EVALUATION OF PATIENT EXPOSURE IN FAST kVp SWITCHING DUAL ENERGY COMPUTED TOMOGRAPHY: PHANTOM STUDY

The aim of this study was to evaluate the suitability of size specific dose estimates (SSDE) to estimate patient dose in Fast kVp switching dual energy CT. An anthropomorphic phantom (RAN-110) was repeatedly scanned (chest, abdomen and the pelvis) using a 64 detector row MDCT (Discovery CT750 HD, GE Healthcare, Milwaukee, WI, USA) with various CT parameters, including Fast kVp switching. Dosimetry was performed using thermo-luminescent dosimeters, positioned both superficially and within the phantom. SSDE was calculated for all slices of the anthropomorphic phantom using both the localiser and axial images. In Fast kVp switching, SSDE underestimated the measured absorbed dose for the chest/abdomen region ~35% at the maximum, but were in closer agreement for the pelvic region about within 10%. In single energy techniques, SSDE could not be applied in the estimation of organ doses, but in Fast kVp switching dual energy techniques, SSDE could be applied for anatomical regions with larger thicknesses.

A new ultrasonic apparatus for ophthalmology using manuel compound scanning

A new ultrasonic equipment for ophthalmological diagnosis has been developed. Manual compound scanning using water immersion made acurate representation of cross-section of the orbital structure possible. A large, focused transducer brought resolution and sensitivity. Gray scale display of the ultrasonogram increased information concerning intensity of echoes. Ultrasonograms of retinoblastoma, vitreous hemorrhage, melanocytoma, optic disc coloboma and unilateral exophthalmos are presented.