Journal of

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Background: The aim of this study is to explore the safety and diagnostic performance of dual-source CT scan in comparison with single source CT scan and conventional angiography in patients with coronary heart diseases.
Materials and methods: A systematic review was performed using CRD standard methods. The Cochrane Library, MEDLINE, EMBASE، Google Scholar and TRIP were searched up to April 2009. The references of the marked studies and gray literature were also searched.

Results: 17 articles were included. 9 articles reported the safety and 12 articles reported the diagnostic performance of DSCT.  Generally DSCT was a non-invasive and safe procedure.  Using DSCT the exposure of patient to X-ray was less than 64-slice single source CT (SSCT) and more than conventional angiography. For the DSCT the mean sensitivity was 90.4%, mean specificity was 82%, mean PPV was 83% and mean NPV was 96%. For the SSCT the mean sensitivity was 90.4%, mean specificity was 82%, mean PPV was 83% and mean NPV was 96%. The mean sensitivity, specificity, PPV and NPV of DSCT were slightly higher than SSCT.

Conclusion: DSCT is a noninvasive and relatively safe technology. The diagnostic performance of DSCT is higher than SSCT, but its performance is not so much high to be able to substitute the conventional invasive angiography which is still the gold standard test.

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Background: According to the importance of health and treatment, it is necessary to use suitable models for planning and setting surgery time. In this study, a mathematical model is offered for operational scheduling of surgeries at surgery rooms of hospitals.
 
Material and Methods: This is an applied study and its data is related to the surgery rooms of Zahedan Al-Zahra eye hospital. Study population was the surgeries performed in March 2016. The mathematical model of scheduling surgeries at the surgery room was optimized in MATLAB₂₀₁₄.
 
Results: Due to limitations on patient admission capacity in hospital surgery ward, 79 surgeries were called off. In the proposed model, the total waiting time index for performing surgeries was 1547.29, and this index was found to be 1842 without the use of the model. Therefore, the waiting time index was improved by 16%. In accordance with the third purpose (objective) function, the tally of delays for predicted surgery ending time in one month was estimated to be 69.15 hours. The process of each surgery includes four defined activities. The end time of the activities related to each surgery has been examined and it has been optimized according to the existing limitations.
 
Conclusion: The proposed model can improve the waiting time by 16% and makes it possible to choose the surgical procedures that should be canceled and delayed according to medical priorities.