X-Ray Grid FAQs

When two grids have the same specifications, why are their transmissions different?

The reason is that the interspace width and height is different. As the x-ray interacts with different amounts of lead and aluminum, its attenuation changes.

Do standard tests cover everything with regard to grid quality?

Grid characteristics change with the x-ray energy used. Primary radiation is affected by linear attenuation coefficient of the interspacer and scatter radiation is affected by linear attenuation coefficient of absorber. These attenuation values are different according to the energy of the x-ray. So, a test value at the specific test condition does not tell everything about grid quality. In order to evaluate the grid under field conditions, the test condition should be the same. If possible, you should see the physical characteristics data through the entire medical x-ray spectrum. The important thing is that as the physical characteristics data is performed in the 6-pie detection area, it cannot represent the whole quality of the grid.

When using a grid, why is there a difference in both sides of the x-ray film?

We refer to this as cutoff. In this case, when the strp angle of the grid is not identical with the target angle of the tube, the titled strips create “shadows” (or cutoff) on the film. The central strips are angled less, and so produce less cutoff.

In which fields are grids used?

Grids are used in oncology, cardiology, angiography, chest radiography, mammography, orthopedics, podiatry and many others. Grids are also used in Digital Radiography (DR) and Computed Radiography (CR).

What grid specifications are recommended for chest radiography?

For conventional radiography, the 103 lp/in, 10:1 is usually used. Depending on the x-ray system used with CR and DR, the 178 lp/in, 200 lp/in, 215 lp/in, and 230 lp/in are most commonly used for chest radiography.

What grid specifications are used for cardiology and angiography?

Normally, the 103 lp/in 8:1 is used. In instances of high-resolution CCD cameras, a 150 lp/in 8:1 would be used. Highline grids, such as 200 lp/in, 215 lp/in, 230 lp/in, are used for DR systems.

What kind of grids has JPI Healthcare produced? Do you have a grid for low dose?

JPI has produced aluminum interspace grids for 38 years. Examples include: JPI Grid – Aluminum interspacer, Aluminum cover, and JPI Grid 2000/2100 – Carbon interspacer, carbon fiber cover. JPI also developed a low dose interspacer, which is manufactured based on the principle of the semi-conductor process. The uniformity of the inner lines is very uniform and the characteristics are strictly controlled.

What is the focal range of a parallel grid?

When calculating the primary radiation loss of a parallel grid based on film density, the Tp loss should be less than 20%. For a parallel grid, this occurs at 150cm. Accordingly, a parallel grid should be used at a distance of more than 150cm.

If there a grid that can be used at a distance of 1.0 m and 1.8m simultaneously? If yes, what are the specifications?

Normally, we recommend a grid of 40”-72” focal range. As the focal distance of this grid is 51.2” (130cm), it could be used at various ranges. In this case, it could be used for table and wall stands. Focal range is decided based on the 40% loss of primary radiation.