International journal of radiation oncology, biology, physics
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Int. J. Radiat. Oncol. Biol. Phys. · Oct 2004
Gamma knife surgery for trigeminal neuralgia: outcome, imaging, and brainstem correlates.
To review our results with gamma knife surgery (GKS) in the treatment of trigeminal neuralgia (TN), and to determine whether pain relief, medication usage, and the development of facial numbness are affected by trigeminal nerve compression, MRI imaging quality, or brainstem radiation dose. ⋯ Gamma knife surgery is effective in the treatment of TN and has a favorable side effect profile. Treatment response and the development of facial numbness do not correlate with MRI imaging quality, presence of nerve compression, or radiation dose to the brainstem.
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Int. J. Radiat. Oncol. Biol. Phys. · Oct 2004
MRI-based treatment planning for radiotherapy: dosimetric verification for prostate IMRT.
Magnetic resonance (MR) and computed tomography (CT) image fusion with CT-based dose calculation is the gold standard for prostate treatment planning. MR and CT fusion with CT-based dose calculation has become a routine procedure for intensity-modulated radiation therapy (IMRT) treatment planning at Fox Chase Cancer Center. The use of MRI alone for treatment planning (or MRI simulation) will remove any errors associated with image fusion. Furthermore, it will reduce treatment cost by avoiding redundant CT scans and save patient, staff, and machine time. The purpose of this study is to investigate the dosimetric accuracy of MRI-based treatment planning for prostate IMRT. ⋯ Magnetic resonance imaging is a useful tool for radiotherapy simulation. Compared with CT-based treatment planning, MR imaging-based treatment planning meets the accuracy for dose calculation and provides consistent treatment plans for prostate IMRT. Because MR imaging-based digitally reconstructed radiographs do not provide adequate bony structure information, a technique is suggested for producing a wire-frame image that is intended to replace the traditional digitally reconstructed radiographs that are made from CT information.
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Int. J. Radiat. Oncol. Biol. Phys. · Oct 2004
Interaction of amifostine and ionizing radiation on transcriptional patterns of apoptotic genes expressed in human microvascular endothelial cells (HMEC).
Amifostine is a prodrug that requires dephosphorylation by alkaline phosphatase to become activated. This process occurs rapidly within the bloodstream after its i.v. administration to patients undergoing cancer treatment with selected radiation and chemotherapies. Vascular endothelial cells will, therefore, represent a normal cell system that is among the first to experience the radioprotective effects of this agent. Amifostine's active free thiol WR-1065 was investigated to determine its effect on radiation-induced changes in transcriptional patterns and subsequent apoptosis in human microvascular endothelial cells (HMEC) growing in vitro. ⋯ WR-1065, the active thiol form of amifostine, is an effective radioprotector of HMEC as determined by use of clonogenic and apoptotic assays for cell survival. Expression profiling successfully defined the transcriptional response of HMEC to both WR-1065 and ionizing radiation exposure, either alone or in combination, and demonstrated both synergistic and antagonistic effects on the expression of different cellular genes, along with corresponding functional responses. The radioprotective effects of amifostine are not limited to its well-characterized physiochemical properties, which include free-radical scavenging, auto-oxidation leading to intracellular hypoxia, and chemical repair by hydrogen atom donation, but include its ability to modulate the complex transcriptional regulation of genes that are involved in apoptosis, cell cycle, and DNA repair.
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Int. J. Radiat. Oncol. Biol. Phys. · Oct 2004
Early FDG-PET imaging after radical radiotherapy for non-small-cell lung cancer: inflammatory changes in normal tissues correlate with tumor response and do not confound therapeutic response evaluation.
To investigate the relationship between positron emission tomography (PET) detected inflammatory changes in irradiated normal tissues and metabolic response at tumor sites in patients receiving radical radiotherapy for non-small-cell lung cancer. The prognostic significance of these changes was also studied. ⋯ Postradiotherapy inflammatory changes detected by FDG-PET are positively correlated with tumor response, suggesting that tumor radioresponsiveness and normal tissue radiosensitivity may be linked. Prognostic stratification provided by PET is not compromised by inflammatory changes if a meticulous visual response assessment technique is used.
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Int. J. Radiat. Oncol. Biol. Phys. · Oct 2004
Potential survival advantage with early androgen deprivation for biochemical failure after external beam radiotherapy: the importance of accurately defining biochemical disease status.
We analyzed our experience treating localized prostate cancer to determine the impact of androgen deprivation (AD) on clinical outcome if administered at the time of isolated biochemical failure (BF) vs. after clinical failure (clinical failure), and the associated impact of various BF definitions. ⋯ The efficacy of AD after BF varies depending on the BF definition. When an optimal BF definition is applied, early AD decreases distant metastasis and improves survival. Prostate-specific antigen elevation to >/=2 or >/=3 ng/mL above nadir seems optimal in establishing clinically significant BF and the timing of AD intervention.