International journal of radiation oncology, biology, physics
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Int. J. Radiat. Oncol. Biol. Phys. · Jun 2002
Effect of prostatic edema on CT-based postimplant dosimetry.
To investigate the magnitude of edema after prostate brachytherapy and its effect on the CT-based postimplant dosimetry based on the sequential CT scans using dose-volume histograms, dose conformity, and homogeneity indices in patients with prostate cancer. ⋯ The decrease in prostate volume from Day 1 to Day 28 after the implant markedly improved the prescription dose covering the prostate from 77% to 85%. Day 28 prostate volumes were still about 10% larger than the preimplant CT volumes for the 25 cases evaluated. Postimplant dosimetry using dose conformity and homogeneity indices is dependent on the timing of CT studies, as a result of changing prostate volumes from edema.
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Int. J. Radiat. Oncol. Biol. Phys. · Jun 2002
Data from a professional society placement service as a measure of the employment market for radiation oncologists.
To aid in understanding the employment market for radiation oncologists, we present annual data for 1991 to 2000 from the American College of Radiology's placement service, the Professional Bureau. This data series is twice as long as any previously available. Secondarily, we compare these data with other data on the employment market. ⋯ The employment market for radiation oncologists weakened in the first half of the 1990s, as had been widely reported; we present the first systematic data showing this. Data from a professional society placement service provide useful and inexpensive information on the employment market.
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Int. J. Radiat. Oncol. Biol. Phys. · May 2002
Clinical TrialObjective assessment of swallowing dysfunction and aspiration after radiation concurrent with chemotherapy for head-and-neck cancer.
To objectively assess swallowing function after an intensive chemoradiation regimen for locally advanced head-and-neck cancer and to assess the clinical implications of swallowing dysfunction. ⋯ After intensive chemoradiotherapy, significant objective swallowing dysfunction is prevalent. It promotes aspiration, which may not elicit a cough reflex and may be associated with pneumonia. Aspiration pneumonia may be an underdocumented complication of chemoradiotherapy for head-and-neck cancer. Future studies should examine whether routine post-therapy videofluoroscopy and training aspirating patients in safe swallowing strategies can reduce this risk.
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Int. J. Radiat. Oncol. Biol. Phys. · May 2002
Clinical TrialRadiotherapy for chordomas and low-grade chondrosarcomas of the skull base with carbon ions.
Compared to photon irradiation, carbon ions provide physical and biologic advantages that may be exploited in chordomas and chondrosarcomas. ⋯ These are the first data demonstrating the clinical feasibility, safety, and effectiveness of scanning beam delivery of ion beams in patients with skull base tumors. The preliminary results in patients with skull base chordomas and low-grade chondrosarcomas are encouraging, although the follow-up was too short to draw definite conclusions concerning outcome. In the absence of major toxicity, dose escalation might be considered.
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Int. J. Radiat. Oncol. Biol. Phys. · May 2002
Activation of the nuclear transcription factor kappaB (NFkappaB) and differential gene expression in U87 glioma cells after exposure to the cytoprotector amifostine.
Amifostine has been approved as a therapy to decrease the incidence of moderate-to-severe xerostomia in patients undergoing postoperative radiation treatment for head-and-neck cancer. As a reducing agent capable of participating in intracellular reductive/oxidative processes, it has the potential to affect redox-sensitive transcription factors and gene expression. Amifostine's active free thiol WR-1065 was investigated to determine its effect on nuclear transcription factor kappaB (NFkappaB) activation and subsequent gene expression in U87 glioma cells. ⋯ The redox-sensitive transcription factor NFkappaB can be activated in U87 glioma cells by the active thiol form of the cytoprotector amifostine. Activation of NFkappaB by the antioxidant WR-1065 is accompanied by a reduced expression of the oncogene c-myc and an enhanced expression of the antioxidant gene MnSOD, a gene whose expression in tumor cells is relatively low, but when overexpressed has been correlated with a suppression of the malignant phenotype. Activation of NFkappaB by WR-1065, however, results in selective rather than global changes in the expression of genes containing NFkappaB-responsive elements.