Introduction to seminar in radiation dose reduction

Exposing the thyroid to radiation: a review of its current extent, risks, and implications

Radiation exposure of the thyroid at a young age is a recognized risk factor for the development of differentiated thyroid cancer lasting for four decades and probably for a lifetime after exposure. Medical radiation exposure, however, occurs frequently, including among the pediatric population, which is especially sensitive to the effects of radiation. In the past, the treatment of benign medical conditions with external radiation represented the most significant thyroid radiation exposures. Today, diagnostic medical radiation represents the largest source of man-made radiation exposure. Radiation exposure related to the use of computerized tomography is rising exponentially, particularly in the pediatric population. There is direct epidemiological evidence of a small but significant increased risk of cancer at radiation doses equivalent to computerized tomography doses used today. Paralleling the increasing use of medical radiation is an increase in the incidence of papillary thyroid cancer. At present, it is unclear how much of this increase is related to increased detection of subclinical disease from the increased utilization of ultrasonography and fine-needle aspiration, how much is due to a true increase in thyroid cancer, and how much, if any, can be ascribed to medical radiation exposure. Fortunately, the amount of radiation exposure from medical sources can be reduced. In this article we review the sources of thyroid radiation exposure, radiation risks to the thyroid gland, strategies for reducing radiation exposure to the thyroid, and ways that endocrinologists can participate in this effort. Finally, we provide some suggestions for future research directions.

Pediatric dose reduction in computed tomography

An appropriate balance between risk (radiation dose) and benefit (based on image quality) for computed tomography (CT) in children is essential. This balance comes through an understanding of CT dose, why we do pediatric CT, and how we do pediatric CT. The following material, then, will approach radiation dose in the context of a larger safety program, and address the challenges with determining radiation dose in contemporary CT technology. Unique considerations with respect to study quality, those factors which influence CT use, and strategies for dose reduction (that is, optimization) will also be reviewed.

Common tasks and problems in paediatric trauma radiology

Scope of this article is to give practical hints for the most common, typical and important topics of trauma radiology in children to those radiologists who are not exclusively occupied with paediatric imaging. Due to the increased radiation sensitivity of children compared with adults balancing radiation protection and necessary image quality is of utmost importance. Outlines for this optimisation process are given. Especially in imaging of the extremities perhaps the greatest difficulties are posed by the dynamically changing face of the immature, growing, only partially ossified skeleton. Lack of experience must be compensated by meticulous comparison with the normal skeletal development as shown in standard textbooks, and by knowledge of the radiological image of the developmental variants. Besides general remarks about paediatric trauma radiology, some important topics are discussed into more detail. Especially the elbow joint poses a challenge for those less experienced with its radiological appearance in children. More than in adults, ultrasound should remain the primary imaging modality of choice especially in the assessment of abdominal trauma, and CT be tailored to radiological and clinical findings. Imaging and diagnosis of non-accidental injury (NAI) may be a less common task for the general radiologist, however, the severe social implications of physical child abuse mandate a basic knowledge about the radiological symptoms and the imaging management of this problem for all physicians occupied with paediatric radiology.