The tariff for the no indication modality was higher or lower than the correct answer. In both situations the imposed cost was calculated as the tariff for the no indication for any modality because these modalities did not apply for diagnosis in the practice. In cases where participants marked the medical imaging modality that was appropriate for diagnosis however they did not recommend imaging as the top priority, if the tariff of the wrong answer was higher than the correct answer we considered the difference of the two NVP-LDE225 price tariffs’ as the imposed cost. If the tariff of the wrong answer was lower than the correct answer, the imposed cost was calculated as zero. For “I don’t know” responses, the median of the

costs of all mentioned Inhibitors,research,lifescience,medical choices was calculated as the imposed cost. We added all the imposed costs together and calculated the total which was subsequently divided by the total number of

respondents. The result was considered Inhibitors,research,lifescience,medical to be the imposed cost per medical student. Finally, we converted Iranian rials into US dollars. Results were reported in US dollars according to the mean of the Inhibitors,research,lifescience,medical contemporary declared currencies reported by the Central Bank of the Islamic Republic of Iran during the study period.11 Results Of the 270 medical students invited to participate, 200 (74%) responded and completed the questionnaires. Participants included 68 female externs, 44 male externs, 52 female interns and 36 male interns. Mean scores and categories of knowledge of indications for each modality and the total for the imaging modalities are shown in table 1. The mean knowledge score was 9.7 (fail) for all modalities. Similar scores were excellent for X-ray, acceptable Inhibitors,research,lifescience,medical for Doppler ultrasonography, and fail for ultrasonography, CT scan and MRI. Table 1 Knowledge of indications for imaging modalities in medical students at Shiraz University of Medical Sciences, Iran during Inhibitors,research,lifescience,medical 2011-2012 In this study, 16.5% of participants chose CT scan or MRI instead of ultrasonography for their answers. A total of 29% selected CT scan with contrast although the true answer was a scan without contrast. Approximately 14.5%

of participants selected CT scan or MRI instead 17-DMAG (Alvespimycin) HCl of X-ray modalities. Cost analysis for the non-indicated requests of imaging modalities is presented in table 2. Table 2 Cost analysis of non-indicated requests for imaging modalities prescribed by medical students of Shiraz University of Medical Sciences, Iran during 2011-2012 Discussion Medical imaging is a support for clinical workups that can improve patient outcome.1 Due to the importance of economy in modern medicine, physicians should pay attention to the high cost burden of medical imaging for health care systems and communities.4 It is noted that in our setting, the only radiology course for medical students is presented during the externship period. Students’ knowledge during the externship period directly impacts both their practice as interns and the imposed costs.