Abstract
Background
Radiological examinations are critical for the evaluation of many disorders in daily practice.
Purpose
To determine the knowledge of ionizing radiation and radiological imaging techniques among physicians of various grades.
Material and Methods
A cross-sectional survey was carried out of 55 physicians with a mean age of 35.7 ± 6.0 years (age range 25–52 years) in a university hospital. A questionnaire which tested physicians’ information about ionizing radiation and their risks was distributed by medical school students.
Results
Among the participants, 32 (58.2%) were consultants and 23 (41.8%) were residents. The mean score was 68.2 ± 11.1 (range 37.8–91.8) out of 100. Consultants’ points were lower than residents (p = 0.040). Consultants had significantly higher frequency of incorrect answer than residents in the question about ‘whether CT scan increases lifetime cancer risk’ (p = 0.036).
Conclusion
Medical practices in years do not enhance the level of the awareness regarding the ionizing radiation.
Most of the radiological approaches, particularly computed tomography (CT), use ionizing radiation which has long been shown to have adverse effects on biological systems. Furthermore, many studies have indicated that the comprehension regarding the harmful effect of ionizing radiation on human body has been underestimated among the physicians, requesting radiological procedures, for the identification and assessment of encountered diseases (1–8).
The purpose of the present study was to determine the difference among physicians of various grades concerning the awareness of undesirable consequences of radiological imaging techniques (RITs) on human body and trigger their attention regarding the hazardous impact of various procedures working with ionizing radiation on patients’ health.
Material and Methods
A cross-sectional survey was carried out among the referring physicians working at the hospital of university with the capacity of 400 beds. Initially it was planned to include 202 physicians into the present study; however, 147 of these physicians were excluded from the study since either they declined to participate in the study or they did not answer the questions. Therefore, 55 physicians (11 women [20%] and 44 men [80%]; mean age 35.7 ± 6.0 years; age range 25–52 years) were included in the present study. The questionnaire was distributed to only clinic departments’ physicians ordering the radiological examinations by the medical school students. To prevent study bias and physician self education through asking questions and reading related materials they were not allowed to use any materials or sources during the test.
The questionnaire consisted of 15 questions with various subquestions (in total 37) evaluating the following information: (a) demographic data; (b) awareness of physicians concerning the harmful effect of ionizing radiation and and RITs; (c) how precisely they were able to estimate the radiation doses exposed during the routine RITs in comparison to a single PA chest radiography (the answers to this question were assessed according to the UNSCEAR 2008 report (9) and previously reported similar studies (2) (Table 1); and (d) the degree of their consciousness regarding the increased threat of developing lifetime cancer for the patient owing to being exposed ionizing radiation during CT scan. For the evaluation of the questionnaire, 2.7 points were given for each correct answer, and the score per participant was assessed out of a total of 100 points. Informed consent was obtained from all the participants.
Questionnaire: Estimate the dose in a single PA chest radiography (Z6*) equivalents of the following radiological examinations
*From UNSCEAR 2008 report (9)
†From Shiralkar et al. (2)
X = accurate range
Statistical analysis
Statistical analysis was done using a SPSS version 13.0 statistical programme (SPSS Inc., Chicago, IL, USA). Data were analyzed statistically by the t-test and Chi-square test. All parametric results were expressed as mean ± SD for each group. Local statistical significance was assumed as p < 0.05 for all parameters.
Results
Among the participating physicians, 32 (58.2%) were consultants, 23 (41.8%) were residents.
All of the residents knew that sonographic examination (US) and magnetic resonance imaging (MRI) do not use ionizing radiation, but radiography does. For the same modalities, the frequency of correct answers of the consultants were lower than the residents, and even 6.2% of consultants answered the question as roentgen does not use ionizing radiation; 12.5% of the consultants still did not know that both CT and mammography use ionizing radiation.
The frequency of the correct answers to the question of ‘what is the dose in a single PA chest radiography equivalents of the following radiological examinations?’ was again higher among the residents in comparison to the consultants. Overall, while most of the participants in both groups (91.3% of the residents and 71.9% of the consultants) successfully estimated the radiation dose of abdominal radiography when compared with a single PA chest radiography, they failed to estimate the doses of abdominal CT (30.4% of residents, 9.4% of consultants), leg arteriography (8.7% of residents, 6.3% of consultants) and barium meal (26.1% of residents, 12.5% of consultants).
