What Is An Anode Angle ?
The anode angle determines the degree of X ray absorption in the anode material. The anode angle has strong relationship with with focal spot size and usable x-ray field size.A decrease in anode angle causes an increase in the absorption length within the target. Accordingly, the maximum photon energy remains unchanged, but hardness increases and yield drops with decreasing anode angle. A small anode angle gives smaller effective focal spot but it’s usable x-ray field is limited. Large anode angle gives large usable x-ray field but the Effective focal spot is larger. To optimize the design, large anode angle with small filament length is used. This will provide small effective focal size with wide field coverage.
The optimum choice of anode angle depends on the clinical application. A small anode angle 7° to 9° is useful in small field of view such as Ciniangiography and neuroangiography. The large anode angles are necessary for general radiographic work to achieve large field of view. Modern X-ray tubes are designed with anode angle of 10° to 13° with focal spot sizes of 0.6 to 1.3 mm.
What Is An Anode Angle In Mammography?
In mammography, the rotating anode is used and the anode angle is design to the horizontal tube mount. The effective anode angle is about 22° – 24° for a source to image distance of 65 cm. this can be achieved either by 0° anode angle and 24°tube till or 16° anode till and 6° tube till.