n-n-dimethyl-n-(18f)fluoromethyl-2-hydroxyethylammonium and Neoplasms

Radiotherapy is a major treatment modality for many cancers. Tumor response after radiotherapy determines the subsequent steps of the patient's management (surveillance, adjuvant or salvage treatment and palliative care). Tumor response assessed during radiotherapy offers a promising opportunity to adapt the treatment plan to reduced or increased target volume, to specifically target sub-volumes with relevant biological characteristics (metabolism, hypoxia, proliferation, etc.) and to further spare the organs at risk. In addition to its role in the diagnosis and the initial staging, Positron Emission Tomography combined with a Computed Tomography (PET/CT) provides functional information and is therefore attractive to evaluate tumor response. The aim of this paper is to review the published data addressing PET/CT as an evaluation tool in irradiated tumors. Reports on PET/CT acquired at various times (during radiotherapy, after initial (chemo-) radiotherapy, after definitive radiotherapy and during posttreatment follow-up) in solid tumors (lung, head-and-neck, cervix, esophagus, prostate and rectum) were collected and reviewed. Various tracers and technical aspects are also discussed. 18F-FDG PET/CT has a well-established role in clinical routine after definitive chemo-radiotherapy for locally advanced head-and-neck cancers. 18F-choline PET/CT is indicated in prostate cancer patients with biochemical failure. 18F-FDG PET/CT is optional in many other circumstances and the clinical benefits of assessing tumor response with PET/CT remain a field of very active research. The combination of PET with Magnetic Resonance Imaging (PET/MRI) may prove to be valuable in irradiated rectal and cervix cancers. Tumor response can be evaluated by PET/CT with clinical consequences in multiple situations, notably in head and neck and prostate cancers, after radiotherapy. Further clinical evaluation for most cancers is still needed, possibly in association to MRI.

Topics: Choline; Fluorodeoxyglucose F18; Humans; Magnetic Resonance Imaging; Multimodal Imaging; Neoplasms; Positron Emission Tomography Computed Tomography; Radiopharmaceuticals; Treatment Outcome

The use of radiopharmaceuticals is the distinguishing characteristics of nuclear medicine. Among the panel of available radiopharmaceuticals in many PET centers around the world, choline is well represented, being widely used to image prostate cancer. Carbon-11 labelled choline can only be produced in centres with a cyclotron available, but the 18F-labelled radiopharmaceutical is distributed and licensed in several countries in Europe. Besides prostate cancer, other possible uses of choline are related to its ability to indirectly evaluate the cell proliferation as a measure of the synthesis of lipids required for cell membrane. In particular, the radiopharmaceutical can be successfully used in those districts where 18F-FDG has a high uptake, like the brain. Moreover, slow growing tumors, not always taking up 18F-FDG, like hepatocellular carcinoma, can also be imaged. We will evaluate possibly uses of this molecule in patients affected by prostate cancer, brain tumors and hepatocellular carcinoma.

Topics: Choline; Humans; Image Enhancement; Isotope Labeling; Neoplasms; Positron-Emission Tomography; Radiopharmaceuticals

The distribution characteristics of 18F-fluoromethylcholine (18F-choline) in tumor and inflammatory tissue were compared with those of 14C or 3H-2-deoxyglucose (2DG) as a substitute for fluorodeoxyglucose (FDG).. A solid tumor model of AH 109A in the back of Donryu rats and an aseptic inflammation model of turpentine oil injection subcutaneously in rats were used for experiments. Tissue distribution was examined at 5, 30 and 60 min after injection of a mixture of 18F-choline and 3H-2DG. Double-tracer high-resolution autoradiographs (ARGs) of tumor and inflammation were obtained using 18F-choline and 14C-2DG. Whole body (WB) ARG was performed with 18F-choline.. Tumor uptake of 18F-choline reached a peak at 30 min, when the tumor to blood ratio was 5.1. Both tumor and inflammation uptake of 2DG were higher than those of 18F-choline. 18F-choline uptake by inflammation was lower than that by tumor. The tumor to brain uptake ratio was 5.7 with 18F-choline and 1.2 with 2DG. In the ARG of inflammation, linear or ring-like structures of 2DG uptake were observed in the wall of the abscess, but were not identified with 18F-choline. Photomicrography showed that the uptake was limited to granulocytes, macrophages and fibroblasts, consistent with sub-acute or chronic inflammation.. 18F-choline uptake by inflammation was lower than that of 2DG in the tissue distribution study, and 18F-choline uptake by abscess wall was significantly lower than that of 2DG in the autoradiography study. Our results may suggest the feasibility of 18F-choline-PET imaging for the differential diagnosis of cancer and chronic inflammation in lung and brain.

Topics: Animals; Autoradiography; Brain; Choline; Deoxyglucose; Fluorine Radioisotopes; Inflammation; Lung; Male; Neoplasm Transplantation; Neoplasms; Radiopharmaceuticals; Rats; Tissue Distribution; Turpentine