Dose optimisation in paediatric radiography – Using regression models to investigate the relative impact of acquisition factors on image quality and radiation dose

Abstract

Objective: To investigate the optimum pelvis X-ray acquisition factors for a 10-year-old child. Secondly, to evaluate the impact of each acquisition factor on image quality (IQ) and radiation dose. Method: Images were acquired using a pelvis phantom and a range of acquisition parameters; e.g. tube potential, additional filtration and source-to-image distance (SID). Automatic exposure control (AEC) was used with two orientations (head towards/away from two outer chambers) and three different chamber selections. Visual IQ was evaluated using relative and absolute-VGA methods. Radiation doses were measured by placing a dosimeter on the anterior surface of the phantom. Regression analysis was used to determine optimum parameters. Results: The optimised technique (178.8 µGy), with diagnostic IQ, was with 89kVp, 130 cm SID and with 1 mm Al + 0.1 mm Cu filtration. This technique was with the head towards the two outer AEC chambers. Regression analysis showed that SID had the lowest impact on IQ (β = 0.002 95% CI −0.001 to 0.005) and dose (β = −0.96 95% CI −0.40 to −1.53). The impact of filtration on dose (β = −76.24 95% CI −86.76 to −85.72) was higher than tube potential (β = −13.44 95% CI −14.34 to −12.53). The following impact ratios were higher on IQ than radiation dose: filtration/kVp; 11.28 times, filtration/SID; 7.01 times and kVp/SID; 0.62 times. Conclusion: Optimised parameters were identified as 89 kVp, 130 cm SID and with 1 mm Al + 0.1 mm Cu additional filtration. Regression analysis demonstrated that filtration and tube potential had the greatest effect on radiation dose and IQ, respectively.

Dose optimization in newborn abdominal radiography: Assessing the added value of additional filtration on radiation dose and image quality using an anthropomorphic phantom

“…The role of additional filtration is essentially to reduce skin dose as it removes lower-energy photons from the X-ray beam, which are completely absorbed by the patient and do not contribute to the creation of the radiological image, while increasing the radiation dose [ 14 , 15 ]. This result is consistent with multiple previous studies that have shown a reduction in radiation dose using aluminum, copper, or compound additional filtration for thoracic [16] , [17] , [18] and abdominal X-rays [ 19 , 20 ] in adults, pelvic X-rays in children [22] , [23] , [24] , and thoracic [25] , [26] , [27] , [28] and pelvic [22] X-rays in newborns.…”

“…Copper and aluminum are commonly used materials for this purpose in medical imaging. Numerous studies have demonstrated the benefits of additional filtration for thoracic [16] , [17] , [18] , abdominal X-rays [ 19 , 20 ] and even thoracic CT [21] in adults, as well as for pelvic X-rays in children [22] , [23] , [24] . In newborns, it has been shown that additional filtration can reduce radiation dose without compromising the quality of thoracic [25] , [26] , [27] , [28] and pelvic X-rays [22] .…”

Increasing Source-Object Distance: A Computed Radiography-based Strategy to Reducing Radiation Dose in Occipital-Frontal Skull X-Ray

“…AEC is designed to keep image noise constant. It automatically adjusts the tube current to ensure that photons absorbed by the air between the object and the source are replenished in sufficient quantity to produce a high-quality diagnostic image (13). In the manual exposure system, the tube current is set based on the preselected current.…”

The Influence of X-Ray Tube Current-Time Variations Toward Signal to Noise Ratio (SNR) in Digital Radiography: A Phantom Study

“…Children were used in studies on dose optimization and image quality by altering parameters, one of which was tube current-time. Radiation exposure is monitored with a dosimeter [25] and used to conduct an assessment of image quality together with the AEC variation [26].…”