ionizing radiation has been increasingly used during the past decades for diagnosing and treating different medical conditions ( 1 ) . however , besides its diagnostic and therapeutic effects , ionizing radiation is also associated with different side effects .
severity of side effects varies with the dose , for which there is threshold value . beyond certain thresholds
, radiation can impair the functioning of tissues and/or organs and can produce acute effects such as skin redness , hair loss , radiation burns or acute radiation syndrome .
for instance , the dose threshold for acute radiation syndrome is about 1000 millisievert per year ( msv / yr ) ( 2 ) .
if the dose is low or delivered over a long period of time ( low dose rate ) , there is greater likelihood for damaged cells to successfully repair themselves ( 3 ) .
however , long - term effects may still occur if cell damage is repaired but incorporates errors , transforming an irradiated cell that still retains its capacity for cell division .
effects of this type will not always occur , but their likelihood is proportional to the radiation dose .
this risk is higher for children and adolescents , as they are significantly more sensitive to radiation exposure than adults ( 3 ) .
epidemiological studies on populations exposed to radiation showed a significant increase of cancer risk at doses above 100 msv / yr ( 4 ) .
accordingly , healthcare professionals particularly nurses are at a great risk for being exposed to harmful effects of ionizing radiation ( 5 ) .
one of the most common indications of radiological examinations is for patients who are hospitalized at intensive care units ( icu ) .
the patients in these units are usually connected to different medical devices and have many catheters and tubes in place and hence , they can not be transferred to the radiology unit for undergoing radiological examinations ( 6 ) .
being aware of the risks of ionizing radiation as well as the probability of radiation exposure and effective strategies for radiation protection is of paramount importance for all healthcare providers particularly those who work in icus . without having such awareness , healthcare professionals may either have unnecessary fear and anxiety over radiation exposure or they may fail to adopt measures to protect themselves from the adverse effects of ionizing radiation ( 8) . the highest permitted level of occupational radiation exposure is 0.25 micro sievert per hour ( sv / h ) or 20 milisievert per year ( msv / y ) ( 9 ) .
however , most hospital staff wrongly believe that all doses of ionizing radiation are harmful to humans and hence they have fear over portable radiological examinations ( 7 ) . the consequent overprotection or under protection may cause considerable damage to patients and healthcare providers health
.   studies have shown that nurses have limited knowledge of radiation safety , exposure and protection ( 8) .
evaluated radiation knowledge and attitude of 68 physicians and 76 nurses who were working in high - exposure clinical settings .
they found that more than 70% of physicians and nurses had limited knowledge regarding hazards of radiation , amount of environmental radiation of each radiological examination , and radiation protection strategies ( 10 ) .
they found that 94.7% of the technicians adopted self - protection strategies while only 26.3% of them employed strategies for protecting patients and other healthcare professionals ( 11 ) , however , in our literature review no study describing iranian nursesknowledge was found .
reliable sources indicated that there is a knowledge gap in the area of icu nurses ' knowledge and behavior concerning protection against portable radiation .
moreover , there are major conflicts between iranian nurses and hospital administrators regarding the safest place during portable radiological examinations .
accordingly , this study was conducted to fill this knowledge gap and to provide further evidence regarding nurses radiation protection knowledge and behavior .
the aim of the present study was to investigate icu nurses knowledge of radiation safety and their behaviors towards portable radiological examinations .
the study setting was the medical , surgical , and the trauma icus of shahid beheshti hospital , kashan , iran . in total
, there were 22 beds in these three icus at the time of the study .
all 45 icu nurses who were working in the study setting were recruited in the study using the census method .
we used a demographic questionnaire , a radiation protection knowledge questionnaire ( rpkq ) , and a checklist , all of which were researcher - made . the demographic questionnaire consisted of five questions related to nurses age , gender , marital status , education level , and icu work experience
the rpkq contained eleven multiple - choice questions on nurses knowledge of x - ray radiation safety .
the five items of the checklist were : going out of the unit , going to the break room , staying at the nursing station , standing behind a lead apron , and using protective equipment .   additionally , we used a geiger - mller counter ( summertown co. , usa ) for measuring real - time ionizing radiation .
this device detects and measures ionizing radiation and shows the dose of radiation on a built - in display .
furthermore , mobile imaging machines were similar in all three sectors and quality control was performed by each department of the hospital at the start of each year .
an expert panel consisting of ten nursing and radiology faculty members was invited to assess the content validity of the rpkq and the checklist .
the means of total relevance , simplicity , and clarity scores were 0.99 , 0.98 , and 0.97 , respectively .
moreover , the face validity of the instrument was assessed by asking ten practicing nurses to judge the readability , clarity , and comprehensibility of the items .
accordingly , ten practicing nurses were asked to complete the rpkq twice with a two - week interval in between .
the test - retest correlation coefficient was equal to 0.85 . in case of any portable radiological examinations during the present study , the second author ( a trained nurse ) referred to the study setting and used a geiger - mller counter to measure ionizing radiation at predetermined locations within the icu .
this device is annually calibrating at the secondary standard dosimetry lab ( ssdl ) located in karaj city of iran .
the measurement locations were nurses break room , nursing station , and behind a lead apron .
the mean of the three measurements was calculated and used for final data analysis . moreover , the same researcher observed and documented nurses radiation protection behavior during the concurrent measurement of radiation . at the end of the study , we invited the study participants to respond to the rpkq
. nurses responded to the items at the end of their shift in the presence of the second author .
the university review board and research ethics committee of kashan university of medical sciences approved this study ( approval letter no .
the objectives of the study and existence of an observer were explained to all participants .
they were all assured of the privacy of their personal information and signed a written informed consent form before participating in this study .  
