FCH Uptake Research Articles

In vitro and in vivo studies with [18F]fluorocholine on digestive tumoral cell lines and in an animal model of metastasized endocrine tumor

The aim of this study was to investigate (a) in vitro the relationship between [(18)F]fluorocholine ([(18)F]FCH) uptake and cell growth in endocrine cell lines and (b) in vivo the uptake of [(18)F]FCH by tumoral sites in an animal model of metastasized endocrine tumor. In vitro studies were conducted on three endocrine and two nonendocrine digestive tumoral cell lines. The proliferative ratio was estimated using the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay. The uptake of [(18)F]FCH and that of [(18)F]fluorodeoxyglucose ([(18)F]FDG) were measured before and after cytotoxic therapy. [(18)F]FCH biodistribution was studied in nude mice and in an endocrine xenografted mice model. The [(18)F]FCH uptake in tumoral cell lines was related to their proliferative capacities as measured by the MTT assay in basal conditions. After cytotoxic therapy, the IC(50) values calculated with the [(18)F]FCH incorporation test were very close to those determined with the MTT assay. Biodistribution studies showed that [(18)F]FCH was predominantly concentrated in the liver and kidney of nude mice. In the STC-1 xenografted animal model, the uptake of [(18)F]FCH in the primary tumor was only 1.1%. On autoradiography and micro-positron emission tomography, there was no uptake of [(18)F]FCH in liver metastases but there was a significant uptake of [(18)F]FDG. In vitro studies suggested that the incorporation of [(18)F]FCH in endocrine tumor cell lines was related to their growth capacities; however, in vivo studies conducted in an endocrine xenografted animal model showed an uptake of [(18)F]FCH in hepatic metastases lower than that in normal liver cells. An influence of the microenvironment or a competition phenomenon for [(18)F]FCH uptake between normal liver and endocrine tumor cells cannot be excluded.

Evaluation of [18F]-choline PET/CT for staging and restaging of prostate cancer

To evaluate the accuracy of [(18)F]-choline (FCH) positron emission tomography/computed tomography (PET/CT) for staging and restaging of prostate cancer. FCH PET/CT was performed in 111 patients with prostate cancer using 200 MBq FCH: 43 patients [mean age 63 years; mean prostrate specific antigen (PSA) 11.58 microg/l] were examined for initial staging, and 68 patients (mean age 66.4 years) were examined for restaging (mean PSA 10.81 microg/l). FCH PET/CT results were correlated to histopathology, bone scan, morphology as revealed by magnetic resonance imaging (MRI) and CT, PET/CT follow-up and PSA follow-up after therapy. FCH PET/CT scans at initial staging correctly showed no metastases in 36/38 patients undergoing radical surgery, as confirmed by PSA levels <0.1 microg/l 6 months postoperatively. Lymphadenectomy was performed in 24 of these patients, revealing four false FCH-negative lymph nodes (LN). In one patient, only lymphadenectomy was performed since a FCH-positive LN was confirmed by histology. Four patients showed FCH-positive bone metastases, as proven by bone scan. FCH PET/CT scans at restaging correctly revealed local recurrence in 36 patients. No pathological FCH uptake was observed in 11 patients with biochemical recurrence. Twenty-three patients showed FCH-positive LN. Twenty LN were surgically removed in seven patients. Histopathology verified metastases in all LN, but revealed two additional metastastic, FCH-negative LN. Seventeen patients showed FCH-positive bone metastases, as proven by bone scan or MRI. Sensitivity to detect recurrent disease was 86%. The results obtained using FCH PET/CT scans for initial N-staging were discouraging, especially in terms of its inability to detect small metastases. Recurrent disease can be localized reliably in patients with PSA levels of >2 microg/l.

Uptake of 18F-fluorocholine, 18F-fluoro-ethyl-L-tyrosine and 18F-fluoro-2-deoxyglucose in F98 gliomas in the rat

The positron emission tomography (PET) tracers (18)F-fluoro-ethyl-L: -tyrosine (FET), (18)F-fluorocholine (N,N-dimethyl-N-[(18)F]fluoromethyl-2-hydroxyethylammonium (FCH]) and (18)F-fluoro-2-deoxyglucose (FDG) are used in the diagnosis of brain tumours. The aim of this study was threefold: (a) to assess the uptake of the different tracers in the F98 rat glioma, (b) to evaluate the impact of blood-brain barrier (BBB) disruption and microvessel density (MVD) on tracer uptake and (c) to compare the uptake in the tumours to that in the radiation injuries (induced by proton irradiation of healthy rats) of our previous study. F98 gliomas were induced in 26 rats. The uptake of FET, FCH and FDG was measured using autoradiography and correlated with histology, disruption of the BBB and MVD. The mean FET, FCH and FDG standardised uptake values (SUVs) in the tumour and the contralateral normal cortex (in parentheses) were 4.19+/-0.86 (1.32+/-0.26), 2.98+/-0.58 (0.51+/-0.11) and 11.02+/-3.84 (4.76+/-1.77) respectively. MVD was significantly correlated only with FCH uptake. There was a trend towards a negative correlation between the degree of BBB disruption and FCH uptake and a trend towards a positive correlation with FET uptake. The ratio of the uptake in tumours to that in the radiation injuries was 1.97 (FCH), 2.71 (FET) and 2.37 (FDG). MVD displayed a significant effect only on FCH uptake. The degree of BBB disruption seems to affect the accumulation of FET and FCH, but not FDG. Mean tumour uptake for all tracers was significantly higher than the accumulation in radiation injuries.

PROSTATE CANCER LOCALIZATION WITH 18FLUORINE FLUOROCHOLINE POSITRON EMISSION TOMOGRAPHY

We evaluated positron emission tomography (PET) with fluorine fluorocholine (F FCH) for the pretreatment localization of prostate cancer. A total of 17 patients with prostate cancer who had not yet received treatment for the disease underwent whole body PET following intravenous administration of 3.3 to 4 MBq/kg F FCH. PET findings were compared with the results of prostate sextant biopsy and other imaging studies, and the clinical course. Tracer uptake in prostate sextants was measured as a maximum standardized uptake value (SUVmax) and evaluated as a predictor of the prostate sextant biopsy result by ROC analysis. Prostate sextants positive for malignancy on biopsy demonstrated significantly higher SUVmax than biopsy negative sextants (mean 5.5 vs 3.3, p <0.001). In all 6 cases in which biopsy identified malignancy on only 1 side of the prostate it was possible to identify correctly the affected side based on higher SUVmax. Area under the ROC curve for SUVmax as a discriminator of biopsy positive sextants was 0.86. In 2 patients PET demonstrated areas of abnormal uptake in the retroperitoneum. Computerized tomography confirmed the presence of retroperitoneal lymphadenopathy in these areas. In the 2 patients these lesions regressed following hormonal treatment for prostate cancer. Malignant tumors in the prostate gland can be localized based on a standardized regional measurement of F FCH uptake. PET with F FCH is potentially useful for staging and localizing prostate cancer.