Unintentional Exposure of Neonates to Conventional Radiography in the Neonatal Intensive Care Units
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Journal of Perinatology (2007) 27, 579–585 r 2007 Nature Publishing Group All rights reserved. 0743-8346/07 $30 www.nature.com/jp ORIGINAL ARTICLE Unintentional exposure of neonates to conventional radiography in the Neonatal Intensive Care Units D Bader1,2, H Datz3,4, G Bartal5,6, AA Juster7,8, K Marks9,10, T Smolkin11,2, S Zangen12,10, A Kugelman1,2, C Hoffmann6,13, G Shani4, A Ben–Shlomo3, M Margaliot3 and S Sadetzki6,14 1Department of Neonatology, Bnai-Zion Medical Center, Haifa, Israel; 2B. Rappaport Faculty of Medicine, Technion, Israel Institute of Technology, Haifa, Israel; 3Radiation Safety Division, Soreq Nuclear Research Center, Yavne, Israel; 4Faculty of Bio-Engineering, Ben-Gurion University, Beer Sheva, Israel; 5Department of Radiology, Meir Medical Center, Kfar Saba, Israel; 6Sackler School of Medicine, Tel- Aviv, Israel; 7Department of Neonatology, Kaplan Medical Center, Rehovot, Israel; 8Hadassah Medical School, Hebrew University, Jerusalem, Israel; 9Department of Neonatology, Soroka Medical Center, Beer Sheva, Israel; 10Faculty of Medicine, Ben- Gurion University, Beer Sheva, Israel; 11Department of Neonatology, Rambam Medical Center, Haifa, Israel; 12Department of Neonatology, Barzilay Medical Center, Ashkelon, Israel; 13Department of Radiology, Chaim Sheba Medical Center, Tel Hashomer, Israel and 14Cancer & Radiation Epidemiology Unit, Gertner Institute, Chaim Sheba Medical Center, Tel Hashomer, Israel Higher awareness and training of the medical teams and radiographers Objective: To evaluate the extent of unintentional exposure to X-rays are required to minimize unnecessary exposure of newborns to ionizing performed during routine diagnostic procedures in the Neonatal Intensive radiation. Care Units (NICUs). Journal of Perinatology (2007) 27, 579–585; doi:10.1038/sj.jp.7211792; Study Design: During a 1-month period, 157 consecutive neonates from published online 12 July 2007 five level-III NICUs were recruited for this study. The mean birth weight was 1747±911 g (range: 564–4080 g), and gestational age was 31.6±3.6 Keywords: X-ray radiation; neonate; overexposure weeks (range: 24–41 weeks). A total of 500 radiographs were performed including chest (68%), abdomen (17%) and combined chest and abdomen (15%). The average number of radiographs taken per infant was 4.2±3.6 (range: 1–21). Unintentional inclusion of body regions Introduction other than those ordered was determined by comparing the areas that Nearly 12% of all births in Western countries are premature, with should be included in the radiation field according to International about 2% of infants born less than 32 weeks of gestation.1–3 recommendations, to those that appeared in the actual radiograph. In the last decade, the survival of preterm infants has risen to Result: A comparison of the recommended borders to the actual nearly 90%, especially of those with a very low birth weight of less boundaries of the radiographs taken show an additional exposure to than 1500 g. Even infants with a birth weight of less than 750 g 1–3 radiation in all three procedures: 85% of chest radiographs also included the have a survival rate of 55%. Advanced neonatal care has also whole abdomen, 64% of abdomen radiographs included both thigh and increase the survival of term infants with serious diseases caused by upper chest and 62% of chest and abdomen radiograph included the thigh. either congenital anomalies or a complicated neonatal course. (The range in all procedures was from ankle to upper head.) Between 2 and These high-risk infants are prone to a variety of diseases and 20% of the relevant targeted body tissues were not included in the exposed morbidities such as respiratory distress syndrome, fields resulting in missing data. The gonads of both sexes were exposed in bronchopulmonary dysplasia, patent ductus arteriosus and 1–3 7% in all chest X-rays. Among male infants, the testes were exposed in 31% necrotizing enterocolitis. of plain abdomen radiographs and 34% of chest and abdomen radiographs. During their prolonged and complicated medical course in the Neonatal Intensive Care Units (NICUs), these neonates are exposed Conclusion: In the NICUs participating in the study, neonates are to repeated diagnostic procedures that involve X-ray radiation.4–6 currently being exposed to X-ray radiation in nonrelevant body regions. Owing to the high frequency of respiratory disease and other morbidities, these infants continue to require additional X-ray Correspondence: Dr D Bader, Department of Neonatology, Bnai-Zion Medical Center, evaluations through early childhood and over time could receive 40 Golomb Street, Haifa 31048, Israel. substantial accumulating doses of radiation.4 E-mail: [email protected] Received 2 February 2007; revised 22 May 2007; accepted 19 June 2007; published online 12 Gonadal exposure to ionizing radiation of the neonate, July 