International journal of radiation oncology, biology, physics
-
Int. J. Radiat. Oncol. Biol. Phys. · Sep 2005
Esophagus sparing with IMRT in lung tumor irradiation: an EUD-based optimization technique.
The aim of this study was to evaluate (1) the use of generalized equivalent uniform dose (gEUD) to optimize dose escalation of lung tumors when the esophagus overlaps the planning target volume (PTV) and (2) the potential benefit of further dose escalation in only the part of the PTV that does not overlap the esophagus. ⋯ Intensity modulated radiation therapy optimizations that utilize gEUD-based cost functions for the PTV and NTCP-based constraints for the OARs result in increased doses to large portions of the PTV in cases where the PTV overlaps the esophagus, while still maintaining (and confining to the overlap region) minimum dose coverage equivalent to the homogeneous PTV optimization cases.
-
Int. J. Radiat. Oncol. Biol. Phys. · Sep 2005
Long-term survival and functional status of patients with low-grade astrocytoma of spinal cord.
To determine survival and changes in neurologic function and Karnofsky performance status (KPS) in a series of patients treated for low-grade astrocytoma of the spinal cord during the past two decades. ⋯ Patients who undergo gross total resection of their tumor may be followed closely. Patients who undergo limited resection should continue to receive postoperative RT (50.4 Gy in 1.8-Gy fractions). The functional measures should be routinely evaluated to appreciate the treatment outcomes.
-
Int. J. Radiat. Oncol. Biol. Phys. · Sep 2005
Outcome of salvage radiotherapy for biochemical failure after radical prostatectomy with or without hormonal therapy.
This study analyzed the outcome of salvage radiotherapy for biochemical failure after radical prostatectomy (RP). By comparing the outcomes for patients who received RT alone and for those who received combined RT and hormonal therapy, we assessed the potential benefits of hormonal therapy. ⋯ After prostatectomy, favorable-group patients may fare well with salvage radiotherapy alone. These patients may be spared the toxicity of androgen ablation. The other patients may benefit most from a combined approach with hormonal treatment. We further suggest that salvage radiotherapy should be given early when the PSA is still low.
-
Int. J. Radiat. Oncol. Biol. Phys. · Sep 2005
Influence of radiotherapy on the latest generation of implantable cardioverter-defibrillators.
Radiotherapy can influence the functioning of pacemakers and implantable cardioverter-defibrillators (ICDs). ICDs offer the same functionality as pacemakers, but are also able to deliver a high-voltage shock to the heart if needed. Guidelines for radiotherapy treatment of patients with an implanted rhythm device have been published in 1994 by The American Association of Physicists in Medicine, and are based only on experience with pacemakers. Data on the influence of radiotherapy on ICDs are limited. The objective of our study is to determine the influence of radiotherapy on the latest generation of ICDs. ⋯ The effect of radiation therapy on the newest generation of ICDs varies widely. If tachycardia monitoring and therapy are functional (programmed on) during irradiation, the ICD might inappropriately give antitachycardia therapy, often resulting in a shock. Although most ICDs did not fail below 80 Gy, some devices had already failed at doses below 1.5 Gy. Guidelines are formulated for the treatment of patients with an ICD.
-
Int. J. Radiat. Oncol. Biol. Phys. · Sep 2005
Retrospective analysis of prostate cancer patients with implanted gold markers using off-line and adaptive therapy protocols.
To determine the efficacy of applying adaptive and off-line setup correction models to bony anatomy and gold fiducial markers implanted in the prostate, relative to daily alignment to skin tattoos and daily on-line corrections of the implanted gold markers. ⋯ Changes in a prostate cancer patient's systematic and random setup characteristics during the course of therapy often violate the gaussian assumptions of adaptive and off-line correction models. Thus, off-line setup correction procedures, especially those directed at prostate localization using markers, will result in limited benefit to a minority of patients. The relative benefit of on-line localization is still potentially significant if the intrafraction motion is relatively small.