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

Abstract

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/cm 2 ) 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 necessaryrapid 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. ARTICLE HISTORY

Combined wIRA-Hyperthermia and Hypofractionated Re-Irradiation in the Treatment of Locally Recurrent Breast Cancer: Evaluation of Therapeutic Outcome Based on a Novel Size Classification

“…The computer-based closed feedback system of this device was set to a maximum skin surface temperature between 42. 5 The treatment protocol ( Figure 2) consisted of weekly contact-free, thermography-controlled wIRA-sHT (for 45-60 min), immediately followed by hypofractionated re-RT (4 Gy once per week up to a total dose of 20 Gy), as described in detail earlier [1,25]. Seventeen patients (8%) received a total dose <20 Gy; 7 patients (3%) received a total dose >20 Gy, of them 1 with a modified scheme of 5 × 5 Gy (1 ×/week) split up in 2 × 2.5 Gy.…”

“…Since 07/2017 all patients were treated with the medical device hydrosun ® -TWH1500 (Hydrosun Medizintechnik, Müllheim, Germany). The computer-based closed feedback system of this device was set to a maximum skin surface temperature between 42.5 and 43 °C, resulting in tissue temperatures >40 °C in a depth of approximately 15 mm, and >39 °C in a depth of approximately 30 mm [25]. Local tumor response (complete response (CR), partial response (PR), no change (NC), progressive disease (PD)) was assessed clinically and-whenever possible-by imaging or biopsy, at the completion of treatment and at follow ups every 6 to 12 weeks in the first year, and every 6 to 12 months thereafter, according to WHO criteria (CR = complete clinical disappearance of all detectable Local tumor response (complete response (CR), partial response (PR), no change (NC), progressive disease (PD)) was assessed clinically and-whenever possible-by imaging or biopsy, at the completion of treatment and at follow ups every 6 to 12 weeks in the first year, and every 6 to 12 months thereafter, according to WHO criteria (CR = complete clinical disappearance of all detectable disease in the treatment fields observed, PR = decrease > 50%, NC = decrease < 50% or increase < 25%, PD = increase > 25%).…”

wIRA: hyperthermia as a treatment option for intracellular bacteria, with special focus on Chlamydiae and Mycobacteria

“…It is produced by light from a halogen bulb passing through a water cuvette to abate the irradiances at 970 nm and 1160 nm, and to exclude wavelengths above 1400 nm. Major contributions of visible light (VIS) can be blocked by using an optical longpass filter with a cutoff wavelength at 590 nm [11,12], whereas black filters block VIS (380-780 nm) entirely [13].…”

“…Piazena et al [31] allocated 11 piglets into three intervention groups and irradiated the skin of their thighs with different doses (irradiances) of wIRA. Skin temperatures were measured before, during and after the wIRA irradiation in a 1-min interval in tissue depths of 2,4,7,8,10,12,16, and 20 mm. The temperature measurement revealed (1) significant individual differences between temperature profiles and the thermoregulatory processes, (2) reproducible vertical temperature profiles through the skin layers and subcutis, showing the highest temperature in 4-6 mm depth of the tissue and (3) that the temperature measured at the skin surface is approximately 1-2 K lower than at 4 mm skin depth, allowing an approximate estimation of the temperature reached in deeper layers by temperature measurements at the skin surface [31].…”

Thermal field formation during wIRA-hyperthermia: temperature measurements in skin and subcutis of piglets as a basis for thermotherapy of superficial tumors and local skin infections caused by thermosensitive microbial pathogens

“…Recently, Notter et al reported promising data showing the efficacy of wIRA-HT in the treatment of large-sized recurrent breast cancer [23,24]. Piazena et al [6] and Vaupel et al [25] provided related physical and photobiological basics with reference to the ESHO quality assurance guidelines for superficial hyperthermia in oncology [26,27].…”