When scoring was done for each correct answer for the questions asked in the present survey, the mean score was 68.2 ± 11.1 (range 37.8–91.8) out of 100. No difference was noticed among the points received by the physicians with regard their practice in years (≥10 years [47.3%] versus ≤10 years [52.7%]) (p = 0.521) and their gender (p = 0.497). However, the consultants’ points (mean 66.5 ± 12.4, range 37.8–91.8) were significantly lower than those of the residents (mean 72.5 ± 7, range 56.7–86.4) (p = 0.040). Two groups were compared according to their answers to each question. The assessment for the answers in response to the question of ‘whether CT scan increases lifetime cancer risk’ showed that the consultants had significantly higher frequency of incorrect answer (40.6%) than the residents (13%) (p = 0.036).
Discussion
The main finding of the present study was that the knowledge level of the residents concerning ionizing radiation and RITs was higher than the consultants. To the best of our knowledge, this is the first study showing such difference between the residents and the consultants regarding their awareness on various RITs.
Several studies, including one performed in Turkey (6), showed that many physicians did not realize that US and MRI do not use ionizing radiation (2, 3, 5–8). The percentage of incorrect answers for the question of ‘whether MRI or US use ionizing radiation’ asked by the previous studies is shown in Table 2. Overall, the awareness of the physicians regarding the ionizing radiation and RITs was higher at the present study than the previous reports (2, 3, 5). The US and MRI are preferable alternative imaging modalities instead of CT, especially for pediatric patients since children are more radiosensitive than adults (10, 11).
Comparison of the percentage of incorrect answers of studies asking whether MRI/US use ionizing radiation
In their study Lee et al. directed the question of ‘whether CT scan increases lifetime cancer risk’ to emergency department physicians and radiologists. They reported that only 9% of emergency department physicians and 47% of radiologists were aware of the fact that CT scans increases the risk of lifetime cancer (4). Moreover, the availability of the state art of the recent high-speed multidetector row CT technology creating more defined images and new applications, attracts the use of CT scans more than ever (4, 12).
Various studies indicated that the length of professional experience, field of clinical training, and hierarchical position of the non-radiologists did not have a significant influence on the estimation of effective doses of different radiological procedures used on the thorax (13). Moreover, at their study Arslanoğlu et al. reported that the number of the physicians having more than 10 years in practice answered incorrectly the question of ‘whether MRI uses ionizing radiation’ is higher than those participants having less experience in years. They suggest that since MRI is a relatively new technique, physicians have been working more than 10 years in practice might have less knowledge about this technology (6).
Similar other studies reported that physicians were unable to accurately estimate the doses that used during some RITs in comparison to the dose used during a single PA chest radiography (1–6). Likewise, Lee et al. showed that only 5% of radiologists accurately estimated the dose used during the single CT scan compared with the dose used during a single PA chest radiography (4). Higher ratios of under-estimations of the radiations that a particular RIT uses could be another reason for the physicians for feeling free to order much more radiological procedures before considering their threat to patients’ future health.
Increasing the knowledge of the physicians on the radiation hazards is a part of radiation protection programs (14). In our university, all residents underwent a ‘Resident Basic Orientation Course’ providing fundamental scientific facts regarding various RITs. As part of this course, they were prompted to ask themselves following questions before ordering a radiological examination: ‘Do I really need this radiological approach for the diagnosis of the problem?’, ‘Are there radiation-free alternative approaches or with low radiation-risk?’ The doses of CT and other radiological examinations were also argued in the lesson. The results of the present survey showed that these types of courses were effective for augmenting the level of awareness of the residents about the undesired effect of the discrete RITs. Several studies reported that radiological safety courses were offered to doctors in order to decrease the number of unnecessary examinations, however, it was also demonstrated that these educational courses by themselves were not enough (1–3, 15).
A limitation of the study is that the dose ranges for specific exams may vary more than the ranges given as correct answers in the quesionnaire.
In conclusion, the present work implies that medical practices in years do not enhance the level of the awareness regarding the ionizing radiation and RITs. Therefore, on-the-job training and relevant courses are critical to increase the effective and justified use of RITs by the doctors and to prevent the use of unnecessary radiation techniques. Courses introducing the scientific facts regarding the RITs should be started in medical schools and continue as part of the jobsite training. Even though national radiology associations are responsible for education of the radiologists on the proper use of RITs, radiologists should support and share their experiences among themselves personally.
Footnotes
ACKNOWLEDGEMENTS
The authors thank Hikmet Basar and Ali Cicek for their help.