Measurements of CTDI and DLP from CT Image Data for Paediatrics Radiological Performance Evaluation and dose Optimisation in Ghana

Abstract

Risk of developing cancer in paediatric patients is higher compared with adults and hence need for optimization strategies in paediatric medical imaging is very critical. The higher risk is attributable to the fact that children have developing organs and tissues which are more sensitive to the effects of radiation, and also they have longer life expectancy which allows more time for any harmful effects of radiation to manifest. Optimization of radiological protection is a means of adjusting imaging parameters and instituting protective measures such that required images are obtained with lowest possible radiation dose, and net benefit is maximized to maintain sufficient image quality for diagnostic purposes. Special consideration is given to the availability of dose reduction measures for paediatric imaging equipment. A unique aspect of paediatric imaging is with regards to the wide range in patient sizes and weights, therefore requiring special attention to optimization and modification of equipment, technique, and imaging parameters. Good radiographic technique for paediatrics include attention to patient positioning, field size and adequate collimation, use of protective shielding, optimization of exposure factors etc. In CT, dose reduction is optimized by the adjustment of scan parameters such as mA, kVp, and pitch in accordance with patient weight, age, region scanned, and study indication. Paediatric radiological imaging should therefore be performed by trained and experienced health personnel in the medical imaging department. The overall aim of the research was to enhance the capability of Ghana to improve the efficiency of existing modalities for paediatric medical imaging and to implement and enhance optimization techniques and methodologies for advanced paediatric medical imaging in CT. In addition to providing appropriate clinical recommendation for clinicians for dose management during CT scan. MVL DICOM application software was used to access image data during abdominal CT scan. Effective dose estimates were estimated as developed by ICRP 103 recommendations. The data collection was based on retrospective extraction of image data, using MVL platform where detailed information of the CTDI_vol and DLP were available for recording. The weighted CTDI (CTDI_W) was estimated by multiplying the volumetric CTDI (CTDI_VOL) by the pitch factor. The effective dose was estimated by the product of the region-specific normalizing constant and the dose length product on each image. For image quality Signal to Noise Ratio was estimated and compare with effective dose for dose optimisation. In conclusion, the mean dose parameters exceeded the recommended dose parameter and hence an urgent need for an action to minimise radiation dose to paediatric patients.