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An investigation into techniques for reducing doses from neo-natal radiographic examinations
C M Wraith1, C J Martin, E J Stockdale
1Bio-Medical Physics and Bio-Engineering Department, Aberdeen Royal Hospitals NHS Trust, UK.
Insights
Infant radiography doses were reduced by 40% using faster processing and increased filtration, maintaining diagnostic image quality. This demonstrates effective methods for lowering radiation exposure in neonatal X-rays.
Area of Science:
- Medical Physics
- Radiological Sciences
- Pediatric Imaging
Background:
- Neonatal radiography is essential for diagnosing infant conditions.
- Minimizing radiation dose in infants is critical due to their radiosensitivity.
- Previous recommendations for dose reduction exist.
Purpose of the Study:
- To investigate and implement dose reduction techniques for infant radiography.
- To evaluate the impact of these techniques on image quality.
- To establish weight-based reference doses for neonatal X-rays.
Main Methods:
- Assessed image quality using test objects and phantoms.
- Evaluated clinical radiographs using European Commission (CEC) criteria.
- Implemented and tested modified X-ray system parameters (filtration, kVp, film/screen speed, processing).
Main Results:
- A 40% reduction in mean entrance dose (to 37 microGy) was achieved with optimized filtration (3.5 mm Al) and higher kVp (60 kVp).
- Faster processing chemicals also contributed to dose reduction.
- Image quality remained satisfactory with the optimized technique, reproducing 87% of features acceptably.
Conclusions:
- Optimized X-ray techniques, including increased filtration and faster processing, can significantly reduce radiation doses in infant radiography.
- Weight-based reference doses are feasible for neonatal patients.
- Maintaining diagnostic image quality is paramount when implementing dose reduction strategies.
Abstract:
A survey of radiation doses received by infants having radiography in a neo-natal unit was undertaken at Aberdeen Maternity Hospital. Options for dose reduction recommended by the CEC Lake Starnberg Group were investigated. Techniques were implemented for clinical evaluation after assessments of image quality with test objects and phantoms. Clinical image quality of radiographs was evaluated by paediatric radiologists using CEC criteria. Results revealed a clear relationship between entrance dose and patient weight, indicating that reference doses for infants could be linked to weight. At the start of the study the mean entrance dose for chest anteroposterior (AP) radiographs was 65 microGy and the dose-area product 12.3 mGy cm2 for a system with 2.5 mm aluminum filtration using 50 kVp X-rays with a 200 speed class film/screen system. A 400 speed class film/screen combination was investigated but not evaluated clinically, because the image quality was not considered acceptable. Addition of 0.1 mm copper to the filtration of the X-ray tube reduced entrance doses by 50%, but the technique was not adopted, because of a poorer image quality with only 72% of features in clinical images being reproduced to an acceptable standard, compared with 87% with the original system. Use of faster processing chemicals, an increase in filtration to 3.5 mm aluminium and a tube potential of 60 kVp resulted in a 40% reduction in mean entrance dose to 37 microGy with satisfactory clinical image quality.