![]() ![]() To improve image quality, we quadrupled the C-arm fluoroscopic X-ray dose per pulse. Methods and Materials: Conventional X-ray fluoroscopic images aremore » degraded by spurious signals and quantum noise from Iridium 192 photons, which make source verification impractical. The purpose of the current study is to introduce the mechanisms and validity of our straightforward C-arm fluoroscopic verification method. This method provided excellent image quality sufficient to detect errors, and it has been in clinical use at our institutions for 20 years. In 1996, we developed a modified C-arm fluoroscopic verification of an HDR Iridium 192 source position prevent these misdeliveries. Misdeliveries could be avoided with real-time verification methods. Even a patient's death has been reported. Purpose: High-dose-rate (HDR) brachytherapy misdeliveries can occur at any institution, and they can cause disastrous results. Nose, Takayuki, E-mail: Chatani, Masashi Otani, Yuki Real-Time Verification of a High-Dose-Rate Iridium 192 Source Position Using a Modified C-Arm Fluoroscope Moreover, the results of the studies described in this thesis contribute significantly to the establishment of standardized numerical values to be used in HDR Ir- 192 dosimetry calculations. A systematic evaluation of the pertinent radiation parameters contributes to a reduction in the overall uncertainty in HDR Ir- 192 dose delivery. Since an accuracy of 5% in the delivered dose is essential to prevent severe complications or tumor regrowth, the use of basic physical constants with uncertainties approaching 6% is unacceptable. Dose errors of up to 0.3%, 6%, and 2% can result from the use of currently accepted values for the half-life, exposure rate constant, and dose buildup effect, respectively. Uncertainty in any of the basic radiation parameters used in dosimetry calculations compromises the accuracy of the calculated dose distribution and the subsequent dose delivery. A rigorous examination of the radiation parameters of several HDR Ir- 192 sources has shown that this extension of physical data from LDR to HDR Ir- 192 may be inaccurate. Radiation Parameters of High Dose Rate Iridium - 192 SourcesĪ lack of physical data for high dose rate (HDR) Ir- 192 sources has necessitated the use of basic radiation parameters measured with low dose rate (LDR) Ir- 192 seeds and ribbons in HDR dosimetry calculations. ![]()
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