This Article Figures Only Full Text Full Text (PDF) Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Duggan, L Articles by Kron, T Search for Related Content PubMed PubMed Citation Articles by Duggan, L Articles by Kron, T

Investigation of dose reduction in neonatal radiography using specially designed phantoms and LiF:Mg,Cu,P TLDs

¹ Newcastle Mater Misericordiae Hospital, Department of Radiation Oncology, Waratah NSW 2298, ² University of Newcastle, School of Mathematical and Physical Sciences (Physics) Callaghan NSW 2308 and ³ University of Newcastle, School of Health Sciences (Medical Radiation Science), Callaghan NSW 2308, Australia

Many departments still do not use recommended radiographic parameters to X-ray neonates. Direct, accurate dose measurements of individual examinations may assist a department in justifying technique modifications that provide a substantial dose reduction without a significant loss of image quality. The aim of this study was to investigate dose reduction techniques for neonates in the intensive care unit. Alterations in beam energy (kVp and filtration) and collimation were investigated using specially designed phantoms mimicking a 700 g and 2000 g neonate, and ultrasensitive LiF:Mg,Cu,P thermoluminescence dosimeters (TLDs).

Differences in entrance surface dose (ESD) and dose at depth (3 cm or 5 cm) were compared for two, overlapping fields centred individually on the chest and abdomen (Technique 1) and one large chest-abdomen field (Technique 2 or babygram). The large phantom was irradiated at 54 kVp, 60 kVp and 70 kVp without additional filtration and at 66 kVp and 70 kVp with a rare-earth hafnium filter. Focus–film distance (FFD) and mAs were adjusted to maintain optical density (OD) on each radiograph.

The baseline dose at 54 kVp and 100 cm FFD was (46±2) µGy. Increasing the tube potential from 54 kVp to 70 kVp without additional filtration reduced the ESD by 27%. However, the addition of a 0.05 mm hafnium filter at 66 kVp further reduced the radiation dose by 13%, to produce an ESD of (28±2) µGy. All contrast details were observable at 66 kVp with hafnium filtration.

Technique 1 may lead to an increase in effective dose due to field overlap, which diverges at depth, and increased scatter at the periphery of the fields.