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If a grid is made to match the size of a 14 x 17 inch image receptor, the surface of the grid that measures 14 x 17 is called the face of the grid. A line, called the center line, is usually drawn on the face of the grid, which lets the radiographer know the direction of the grid lines, since they are hidden by the grid’s cover.
- Overview of Technical Parameters
- MA
- KVP
- Sid
- Bucky Factor
- Golden Equation
As a technologist you are often faced with the situation where you need to make a change to a protocol but want to keep the exposure on the detector the same. In this scenario it is really important to understand the technical parameters and their influence the exposure, so that when changing parameters you do not end up under-exposing or over-expo...
The tube current and time in the x-ray exam are the parameters that are most frequently changed and you should consider this as your first go-to adjustment in order to change the x-ray exposure without impacting the quality of the exam in other ways. Increasing the tube current is actually just providing more electrons that with smash into the x-ra...
The kVp is the most important technical parameter as it has a very strong dependence on the x-ray exposure (kVp5). This strong dependence on the kVp for the exposure at the image receptor is because of the higher flux and stronger penetration of higher kVp imaging. Additionally, the kVp also changes the inherent contrast in the x-ray images. Since ...
The Source to Image Distance (SID) affects the exposure at the image receptor since the x-ray beam is divergent (i.e. spreading out as it gets further from the x-ray tube). Since the x-rays are spreading out the exposure depends on the SID as 1/SID2 . In our post on the basic x-ray properties we demonstrate how the divergent beam leads to the 1/R2d...
Finally, the Bucky factor is a unitless quantity which is the ratio of the x-ray exposure reaching the grid to the x-ray exposure reaching the image receptor. If no grid is used this definition will lead to a Bucky factor of 1.0. The Bucky factor for grids is dependent upon the grid ratio (grid height: grid spacing) and the kVp. It typically ranges...
Now that we have all pieces we can put these 5 simple relationshipstogether to make what we call the golden equation. You can give it your own cool name too. We just call it the golden equation since it has all of the factors that you need to consider so that as you change one factor you can compensate to keep your exposure constant. Also this is j...
Grids are chiefly characterized by the grid ratio, grid frequency, and focal distance. The grid ratio is a measure of the height of the lead strip to the interspace distance, and is a good measure of the selectivity of primary to scatter transmission.
Feb 6, 2015 · The purpose of this experiment was to test the alignment of the radiographic grid in the bucky mechanism with respect to the central ray of the x-ray tube. In this experiment, grid misalignment can be detected by analyzing the optical densities of the resultant dot images obtained using a grid alignment tool shown in Figure 3.
On the basis of not deviating from the center line of the X-ray grid, the X-ray center line can be inclined at a certain angle according to the inclination direction of the lead rod, so that the X-ray radiation direction is consistent with the lead.
Explain how the object-image distance is used to control magnification. Explain how the source-image distance is used to control magnification. Describe the clinical applications of the most common source-image distances. Calculate the image size, object size, magnification factor and percent of magnification.
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Oct 23, 2018 · X-ray grids are presently constructed with lead strips to absorb scatter radiation and an interspacer (most commonly aluminum) to allow the primary radiation to pass to the film or receptor.
