International journal of radiation oncology, biology, physics
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Int. J. Radiat. Oncol. Biol. Phys. · Oct 1999
Effect of post-implant edema on the rectal dose in prostate brachytherapy.
To characterize the effect of prostate edema on the determination of the dose delivered to the rectum following the implantation of 125I or 103Pd seeds into the prostate. ⋯ The rectal surface dose determined by analysis of a post-implant CT scan of an 125I or 103Pd prostate seed implant depends upon the timing of the CT scan. The dose indicated by the CT scan on day 30 is typically at least 50% greater than that indicated by the CT scan on day 0. Because of this difference, it is important to keep the timing of the post-implant CT in mind when specifying dose thresholds for rectal morbidity.
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Int. J. Radiat. Oncol. Biol. Phys. · Oct 1999
The importance of adequate follow-up in defining treatment success after external beam irradiation for prostate cancer.
We reviewed our institution's experience treating patients with localized prostate cancer with external beam radiation therapy (RT) to determine how differences in the length of follow-up affect the determination of treatment outcome using the American Society for Therapeutic Radiology and Oncology (ASTRO) Consensus Panel Definition of biochemical failure (BF). ⋯ When the ASTRO Consensus Panel definition of BF is used to calculate treatment success with external beam RT for prostate cancer, adequate follow-up is critical. Depending upon the length of time after treatment, significantly different rates of BC (varying by 15% to 30%) can be calculated for the same time interval chosen for analysis. These results suggest that data should only be reported if the length of follow-up extends at least beyond the time point at which actuarial results are examined for the majority of patients.
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Int. J. Radiat. Oncol. Biol. Phys. · Sep 1999
The effect of patient position and treatment technique in conformal treatment of prostate cancer.
The relative value of prone versus supine positioning and axial versus nonaxial beam arrangements in the treatment of prostate cancer remains controversial. Two critical issues in comparing techniques are: 1) dose to critical normal tissues, and 2) prostate stabilization. ⋯ Prone flat positioning was advantageous over other positions and beam arrangements in rectal sparing. This study suggests that patient position is a more critical a factor in conformal therapy than beam arrangement, and may improve the safety of dose escalation.
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Int. J. Radiat. Oncol. Biol. Phys. · Sep 1999
Comparative StudyComparison of intensity-modulated tomotherapy with stereotactically guided conformal radiotherapy for brain tumors.
Intensity-modulated radiotherapy (IMRT) offers the potential to more closely conform dose distributions to the target, and spare organs at risk (OAR). Its clinical value is still being defined. The present study aims to compare IMRT with stereotactically guided conformal radiotherapy (SCRT) for patients with medium size convex-shaped brain tumors. ⋯ The Peacock method provided improved PTV coverage, albeit small, in this group of convex tumors. Although the OAR doses were higher using the Peacock plans, all doses remained within the clinically defined threshold and were clinically acceptable. Further improvements may be expected using other methods of IMRT planning that do not limit the treatment delivery to transaxial arcs. Each IMRT system needs to be individually assessed as the paradigm utilized may provide different outcomes.
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To demonstrate the technique and feasibility of prostate brachytherapy performed with local anesthesia only. ⋯ The substitution of local anesthesia has facilitated rapid introduction of a high-volume brachytherapy program at an institution that previously had none, without requiring the allocation of significant operating room time. Although the patients reported here were implanted without conscious sedation, we are starting to try various sedatives and analgesics for patients who we anticipate will have substantial anxiety with the procedure.