germanium and Carcinoma--Squamous-Cell

An autoradiography method revealed intratumoral inhomogeneity in various solid tumors. It is becoming increasingly important to estimate intratumoral inhomogeneity. However, with low spatial resolution and high scatter noise, it is difficult to detect intratumoral inhomogeneity in clinical settings. We developed a new PET system with CdTe semiconductor detectors to provide images with high spatial resolution and low scatter noise. Both phantom images and patients' images were analyzed to evaluate intratumoral inhomogeneity.. This study was performed with a cold spot phantom that had 6-mm-diameter cold sphenoid defects, a dual-cylinder phantom with an adjusted concentration of 1:2, and an "H"-shaped hot phantom. These were surrounded with water. Phantom images and (18)F-FDG PET images of patients with nasopharyngeal cancer were compared with conventional bismuth germanate PET images. Profile curves for the phantoms were measured as peak-to-valley ratios to define contrast. Intratumoral inhomogeneity and tumor edge sharpness were evaluated on the images of the patients.. The contrast obtained with the semiconductor PET scanner (1.53) was 28% higher than that obtained with the conventional scanner (1.20) for the 6-mm-diameter cold sphenoid phantom. The contrast obtained with the semiconductor PET scanner (1.43) was 27% higher than that obtained with the conventional scanner (1.13) for the dual-cylinder phantom. Similarly, the 2-mm cold region between 1-mm hot rods was identified only by the new PET scanner and not by the conventional scanner. The new PET scanner identified intratumoral inhomogeneity in more detail than the conventional scanner in 6 of 10 patients. The tumor edge was sharper on the images obtained with the new PET scanner than on those obtained with the conventional scanner.. These phantom and clinical studies suggested that this new PET scanner has the potential for better identification of intratumoral inhomogeneity, probably because of its high spatial resolution and low scatter noise.

Topics: Adult; Aged; Bismuth; Cadmium Compounds; Carcinoma, Squamous Cell; Female; Germanium; Glucose; Humans; Male; Nasopharyngeal Neoplasms; Neoplasms; Phantoms, Imaging; Positron-Emission Tomography; Semiconductors; Tellurium; Time Factors

The purpose of this study was to evaluate the influence of (68)Ge-based and CT-based attenuation correction as well as two standard image reconstruction algorithms on the appearance of artefacts due to dental hardware. Additionally, the intensity of such artefacts was compared with (18)F-fluorodeoxyglucose (FDG) uptake in patients with known oral cavity squamous cell cancer.. Thirty-two metallic and non-metallic objects used for dentistry/dental surgery were scanned in a water-bath filled with FDG on a combined PET/CT scanner. Images were reconstructed with either CT-based or (68)Ge-based transmission data and by using iterative reconstruction or filtered backprojection. The intensity of artefacts was assessed visually using a subjective scale from 0 (no artefact visible) to 4 (very strong artefact), and by quantitative measurements. In a second study, images of 30 patients with known squamous cell cancer and dental hardware were retrospectively analysed by two observers, again using a visual assessment grading system. Wilcoxon signed rank test was used for statistical comparisons.. Eighteen of 32 objects caused artefacts, which were visible with both attenuation correction methods. CT-based attenuation correction was visually more intense than (68)Ge-based attenuation correction (P<0.0001), and the measured (18)F concentration was also higher (P=0.0002). No difference was found between the reconstruction algorithms. In 28 of 30 patients the primary tumour was visible. FDG uptake in the primary tumour was significantly higher than measured (18)F concentration in artefacts (P<0.0001).. Attenuation correction of PET images generates artefacts adjacent to dental hardware that mimic FDG uptake. In this series, the primary lesion was discriminated from artefacts.

Topics: Adult; Aged; Aged, 80 and over; Artifacts; Carcinoma, Squamous Cell; Dental Alloys; Dental Prosthesis; Female; Fluorodeoxyglucose F18; Germanium; Head and Neck Neoplasms; Humans; Image Enhancement; Image Processing, Computer-Assisted; Male; Middle Aged; Orthopedic Fixation Devices; Phantoms, Imaging; Radioisotopes; Radiopharmaceuticals; Retrospective Studies; Tomography, Emission-Computed; Tomography, X-Ray Computed

Topics: Adenocarcinoma; Adult; Aged; Antineoplastic Agents; Carcinoma, Squamous Cell; Drug Evaluation; Female; Germanium; Humans; Lung Neoplasms; Male; Middle Aged; Neoplasm Staging; Organometallic Compounds; Spiro Compounds

Topics: Adult; Carcinoma, Squamous Cell; Drug Evaluation; Female; Germanium; Humans; Infusions, Parenteral; Middle Aged; Organometallic Compounds; Prognosis; Spiro Compounds; Uterine Cervical Neoplasms

Lethal and other biological effects of 2-aza-8-germanspiro[4,5]decane-2-propanamine-8,8-diethyl-N,N-dimethyl dichloride (NSC 192965; spirogermanium), representing a new chemical class of compound exhibiting antitumor activity, have been studied in vitro. Survival curves for NIL 8 hamster cells were exponential with greater kill occurring with increasing drug concentrations and longer exposure times. Cytotoxicity was temperature dependent. "Quiescent" cultures were significantly less sensitive to spirogermanium than were logarithmically growing cells. These lethal effects showed no phase specificity. There was no evidence of progression delay through the cycle following spirogermanium treatment. When spirogermanium was tested against a range of human cell lines, the consistency of the values for the drug concentration required to reduce survival by 50% on the exponential part of the survival curve, derived from colony-forming assays, was most marked. The survival curves, characterized by an initial shoulder, were steep and exponential with measurements possible over only a narrow concentration range since complete cell lysis occurred at levels causing a greater than 2-log kill. Cell membrane damage by spirogermanium, as judged by dye exclusion, was progressive with time and increasing drug concentrations. Protein synthesis proved most susceptible to the drug. Spirogermanium concentrations cytotoxic to tumor cells were also toxic to cultured rat neurons, confirming the clinical neurological toxicity encountered. The precise mode of action of spirogermanium remains to be established, and these data further illustrate its apparent lack of specificity.

Topics: Animals; Antineoplastic Agents; Carcinoma, Squamous Cell; Cell Cycle; Cell Line; Cell Survival; Cells, Cultured; Colonic Neoplasms; Cricetinae; Female; Germanium; Humans; Mesocricetus; Neuroblastoma; Neurons; Organometallic Compounds; Ovary; Rats; Spiro Compounds

Topics: Adult; Aged; Antineoplastic Agents; Carcinoma, Squamous Cell; Drug Evaluation; Female; Germanium; Humans; Middle Aged; Neoplasm Recurrence, Local; Organometallic Compounds; Ovarian Neoplasms; Spiro Compounds