Device Selection – Which magnet to use? Quadrapolar, Hexapolar or Octapolar

 

There are three different types of multipolar Q magnets to choose from…

  1. Quadrapolar – 4 alternating poles
  2. Hexapolar – 6 alternating poles
  3. Octapolar – 8 alternating poles
    (See table below)

What they all have in common (and what sets them apart from common bipolar magnets) are interpole boundaries that produce steep magnetic field gradients. This is where the research suggests the main pain relieving and tissue healing properties of a static magnetic field reside.

The research clearly shows that Quadrapolar magnets have physiological effects that are not shared with your common bipolar magnets.

 

Quadrapolar magnet blocking a nerves Action Potential firing

Quadrapolar magnet blocking a nerves Action Potential firing (McLean 1991, see ref below)

 

The active area of the magnet, or sweet spot is located at the boundary between the alternating poles, shown in red in the image below. Since magnetic field lines are invisible to the naked eye, this can be difficult to visualise. But sprinkling iron filings on the magnet gives a picture of the direction of the field lines as seen below. The iron filings follow the direction of the magnetic field gradient between the poles shown by the red arrow.

Left Image: Iron filings showing direction of magnetic field lines over a Quadrapolar magnet. Right Image: Red regions showing physiological active areas of magnet.

Iron filings showing direction of magnetic field lines over a Quadrapolar magnet. Red regions showing physiological active areas (sweet spot) of magnet.

 

Other research has confirmed that the point between the poles is where the magnetic field is most biologically active. The image below was taken from a study on myosin phosphorylation, which is an indicator of biological effects initiated by magnetic fields (see references at the bottom of this post).

 

MER-Phosphorylation

 

Position A, at the boundary of the alternating poles was by far the most biologically active.

In other published research, this is called the maximally effective region (MER). The image below is from the research paper that describes the MER (see reference at the bottom of this post).

 

MER

McLean et al (2001)

 

The table below details the differences in design, active areas and depth of penetration for the three different models: Quadrapolar, Hexapolar and Octapolar magnets.

 

QUADRAPOLAR

HEXAPOLAR

OCTAPOLAR

 Multipolar-Quadrapole-3D4

 Multipolar-Hexapole-3D6 Multipolar-Octapole-3D8
 Quadrapolar-4Pain-Relief-HeaderQMagnets.jpg  Hexapolar-6
 QF28-6-Depth-Measure-Line  HF28-6-Depth-Measure-Out  OF50-3-Depth-Measure-Line
Quadrapolar 4 active areas Hexapolar 6 active areas Octapolar 8 active areas
QF28-6 HF28-6 OF50-3

 

So, it can be seen that the Quadrapolar magnet has 4 active areas, the Hexapolar 6 and the Octapolar 8 active areas.

Does more active areas equal better results?

Well, like most responses to questions about static magnets, the answer is; it depends. Because what you gain in active areas, you lose in depth of penetration as seen in the table above (the reason the Octapolar penetrates further than the Hexapolar is because its twice the size). Also, the Octapolar OF50-3 is 50mm or 2 inches in diameter which is great for the lower back or a large haematoma on the thigh, but it’s not going to be very practical for a small joint such as the elbow or a finger.

So select a Quadrapolar magnet when depth of penetration is most needed…

  • Lower back (use OF50-3 when targeting two adjacent spinal levels)
  • Hip joint
  • Through a plaster cast
  • Through a generous layer of adipose tissue

 

Conditions and placements where the Hexapolar magnets may be more effective are where the target tissue is more superficial. Examples such as…

At this time, there is only one Octapolar model, the OF50-3. It should be used when you need to…

  • Cover a large surface area such as a large haematoma.
  • Target two adjacent spinal levels such as L4/5 and L5/S1 as in this case study.

 

Having the field penetrate deep enough is often critical to the success of the treatment, see this example of how Q magnets penetrate for low back pain over the lumbar spine.

 

REFERENCES:

Engstrom, S., M. S. Markov, et al. (2002). “Effects of non-uniform static magnetic fields on the rate of myosin phosphorylation.” Bioelectromagnetics 23(6): 475-479. PMID 12210566; doi:10.1002/bem.10035

McLean, M., S. Engstrom, et al. (2001). “Static Magnetic Fields for the Treatment of Pain.” Epilepsy & Behavior 2(3): S74-S80 doi:10.1006/ebeh.2001.0211

McLean, M. J., R. R. Holcomb, et al. (1991). “Effects of Steady Magnetic Fields on Action Potentials of Sensory Neurons in Vitro.” Environmentalist 8(2). Click to download.

 

 

 

 

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