International journal of radiation oncology, biology, physics
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Int. J. Radiat. Oncol. Biol. Phys. · Nov 2004
Development of methods for beam angle optimization for IMRT using an accelerated exhaustive search strategy.
The purpose of this article is to explore the use of the accelerated exhaustive search strategy for developing and validating methods for optimizing beam orientations for intensity-modulated radiation therapy (IMRT). Combining beam-angle optimization (BAO) with intensity distribution optimization is expected to improve the quality of IMRT treatment plans. However, BAO is one of the most difficult problems to solve adequately because of the huge hyperspace of possible beam configurations (e.g., selecting 7 of 36 uniformly spaced coplanar beams would require the intercomparison of 8,347,680 IMRT plans). ⋯ Exhaustive search with fast IMRT algorithms provides a novel and realistic approach to study the characteristics of IMRT dose distributions as a function of beam angles and to design practical BAO strategies for IMRT planning.
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Int. J. Radiat. Oncol. Biol. Phys. · Nov 2004
Rectal bleeding after hypofractionated radiotherapy for prostate cancer: correlation between clinical and dosimetric parameters and the incidence of grade 2 or worse rectal bleeding.
To investigate the incidence and severity of rectal bleeding after high-dose hypofractionated radiotherapy (RT) for prostate cancer, and to explore the factors affecting the incidence of Grade 2 or worse rectal bleeding. ⋯ A history of diabetes mellitus was the most statistically significant risk factor for the occurrence of Grade 2 or worse rectal bleeding after high-dose hypofractionated RT, although dosimetric factors were also closely associated with the risk of rectal bleeding.
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Int. J. Radiat. Oncol. Biol. Phys. · Nov 2004
Defining a radiotherapy target with positron emission tomography.
F-18 fluorodeoxyglucose positron emission tomography (FDG-PET) imaging is now considered the most accurate clinical staging study for non-small-cell lung cancer (NSCLC) and is also important in the staging of multiple other malignancies. Gross tumor volume (GTV) definition for radiotherapy, however, is typically based entirely on computed tomographic data. We performed a series of phantom studies to determine an accurate and uniformly applicable method for defining a GTV with FDG-PET. ⋯ An FDG-PET-based GTV can be systematically defined using a threshold SUV according to the regressive function described above. The threshold SUV for defining the target is strongly dependent on the mean target SUV of the target, and can be uniquely determined through the proposed iteration process.
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Int. J. Radiat. Oncol. Biol. Phys. · Nov 2004
Randomized Controlled Trial Multicenter Study Clinical TrialEffect of oral sucralfate on late rectal injury associated with radiotherapy for prostate cancer: A double-blind, randomized trial.
To assess whether oral sucralfate is effective in preventing late rectal injury in prostate cancer patients treated with radiotherapy. ⋯ This trial demonstrated no statistically significant reduction in the incidence of late rectal toxicity in patients randomized to receive sucralfate. However, this result was considered inconclusive, because the trial was unable to exclude clinically important differences in the late toxicity rates.
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To investigate and compare the biologically effective doses, equivalent doses in 2-Gy fractions, log tumor cells killed, and late effects that can be estimated for the large fractions in short overall times that are now being delivered in various clinically used schedules in several countries for the treatment of cancer in human lungs, liver, and kidney. ⋯ Such large doses can apparently be given, with suitable precautions and experience. Ongoing clinical trials from an increasing number of centers will be reporting the results of tumor control and complications from this new modality of biologically higher doses.