Coils in PEMF therapy
We can see here the magnetic field lines for a cylindrical PEMF coil. The red rectangle shows the position of the body for the person during pulsed electromagnetic field treatment.
The actual pulsed electromagnetic field energy for this PEMF cylindrical coil is for the major part local and inside the cylinder coil and its efficacy does not extend outside the cylindrical coil.
The therapy is local in the area where the coil is placed and such systems are unsuitable for whole body therapy.
The patient is required to be inside the cylindrical coil itself, which is often complicated, specifically for elderly people.
The cylindrical coil was developed many years ago and was at that time the only solution to obtain sufficient electromagnetic field intensity in order to be effective because the electronics available in those years was unable to drive sufficient intensity into modern surface coils. These types of cylindrical coils have become obsolete but are still sold together with obsolete PEMF systems.
Here we see the electromagnetic field lines for surface coils. The red rectangle indicates the position of the body. The energy of this surface coil extends evenly over the surface, even if several coils are arranged inside a flat pad or mat applicator. The PEMF fields also extend over a larger surface area.
The PEMF system must drive all the coils at the same time and some manufacturers control multiple coils in their large mattress one after the other because their generator is not powerfull enough! This results in an average applied PEMF energy, which is much lower than written in their specifications: e.g. if there are 10 coils in their mattress this results in only 10% of the rated energy or alternatively only during 10% of the therapy time each coil is actually activated with the intensity as specified!
Also there are manufacturers who use only one large coil in their mattress, which is a long copper around the outer side of the mattress. No mathematician needs to prove that the pulsed electromagnetic field in such a mattress is a close to zero because it is technically impossible to obtain an even distribution of the pulsed magnetic energy field over the full surface area of such a mattress!
The pulsed magnetic field generators for all the Parmeds home and professional models are designed to drive all the coils in the applicators all at the same time during the complete treatment session. The coils inside the mattress are located in such a way that the electromagnetic field is spread evenly, as far as this is technically possible.
There are very efficient high intensity coils available for localized therapy like for spine and hips or for hands, elbows and feet. The very high intensity coils generates with the Parmeds Super system up-to 100 milli Tesla, resulting in e.g. excellent knee pain relief for osteoarthritis because cartilage is actually regenerated!