Here we see the magnetic field lines for a cylinder PEMF coil. The red rectangle indicates the position of the body for the person undergoing pulsed electromagnetic field therapy treatment.
The effective pulsed electromagnetic field energy for this PEMF cylinder coil is mostly local and inside the cylinder and its efficacy hardly extends outside the cylinder itself. The treatment is localized to the area where the coil is located and such a system is not suitable for whole body therapy.
The person needs to be inside the cylinder, which is often a cumbersome process, especially for elderly people.
The body cylinder was developed decades ago and was the only solution to generate sufficient electromagnetic field energy in order to be effective since the electronics available during the 80's were unable to drive sufficient energy into surface coils.
These types of cylinders have become obsolete and are still sold only in combination with obsolete PEMF devices.
Here we see the magnetic field lines for surface coils. The red rectangle indicates the position of the body.
The energy of the surface coil extends evenly over the surface, even in case multiple coils are arranged inside a flat pad or mattress applicator. In addition the electromagnetic fields extend over a larger area.
The PEMF device should of course be able to drive all the coils at the same time and not just one after the other. In the latter case the actual PEMF energy is much lower than rated in the specifications because only each coil works with the specified intensity at a time.
Using only one large coil in a full body mat will not evenly spread PEMF energy over the full surface of such a mat.
Electromagnetic field generators for PEMF devices should energize all coils in the mats at the same time during the complete therapy session.
Not only full body mats should be available but in addition also high intensity (high energy) coils for local PEMF therapy, like for joint treatments.