ABSTRACT
Objective:To provide a new morning check method for the output dose stability of the multileaf collimator (MLC) of the CyberKnife M6 (CK-M6) system.Methods:The CT images of a verification phantom with a size of 20 cm × 20 cm × 10 cm were transmitted into the Precision Treatment Plan ning System (ver. 1.1.1.1). The high-precision alignment between the accelerator output front and the fixed position of the phantom surface was achieved using the fiducial tracking method. A 10 cm × 10 cm radiation field was formed by the MLC and a DailyCheck plan with an output of 200 MU was designed. The repeatability, sensitivity, and accuracy of the DailyCheck plan were measured, and the CK-M6 system was continuously tested for one month using the artificial fixed method and the DailyCheck plan designed in this study. Results:The average and the standard deviation of 10 repeated measurements by the DailyCheck plan were 492.28 pC and 0.09, respectively, indicating good stability. There was a linear correlation between the measured values and the output dose, with a correlation coefficient of R2 > 0.999. Moreover, there was a position deviation of 2 mm between the phantom and the accelerator output front, and the result ant effect on the measured values was equivalent to a dose deviation caused by an output of 1.24 MU. The result from the continuous measurement of both the artificial fixed method and the DailyCheck plan fell within permissible limits, showing high consistency. Conclusions:The DailyCheck plan established through the fiducial tracking of a verification phantom can achieve the convenient, quick, and accurate daily detection of the output dose stability of the MLC of CK-M6. Therefore, this method can be widely applied in the clinical quality control of the CK-M6 system.
ABSTRACT
This study presents an electronic portal imaging devices (EPIDs) based on daily check tool for Linac that is usable for different cancer centers.Several images of open rectangle fields were acquired with EPID and the key items of daily Linac check were derived from the obtained images using an in-house developed automatic analysis software.The experiment results showed that each parameter calculated by this tool is as reliable as the corresponding result measured by the commercial quality assurance devices and its measuring efficiency is much higher.
Subject(s)
Electronics, Medical , Electrons , Particle Accelerators , Phantoms, Imaging , Radiometry , SoftwareABSTRACT
Objective To investigate the effect of daily quality checklist on intensive care unit (ICU) the incidence of severe patients with hospital associated infection (HAI). Methods A historical control study was conducted. In Tianjin Fifth Center Hospital from June 2016 to May 2017, 286 severe patients with mechanical ventilation (MV) and using ICU daily quality checklist were assigned as the experimental group, and from June 2015 to May 2016, 291 severe patients who did not use the daily quality checklist were selected as the control group. In the control group, the routine treatment, nursing care and ward rounds were the daily ordinary work; in the experimental group, the severe disease ICU quality checklist system was strictly carried out, and every day the doctor and nurse on duty applied the checklist to assess and verify the medical quality given to the patient, including sedation, analgesia, MV, glycemic control, nutrition, etc 16 items. The incidences of ventilation associated pneumonia (VAP), catheter-related bloodstream infection (CRBSI), catheter-associated urinary tract infection (CAUTI), 28-day mortality, time of MV and the length of ICU stay were compared between the two groups. Results Compared with the control group, the incidences of VAP, CRBSI and CAUTI of experimental group were obviously decreased (VAP: 1.78‰ vs. 5.09‰, CRBSI: 1.46‰vs. 5.21‰; CAUTI: 1.39‰ vs. 4.41‰, all P ＜ 0.05), the time of MV and the length of ICU stay in experimental group were significantly shorter than those in the control group [the time of MV (days): 7.81±2.74 vs. 10.62±3.67, the length of ICU stay (days): 8.40±1.94 vs. 11.35±2.47, both P ＜ 0.05]; there was a decreasing tendency of 28-day mortality in experimental group compared with that in control group [5.24% (15/286) vs. 6.19% (18/291)], but no statistical significant difference was seen (P ＞ 0.05). Conclusion Implementation of daily quality checklist can effectively decrease the incidence of HAI in ICU patients, reduce the time of MV and the length of ICU stay.