Basic Principles of Millimeter Wave Therapy

Millimeter wave therapy involves exposing specific areas of the human body, such as the skin surface or acupuncture points, to electromagnetic waves of specific frequencies and intensities. The radiation power density is typically below 10 mW/cm², which does not cause significant thermal effects (tissue temperature increase of less than 0.5°C) nor result in ionizing damage or physical destruction. Research has shown that the biological effects of millimeter waves are frequency-dependent, with certain frequencies (e.g., 42.25 GHz, 53.57 GHz, 61.22 GHz) considered more therapeutically effective.

Analgesic Effects of Millimeter Waves

According to the reviewed literature, millimeter wave therapy has demonstrated analgesic effects in various types of pain, including:

• Experimental pain: In healthy volunteers, millimeter wave exposure significantly increased pain tolerance thresholds.

• Headache: Relief was observed in patients with hypertension and cerebrovascular diseases.

• Joint pain: Effectiveness was reported in osteoarthritis, rheumatoid arthritis, and juvenile rheumatoid arthritis.

• Postoperative pain: MWT accelerated wound healing while significantly reducing postoperative pain.

• Neuropathic pain: Including trigeminal neuralgia and cancer-related pain.

Notably, the analgesic effect of millimeter waves often appears within minutes of exposure and can last from several hours to several days. Some studies have also found that MWT applied to areas distant from the pain site (e.g., acupuncture points) can still produce analgesic effects, suggesting a possible link to the meridian system of Traditional Chinese Medicine or to neuro-endocrine-immune networks.

Proposed Mechanisms of Action

Although the exact mechanisms of millimeter wave therapy are not fully understood, existing research suggests several possibilities:

• Activation of the endogenous opioid system: Animal studies have shown that naloxone (a non-specific opioid receptor antagonist) can block the analgesic and anti-tumor effects of MWT.

• Modulation of immune function: MWT has been shown to affect T-lymphocytes, B-lymphocytes, immunoglobulins, and other immune parameters.

• Influence on the nervous system: Millimeter waves can induce c-fos gene expression in the central nervous system, which is involved in pain regulation.

Safety and Side Effects

In available clinical studies, no serious adverse reactions to millimeter wave therapy have been reported. Some patients may experience transient local warmth, mild fatigue, or drowsiness, which are generally considered acceptable or even desirable adjunctive effects.

Conclusion

Millimeter wave therapy, as a safe, non-invasive, and rapidly acting analgesic modality, holds promising clinical potential. With the advancement of high-quality clinical research, MWT may become an effective complement to conventional pharmacotherapy, offering new options for patients with chronic pain.