Exposure of extremely low birth weight infants to diagnostic X-Rays: a longitudinal study

Our estimates of neonatal radiation exposure fall short of reality

The purpose of this study is to evaluate radiation exposure in newborns undergoing imaging tests during the first 30 days of neonatal intensive care unit (NICU) hospitalization. A retrospective cohort study was conducted from November 2018 to April 2019 with newborns admitted to the NICU. Thermoluminescent dosimeters (TLD-100™) measured radiation emitted during imaging exams over 1 month, with a comparison between measured and estimated radiation. The cohort exhibited a median gestational age of 33.0 (31.0, 37.0) weeks, a median birth weight of 1840 (1272, 2748) g, and a median length of stay of 25.5 (11.7, 55.0) days. Eighty-four patients underwent 314 imaging tests, with an estimated radiation dose (ERD) per patient of 0.116 mSv and a measured radiation dose (MDR) of 0.158 mSv. ERD consistently underestimated MDR, with a mean difference of -0.043 mSv (-0.049 to -0.036) in the Bland-Altman analysis. The regression equation was as follows: difference MRD - ERD = -1.7 × (mean (MRD + ERD)) + 0.056. The mean estimated radiation dose per exam was 0.030 mSv, and the chest X-rays accounted for 63.26% of total exams. The median number of radiographic incidences per patient was 2 (1, 4), with 5 patients undergoing three or more exams in a single day.

CONCLUSION

Radiation exposure in these newborns was underestimated, emphasizing the need for awareness regarding associated risks and strict criteria for requesting radiological exams. Lung ultrasound is a radiation-free and effective option in managing respiratory diseases in newborns, reducing the reliance on chest X-rays.

WHAT IS KNOWN

• Radiation used in diagnostic exams is not risk-free. • Radiation risk is much higher in small Infants due to the exposure area and the prolonged expectance of life.

WHAT IS NEW

• Radiation exposure is underestimated in the neonatal population. • The study found a mean radiation exposure in neonates about 5% of the mean annual dose in the general population.

Ultrasound assessment of endotracheal tube depth in neonates: a prospective feasibility study

OBJECTIVE

To examine the reliability of a novel ultrasound (US) method for assessment of endotracheal tube (ETT) position in neonates.

DESIGN

Prospective, observational, single-centre, feasibility study.

SETTING

Level III neonatal intensive care unit.

PATIENTS

Term and preterm neonates requiring endotracheal intubation.

INTERVENTION

US measurement of the ETT tip to right pulmonary artery (RPA) distance was used to determine ETT position according to one-fourth to three-fourths estimated tracheal length for weight. US demonstration of pleural sliding and diaphragmatic movement was also assessed. Chest radiography (CXR) was performed following each intubation.

MAIN OUTCOME MEASURES

Agreement between US assessment of ETT tip position and CXR served as the gold standard. Sensitivity, specificity, positive and negative predictive values for each US method and correlation between ETT tip to RPA distance on US, and ETT tip to carina distance on CXR were assessed.

RESULTS

Forty-two US studies were performed on 33 intubated neonates. US evaluation of ETT-RPA distance identified 100% of ETTs positioned correctly: 77% deep and 80% high, demonstrating strong agreement with CXR (kappa=0.822). Sensitivity was 78%, specificity 100%, positive predictive value 100% and negative predictive value 86%. US ETT-RPA distance strongly correlated with CXR ETT-carina distance (r=0.826). No significant agreement was found between CXR and US assessment of pleural sliding and diaphragmatic movement. No adverse events were encountered during US scans.

CONCLUSION

US evaluation of ETT-RPA distance demonstrated excellent accuracy for determining ETT position in neonates compared with CXR. More research is needed to support its feasibility in clinical settings.

Radiation dose reduction for chest radiography of infants in intensive care units using a high peak kilovoltage-technique

BACKGROUND

Chest radiography is an important tool in the care of infants in intensive care units. Image optimization must be monitored to minimize radiation exposure in this susceptible population.

OBJECTIVE

To examine the use of a high tube peak kilovoltage technique to achieve radiation dose reduction while maintaining adequate image quality.

