International journal of radiation oncology, biology, physics
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Int. J. Radiat. Oncol. Biol. Phys. · Mar 2005
Methodology for biologically-based treatment planning for combined low-dose-rate (permanent implant) and high-dose-rate (fractionated) treatment of prostate cancer.
The combination of permanent low-dose-rate interstitial implantation (LDR-BRT) and external beam radiotherapy (EBRT) has been used in the treatment of clinically localized prostate cancer. While a high radiation dose is delivered to the prostate in this setting, the actual biologic dose equivalence compared to monotherapy is not commonly invoked. We describe methodology for obtaining the fused dosimetry of this combined treatment and assigning a dose equivalence which in turn can be used to develop desired normal tissue and target constraints for biologic-based treatment planning. ⋯ We describe new methodology for biologically based treatment planning for patients who receive combined low-dose-rate brachytherapy and external beam radiotherapy for prostate cancer. Using relevant mathematical tools, we demonstrate the feasibility of fusing dose distributions from each treatment for this combined regimen, which can then be expressed as isoeffective dose distributions. Based on this information, dose constraints for the rectum and urethra are described which could be used for planning such combination regimens.
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Int. J. Radiat. Oncol. Biol. Phys. · Mar 2005
Results of the 2003 Association of Residents in Radiation Oncology (ARRO) surveys of residents and chief residents in the United States.
To document demographic characteristics of current residents, career motivations and aspirations, and training program policies and resources. ⋯ Median program resources and numbers of outliers are documented to allow residents and program directors to assess the relative adequacy of experience in their own programs. Policy-making bodies and individual programs should consider these results when developing interventions to improve educational experiences of residents and to increase retention of radiation oncologists in academic practice.
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Int. J. Radiat. Oncol. Biol. Phys. · Mar 2005
Review Meta AnalysisProposal of human spinal cord reirradiation dose based on collection of data from 40 patients.
Driven by numerous reports on recovery of occult radiation injury, reirradiation of the spinal cord today is considered a realistic option. In rodents, long-term recovery was observed to start at approximately 8 weeks. However, prospective clinical studies are lacking. Therefore, a combined analysis of all published clinical data might provide a valuable basis for future trials. ⋯ On the basis of these literature data (and with due caution), the risk of myelopathy appears small after < or =135.5 Gy(2) when the interval is not shorter than 6 months and the dose of each course is < or =98 Gy(2). We would recommend limiting the dose to this level, whenever technically feasible. However, it appears prudent to propose the collection of prospective data from a greater number of patients receiving doses in the range of 136-150 Gy(2) to assess the safety of higher retreatment doses for those patients in whom limited doses might compromise tumor control.
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Int. J. Radiat. Oncol. Biol. Phys. · Mar 2005
ReviewIntegration of surgery with fractionated stereotactic radiotherapy for treatment of nonfunctioning pituitary macroadenomas.
To evaluate the efficacy of fractionated stereotactic radiotherapy (FSRT) after surgery in the management of residual or recurrent nonfunctioning pituitary adenomas with respect to tumor control and the development of complications. ⋯ The findings of this analysis support the use of surgery followed by FSRT as a safe, effective, and integrated treatment for nonfunctioning pituitary adenomas. Additional follow-up is needed to document the long-term tumor control rates, preservation rates for vision and pituitary function, and neurocognitive outcomes.
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Int. J. Radiat. Oncol. Biol. Phys. · Mar 2005
Clinical TrialThe impact of daily setup variations on head-and-neck intensity-modulated radiation therapy.
Intensity-modulated radiation therapy (IMRT) in the treatment of head-and-neck (H&N) cancer provides the opportunity to diminish normal tissue toxicity profiles and thereby enhance patient quality of life. However, highly conformal treatment techniques commonly establish steep dose gradients between tumor and avoidance structures. Daily setup variations can therefore significantly compromise the ultimate precision of idealized H&N IMRT delivery. This study provides a detailed analysis regarding the potential impact of daily setup variations on the overall integrity of H&N IMRT. ⋯ The successful implementation of H&N IMRT requires accurate and reproducible treatment delivery over a 6- to 7-week treatment course. The adverse impact of daily setup variation, which occurs routinely with conventional H&N masking techniques, may be considerably greater than recognized. Isocenter verification checks on two-dimensional orthogonal films may not sufficiently alert the clinician to the magnitude of three-dimensional offset vectors and the resultant impact on the quality of overall IMRT delivery. Unrecognized geographic miss and resultant target underdose may occur. Similarly, selected normal structures such as parotid glands may receive higher doses than intended. The results of this study suggest that more rigorous immobilization techniques than conventional masking and routine patient setup tracking methodologies are important for the accurate monitoring and successful delivery of high-quality IMRT for H&N cancer.