Ultrasonic therapy

Preclinical trials of the method of solid-phase sonosensitization were carried out at N.N. Blokhin Russian Research Oncological Center. The experiments included estimation of the therapeutic efficiency, harmlessness, and the effect on metastatic disease. These studies showed a high therapeutic efficiency of the method, that is, tumor regression by 75-80% on average with an increase in the animal lifetime by a factor to 2, good exposure tolerance, and the absence of the effect on metastatic disease. Currently, the method of ultrasonic therapy with solid-phase sonosonosensitizers is in clinical trials. 

More recently, the use of piezoelectric devices has grown dramatically as a consequence of increases in automation and consumer attraction to modern sophisticated gadgets. Piezoelectric devices are used in many of today s applications, including automotive—wheel balances, seat-belt buzzers, tread-wear indicators, keyless door entry, and airbag sensors computer/electronic—microphones, speakers, microactuators for hard disks and notebook transformers commercial/consumer—ink-jet printing heads, strain gauges, ultrasonic welders, and smoke detectors medical—insulin pumps, ultrasonic therapy, and ultrasonic cataract-removal devices. 

High-frequency or diagnostic ultrasound in clinical imaging (3-10 MHz) Medium-frequency or therapeutic ultrasound in physical therapy (0.7-3.0 MHz) Low-frequency or power ultrasound for lithotripsy, cataract emulsification, liposuction, tissue ablation, cancer therapy, dental descaling, and ultrasonic scalpels (18-100 kHz)... 

R.H. Simon, S.Y. Ho, D.F. Uphoff, S.C. Lange and J.S. D Arrigo, Applications of lipid-coated microbubble ultrasonic contrast to tumor therapy, Ultrasound Med. Biol. 19 (1993) 123-125. 

Greenspan, B.J. Ultrasonic and electrodynamic methods of aerosol generation. In Inhalation Aerosols Physical and Biological Basis for Therapy Hickey, A.J., Ed. Marcel Dekker, Inc. New York, 1996 313-335. 

Modern nebulisers for domestic and hospital use generate aerosols continuously for chronic therapy of respiratory disorders. A Venturi-type system is shown in Fig. 9.48(a) and an ultrasonic device in Fig. 9.48(b). The particle size distribution and hence efficiency of such... 

Figure 6 shows a photograph of three jet nebulizers. Numerous jet nebulizers are being marketed, and, indeed, some concern has been expressed about the nebulizer epidemic [140,141]. The first two nebulizers shown were selected because they are both used to deliver pentamidine to patients suffering from Pneumocystis carinii pneumonia, a secondary infection in AIDS. Of note, ultrasonic nebulizers have also been used for this purpose. Treatment of this particular disease is the most notable example of nebulizer therapy in recent years. Significantly, no other method of pentamidine aerosol generation is currently available. 

Different auxiliary methods of administration can be used in conjunction with nebulizers to deliver aerosol to the patient [144]. A mouthpiece may be inserted in the mouth or a face mask may be attached tightly to the face. A large-bore inlet adapter attaches tubing from the nebulizer outlet to the mouthpiece or mask. It is possible to compensate for exhaled aerosol without increasing resistance to prevent condensation. A face tent fits more loosely around the patient s mouth, allowing speech. The latter arrangement is frequently used with ultrasonic nebulizers. A tracheostomy mask may be fitted to the patient s tracheostomy tube directly and requires a T-shaped adapter. Environmental chambers are used to enhance therapy and include incubators, pediatric croup tents, and hoods. 

Jet and ultrasonic nebulizers have been used to aerosolize antimicrobial therapy. Jet nebulizers used compressed air or oxygen passed through a liquid to produce an aerosol gas. With ultrasonic devices, a piezoelectric element vibrates to generate small aerosol particles. Both systems have advantages and limitations related to their components and technique of use. These are discussed in more detail elsewhere in this text (see Chs. 8, 12). 

Jet nebulisers in the home situation are increasingly replaced by (vibrating) membrane inhalers which give better control over the medicine delivery to the respiratory tract than the classic jet and ultrasonic nebulisers, and may increase the adherence to the therapy. 

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