Paul C. Shrimpton

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A review of patient doses from CT examinations in the UK for 2003 has been conducted on the basis of data received from over a quarter of all UK scanners, of which 37% had multislice capability. Questionnaires were employed to collect scan details both for the standard protocols established at each scanner for 12 common types of CT examination on adults and(More)
This report summarises work undertaken in support of a European Commission (EC) Concerted Action on CT that has included both a review and further development of the framework for CT dosimetry. The system previously established by the EC for reference doses in CT (with the quantities weighted CTDI (CTDIw) and dose-length product (DLP)) has been expanded to(More)
The complex conditions of irradiation in computed tomography (CT), involving highly-collimated X-ray beams, necessitate the use of specially-defined dose descriptors such as the computed tomography dose index (CTDI). When used in a weighted form (CTDIW), this concept can describe the absorbed dose from a single slice in standard head and body phantoms. The(More)
The radiation risks from medical x-ray examinations have been evaluated as a function of the age and sex of the patient in terms, separately, of the lifetime risk of radiationinduced cancer to the patient and the risk of deleterious heritable effects appearing in the progeny of the patient. These risks have been estimated on the basis of the risk models(More)
Monte Carlo simulations of CT examinations have been performed to estimate effective doses, normalized to axial air kerma, for six mathematical phantoms representing ages from newborn to adult, and for three CT scanner models covering a range of designs. Organ doses were calculated for CT exposures of contiguous, 1 cm wide, transverse slices in each phantom(More)
Estimating the dose delivered to the patient in X-ray computed tomography (CT) examinations is not a trivial task. Monte Carlo (MC) methods appear to be the method of choice to assess the 3D dose distribution. The purpose of this work was to extend an existing MC-based tool to account for arbitrary scanners and scan protocols such as multi-slice CT (MSCT)(More)
CT has developed dramatically: scanning is faster, images are better, applications have grown and, of course, radiation doses have come down, have they not? Well, no, actually; quite the contrary in fact. When CT was new it was appreciated that it was a relatively high dose technique but there was overriding clinical justification for using it; in the brain(More)
The radiation risks from a range of medical x-ray examinations (radiography, fluoroscopy, and computed tomography) were assessed as a function of the age and sex of the patient using risk models described in Publication 103 (ICRP, 2007) and UNSCEAR (2006, Annex A). Such estimates of risk based on typical organ doses were compared with those derived from(More)