Using 3 5 mm X-ray beam collimation, it took 30 50 s to scan the patient's abdomen and pelvis, which led to breathing artifacts in many patients.
The mouse was placed in a light-tight box and irradiated by X-rays (75 kVp, 0.24 mA, 331 mm X-ray tube to mouse distance, 30 s exposure).
The geometry parameters were chosen as follows: detector-sample distance = 21 mm, X-ray tube-sample distance = 16 mm, detector-X-ray tube angle = 45° and sample-X-ray tube angle = 90°.
The SOMATOM Sensation Cardiac 64 CT system (Siemens Japan CO., LTD., Tokyo, Japan) was used and operated at the following settings: X-ray tube voltage 120 kV, tube current 770 850 mA s, collimation 32 rows × 0.6 mm, X-ray tube rotation speed 0.33 s/rot, helical pitch 0.2, and field of view 200 mm.
To minimize the beam hardening artifacts a 0.5 mm aluminum X-ray beam filter was used to attenuate soft X-rays at the source.
The collector was designed to converge a ϕ 100 mm parallel X-ray beam into a ϕ 4 mm focus.
The X-ray source is a 50 kVp X-ray tube with a silver target with a filter to centre the X-ray spectrum on 22 keV.A 100 mm diameter X-ray image intensifier (XRII) is used to collect the two-dimensional projection images.
The error associated with the use of conventional plane x-rays to measure FO was found to be 3.5 ± 2.5 mm, the x-ray technique generally underestimating the measure of FO.
However the analysis for the black materials may be semi-quantitative because the black materials are as thin as less than 0.2 mm and X-ray penetrates into the under layer such as sandstone, laterite and bricks.
CT data was used for attenuation correction (120 mAs Care Dose; 110 Kv, slice 5 mm) and X-ray contrast medium was injected (65 ml ULTRAVIST®, rate 1.6 1.8 ml/s and delay 50 s).
