International journal of radiation oncology, biology, physics
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Int. J. Radiat. Oncol. Biol. Phys. · Mar 2005
Results of the 2003 Association of Residents in Radiation Oncology (ARRO) surveys of residents and chief residents in the United States.
To document demographic characteristics of current residents, career motivations and aspirations, and training program policies and resources. ⋯ Median program resources and numbers of outliers are documented to allow residents and program directors to assess the relative adequacy of experience in their own programs. Policy-making bodies and individual programs should consider these results when developing interventions to improve educational experiences of residents and to increase retention of radiation oncologists in academic practice.
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Int. J. Radiat. Oncol. Biol. Phys. · Mar 2005
Dose-response relationship in locoregional control for patients with stage II-III esophageal cancer treated with concurrent chemotherapy and radiotherapy.
To evaluate the correlation between radiation dose and locoregional control (LRC) for patients with Stage II-III unresectable esophageal cancer treated with concurrent chemotherapy and radiotherapy. ⋯ Our data suggested a positive correlation between radiation dose and LRC in the population studied. A higher radiation dose was associated with increased LRC and survival in the dose range studied. The data also suggested that better LRC was associated with a lower rate of distant metastasis. A threshold of tumor response to radiation dose might be present, as suggested by the flattened slope in the high-dose area on the dose-response curve. A carefully designed dose-escalation study is required to confirm this assumption.
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Int. J. Radiat. Oncol. Biol. Phys. · Mar 2005
Increased therapeutic ratio by 18FDG-PET CT planning in patients with clinical CT stage N2-N3M0 non-small-cell lung cancer: a modeling study.
With this modeling study, we wanted to estimate the potential gain from incorporating fluorodeoxyglucose-positron emission tomography (FDG-PET) scanning in the radiotherapy treatment planning of CT Stage N2-N3M0 non-small-cell lung cancer (NSCLC) patients. ⋯ In this group of clinical CT Stage N2-N3 NSCLC patients, use of FDG-PET scanning information in radiotherapy planning reduced the radiation exposure of the esophagus and lung, and thus allowed significant radiation dose escalation while respecting all relevant normal tissue constraints. This, together with a reduced risk of geographic misses using PET-CT, led to an estimated increase in TCP from 13% to 18%. The results of this modeling study support clinical trials investigating incorporation of FDG-PET information in CT-based radiotherapy planning.
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Int. J. Radiat. Oncol. Biol. Phys. · Mar 2005
Adequate margins for random setup uncertainties in head-and-neck IMRT.
To investigate the effect of random setup uncertainties on the highly conformal dose distributions produced by intensity-modulated radiotherapy (IMRT) for clinical head-and-neck cancer patients and to determine adequate margins to account for those uncertainties. ⋯ The margins to account for random setup uncertainties, in our clinical IMRT solution, should be 1.5 mm and 3.0 mm in the case of sigma = 2 mm and sigma = 4 mm, respectively, for the CTV(primary). Larger margins (5.0 mm), however, should be applied to the CTV(elective), if the goal of treatment is a V(95) value of at least 99%.
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Int. J. Radiat. Oncol. Biol. Phys. · Mar 2005
Methodology for biologically-based treatment planning for combined low-dose-rate (permanent implant) and high-dose-rate (fractionated) treatment of prostate cancer.
The combination of permanent low-dose-rate interstitial implantation (LDR-BRT) and external beam radiotherapy (EBRT) has been used in the treatment of clinically localized prostate cancer. While a high radiation dose is delivered to the prostate in this setting, the actual biologic dose equivalence compared to monotherapy is not commonly invoked. We describe methodology for obtaining the fused dosimetry of this combined treatment and assigning a dose equivalence which in turn can be used to develop desired normal tissue and target constraints for biologic-based treatment planning. ⋯ We describe new methodology for biologically based treatment planning for patients who receive combined low-dose-rate brachytherapy and external beam radiotherapy for prostate cancer. Using relevant mathematical tools, we demonstrate the feasibility of fusing dose distributions from each treatment for this combined regimen, which can then be expressed as isoeffective dose distributions. Based on this information, dose constraints for the rectum and urethra are described which could be used for planning such combination regimens.