International journal of radiation oncology, biology, physics
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Int. J. Radiat. Oncol. Biol. Phys. · Dec 2004
Clinical TrialDysphagia and aspiration after chemoradiotherapy for head-and-neck cancer: which anatomic structures are affected and can they be spared by IMRT?
To identify the anatomic structures whose damage or malfunction cause late dysphagia and aspiration after intensive chemotherapy and radiotherapy (RT) for head-and-neck cancer, and to explore whether they can be spared by intensity-modulated RT (IMRT) without compromising target RT. ⋯ The structures whose damage may cause dysphagia and aspiration after intensive chemotherapy and RT are the pharyngeal constrictors and the glottic and supraglottic larynx. Compared with 3D-RT, moderate sparing of these structures was achieved by stIMRT, and an additional benefit, whose extent varied among the patients, was gained by doIMRT, without compromising target doses. Clinical validation is required to determine whether the dosimetric gains are translated into clinical ones.
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Int. J. Radiat. Oncol. Biol. Phys. · Dec 2004
Factors predicting local tumor control after gamma knife stereotactic radiosurgery for benign intracranial meningiomas.
To determine the long-term outcomes and prognostic factors in benign intracranial meningiomas treated with gamma knife stereotactic radiosurgery (GK-SRS). ⋯ This report adds to the literature that supports the efficacy and safety of GK-SRS in the management of patients with benign intracranial meningiomas. Our report identified male patients, patients with a CI <1.4, and tumor size greater than 10 cc to have a worse prognosis. Patients who were treated with less conformal plans to cover the dural tail had better outcomes. Our data clearly demonstrate the need to adequately cover the dural tail in patients treated with GK-SRS for benign intracranial meningiomas.
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Int. J. Radiat. Oncol. Biol. Phys. · Dec 2004
Comparison of rectal dose-wall histogram versus dose-volume histogram for modeling the incidence of late rectal bleeding after radiotherapy.
To compare the fits of normal-tissue complication probability (NTCP) models based on rectal dose-wall histograms (DWHs) vs. dose-volume histograms (DVHs) when the two are used to analyze a common set of late rectal toxicity data. ⋯ A consistent, although modest, improvement occurs in the fits of NTCP models to the UTMDACC 2-year late rectal bleeding data when the fit is based on the rectal dose-wall histogram instead of on the dose-volume histogram for entire rectum, including contents.
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Int. J. Radiat. Oncol. Biol. Phys. · Dec 2004
Comparative StudyProstate seed implantation using 3D-computer assisted intraoperative planning vs. a standard look-up nomogram: Improved target conformality with reduction in urethral and rectal wall dose.
To compare dosimetric outcomes between two real-time prostate seed implantation (PSI) techniques to evaluate the impact of three-dimensional (3D) intraoperative computer planning on target coverage, conformality, and preset urethral and rectal dose constraints. ⋯ The adoption of 3D computer intraoperative dose planning and optimization for prostate seed implantation resulted in dramatic reductions in urethral and rectal wall doses, while consistently producing excellent target coverage with reduced dose variability above 180 Gy and below 140 Gy, compared with the use of a standard look-up nomogram. Additionally, the reduction in total mCi and number of seeds needed to achieve improved conformality was substantial and may have implications for cost savings.
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Int. J. Radiat. Oncol. Biol. Phys. · Dec 2004
Online image-guided intensity-modulated radiotherapy for prostate cancer: How much improvement can we expect? A theoretical assessment of clinical benefits and potential dose escalation by improving precision and accuracy of radiation delivery.
To quantify the theoretical benefit, in terms of improvement in precision and accuracy of treatment delivery and in dose increase, of using online image-guided intensity-modulated radiotherapy (IG-IMRT) performed with onboard cone-beam computed tomography (CT), in an ideal setting of no intrafraction motion/deformation, in the treatment of prostate cancer. ⋯ The ideal maximum dose increment achievable with online IG-IMRT is, on average, 13% with respect to the dose-limiting organ of rectum. However, there is a large interpatient variation, ranging <5%-41%. The results can be applied to calibrate other practical online image-guided techniques for prostate cancer radiotherapy, when intratreatment organ motion/deformation and machine delivery accuracy are considered.