MATERIALS AND METHODS

A retrospective study was conducted. Radiation doses of chest radiographs performed in the pediatric intensive care units in our institution were calculated. The radiographs were divided into two groups based on the value of the peak kilovoltage used: above and below 60 kilovolts (kV). Image quality was blindly assessed by two fellowship-trained pediatric radiologists. Air kerma, effective dose and quality score for the high versus the low peak kilovoltage group were compared and analyzed.

RESULTS

The study included 376 radiographs. One hundred and seven radiographs were performed using peak kilovoltage values equal to or above 60 kV and 269 radiographs were performed using values under 60 kV. The average air kerma for the lower peak kilovoltage group was 56.6 microgray (µGy) (30.7-81.9) vs. 22.9 µGy (11.8-34.4) for the higher peak kilovoltage group (P<0.0001). The mean difference in effective dose between the groups was 11.68 (P<0.0001). The mean difference for the quality score was 0.06 (±0.03, P=0.10), not statistically significant.

CONCLUSION

A high peak kilovoltage technique may enable a statistically significant radiation dose reduction without compromising the diagnostic value of the image.

Radiation Exposure in the Neonatal Intensive Care Unit in Newborns and Staff

OBJECTIVE

 Portable X-rays remain one of the most frequently used diagnostic procedures in neonatal intensive care units (NICU). Premature infants are more sensitive to radiation-induced harmful effects. Dangers from diagnostic radiation can occur with stochastic effects. We aimed to determine the radiation exposure in premature infants and staff and determine the scattering during X-ray examinations in the NICU.

STUDY DESIGN

 In this prospective study, dosimeters were placed on premature infants who were ≤1,250 g at birth and ≤30 weeks of gestational age who stayed in the NICU for at least 4 weeks. The doses were measured at each X-ray examination during their stay. The measurements of the nurses and the doctors in the NICU were also performed with dosimeters over the 1-month period. Other dosimeters were placed in certain areas outside the incubator and the results were obtained after 1 month.

RESULTS

 The mean radiation exposure of the 10 premature infants, monitored with dosimeters, was 3.65 ± 2.44 mGy. The mean skin dose of the six staff was 0.087 ± 0.0998 mSV. The mean scattered dose was 67.9 ± 26.5 µGy.

CONCLUSION

 Relatively high exposures were observed in 90% of the patients and two staff. The radiation exposure levels of premature infants and staff may need to be monitored continuously.

KEY POINTS

· The premature infants are exposed to radiation due to the bedside X-rays.. · The radiation exposure levels of premature infants and staff may need to be monitored continuously.. · Measures and alternative methods to reduce radiation exposure should be encouraged..

Cost-effectiveness Analysis of Screening Extremely Low Birth Weight Children for Hepatoblastoma Using Serum Alpha-fetoprotein

OBJECTIVES

To evaluate the cost-effectiveness of screening children born at extremely low birth weight (ELBW) for hepatoblastoma using serial serum alpha-fetoprotein measurements.

STUDY DESIGN

We created a decision tree to evaluate the cost effectiveness of screening children born at ELBW between 3 and 48 months of age compared with current standard of care (no screening). Our model used discounted lifetime costs and monetary benefits in 2018 US dollars, based on estimates in the published literature. The effects of uncertainty in model parameters were also assessed using univariate sensitivity analyses, in which we changed the values for one parameter at a time to assess the effect on the estimated incremental cost-effectiveness ratio.

RESULTS

For the estimated 55 699 children born at ELBW in the US each year, this screening is associated with 77.7 additional quality-adjusted life-years (QALYs) at a cost of $8.7 million. This results in an incremental cost-effectiveness ratio of about $112 000/QALY, which is considered cost effective from a US societal perspective. For children diagnosed with hepatoblastoma, our model finds that the screening regimen is associated with a 10.1% increase in survival, a 4.18% increase in expected QALYs, and a $245 184 decrease in expected cost.

CONCLUSIONS

Screening ELBW children for hepatoblastoma between 3 and 48 months of age dominates the alternative and is cost effective from a societal perspective.

