International journal of radiation oncology, biology, physics
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Int. J. Radiat. Oncol. Biol. Phys. · Mar 2010
Review Meta AnalysisRadiation dose-volume effects in the spinal cord.
Dose-volume data for myelopathy in humans treated with radiotherapy (RT) to the spine is reviewed, along with pertinent preclinical data. Using conventional fractionation of 1.8-2 Gy/fraction to the full-thickness cord, the estimated risk of myelopathy is <1% and <10% at 54 Gy and 61 Gy, respectively, with a calculated strong dependence on dose/fraction (alpha/beta = 0.87 Gy.) Reirradiation data in animals and humans suggest partial repair of RT-induced subclinical damage becoming evident about 6 months post-RT and increasing over the next 2 years. Reports of myelopathy from stereotactic radiosurgery to spinal lesions appear rare (<1%) when the maximum spinal cord dose is limited to the equivalent of 13 Gy in a single fraction or 20 Gy in three fractions. However, long-term data are insufficient to calculate a dose-volume relationship for myelopathy when the partial cord is treated with a hypofractionated regimen.
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Int. J. Radiat. Oncol. Biol. Phys. · Mar 2010
Reduction of dose delivered to organs at risk in prostate cancer patients via image-guided radiation therapy.
To determine whether image guidance can improve the dose delivered to target organs and organs at risk (OARs) for prostate cancer patients treated with intensity-modulated radiotherapy (IMRT). ⋯ Currently, margins used in IMRT plans are adequate to deliver a dose to the prostate with conventional patient positioning using skin tattoos or bony anatomy. The use of image guidance may facilitate significant reduction of planning margins. Future studies to assess the efficacy of decreasing margins and improvement of treatment-related toxicities are warranted.
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Int. J. Radiat. Oncol. Biol. Phys. · Mar 2010
Cardiac mortality in patients with stage I and II diffuse large B-cell lymphoma treated with and without radiation: a surveillance, epidemiology, and end-results analysis.
Standard therapy for stage I and II diffuse large B-cell lymphoma consists of combined modality therapy with anthracycline-based chemotherapy, anti-CD20 antibody, and radiation therapy (RT). Curative approaches without RT typically utilize more intensive and/or protracted chemotherapy schedules. Anthracycline-based chemotherapy regimens are associated with a dose-dependent risk of left ventricular systolic dysfunction. We hypothesize that patients treated without RT, i.e., those who are treated with greater total chemotherapy cycles and hence cumulative anthracycline exposure, are at increased risk of cardiac mortality. ⋯ Increased anthracycline exposure in patients treated only with chemotherapy regimens may result in an increase in cardiac deaths, detectable only through analysis of large sample sizes. Confirmatory evaluation through meta-analysis of randomized data and design of large prospective trials is warranted.
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Int. J. Radiat. Oncol. Biol. Phys. · Mar 2010
Comparative StudyRadiotherapy treatment plans with RapidArc for prostate cancer involving seminal vesicles and lymph nodes.
Dosimetric results and treatment delivery efficiency of RapidArc plans to those of conventional intensity-modulated radiotherapy (IMRT) plans were compared using the Eclipse treatment planning system for high-risk prostate cancer. ⋯ For PTVs including prostate, seminal vesicles, and lymph nodes, IMRT performed better in dose sparing for bladder, rectum, and small bowel than did RapidArc. For PTVs including prostate and seminal vesicles, RapidArc with two arcs provided plans comparable to those for IMRT. The treatment delivery is more efficient with RapidArc.
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Int. J. Radiat. Oncol. Biol. Phys. · Mar 2010
Late effects after radiotherapy for locally advanced cervical cancer: comparison of two brachytherapy schedules and effect of dose delivered weekly.
To compare the severe late effects (Grade 3 or greater) for two groups of cervical cancer patients treated with the same external beam radiotherapy and two high-dose-rate intracavitary brachytherapy regimens and to investigate the influence of the dose delivered each week. ⋯ To establish dose-response relationships for late complications, three-dimensional imaging and dose-volume histogram parameters are needed. We found some indications that 20 Gy/wk is an upper tolerance level when the dose to the International Commission on Radiation Units and Measurements rectum point is 81 Gy(alpha/beta=3) (isoeffective [equivalent] dose of 2-Gy fractions). However, additional investigations using three-dimensional data are needed.