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Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The tumor cell uptake of three tracers that can be labeled with isotopes suitable for PET imaging--FDG, L-methionine and thymidine--were examined in vitro in a human ovarian carcinoma cell line (HTB77IP3) at varying times following 30 Gy 60Co irradiation and were compared to a nonirradiated control group. FDG, methionine and thymidine uptake per tissue culture well all increased following irradiation when compared to basal values, although to a much lower extent than the increases in uptake seen in a nonirradiated group. This increase in tracer uptake occurred despite a 6.25-fold decline in viable cell numbers. When examined per cell, FDG uptake per cell increased 9.77-fold, methionine 7.82-fold and thymidine 9.48-fold over basal levels from Day 0 to Day 12 following irradiation. Part of these increases may be due to giant cell formation and/or radiation repair processes that require energy, protein and DNA substrates. While the in vitro system differs from in vivo systems due to the absence of a blood supply in vitro, a lack of infiltrating leukocytes and other factors, our data suggest that early assessment of human adenocarcinoma response to radiotherapy by PET with these tracers may be complicated by this normal increase in tracer uptake postirradiation. Clearly, in this human cancer cell line, early radiation-induced cell death is not associated with an early decline in tumor cell uptake of FDG, methionine or thymidine.
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PMID:In vitro assessment of 2-fluoro-2-deoxy-D-glucose, L-methionine and thymidine as agents to monitor the early response of a human adenocarcinoma cell line to radiotherapy. 825 26

In patients with malignant gliomas, [18F]fluorodeoxyglucose positron emission tomography (FDG-PET) may discriminate tumor progression from radionecrosis. We evaluated data from 50 patients undergoing FDG-PET for suspicion of tumor progression. Forty-nine were treated with surgery, 48 with radiotherapy, and 37 with chemotherapy. Twenty-one had intensive radiotherapy with either three daily treatments in two 5-day periods and intravenous carboplatin (17) or interstitial brachytherapy or stereotactic radiotherapy. Twenty underwent surgery after magnetic resonance imaging/FDG-PET; 9 demonstrated increased uptake of FDG and evidence of tumor, whereas 6 had decreased uptake and no evidence of tumor. In 5 patients, there was no correlation (all had intensive radiotherapy). In 17 patients who received bromodeoxyuridine intravenously just before surgery, the bromodeoxyuridine labeling index corresponded to the histological appearance in all but 2 patients (both had received intensive radiotherapy). In 30 patients without surgery, decreased uptake of FDG suggested prolonged survival; increased uptake of FDG did not predict survival. Eight of 10 with intensive radiotherapy had decreased label uptake. We conclude FDG-PET for evaluation of patients with possible recurrent tumors requires more study. In patients with intensive radiotherapy, FDG-PET results cannot be correlated accurately with tumor progression.
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PMID:Use of [18F]fluorodeoxyglucose positron emission tomography in patients with primary malignant brain tumors. 849 31

A 52-year-old man with metastatic poorly differentiated bronchogenic carcinoma and serum calcium levels as high as 14.6 had intense Tc-99m MDP uptake found throughout the stomach wall on SPECT imaging. FDG uptake assessed by PET imaging was not elevated in the stomach, whereas multiple hyper-metabolic tumor foci could be found throughout the body. Three months later, when calcium levels normalized, no Tc-99m MDP uptake was found in the stomach despite persistence of neoplastic lesions elsewhere. This case study indicates that gastric MDP uptake in patients with malignancy related hypercalcemia can be reversible and not necessarily indicative of neoplastic infiltration.
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PMID:Reversible Tc-99m diphosphonate uptake in gastric tissue associated with malignancy related hypercalcemia. A comparative study using PET FDG whole body imaging. 852 50

The most commonly used radionuclides for cancer patients in Japan have been still 67Ga and 201T1 chloride. In addition to the diagnosis of lung cancer and thyroid tumor, 201T1 is recently applied to patients with brain tumor, bone and soft tissue tumor and parathynoid adenoma. Comparing to Nuclear Cardiology and Brain Nuclear Medicine, where many new radiopharmaceuticals have been developed, there are few new drugs in Nuclear Oncology. In other words, new radiopharmaceuticals are expected to be developed for the diagnosis and/or therapy of cancer. In addition to 131I for thyroid cancer, new radiopharmaceuticals such as 111In-octreotide and 99mTc(V)-DMSA have been clinically employed. In spite of strong expectation, radiolabeled monoclonal antibodies have not been clinically used in Japan. However, the technique of humanized antibodies has been established and in U.S.A., 131I-labeled antibodies are reported to be effective for the treatment of malignant lymphoma. 89Sr is useful for the relief of bone pain caused by the bone metastasis. New findings that SPECT of 18F-FDG, a positron emitter, has been revealed to have a great potential in the management of cancer patients, will give a great impact on Nuclear Oncology.
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PMID:[Current status of nuclear oncology in Japan]. 852 36

