Neonatal digital chest radiography– should we be using additional copper filtration?

Objectives: Copper filtration removes lower energy X-ray photons, which do not enhance image quality but would otherwise contribute to patient dose. This study explores the use of additional copper filtration for neonatal mobile chest imaging. Methods: A controlled factorial-designed experiment was used to determine the effect of independent variables on image quality and radiation dose. These variables included: copper filtration (0Cu, 0.1Cu and 0.2Cu), exposure factors, SID and image receptor position (direct +tray). Image quality was evaluated using absolute visual grading analysis (VGA) and contrast-to-noise ratio (CNR) and entrance surface dose (ESD) was derived using an ionising chamber within the central X-ray beam. Results: VGA, CNR and ESD significantly reduced (p < 0.01) when using added copper filtration. For 0.1Cu, the percentage reduction was much greater for ESD (60%) than for VGA (14%) and CNR (20%), respectively. When compared to the optimal combinations of parameters for incubator imaging using no copper filtration, an increase in kV and mAs when using 0.1mmCu resulted in better image quality at the same radiation dose (direct) or, equal image quality at reduced dose (in-tray). The use of 0.1mmCu for neonatal chest imaging with a corresponding increase in kV and mAs is therefore recommended. Conclusions: Using additional copper filtration significantly reduces radiation dose (at increased mAs) without a detrimental effect on image quality. Advances in knowledge: This is the first study, using an anthropomorphic phantom, to explore the use of additional Cu for DR neonatal chest imaging and therefore helps inform practice to standardise and optimise this imaging examination.

Influence of the use of various imaging units and projections on the radiation dose received by children during chest digital radiography

Objective To investigate the impact of the use of different imaging units and projections on radiation dose and image quality during chest digital radiography (DR) in 3- and 4-year-old children. Methods Two hundred forty 3- and 4-year-old participants requiring chest DR were included; they were divided into three groups: supine anterior-posterior projection (APP), standing APP and standing posterior-anterior projection (PAP). Each group included 40 participants who were evaluated using the same imaging unit. The dose area product (DAP) and the entrance surface dose (ESD) were recorded after each exposure. The visual grading analysis score (VGAS) was used to evaluate image quality, and the longitudinal distance (LD) from the apex of the right lung to the apex of the right diaphragm was used to evaluate the inspiration extent. Results DAP and ESD were significantly lower in the standing PAP and APP groups than in the supine APP group (P<0.05), but LD was significantly higher in the standing PAP and APP groups than in the supine APP group (P<0.05). Additionally, the pulmonary field area was significantly higher for the standing PAP group than for the standing and supine APP groups (P<0.05). The correlations between ESD, DAP, and VGAS were positive (P<0.001), showing that larger ESD and DAP correspond to higher VGAS. The correlations between ESD, DAP, and body mass index (BMI) were also positive (P<0.05), indicating that higher BMI corresponds to larger ESD and DAP. Finally, no differences in DAP, ESD, VGAS, LD, pulmonary field area, or BMI were noted between males and females (P>0.05). Conclusion The radiation dose to superficial organs may be lower with standing PAP than with standing APP during chest DR. Standing PAP should be selected for chest DR in 3- and 4-year-old children, as it may decrease the required radiation dose.

CAN SCATTER CORRECTION SOFTWARE REPLACE A GRID IN DR PELVIC EXAMINATIONS?

The purpose was to examine if scatter correction software could replace a grid while maintaining image quality and reducing radiation dose for pelvic DR examinations. Grid images was produced with 70 kV and 16mAs. Anthropomorphic- and Contrast Detail RADiography (CDRAD) non-grid images were produced with 60 kV, 80 kV and 90 kV combined with five different mAs and scatter correction software. The anthropomorphic images were analyzed by absolute Visual Grading Analysis (VGA). The CDRAD images were analyzed using the CDRAD analysis software. The results showed a total of 54.6% non-grid images were evaluated as unsuitable for diagnostic use by the VGA. The CDRAD grid images showed that the IQF_inv values were significantly different (p = 0.0001) when compared to every group of non-grid images. Hereby, the conclusion stated that the scatter correction software did not compensate for the loss in image quality due to scattered radiation at the exposure levels included in a pelvic examination.

Assessing the Effect of Packing the Sulcus on Image Quality in Equine Digital Radiography

The requirement to pack the sulcus of the equine foot as an aid to diagnostic interpretation before acquisition of dorsoproximal-palmarodistal oblique projections is debatable. The purpose of this study was to investigate the benefit of packing the sulcus in the assessment of normal anatomy. 23 cadaver limbs were radiographed in a podoblock (https://www.podoblock.com/products-page/podoblock/podoblock/). A non-packed image (NP) and a packed image (P) of the same foot were acquired. The image quality of P was graded against the reference NP by five observers, where −1=P was superior, 0=no difference between P and NP, and +1=NP was superior. Four anatomical criteria were used: the distal solar margin of the distal phalanx (DP), the vascular channels of DP, the palmar aspect of the distal interphalangeal joint and the articulation of the navicular bone with DP. A total Visual Grading Analysis Score of 0.28 indicates a preference for NP images. Packing was of benefit in only 10.8 per cent of cases. While judicious high-quality packing may be of benefit in a minority of cases, the routine packing of the sulcus in equine radiography was not found to be of benefit in the assessment of anatomical features in this study.

An investigation into the validity of utilising the CDRAD 2.0 phantom for optimisation studies in digital radiography

Objectives: To determine if a relationship exists between low contrast detail (LCD) detectability using the CDRAD 2.0 phantom, visual measures of image quality (IQ) and simulated lesion visibility (LV) when performing digital chest radiography (CXR). Methods: Using a range of acquisition parameters, a CDRAD 2.0 phantom was used to acquire a set of images with different levels of image quality. LCD detectability using the CDRAD 2.0 phantom, represented by an image quality figure inverse (IQFinv) metric, was determined using the phantom analyser software. A Lungman chest phantom was loaded with two simulated lesions, of different sizes/placed in different locations, and was imaged using the same acquisition factors as the CDRAD 2.0 phantom. A relative visual grading analysis (VGA) was used by seven observers for IQ and LV evaluation of the Lungman images. Correlations between IQFinv, IQ and LV were investigated. Results: Pearson’s correlation demonstrated a strong positive correlation (r = 0.91; p < 0.001) between the IQ and the IQFinv. Spearman’s correlation showed a good positive correlation (r = 0.79; p < 0.001) and (r = 0.68; p < 0.001) between the IQFinv and the LV for the first lesion (left upper lobe) and the second lesion (right middle lobe), respectively. Conclusions: From results presented in this study, the automated evaluation of LCD detectability using CDRAD 2.0 phantom is likely to be a suitable option for IQ and LV evaluation in digital CXR optimisation studies. Advances in knowledge: This research establishes the potential of the CDRAD 2.0 phantom in digital CXR optimisation studies.