VI p (deel 1): Numerieke simulatie van het precisie spuitgietproces

A review with 3 refs. Thermal and flow-induced stress, d. variations, creep, and moisture absorption affect the dimensional precision of injection-molded products, but these phenomena are hard to understand. No abs. statements can be made with regard to the dimensional precision of injection-molded products at given material properties and process conditions. But the effect of process conditions and material properties can be estd. and, what's even better, understood with simulations, as discussed in this article on

Dose management in CT facility

Computed Tomography (CT) examinations have rapidly increased in number over the last few years due to recent advances such as the spiral, multidetector-row, CT fluoroscopy and Positron Emission Tomography (PET)-CT technology. This has resulted in a large increase in collective radiation dose as reported by many international organisations. It is also stated that frequently, image quality in CT exceeds the level required for confident diagnosis. This inevitably results in patient radiation doses that are higher than actually required, as also stressed by the US Food and Drug Administration (FDA) regarding the CT exposure of paediatric and small adult patients. However, the wide range in exposure parameters reported, as well as the different CT applications reveal the difficulty in standardising CT procedures. The purpose of this paper is to review the basic CT principles, outline the recent technological advances and their impact in patient radiation dose and finally suggest methods of radiation dose optimisation