2007 particularly preterm infants, is another important issue since Radiography in the Neonatal Intensive Care Unit D Bader et al 580 irradiation before adulthood may have long-term harmful effects The study population was stratified according to the infant’s on the size and function of the gonads.7–9 birth weight. Length of hospitalization (in days) and the number Detailed studies on the field size and body tissues included in of X-ray radiographs taken per infant during their particular initial each X-ray taken on these infants are scarce.10 Considering the hospital admission, was recorded. health hazards of ionizing radiation, the objective of this study was to evaluate unnecessary radiation exposure to body tissues outside Imaging technique the anatomical region of interest in five NICUs in Israel. The three most commonly performed diagnostic plain X-ray These data could be used as a first step in minimizing the risk examinations undertaken in the NICUs were investigated: chest, of radiographic examinations in infants. abdomen, and chest and abdomen (babygram). For each type of radiograph, the exposure fields were defined, and compared to those recommended by the International Methods guidelines.11–13 The acceptable minimal field size was set by Patients recognizable anatomical landmarks for specific examination. In The Institutional and Ministry of Health approvals for this study our population (during the neonatal period), the tolerance level were obtained for all NICUs and informed consent was obtained was reduced to 2.0 cm at each edge on the measured film. For from the parents of each infant. None of the parents refused to example, an ideal chest radiograph would include the lower participate in this study. Level III NICUs located in five general cervical area at the top of the radiograph and the upper edge of the hospitals participated in the study (Bnai-Zion, Barzilay, Kaplan, abdominal area at the bottom (T12\L1), while the skull, upper Soroka and Rambam Medical Centers). These NICUs are a limbs and the middle-upper abdominal area should not be representative sample, caring for 22% of all infants born each year included. The ideal abdominal radiograph would include the in Israel (144 000 deliveries in 2003). All infants admitted to the diaphragms at the top and stop just inferior to the symphysis pubis NICUs during January 2003 were eligible to participate. This (Figure 1). Violation of the International recommendation was prospective study is part of a larger study designed to evaluate defined as 2.0 cm beyond the recommended boundaries. All the dosimetry of X-rays performed in NICUs. departments participating in this study adopt the guidelines on A total of 100 plain X-ray radiographs were obtained from each Quality Criteria for Diagnostic Radiograph in Pediatrics.13 center during January 2003. The three most commonly performed Unintentional inclusion of body tissues was determined by radiographs (abdomen, chest, and chest and abdomen comparing the body tissues that should have been exposed in the (babygram)) were ordered consecutively by the NICU teams, based type of radiograph ordered, to those that appeared in the actual on the medical condition of each infant (chest radiograph for radiograph taken. Each radiograph was determined to be either in Respiratory Distress Syndrome and so on). There were no inclusion accordance or in violation of the international guidelines by the or exclusion criteria for each type of radiograph. Radiographs were principal investigator in each center. preformed by certified radiographers, day and night, as requested by the medical teams of each NICUs. The study was completed at Analysis each center during the month of the study after 100 consecutive For analysis, we derived the percent of exposure for each body plain X-ray images were taken. region by dividing the number of times a certain region was Chest X ray Abdominal X Ray Int. recommendation Int. recommendation Figure 1 International recommendation for a typical chest and abdomen X-rays. Journal of Perinatology Radiography in the Neonatal Intensive Care Unit D Bader et al 581 96% 98% 100 80% 80 74% 64% 64% 60 45% 38% 40 22% 20 10% Percentage Frequencies of Organs at Examinations 0% 0 A K T G P Ab L.C U.C N L.H U.H Exposed organs Violation of International recommendations International recommendations A-Ankle; K-Knee; T -Thigh; G-Gonads; P-Pelvis; Ab-Abdomen; L.C-Lower Chest; U.C-Upper Chest; N-Neck; L.H-Lower Head; U.H-Upper Head Figure 2 Abdomen X-ray examination, necessary and unnecessary exposure of body organs. 99% 100% 95% 100 85% 80 60 41% 40 20 13% 7% 4% 1% 2% Percentage Frequencies of Organs at Examinations 0% 0 A K T G P Ab L.C U.C N L.H U.H Exposed organs Violation of International recommendations International recommendations A-Ankle; K-Knee; T-Thigh; G-Gonads; P-Pelvis; Ab-Abdomen; L.C-Lower Chest; U.C-Upper Chest; N-Neck; L.H-Lower Head; U.H-Upper Head Figure 3 Chest X-ray examination, necessary and unnecessary exposure of body organs.