Heating technologies

Various medical devices from different manufacturers are usable for triggering of Thermosomes in clinical applications

Thermosomes are triggered with specific medical devices to selectively heat the local target tissue where drug delivery shall occur (such as a tumor). Mild temperature elevations to 40-42°C are sufficient to trigger drug delivery and are well-tolerated and not harmful to patients. For clinical use, a variety of different heating technologies and manufacturers exist, of which the most prominent ones are summarized here. Further information can also be found at the following scientific and non-for-profit societies:

High Intensity Focused Ultrasound (HIFU)

Thermal therapy based on High Intensity Focused Ultrasound (HIFU), potentially supported/combined with Magnetic Resonance Imaging (MRI), has been developed for non-invasive thermal ablation (T>50°C). It is clinically approved for the treatment of non-malignant tumors of the uterus and bone metastasis, and is under current investigation for the treatment of prostate cancer and various other cancer indications. With technical adaptations, MR-HIFU systems may potentially be used at low temperature hyperthermia applications at 40-42°C in the future (low intensity focused ultrasound, LIFU). Exemplary manufacturers:

Deep regional radiofrequency (RF) hyperthermia

For deep-seated tumors located more than 3cm under the skin surface, radiofrequency (RF) hyperthermia systems (microwave) are used in clinical practice. They consist of dipole antenna pairs surrounding the patient. Each antenna pair can be controlled in phase, amplitude, frequency and electric field to focus the heat in the tumor area at a precision of a few cm. Treatment monitoring might be provided by MRI which can characterize temperature change as well as perfusion (MRI-hyperthermia hybrid system). Several clinical trials exist supporting the feasibility and effectiveness of the method in combination with standard chemotherapy or radiotherapy for the treatment of solid tumors. As such, they are recommended in medical guidelines and applied in clinical practice in routine at specialized, high-end medical centers such as the University Hospital of the Ludwig-Maximilians-Universitaet Munich, Germany, or the Erasmus Medical Center, Rotterdam, Netherlands. Exemplary manufacturers:

Superficial radiofrequency hyperthermia

Comparable to deep regional RF hyperthermia, these systems are specifically designed for the treatment of superficial tumors. They use applicators emitting mostly microwaves, which are placed on the tumor surface via a contacting medium. Several types of applicators have been used clinically, such as waveguide applicators, horn, spiral, current sheet, and compact applicators. The therapeutic depth of these applicators is approximately 2 to 3 centimeters. Exemplary manufacturers:

Bladder heating devices

For the locally-focused heating of the bladder, a specifically to the bladder tailored RF hyperthermia device (Synergo®) can be used. It is based on the insertion of an antenna system into the bladder with additional sensors at the bladder wall and allows precise RF-heating of various layers of the bladder wall. Exemplary manufacturers:

Radiofrequency ablation

Radiofrequency ablation (RFA) is a procedure for tissue ablation (T>50°C) using a medium frequency alternating current. The RFA-probe is invasively inserted into the tissue. In oncology, this method is mainly used for the thermal destruction of liver tumors with diameters of up to 5 cm. RFA devices are produced by several manufacturers and commonly available in larger hospitals.