International journal of radiation oncology, biology, physics
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Int. J. Radiat. Oncol. Biol. Phys. · Jan 2008
Cervical cancer regression measured using weekly magnetic resonance imaging during fractionated radiotherapy: radiobiologic modeling and correlation with tumor hypoxia.
To measure regression of cancer of the uterine cervix during external beam radiotherapy using magnetic resonance imaging, derive radiobiologic parameters from a mathematical model of tumor regression, and compare these parameters with the pretreatment measurements of tumor hypoxia. ⋯ The results of our study have shown that cervical cancer regresses during external beam radiotherapy, although marked variability is present among patients and is influenced by underlying biologic processes, including cellular sensitivity to radiotherapy and proliferation. Better understanding of the biologic mechanisms might facilitate novel adaptive treatment strategies in future studies.
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Int. J. Radiat. Oncol. Biol. Phys. · Jan 2008
Toxicity profile with a large prostate volume after external beam radiotherapy for localized prostate cancer.
To assess the impact of prostate volume on health-related quality of life (HRQOL) before and at different intervals after radiotherapy for prostate cancer. ⋯ Patients with a large prostate volume have a great risk of irritative/obstructive symptoms (particularly dysuria) in the acute radiotherapy phase. These symptoms recover rapidly and do not influence long-term HRQOL.
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Int. J. Radiat. Oncol. Biol. Phys. · Jan 2008
Long-term outcome after static intensity-modulated total body radiotherapy using compensators stratified by pediatric and adult cohorts.
To report the long-term outcome after total body irradiation with intensity-modulating compensators and allogeneic/autologous transplantation, especially in terms of therapy-related toxicity in pediatric and adult cohorts. ⋯ Static intensity-modulated total body irradiation with a total dose of 12 Gy before allogeneic/autologous transplantation is a successful treatment with good long-term outcome and acceptable therapy-related toxicities. Constraining the lung dose to 11 Gy substantially lowered the actuarial treatment-related mortality. This effect was especially striking in the pediatric patients.
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Int. J. Radiat. Oncol. Biol. Phys. · Jan 2008
IMRT delivery performance with a varian multileaf collimator.
The use of a multileaf collimator (MLC) for intensity-modulated radiotherapy poses unique dosimetric issues. The nature of intensity-modulated radiotherapy dosimetry, centered on leaf position accuracy, is common to all MLCs. However, the mechanical and software designs of MLCs from the different manufacturers distinguish them. ⋯ Moreover, inadequate modeling of the MLC in the planning system can be perceived as erratic performance. Individually, some problems have been shown to be insignificant; others are correctable using software. If these problems are rectified or at least understood by the physicist, quality assurance can be simplified.