intraprostatic tumor characterization and localization in recurrent prostate cancer after EBRT. METHODS: This retrospective study was conducted in patients who were being followed up after EBRT for histological proven prostate cancer. We selected the patients with a local recurrence by [11C]choline PET/CT fusion. The results of PET were compared with the results of histology and with clinical follow-up. RESULTS: Forty-two patients with a local recurrence suggested by PET were included in this study. According to PET results: of the 42 patients, 15 (36%) had a focal recurrence, 27 (64%) showed a diffuse recurrence. The overall concordance of PET with histology concerning detection of recurrence was 76% (32 patients had positive PET results and positive biopsies). We confirmed the local recurrence as visualized by PET in 37/42 (88%) patients using a composite reference with histology and clinical follow up after local salvage treatment. The concordance of the intraprostatic distribution of the tumor with PET with histology from transrectal prostate biopsies (median biopsies 7, range 4-12) was 47% (7/15) in unilateral cases and 41% (11/27) in bilateral cases. No significant differences were seen between the 2 groups in serum PSA at time of PET (P=0.509) and SUV (P=0.739) using Student's t-test. CONCLUSION: Intraprostatic characterization of recurrent prostate cancer after EBRT with 11C-choline PET is feasible at present but shows a moderate concordance with routine transrectal prostate biopsies. The accuracy is too low for the routine use of this modality in the present scenario.
Subject(s)
Choline , Neoplasm Recurrence, Local/diagnostic imaging , Neoplasm Recurrence, Local/prevention & control , Positron-Emission Tomography/methods , Prostatic Neoplasms/diagnostic imaging , Prostatic Neoplasms/radiotherapy , Radiotherapy, Conformal/methods , Aged , Carbon Radioisotopes , Female , Humans , Male , Middle Aged , Radiopharmaceuticals , Reproducibility of Results , Sensitivity and SpecificityABSTRACT
Amyloidosis is a disease characterized by depositions of amyloid in organs and tissues. It can be localized (in just one organ) or systemic. Cardiac amyloidosis is a debilitating disease and can lead to arrhythmias, deterioration of heart function and even sudden death. We reviewed PubMed/Medline, without time constraints, on the different nuclear imaging modalities that are used to visualize myocardial amyloid involvement. Several SPECT tracers have been used for this purpose. The results with these tracers in the evaluation of myocardial amyloidosis and their mechanisms of action are described. Most clinical evidence was found for the use of (123)I-MIBG. Myocardial defects in MIBG activity seem to correlate well with impaired cardiac sympathetic nerve endings due to amyloid deposits. (123)I-MIBG is an attractive option for objective evaluation of cardiac sympathetic level and may play an important role in the indirect measurement of the effect of amyloid myocardial infiltration. Other, less sensitive, options are (99m)Tc-aprotinin for imaging amyloid deposits and perhaps (99m)Tc-labelled phosphate derivatives, especially in the differential diagnosis of the aetiology of cardiac amyloidosis. PET tracers, despite the advantage of absolute quantification and higher resolution, are not yet well evaluated for the study of cardiac amyloidosis. Because of these advantages, there is still the need for further research in this field.