Radiation Exposure of Premature Infants Beyond the Perinatal Period

OBJECTIVES

To determine the odds of premature compared with term infants exceeding the recommended radiation exposure threshold in the first year after discharge from birth hospitalization.

METHODS

In this observational retrospective cohort study, we compared the radiation exposure of premature and term infants between 2008 and 2015 in an urban hospital system. The primary outcome was crossing the radiation exposure threshold of 1 millisievert. We assessed prematurity's effect on this outcome with multivariable logistic regression.

RESULTS

In our study, 20 049 term and 2047 preterm infants met inclusion criteria. The population was approximately one-half female, predominantly multiracial or people of color (40% African American and 44% multiracial), and of low socioeconomic status. Premature infants had 2.25 times greater odds of crossing the threshold compared with term infants after adjustment for demographics (95% confidence interval [CI]: 1.66-3.05). Adjustment for complex chronic conditions, which are validated metrics of pediatric chronic illness, attenuated this association; however, premature infants still had 1.58 times greater odds of crossing the threshold (95% CI: 1.16-2.15). When the final model was analyzed by degree of prematurity, very preterm and extremely preterm infants were significantly more likely to cross the threshold (1.85 [95% CI: 1.03-3.32] and 2.53 [95% CI: 1.53-4.21], respectively), whereas late preterm infants were not (1.14 [95% CI: 0.73-1.78]).

CONCLUSIONS

Premature infants crossed the recommended radiation threshold more often than term infants in the year after discharge from birth hospitalization.

The concordance of ultrasound technique versus X-ray to confirm endotracheal tube position in neonates

OBJECTIVE

Given the distressingly high incidence of ETT malposition in the neonatal population, patients are exposed to ionizing radiation to confirm endotracheal tube (ETT) position. Our objective is to determine if ultrasound technique is concordant with X-ray in determining whether an ETT is deeply positioned or not.

STUDY DESIGN

Prospective observational clinical trial. After obtaining informed consent, patients with an ETT who required X-ray for clinical reasons underwent sonographic evaluation of the ETT by an ultrasound technologist or pediatric radiologist, usually within the hour.

RESULTS

A total of 56 image pairs were obtained from 29 patients. Ninety-eight percent of the ultrasound/X-ray image pairs were suitable for analysis. The concordance of ultrasound with X-ray to identify deeply and not deeply positioned ETTs was 95% (53/56). The sensitivity of ultrasound to detect deeply positioned ETTs on X-ray was 86% (6/7). The specificity of ultrasound to detect ETTs that were not deeply positioned on X-ray was 96% (47/49).

CONCLUSIONS

As the largest clinical trial of its kind to date, with the greatest number of ultrasound operators, we have further established US as a feasible imaging modality to determine whether an ETT is deeply positioned or not.

Radiation exposure in 212 very low and extremely low birth weight infants

OBJECTIVE

We determined the frequency and estimated effective radiation dose (E) from conventional diagnostic radiographs for infants who had birth weight of <or=1500 g (very low birth weight [VLBW] infants) and were treated in a NICU.

METHODS

Entrance skin doses were experimentally measured for all standard weight-dependent exposure settings. For each radiograph in the radiologic file, the exposed area on the film was measured manually. Together with clinical data obtained from the Vermont Oxford Network, medical charts, and radiologic files, we estimated E. E values per radiograph and per child were compared with recommended reference values and annual natural background radiation (NBR). We used reference data to estimate the risk for radiation-induced cancers.

RESULTS

Of 212 VLBW infants, 194 required at least 1 conventional radiograph. Measured entrance skin dose varied between 11.8 and 15.0 microGy. Calculated E received was 16 microsievert (microSv; median) per radiograph and 71.5 microSv (median) per infant for the whole stay. Infants with birth weight <or=750 g, length of stay >or=16 weeks, congenital malformations, or oxygen dependence for >or=36 weeks were at risk for high numbers of radiographs and high radiation dose. Compared with the annual NBR, the median of 4 radiographs per infant contributes 12 days of NBR. We estimated that only 1 of 60000 NICU-treated VLBW infants will develop a fatal malignancy up to 15 years of age.

CONCLUSIONS

We found that NICU-treated VLBW infants had low radiation exposure compared with the annual NBR.