Characterising CT automatic exposure control systems using a CeLT phantom

Abstract

are broad stroke in nature therefore not sufficient for local DRL’s in a paediatric context. Paediatric patients are all sizes and shapes with different physiology and metabolic systems influencing the effects of radiation and therefore dose. Along with the nature of the patient the specific scanner plays an important role in determining the dose received by the patient. With the introduction of multi-slice CT scanner technology dose has been on the increase though lately with the worldwide emphasis on radiation dose reduction in CT that has been reversed, iterative reconstruction is also now being marketed as a major dose reduction (<1 mSv) technique. Following the outcome of the CT dose survey of 2010 the Medical Exposures Radiation Unit now requires CT DRL’s to be established and audited annually. This is in line with the European Medical Exposures Directive (MED), introduced into Irish law by SI 478 (2002). Mandatory paediatric protocols which are age and size based are now required along with the recording of a dose parameter such as the DLP and CTDI, caveat these are usually based on adult phantoms. Following analysis of our system prior to completing the national audit we have established our own local DRL’s which are age and size based. I will present our data over the last two years and compare them the national audit findings and international data. The challenge for paediatric imaging is to establish meaningful local DRL’s which are scanner and centre based. References