ABSTRACT
Background: breast cancer survival has been analyzed by many standard data mining algorithms. A group of these algorithms belonged to the decision tree category. Ability of the decision tree algorithms in terms of visualizing and formulating of hidden patterns among study variables were main reasons to apply an algorithm from the decision tree category in the current study that has not studied already
Methods: the classification and regression trees [CART] was applied to a breast cancer database contained information on569 patients in 2007-2010. The measurement of Gini impurity used for categorical target variables was utilized. The classification error that is a function of tree size was measured by 10-fold cross-validation experiments. The performance of created model was evaluated by the criteria as accuracy, sensitivity and specificity
Results: the CART model produced a decision tree with 17 nodes, 9 of which were associated with a set of rules. The rules were meaningful clinically. They showed in the if-then format that Stage was the most important variable for predicting breast cancer survival. The scores of accuracy, sensitivity and specificity were: 80.3%, 93.5% and 53%, respectively
Conclusions: the current study model as the first one created by the CART was able to extract useful hidden rules from a relatively small size dataset
ABSTRACT
Background: Radiotherapy has been used to treat many types of cancers over the past years. Radiotherapy generates side effects on normal tissues
Radiosensitizer products provide decrease in tumor proliferation and reduce radiation dose in radiotherapy. Docosahexaenoic Acid [DHA] as an omega-3 polyunsaturated fatty acid has anti-proliferative effects on malignant cells. In this study, the effects of DHA accompanied by ionizing radiation on growth rate and survival fraction of HT29 colorectal cancer cells were evaluated
Methods: The present study was performed at the Institute of Biotechnology, affiliated to Urmia University, Urmia, Iran in the year 2013. In this laboratory experiment, malignant cells were cultured in RPJVfl-1640 supplemented with 10% fetal bovine serum. HT-29 cells were cultured at 5xl05 cells/well into 6-well culture plates for overnight. Thereafter, the cells were pretreated with either 50 or 100 uM DHA for 4 hours and malignant cells were irradiated with either dose of 2 or 10 Gy. Cell viability was evaluated by trypan blue staining after 48 hours
Moreover, malignant cells were pretreated with either 50 or 100 uM DHA for 48 hours and irradiated with dose of 2 to 10 Gy. Thereafter, survival rate was evaluated by 3-[4,5-Dimethylthiazol-2-Yl]-2,5-Diphenyltetrazolium Bromide [MTT] assay after 6 days
Results: Cell viabilities were found to be 59.8% and 17.5% for 50 uM DHA in combination with doses of 2 and 10 Gy respectively. Using 100 uM DHA diminished cell vi-ability up to 47% and 13.9% following doses of 2 and 10 Gy respectively
Treatment of cells with DHA accompanied by increasing doses of y-rays significantly diminished survival rate. In treated cells with 50 and 100 uM DHA, survival rate were measured to be 79.1%, 57.6%, 42.8%, 40.5%, 34% and 55.8%, 43.7%, 33.6%, 27.9%, 23.5% for doses of 2,4, 6, 8 and 10 Gy respectively
Conclusion: Our study indicates that DHA decreases colorectal cancer cells proliferation and could provide a new radiosensitizer drug to enhance the efficacy of colorectal cancer radiotherapy
ABSTRACT
Picture Archiving and Communication System [PACS] provides the possibility of electronic transfer and storage of medical images in different units of treatment and educational centers. The aim of this study was to determine the problems and obstacles related to implementation of PACS in Urmia Imam Khomeini hospital. In this descriptive study, 88 physicians, nurses, radiographers, health information managers and executive managers in Urmia Imam Khomeini hospital were assessed. The sample size was accordance to the size of population; so, the census method was used for sampling. Data collection was performed by two questionnaires. The validity and reliability of the questionnaires were confirmed by content validity and test-retest method respectively. The four areas composed of human resources, management, organizational and technological factors which evaluated with those questionnaires. The data analysis was conducted based on the descriptive analysis. Results in four areas showed that the knowledge of employees and managers with the concept of PACS was 43.1% and 83.3% respectively. The findings also indicated that the interest of employees and managers to implementing such a system were 80% and 66.7% respectively. Based on the opinions of both managers and employees, it was found that the lack of awareness of hospital executive managers was the most important obstacle in the implementation of the PACS. Considering the progress in the medical informatics domain and applications of health information systems, it is necessary that the executive managers apply such systems in hospitals
ABSTRACT
Introduction: scatter radiation is one of the major sources of error in nuclear medicine data processing. Different methods of scatter correction have been introduced in order to improve the quality of data. However the best method is to avoid recording of scatter photons in acquisition. The only difference between scattered and non-scattered photons is the energy. Pulse height analyzer is the only option available to discriminate primary photons from scattered ones. Energy resolution of the gamma camera is gradually improving consequently the energy window width has to be decreased accordingly. In this study we tried to determine the most appropriate energy window width for present gamma camera systems
Methods and Materials: since it is not possible to retrieve the data spectrum from the most of the gamma camera systems, a simple method was developed to extract the data from the image of the energy spectrum. Using a scatter phantom different level of scatter and count rate were generated and corresponding energy spectrum data were analyzed. It was assumed that around the peak of the spectrum, the primary photons obey a Gaussian distribution
Results: the data were analyzed using three different methods. All methods prove that the optimum window width regarding the present gamma camera energy resolution is 15%. At this level, the scattered radiation is decreased to 5%. In comparison to the conventional widow width of 20%, the sensitivity does not change dramatically
Conclusion: at the present, for most gamma camera, the energy window width of 20% is recommended. However occasionally energy window width of 15% and 25% are also used. In this study the energy spectrum at different levels of scatter were analyzed and the most suitable energy window width was found to be 15% for the gamma camera having approximate energy resolution of 11%. At this window setting the scatter decreases to 5% of the total counts recorded. Visually the quality of the images dose not improves significantly. However accuracy of data quantification improve significantly