International journal of radiation oncology, biology, physics
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Int. J. Radiat. Oncol. Biol. Phys. · Apr 2012
Megavoltage cone beam computed tomography dose and the necessity of reoptimization for imaging dose-integrated intensity-modulated radiotherapy for prostate cancer.
Megavoltage cone beam computed tomography (MV-CBCT) dose can be integrated with the patient's prescription. Here, we investigated the effects of imaging dose and the necessity for additional optimization when using intensity-modulated radiotherapy (IMRT) to treat prostate cancer. ⋯ Reoptimization is clearly beneficial for reducing dose to critical organs, elevated by addition of high-MU CBCT, especially for the bladder. For low-MU CBCT aimed at bony structure visualization, compensation is sufficient.
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Int. J. Radiat. Oncol. Biol. Phys. · Apr 2012
Accelerated partial breast irradiation is safe and effective using intensity-modulated radiation therapy in selected early-stage breast cancer.
To report the feasibility, toxicity, cosmesis, and efficacy of using intensity-modulated radiation therapy (IMRT) with respiratory gating to deliver accelerated partial breast irradiation (APBI) in selected Stage I/II breast cancer after breast-conserving surgery. ⋯ APBI can be safely and effectively administered using IMRT. In retrospective analysis, IMRT enabled the achievement of normal tissue dose constraints as outlined by Radiation Therapy Oncology Group 04-13/NSABP B-13 while providing excellent conformality for the CTV. Local control and cosmesis have remained excellent at current follow-up, with acceptable rates of acute/late toxicities. Our data suggest that cosmesis is dependent on target volume size. Further prospective multi-institutional trials should be performed to evaluate IMRT to deliver APBI.
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Int. J. Radiat. Oncol. Biol. Phys. · Apr 2012
Safety and efficacy of stereotactic radiosurgery and adjuvant bevacizumab in patients with recurrent malignant gliomas.
Patients with recurrent malignant gliomas treated with stereotactic radiosurgery (SRS) and multiagent systemic therapies were reviewed to determine the effects of patient- and treatment-related factors on survival and toxicity. ⋯ The combination of salvage radiosurgery and bevacizumab to treat recurrent malignant gliomas is well tolerated and seems to be associated with improved outcomes. Prospective multiinstitutional studies are required to determine efficacy and long-term toxicity with this approach.
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Int. J. Radiat. Oncol. Biol. Phys. · Apr 2012
Comparative StudyReduced acute bowel toxicity in patients treated with intensity-modulated radiotherapy for rectal cancer.
We have previously shown that intensity-modulated radiotherapy (IMRT) can reduce dose to small bowel, bladder, and bone marrow compared with three-field conventional radiotherapy (CRT) technique in the treatment of rectal cancer. The purpose of this study was to review our experience using IMRT to treat rectal cancer and report patient clinical outcomes. ⋯ In the management of rectal cancer, IMRT is associated with a clinically significant reduction in lower GI toxicity compared with CRT. Further study is needed to evaluate differences in late toxicity and long-term efficacy.
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Int. J. Radiat. Oncol. Biol. Phys. · Apr 2012
Normal tissue complication probability estimation by the Lyman-Kutcher-Burman method does not accurately predict spinal cord tolerance to stereotactic radiosurgery.
To determine whether normal tissue complication probability (NTCP) analyses of the human spinal cord by use of the Lyman-Kutcher-Burman (LKB) model, supplemented by linear-quadratic modeling to account for the effect of fractionation, predict the risk of myelopathy from stereotactic radiosurgery (SRS). ⋯ The spinal cord tolerance to the dosimetry of SRS is higher than predicted by the LKB model using any set of accepted parameters. Only a high α/β value in the LKB model and only a large volume effect in the logistic model with Schultheiss data could explain the low number of complications observed. This finding emphasizes that radiobiological models traditionally used to estimate spinal cord NTCP may not apply to the dosimetry of SRS. Further research with additional NTCP models is needed.