the mean , standard deviation , and percentage of nurses radiation protection knowledge , the frequency of their radiation protection behaviors , and the mean of radiation dose were calculated for the final analysis .
one - sample t test was used for comparing the mean radiation dose with the highest permitted level of occupational radiation exposure .
the university review board and research ethics committee of kashan university of medical sciences approved this study ( approval letter no .
the objectives of the study and existence of an observer were explained to all participants .
they were all assured of the privacy of their personal information and signed a written informed consent form before participating in this study .
the mean , standard deviation , and percentage of nurses radiation protection knowledge , the frequency of their radiation protection behaviors , and the mean of radiation dose were calculated for the final analysis .
one - sample t test was used for comparing the mean radiation dose with the highest permitted level of occupational radiation exposure .
in total , 45 nurses were recruited in the study , yet , 44 nurses replied to the study questionnaire completely .
the age of study participants ranged between 25 and 45 years with a mean of 32  5.81 years .
the range and the mean of participants work experience were 7.39  3.89 and 1 - 15 years , respectively .  
the mean of participants radiation protection knowledge was 4.77  1.38 . the highest and the lowest scores were 2 and 8 , respectively . the highest and the lowest scored questions of the rpkq were question numbers 4 and 8 , respectively ( table 1 ) .
we found that 37 nurses ( 84% ) left the icu and missed to monitor their patients during portable radiological examinations .
table 3 shows the findings of the radiation dosimetry at different locations within the three icus .
the highest dose of radiation was related to the nursing station of the surgical icu .
the results of the one - sample t test revealed that the mean dose of radiation was significantly lower than the highest permitted level of occupational radiation exposure ( p value < 0.001 ; table 4 ) .  
also reported that while more than 70% of physicians and nurses personally believed that they had great radiation protection knowledge , their knowledge was poor to moderate ( 10 ) .
the nurses limited radiation protection knowledge can be attributed to limited college - based and in - service educations about radiation safety and protection .
aps ( 12 ) , salti and whaites ( 13 ) and ilguy et al . ( 14 ) also conducted three studies in different countries and found that dental practitioners had limited radiation safety and protection knowledge .
however , slechta , reagan and shah found that radiology technicians knowledge of x - ray radiation protection was 75 - 82% ( 13 - 16 ) .
the discrepancies among the findings of different studies can be attributed to differences in the settings , samples , and data collection instruments of the studies .  
we also found that most of the participating nurses left the icu during portable radiological examinations . in this study leaving the icu was the most common radiation protection strategy .
this finding can be related to their limited knowledge of safe distance from the source of radiation during portable radiological examinations .
however , flor and gelbcke found that nurses who worked in catheterization laboratories did not even use the basic safety equipment because they considered such equipment as heavy and uncomfortable ( 17 ) .
the conflict between our findings and the findings of flor and gelbcke can be attributed to the fact that catheterization nurses are constantly exposed to radiation and hence , they underestimate the risks of ionizing radiation and ignore the importance of using safety equipment .
the study findings also revealed that only three nurses out of the 44 participating nurses stayed at the nursing station and continued monitoring patients during radiological examinations .
nurses who leave the icu during portable radiological examinations may fail to diagnose patients accidental disconnection from mechanical ventilation devices .
such accidental disconnection can cause potential complications such as hypoxia , increased length of hospital stay , and increased mortality rate ( 18 ) .
we also found that the dose of radiation in the study setting was significantly lower than the highest permitted level of radiation exposure .
similar findings of different studies in this area demonstrate that the dose of radiation during portable radiological examinations in different locations of clinical settings is probably lower than the highest permitted level .
the findings of this study may guide nurses about the correct behaviors during portable radiological examinations .
this study was performed only in one medical center and the study sample size was small .
furthermore we used an analog dosimeter , which may not be as accurate as the digital version .
future studies with larger sample sizes and use of digital dosimeters may overcome these limitations .
the study findings indicate that portable radiological examinations do not expose healthcare providers to high doses of ionizing radiation . accordingly
, clinical settings , which have been designed and organized according to proper safety standards , can be considered safe and free from ionizing radiation during portable radiological examinations .
 background : radiological examinations for patients who are hospitalized at intensive care units are usually performed using portable radiography devices . 
 however they may require knowledge and safety precautions of nurses.objectives:the aim of the study was to investigate icu nurses knowledge of radiation safety and their behaviors towards portable radiological examinations.materials and methods : in total , 44 intensive care nurses were recruited for this cross - sectional descriptive study using census sampling during april and may 2014 . 
 the study setting was at intensive care units of shahid beheshti hospital of kashan , iran . 
 an eleven - item questionnaire and a five - item checklist were used for evaluating nurses radiation protection knowledge and behaviors , respectively . 
 an expert panel consisting of ten nursing and radiology faculty members confirmed the content validity of the questionnaire and the checklist . 
 moreover , a geiger - mller counter was used for measuring ionizing radiation during portable radiological examinations . 
 study data were analyzed using the spss software version 13.0 . 
 mean , standard deviation , frequency and one - sample t test were used for description of the data . 
 the level of significance was set at below 0.05.results:the mean of participants radiation protection knowledge was 4.77  1.38 . 
 the most prevalent radiation protection behavior of nurses was leaving the intensive care unit during portable radiological examinations . 
 only 6.8% of nurses stayed at the nursing station during radiological examinations . 
 the highest dose of radiation was 0.11 micro sievert per hour ( sv / h ) , which was much lower than the highest permitted level of radiation exposure i.e. 0.25 sv / h.conclusions : portable radiological examinations did not expose healthcare providers to high doses of ionizing radiation . 
 nurses radiation protection knowledge was limited and hence , they require in - service education programs . 
1. Background
2. Objectives
3. Materials and Methods
3.1. Ethical Considerations
3.2. Data Analysis
4. Results
5. Discussion