International journal of radiation oncology, biology, physics
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Int. J. Radiat. Oncol. Biol. Phys. · Jan 2008
Improving patient safety in anesthesia: a success story?
Anesthesia is necessary for surgery; however, it does not deliver any direct therapeutic benefit. The risks of anesthesia must therefore be as low as possible. Anesthesiology has been identified as a leader in improving patient safety. ⋯ Studies of error during anesthesia and Closed Claims studies have identified sources of risk and methods to reduce the risks associated with anesthesia. These include changes in technology, such as anesthetic delivery systems and monitors, the application of human factors, the use of simulation, and the establishment of reporting systems. A review of the important events in the past 50 years illustrates the many steps that have contributed to the improvements in anesthesia safety.
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Int. J. Radiat. Oncol. Biol. Phys. · Jan 2008
Randomized Controlled Trial Multicenter Study Comparative StudyPreoperative chemoradiotherapy for rectal cancer: randomized trial comparing oral uracil and tegafur and oral leucovorin vs. intravenous 5-fluorouracil and leucovorin.
To compare, in a randomized trial, 5-fluorouracil (FU) plus leucovorin (LV) (FU+LV) vs. oral uracil and tegafur (UFT) plus LV (UFT+LV) given concomitantly with preoperative irradiation in patients with cT3-4 or N+ rectal cancer. ⋯ Although this study lacked statistical power to exclude clinically significant differences between both groups, the outcome of patients treated with UFT+LV did not differ significantly from that of patients treated with FU+LV, and hematologic toxicity was significantly lower in the experimental arm.
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Int. J. Radiat. Oncol. Biol. Phys. · Jan 2008
Siemens multileaf collimator characterization and quality assurance approaches for intensity-modulated radiotherapy.
Application of the multileaf collimator (MLC) has evolved from replacing blocks to create treatment fields to creating photon fluence modulation for intensity-modulated radiotherapy (IMRT). Multileaf collimator system performance requirements are far more stringent for such applications and will require increased performance for future applications, such as motion tracking. This article reviews Siemens MLC systems, including a technical description and dosimetric characteristics of 56-, 82-, and 160-leaf designs. ⋯ Measured values of X-ray transmission (intra-leaf, inter-leaf, and through abutting leaf pairs) and penumbra (leaf end, leaf tongue, leaf groove) are presented with an evaluation of their characterization by a treatment-planning system. The dosimetric impact of planning system model inadequacies is demonstrated for collimator scatter, dose profile values within 30 mm of the field edge, and the resultant effect demonstrated on clinical cases. Finally, a description of automated quality assurance delivery, analysis, and calibration protocols applicable for the specific vendor's system is provided.
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Int. J. Radiat. Oncol. Biol. Phys. · Jan 2008
Multileaf collimator characteristics and reliability requirements for IMRT Elekta system.
Understanding the characteristics of a multileaf collimator (MLC) system, modeling MLC in a treatment planning system, and maintaining the mechanical accuracy of the linear accelerator gantry head system are important factors in the safe implementation of an intensity-modulated radiotherapy program. We review the characteristics of an Elekta MLC system, discuss the necessary MLC modeling parameters for a treatment planning system, and provide a novel method to establish an MLC leaf position quality assurance program. ⋯ The sensitivity of this test for determining the relative leaf positions was observed to be better than 0.1 mm. The Elekta MLC leaf position accuracy measured with this system has been better than 0.3 mm.
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Int. J. Radiat. Oncol. Biol. Phys. · Jan 2008
(125)I monotherapy using D90 implant doses of 180 Gy or greater.
The purpose of this study was to characterize the oncologic results and toxicity profile of patients treated with (125)I implants using the dose delivered to 90% of the gland from the dose-volume histogram (D90) of greater than 144 Gy. ⋯ Patients with a minimum D90 of 180 Gy had outstanding local control based on prostate-specific antigen control and biopsy data. Toxicity profiles, particularly for long-term urinary and sexual function, were excellent and showed that D90 doses of 180 Gy or greater performed using the technique described were feasible and tolerable.