To assess the early response of intracranial tumors to Gamma Knife surgery, we performed a prospective investigation of 42 patients treated by Gamma Knife surgery for different types of intracranial tumors. The clinical condition, tumor volume, treatment results and their temporal correlation with the irradiation were analyzed, based on MRI performed on the same MR scanner. Volume reduction in the tumors measured at the latest follow-up ranged from 0.2 to 100%. All except 1 malignant tumor showed decreasing size and improving peritumoral edema 1-7 months after radiosurgery. In 30 benign tumors, 13 showed either a decrease or no change in volume. However, an initial volume increase was observed in 17 tumors, with a maximum at 3-9 months, which subsequently regressed. In 2 meningioma patients, peritumoral edema increased and needed steroid treatment. Sequential PET-FDG imaging of the patients showed decreasing FDG uptake, indicating a decrease tumor in metabolism. The PET findings correlated well with the loss of contrast enhancement on MR images. In conclusion, intracranial tumors respond to Gamma Knife surgery from an early stage. Different tumors have different responses to radiosurgery. It is too early to offer a prognosis of long-term effects based on the limited material. However, sequential clinical, MR and PET follow-ups provide an excellent opportunity to investigate the evolving irradiation effects in vivo.
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PMID:Early effects of Gamma Knife surgery on malignant and benign intracranial tumors. 858 27

Experimental single-dose neural irradiation was performed in rats and monkeys. Acute and 'early' late damage was observed following single high-dose treatments. By contrast, following a single low-dose treatment, neither 'early' nor 'delayed' late damage was noted. Based on these experiments, a clinical trial of fractionated Gamma Knife surgery for malignant gliomas was begun, and patients were followed by FDG-PET studies. An acute response of the tumor was obtained without damage to the surrounding brain. Fractionated Gamma Knife surgery is a potential alternative treatment for malignant gliomas.
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PMID:Fractionated Gamma Knife radiosurgery for malignant gliomas: neurobiological effects and FDG-PET studies. 858 35

Positron Emission Tomography (PET) is rapidly evolving into a useful imaging modality for early and accurate detection of malignant tumor sites. Several recent studies have documented improved efficacy of detecting recurrent colorectal and hepatic (primary and metastatic) tumor sites with a sensitivity ranging from 92% to 100% and an accuracy of 90% to 96%. PET-FDG imaging using 2-[18F]-fluoro-2-deoxy-D-glucose has been found to be superior to computed tomography (CT) in detecting recurrent colorectal, hepatic, and abdominopelvic recurrent tumor sites from different primary cancers. PET-FDG imaging can be a cost-effective tool in the screening of patients with an elevated carcinoembryonic antigen and/or equivocal CT findings and suspected colorectal cancer. The role of PET scanning using FDG or C-11-5-HTP or C-11-L-DOPA appears promising in pancreatic carcinoma and functional endocrine tumors. Further studies are being carried out to assess the role of PET scanning in other gastrointestinal cancers.
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PMID:Role of positron emission tomography scanning in evaluating gastrointestinal neoplasms. 862 53

In a prospective study 16 patients with cervical lymph node metastases from an occult tumor were analyzed by (18F)FDG positron emission tomography (PET). The aim of this study was to locate the primary tumor. In 7 patients a localized increase in activity was seen on PET, with this site of activity histologically proven in 4 patients. No biopsies were taken in 3 patients in areas with a high risk of complications. In a follow-up procedure at 2-22 months after primary radiation therapy in the other 9 patients, no primary tumor has been identified to date.
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PMID:[Positron emission tomography for primary tumor detection in lymph node metastases with unknown primary tumor]. 870 30

The clinical usefulness of FDG-PET in the prediction and assessment of response to radiation therapy in patients with bronchogenic carcinoma was evaluated. Thirty patients with untreated bronchogenic carcinoma were included in the study. All patients received FDG-PET before the initiation of radiation therapy, while 20 also received it after completing the therapy. The tumor to muscle ratio (TMR) was used as an index of the FDG uptake. The tumor response to therapy was classified as either a partial response (PR, n = 21) or no change (NC, n = 9) according to changes in the tumor size. Prognosis was made 6 months after the initiation of therapy, and was classified as either relapse (n = 19) or non-relapse (n = 9). The FDG uptakes both before and after therapy were compared with tumor response and prognosis. A high FDG uptake was noted in all 30 lesions before therapy. No significant differences in the uptake before therapy was observed according to the histological types nor T factors (UICC). The lesions with a higher uptake (TMR more than 7) responded better to therapy than those with a lower uptake (p < 0.05). The decrease in the uptake after therapy tended to be more prominent in the PR group than in the NC group. The rate of relapse was higher in lesions with a higher uptake before therapy (TMR more than 10) than in those with a lower uptake. The relapse group also showed a higher uptake after therapy than the non-relapse group. In addition, all 6 lesions showing a higher uptake (TMR more than 5) after therapy eventually relapsed (p < 0.05). Two lesions demonstrating a lower uptake both before and after therapy did not relapse, although no tumor regression due to the therapy was observed. These results indicate that FDG-PET plays a complementary role in both predicting and assessing the therapeutic response and prognosis in patients with bronchogenic carcinoma.
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PMID:A clinical evaluation of FDG-PET to assess the response in radiation therapy for bronchogenic carcinoma. 880 Apr 48

Fluorine-18-fluorodeoxyglucose (18F-FDG) single photon emission CT(SPECT) imaging was performed in four patients with malignant neoplasms. Acquisition of SPECT was started 40 minutes after intravenous administration of 370MBq of 18F-FDG using dual-headed gamma camera equipped with 511keV collimators. Whole body planar scintigraphy was also obtained after the SPECT study. Tumor uptake of 18F-FDG was detected in three of four patients on both SPECT and planar images, and a 2.5 x 1.5 cm lung tumor was clearly visualized on SPECT image. Excellent SPECT image of 18F-FDG using a conventional gamma camera system is promising for the wide use of this system in cancer diagnosis.
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PMID:[Tumor diagnosis using 18F-FDG SPECT]. 883 Dec 28


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