Neonates do not need to be handled for radiographs

Optimising image quality and radiation dose for neonatal incubator imaging

INTRODUCTION

Neonates often require imaging within incubators however limited evidence exists as to the optimal method and acquisition parameters to achieve these examinations. This study aims to standardise and optimise neonatal chest radiography within incubators.

METHODS

A neonatal anthropomorphic phantom was imaged on two different incubators under controlled conditions using a DR system. Exposure factors, SID and placement of image receptor (direct v tray) were explored whilst keeping all other parameters consistent. Image quality was evaluated using absolute visual grading analysis (VGA) with contrast-to-noise ratio (CNR) also calculated for comparison. Effective dose was established using Monte Carlo simulation using entrance surface dose within its calculations.

RESULTS

VGA and CNR reduced significantly (p < 0.05) whilst effective dose increased significantly (p < 0.05) for images acquired using the incubator tray. The optimal combinations of parameters for incubator imaging were: image receptor directly behind neonate, 0.5 mAs, 60 kV at 100 cm SID, however, if tray needs to be used then these need to be adapted to: 1 mAs at maximum achievable SID. Effective dose was highest for images acquired using both incubator tray and 100 cm SID owing to a decrease in focus to skin distance. There is significant increase (p < 0.01) in VGA between using 0.5 mAs and 1 mAs but an apparent lack of increase between 1 and 1.5 mAs.

CONCLUSION

Using the incubator tray has an adverse effect on both image quality and radiation dose for incubator imaging. Direct exposure is optimal for this type of examination but if tray needs to be used, both mAs and SID need to be increased slightly to compensate.

IMPLICATIONS FOR PRACTICE

This study can help inform practice in order to both standardise and optimise chest imaging for neonates in incubators.

A systematic review of incubator-based neonatal radiography - What does the evidence say?

OBJECTIVES

This systematic review aimed to explore the impact of incubator design (canopy, mattress, and mattress support) on neonatal imaging in terms of imaging technique, radiation dose and image quality.

KEY FINDINGS

A systematic literature review was performed by searching multiple healthcare databases. Following study selection and extraction, 7 articles were deemed eligible and included within the study. Of these 7 studies, six were experimental phantom based with the remaining one being a retrospective analysis. Four studies reported a percentage reduction in beam attenuation for incubator components ranging from 12% to 72% with one other study reporting a reduction but with no numerical data. This wide variation in radiation beam attenuation from the incubator components was correlated with image quality within five studies, two suggesting reduced image quality when using the incubator tray under the mattress support whilst the other three found no significant difference. Although the seven studies reported that incubator components reduced X-ray beam intensity, there was limited evidence on whether this required an increase in exposure factors. Only one study suggested increasing exposure parameters to accommodate for the increase in beam attenuation when using an incubator tray.

CONCLUSION

The literature clearly demonstrates that with existing incubator designs, there is considerable beam attenuation between placing the image receptor directly behind the neonate as oppose to the incubator tray. However, this radiation beam attenuation is not well correlated to neonatal radiation dose or image quality effects and therefore is very confusing when considering clinical implementation.

IMPLICATIONS FOR PRACTICE

This review highlights the need for standardisation and further optimisation work to ensure best practice for this vulnerable patient group.

Effect of comfort pads and incubator design on neonatal radiography

BACKGROUND

There has been increasing interest in patient dose reduction in neonatal intensive care units. Removing comfort pads for radiography has been identified as a potential means to decrease patient dose.

OBJECTIVE

To assess the effect of comfort pads and support trays on detector entrance exposure (DEE) and image quality for neonatal radiography, and its implication for patient dose.

MATERIALS AND METHODS

Comfort pads and support trays from three incubator and warmer systems were examined. The attenuation of the primary beam by these structures was measured using a narrow beam geometry. Their effect on DEE and image quality was then assessed using typical neonatal chest radiography techniques with three configurations: 1) both the comfort pad and support included in the beam, 2) only the support tray included and 3) both the comfort pad and support tray removed.

RESULTS

Comfort pads and support trays were found to attenuate the primary beam by 6-15%. Eliminating these structures from the X-ray beam's path was found to increase the detector entrance exposure by 28-36% and increase contrast-to-noise ratio by more than 21%, suggesting room for patient dose reduction when the same image quality is maintained.

CONCLUSION

Comfort pads and tray support devices can have a considerable effect on DEE and image quality, with large variations among different incubator designs. Positioning the image detector directly underneath neonatal patients for radiography is a potential means for patient dose reduction. However, such benefit should be weighed against the risks of moving the patient.

Imaging the neonate in the incubator: an investigation of the technical, radiological and nursing issues

Modern neonatal incubators incorporate an X-ray tray device into the mattress support structure to facilitate patient examination with minimal disturbance and distress. However, the usual method of examination is to place the image plate directly underneath the baby. Users often cite radiological reasons for not using X-ray trays but modern quantitative evidence is lacking. This work looks at the technical and clinical aspects of imaging neonates in incubators and the impact that these may have in determining the imaging protocol. A number of hospitals were surveyed to determine their current method of examination and the reasons for their preference. Experimental measurements of the radiological impact of using (or not using) the X-ray tray were performed for a range of neonatal incubators. The average dose to the image plate was 5.9 microGy (range 5.4-6.4 microGy) for the "plate on mattress" method and 3.0 microGy (2.0-3.8 microGy) when using the tray--a 49% reduction owing to the mattress support materials. However, when using a computed radiography (CR) imaging system, the image quality differences were marginal. Survey results indicated that nurses preferred to use the tray but that radiographers were reluctant. We conclude that incubator manufacturers could do much to improve the radiological performance of their equipment and we offer recommendations. We also conclude that, with appropriate nurse and radiographer training and the advent of CR imaging systems, use of X-ray tray facilities may optimize imaging of the neonate in the incubator.

Revisit image control for pediatric chest radiography

PURPOSE

The aim of this study was to analyze the fraction defectiveness and efficacy of the patient immobilization device (PID) for pediatric chest radiography.

MATERIALS AND METHODS

We examined 840 plain chest radiographs in six hospitals, including four children's hospitals and two general hospitals. The mean age of the patients was 1.9 years (range 0-5 years). Two board-qualified pediatric radiologists rated (into three grades, by consensus) the degree of inspiration, rotation, lordosis, scoliosis, and cutoff or coning as well as the quality of the chest radiographs.

RESULTS

The incidence of "poor" and "very poor" quality examinations was 2/140 and 3/140 in each of two children's hospitals using PID. The corresponding figures were 9/139 and 17/140 in the two children's hospitals that did not use PID. The general hospital using PID had 14/140 "poor" and "very poor" examinations. The general hospital that did not use PID had 28/140 "poor" and "very poor" examinations. Thus, statistically better quality chest radiography was obtained with the use of PID (P < 0.001). Likewise, rotation, lordosis, and scoliosis were less frequently diagnosed as present when PID was used (P < 0.001, 0.001, 0.05). Cutoff or coning had no relation to the use of PID (P = 0.13). No significant difference was found between the degree of inspiration and the use of PID (P = 0.56).

CONCLUSION

Fraction defectiveness in the general hospital that did not use PID was as much as 14 times higher than that of the children's hospitals that used PID. The patient immobilization device is recommended for hospitals with technologists not specifically trained for pediatric examination.