X-ray image intensifier performance and patient doses for combinations of supplemental beam filters and vascular contrast agents

Abstract

We present an investigation of the fluoroscopic imaging and dosimetric performances of iodine- and gadolinium-based vascular contrast agents in combination with K-absorption edge filters of atomic numbers between 50 (tin) and 82 (lead). These combinations were studied using a theoretical model for a range of diagnostic x-ray spectra (55 to 100 kVp) and for water phantoms representative of thin and thick anatomies. Performance was characterized by radiographic contrast, a derived image quality index, the patient integral and entrance skin doses, and the x-ray tube load. For a given thickness of anatomy, an optimum combination of spectrum kVp, contrast agent and supplemental filter was defined by maximum imaging performance for a minimum or tolerable x-ray tube load and patient dose. It was possible to both improve imaging performance and reduce dose by the use of an appropriate combination of spectrum kVp and filter. For gadolinium-based contrast, performance was optimized with tungsten filtration at 90 kVp for both thin and thick anatomies. It was not possible, however, to optimize the iodinated contrast performance with a single combination of supplemental filter and spectrum kVp. The optimal performance for iodinated contrast was achieved with gadolinium filtration at 60 kVp for thin anatomy and with ytterbium filtration at 80 kVp for thick anatomy. The best performance for thin anatomy was that of the combination of iodinated contrast/gadolinium filter at 60 kVp and the best performance for thick anatomy was that of the combination of gadolinium-based contrast/tungsten filter at 90 kVp.

Dose Reduction and Image Quality Optimization of Pediatric Chest Radiography Using a Tungsten Filter

“…However, these heavy element filters can only be effective if the patient’s thickness is limited to a certain range or if they are used for special medical applications. When using a bandwidth filter (K-edge filter), the appropriate tube voltage range is 70–80 kVp, which has been proven to be better for pediatric imaging, in which the subject is thin [ 18 , 19 , 20 , 21 , 22 , 23 ]. This study evaluated the radiation dose in patients with changes in image quality when pediatric chest radiography was performed using various filters.…”