International journal of radiation oncology, biology, physics
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Int. J. Radiat. Oncol. Biol. Phys. · Mar 1998
Electronic portal imaging with on-line correction of setup error in thoracic irradiation: clinical evaluation.
To analyze setup errors and the feasibility of their on-line correction using electronic portal imaging in the irradiation of lung tumors. ⋯ Setup errors in thoracic radiation therapy are clinically important. On-line correction can be performed accurately with an objective measurement tool, although this prolongs the irradiation procedure for one field with 65%.
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Int. J. Radiat. Oncol. Biol. Phys. · Mar 1998
Does delay in breast irradiation following conservative breast surgery in node-negative breast cancer patients have an impact on risk of recurrence?
This retrospective review was conducted to determine if delay in the start of radiotherapy after definitive breast surgery had any detrimental effect on local recurrence or disease-free survival in node-negative breast cancer patients. ⋯ This retrospective study suggests that delay in start of breast irradiation beyond 12 and up to 16 weeks does not increase the risk of recurrence in node-negative breast cancer patients. The certainty of these results are limited by the retrospective nature of this analysis and the lack of information concerning the late local failure rate.
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Int. J. Radiat. Oncol. Biol. Phys. · Mar 1998
Tumour radiosensitization by high-oxygen-content gases: influence of the carbon dioxide content of the inspired gas on PO2, microcirculatory function and radiosensitivity.
To measure the effects of breathing high-oxygen-content gases, with a CO2 fraction of between 0 and 10%, on tumour radiosensitivity, blood flow and oxygenation. ⋯ The data imply that the decreased radiosensitization seen at extended breathing times of oxygen is unrelated to blood flow changes. The fact that radiosensitization is seen with extended breathing times of gases containing 2.5% and 5% CO2, despite blood flow decreases, is indicative of other overriding physiological changes, perhaps related to oxygen utilisation. The studies overall indicate that, at least in the tumour investigated, radiosensitization is not affected if the CO2 content of the inspired gas is reduced from 5% to 2.5%, or even 1%. Further evaluation of the radiosensitizing effects of such gas mixtures is now warranted. In addition, comparison with recent studies of other tumour types, where carbogen has been shown to improve tumour blood flow, suggests that this may be a tumour-specific phenomenon. Based on these data, further effort is required to elucidate the physiological mechanisms that determine these blood flow changes.