The system
We successfully developed a radiographic X-ray system using a cerium anode.
In clinical settings,
iodine and barium are widely used as contrast materials,
and they have the peak mass attenuation coefficient called as K-edge at 33.2 KeV (kilo electron volt) and 32.1 KeV,
respectively.
The effect of contrast materials is created by the difference of the mass attenuation coefficient between tissues of human body and the materials.
Therefore,
the X-ray energy close to the mass attenuation coefficient of the contrast materials used is ideal with clear visualization.
The homogeneous X-ray of cerium has the peak energy at 34.4 KeV,
and the energy range is narrow and focused.
On the other hand,
the energy of tungsten which is widely used as anode of conventional X-ray system is broad of range and not concentrated2 (see figure 1).
Therefore,
the system we developed has a clear advantage over the conventional system for detecting tiny amount of the materials and visualizing micro vessels.
The cerium is not heat resistant; therefore the cerium anode is rotated continuously in order to radiate fever.
Animal experiences (mice)
Thirty-two mice were anesthetized.
Barium (Barytgen,
Fushimi Pharmaceutical Co.,
Japan) filtrated through 10 μm meshes and concentrated by centrifugation (3000 rpm,
10 minutes) was injected into the beating hearts.
Then,
the brains were taken out and put in formalin.
After one week,
the brains were irradiated by our system.
Animal experiment (dogs)
Three dogs were anesthetized.
Following thoracotomy,
the descending aorta was clamped.
Concentrated (3000 rpm,
10 minutes) barium was injected into the ascending aorta with the heart beating.
The brains were taken out and put in formalin.
One week later,
the brains were irradiated.
Animal experiment (living dogs)
Two dogs were anesthetized.
The external carotid artery was catheterized towards the common carotid artery.
The heads of dogs were irradiated at half-second intervals during iodine (Iomeron 400,
Eisai Global,
Japan) perfusion of the brain with the heart beating.