Biophysical and photobiological basics of water-filtered infrared-A hyperthermia of superficial tumors

Int J Hyperthermia. 2018;35(1):26-36. doi: 10.1080/02656736.2018.1469169. Epub 2018 May 10.


Thermography-controlled, water-filtered infrared-A (wIRA) is a novel, effective and approved heating technique listed in the ESHO quality assurance guidelines for superficial hyperthermia clinical trials (2017). In order to assess the special features and the potential of wIRA-hyperthermia (wIRA-HT), detailed and updated information about its physical and photobiological background is presented. wIRA allows for (a) application of high irradiances without skin pain and acute grade 2-4 skin toxicities, (b) prolonged, therapeutically relevant exposure times using high irradiances (150-200 mW/cm2) and (c) faster and deeper heat extension within tissues. The deeper radiative penetration depth is mainly caused by forward Mie-scattering. At skin surface temperatures of 42-43 °C, the effective heating depth is 15 mm (T ≥ 40 °C) and 20 mm (T ≥ 39.5 °C). Advantages of wIRA include its contact-free energy input, easy power steering by a feed-back loop, extendable treatment fields, real-time and noninvasive surface temperature monitoring with observation of dynamic changes during HT, and - if necessary - rapid protection of temperature-sensitive structures. wIRA makes the compliant heating of ulcerated and/or bleeding tumors possible, allows for HT of irregularly shaped and diffusely spreading tumors, is independent of individual body contours, allows for very short 'transits' between HT and RT (1-4 min) or continuous heating between both therapeutic interventions. New treatment options for wIRA-HT may include malignant melanoma, vulvar carcinoma, skin metastases of different primary tumors, cutaneous T-and B-cell lymphoma, large-area hemangiomatosis, inoperable squamous cell, basal cell and eccrine carcinoma of the skin with depth extensions ≤20 mm.

Keywords: Water-filtered infrared-A; contact-free hyperthermia; photobiology of wIRA hyperthermia; physics of wIRA hyperthermia; recurrent breast cancer; superficial hyperthermia.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Humans
  • Hyperthermia, Induced / methods*
  • Infrared Rays / therapeutic use*
  • Neoplasms / pathology
  • Neoplasms / therapy*
  • Water / chemistry*


  • Water