International journal of radiation oncology, biology, physics
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Int. J. Radiat. Oncol. Biol. Phys. · Nov 2005
Changes in tumor cell response due to prolonged dose delivery times in fractionated radiation therapy.
Dynamic radiation therapy, such as intensity-modulated radiation therapy, delivers more complex treatment fields than conventional techniques. The increased complexity causes longer dose delivery times for each fraction. The cellular damage after a full treatment may depend on the dose rate, because sublethal radiation damage can be repaired more efficiently during prolonged dose delivery. The goal of this study was to investigate the significance of this effect in fractionated radiation therapy. ⋯ If the total dose delivery time for a treatment fraction in radiation therapy increases to about 20 min, a correction for dose rate effects may have to be considered in treatment planning. Adjustments in effective dose may be necessary when comparing intensity-modulated radiation therapy with conventional treatment plans.
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To describe radiation techniques and evaluate outcomes for orbital lymphoma. ⋯ A dose of 30 Gy is sufficient for indolent orbital lymphoma. Distant relapse rate in patients with localized orbital lymphoma was lower than that reported for low-grade lymphoma presenting in other sites. Orbital radiotherapy can be used for salvage of recurrent indolent lymphoma.
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Int. J. Radiat. Oncol. Biol. Phys. · Nov 2005
Whole pelvic radiotherapy for prostate cancer using 3D conformal and intensity-modulated radiotherapy.
To investigate the correlations between observed clinical morbidity and dosimetric parameters for whole pelvic radiotherapy (WPRT) for prostate cancer using either three-dimensional conformal radiotherapy (3D-CRT) or intensity-modulated radiotherapy (IMRT). ⋯ Compared to conventional 2D planning, conformal planning for WPRT resulted in significant reductions in the doses delivered to the bowel, rectum, and bladder. IMRT was superior to 3D-CRT in limiting the volume of bowel and rectum within high-dose regions. These dosimetric findings correlated with low rates of acute and late GI morbidity.
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Int. J. Radiat. Oncol. Biol. Phys. · Nov 2005
Review Meta AnalysisDose response and factors related to interstitial pneumonitis after bone marrow transplant.
Total body irradiation (TBI) and chemotherapy are common components of conditioning regimens for bone marrow transplantation. Interstitial pneumonitis (IP) is a known regimen-related complication. Using published data of IP in a multivariate logistic regression, this study sought to identify the parameters in the bone marrow transplantation conditioning regimen that were significantly associated with IP and to establish a radiation dose-response function. ⋯ Dose responses for both lung radiation dose and cyclophosphamide dose were identified. A conditioning regimen of 12 Gy TBI in 6 daily fractions induces an IP incidence of about 11% in the absence of lung shielding. Shielding the lung to receive 50% of this dose lowers the estimated incidence to about 2.3%. Because the lungs can be adequately shielded, we recommend against using busulfan as a substitute for fractionated TBI with cyclophosphamide.
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Int. J. Radiat. Oncol. Biol. Phys. · Nov 2005
Randomized Controlled Trial Multicenter StudyBiophysical analysis of the acute toxicity of radiotherapy in Hodgkin's lymphoma--a comparison between extended field and involved field radiotherapy based on the data of the German Hodgkin Study Group.
To determine biophysical parameters from the complication probability data during and after radiotherapy of Hodgkin's lymphoma (HL), based on the number of gastrointestinal side effects that were found in the multicenter HD8 trial of the German Hodgkin Lymphoma Study Group. ⋯ Radiotherapy volume reduction from extended field to involved field after two cycles of COPP/ABVD chemotherapy gives similar results and less toxicity in patients with early-stage, unfavorable HL. Biophysical parameters could be determined from the complication probability data after RT of HL. Because of the exponential dependence, this biophysical model is unstable. It represents a "start model" until further data can be incorporated.