When it comes to selecting the right anti-scatter x-ray grid for your needs, it’s important to consider a number of factors before making your selection. The quality of the grid you choose matters, and though budgets can be strained in radiology departments due to economic pressures, in the end, your choice of x-ray grid can have a significant impact on your patients and your work.
With that in mind, below are 4 rules of thumb to follow when purchasing a grid.
*Please keep in mind these rules won’t apply in some circumstances, and if you have questions about grid selection, contact a Reina Imaging representative to learn more.*
- Choose the Right Ratio
- The suggested ratio options for mobile grids used outside of equipment are 6:1, 8:1 and 10:1. You can go higher and lower, but we would not recommend it for mobile/portable/cross table work. The higher the ratio the better the scatter cleanup, but the greater chance for grid cutoff due to misalignment. The lower the ratio, the less scatter cleanup – but this means an increased positioning latitude, i.e., lower ratios are great for easy-to-position environments, while high ratios are optimal for thicker anatomy, but are more difficult to position.
- Select the Proper LPI (lines per inch)
- In a digital environment, line pair frequency is primarily software driven. Though there can be more than one proper selection – there are right and wrong LPI matches for each digital system. If the incorrect LPI (or LPCM – lines per centimeter) is used it may be visualized as a moiré pattern or grid aliasing. It’s always best to call your local Reina Imaging expert if unsure, as OEMs can change their line pair frequency software requirements frequently.
- Pick the Best Focal Range
- Every grid has a fulcrum – this is where the grid’s optimum SID (source to image distance) is located. All grids can be used within a focal range with very limited consequence – image degradation. The two most widely used ranges are 34 – 44 in. and 40 – 72 in., however, parallel grids can be used from 48 in. – infinity. Which focal range you select depends on the intended use of the grid. If the grid is used too far or too close (outside the range), there will be grid cutoff, and you’ll want to avoid this.
- Choose from Short and Long Dimension
- This refers to the Pb (lead) line orientation. Long dimension grids have lead lines that run parallel to the long axis while short dimension grids run parallel to the short axis. Here’s the catch when selecting one over the other – long dimension grids can be used in both portrait and landscape orientation, while short dimension grids should only be used in landscape. This has to do with divergent beam paths and grid cutoff. We only recommend a short dimension grid if you will be using it exclusively in landscape (or crosswise). If you are unsure, it’s a safer bet to stick with a long dimension grid.
Proper grid selection is a critical decision for your medical office. Selecting the wrong grid can cost you a lot of time and effort in the long run, and just a little more research or a small shift in budget might save you from years of frustration.
In this case, a little extra effort before you make your purchase goes a long way.
