Pulmonary embolism: radiation dose with multi-detector row CT and digital angiography for diagnosis.

Purpose: To compare radiation dose delivered at four- and 16-detector row computed tomography (CT) with a dose-modulation program and that delivered at digital angiography for evaluation of pulmonary embolism (PE).

Materials And Methods: The part of the study involving patients (seven women, four men; mean age, 62 years +/- 16 [standard deviation]; range, 41-85 years) was approved by the institutional review board. Patients gave written informed consent.

Role of 2'-2' difluorodeoxycytidine (gemcitabine)-induced cell cycle dysregulation in radio-enhancement of human head and neck squamous cell carcinomas.

Background And Purpose: To try to get a better insight on the interaction between dFdC and ionizing radiation at the cellular level, we examined in vitro the effect of dFdC on the cell cycle of two human head and neck squamous cell carcinoma cell lines (SQD9 and SCC61).

Patients And Methods: Experimental conditions yielding radio-enhancement were used. Confluent cells were incubated with dFdC (5 microM) for different incubation times, washed, pulse-labeled with BrdUrd (10 microM), fixed and then processed for flow cytometry analysis.

Role of deoxycytidine kinase (dCK) activity in gemcitabine's radioenhancement in mice and human cell lines in vitro.

Background: Gemcitabine (dFdC, 2',2'-difluorodeoxycytidine) is a deoxycytidine nucleoside analog which has a marked effect on several enzymes involved in DNA synthesis and repair. Gemcitabine has been tested as a radiosensitizer in various biological models, and radiation dose modification factors (DMF) have been reported in the range between 1.1 and 2.