[THE BONE DEFECT HEALING UNDER THE INFLUENCE OF RADIAL EXTRACORPOREAL SHOCK-WAVE THERAPY IN EXPERIMENT]

In experiment on 24 rabbits the processes of reparative osteogenesis in perforated defect of proximal tibial metaphysis under the influence of extracorporeal shock-wave therapy were studied. In accordance to data of clinical, roentgenological and morphological investiagations, conducted in terms 5, 15, 30 and 45 days of observation, there was established, that under the influence of extracorporeal shock-wave therapy in the bone marrow in the traumatic region a vasodilatation, as well as the blood cells exit from capillaries and sinusoid vessels with creation of massive regions of osseous endostal regenerate, guaranteeing the tibial integrity restoration, occurs.

Physical Medicine Devices; Reclassification of Shortwave Diathermy for All Other Uses, Henceforth To Be Known as Nonthermal Shortwave Therapy. Final order; technical correction

The Food and Drug Administration (FDA) is issuing a final order to reclassify shortwave diathermy (SWD) for all other uses, a preamendments class III device, into class II (special controls), and to rename the device "nonthermal shortwave therapy'' (SWT). FDA is also making a technical correction in the regulation for the carrier frequency for SWD and SWT devices.

Environmental impact of the use of radiofrequency electromagnetic fields in physiotherapeutic treatment

BACKGROUND

Electromagnetic fields used in physiotherapeutic treatment affect not only patients, but also physiotherapists, patients not undergoing treatment and electronic medical equipment.

OBJECTIVE

The aim of the work was to study the parameters of the electromagnetic fields of physiotherapeutic devices with respect to requirements regarding the protection of electronic devices, including medical implants, against electromagnetic intererence, and the protection of the general public (patients not undergoing treatment and bystanders), as well as medical personnel, against the health hazards caused by electromagnetic exposure.

MATERIAL AND METHODS

The spatial distribution of electric and magnetic field strength was investigated near 3 capacitive short-wave and 3 long-wave diathermies and 3 ultrasound therapy units, as along with the capacitive electric currents caused by electromagnetic field interaction in the upper limbs of the physiotherapists operating these devices.

RESULTS

The physiotherapists' exposure to electromagnetic fields depends on the spatial organisation of the workspace and their location during treatment. Electric fields able to interfere with the function of electronic medical implants and in whic anyone not undergoing treatment should not be present were measured up to 150-200 cm away from active applicators of short-wave diathermy, and up to 40-45 cm away from long-wave diathermy ones. Electric fields in which workers should not be present were measured up to 30-40 cm away from the applicators and cables of active short-wave diathermy devices. A capacitive electric current with a strength exceeding many times the international recommendations regarding workers protection was measured in the wrist while touching applicators and cables of active short-wave diathermy devices.

CONCLUSIONS

The strongest environmental electromagnetic hazards occur near short-wave diathermy devices, and to a lesser degree near long-wave diathermy devices, but were not found near ultrasound therapy units.

Second-generation treatment: microwave

Microwave endometrial ablation is an effective treatment for heavy menstrual loss that achieves high satisfaction rates, is acceptable to patients, and is recommended by the National Institute of Clinical Excellence. It has been evaluated extensively in randomized trials against first- and second-generation endometrial ablative techniques. Its simplicity of use and short treatment time make it suitable for outpatient treatments, whilst it can also treat larger and irregular cavities. This article reviews the available clinical research and scientific basis of this endometrial ablation technique.

Treatment of rheumatoid arthritis with electromagnetic millimeter waves applied to acupuncture points--a randomized double blind clinical study

The aim of the study was to evaluate the efficacy and safety of electromagnetic millimeter waves (MW) applied to acupuncture points in patients with rheumatoid arthritis (RA). Twelve patients with RA were exposed to MW with power 2.5 mW and band frequency 54-64 GHz. MW were applied to the acupuncture points of the affected joints in a double blind manner. At least 2 and maximum 4 points were consecutively exposed to MW during one session. Total exposure time consisted of 40 minutes. According to the study design, group I received only real millimeter wave therapy (MWT) sessions, group II only sham sessions. Group III was exposed to MW in a random cross-over manner. Pain intensity, joint stiffness and laboratory parameters were recorded before, during and immediately after the treatment. The study was discontinued because of beneficial therapeutic effects of MWT. Patients from group I (n=4) reported significant pain relief and reduced joint stiffness during and after the course of therapy. Patients from group II (n=4) revealed no improvement during the study. Patients from group III reported the changes of pain and joint stiffness only after real MW sessions. After further large-scale clinical investigations MWT may become a non-invasive adjunct in therapy of patients with RA.

Development and application of a quality control procedure for short-wave diathermy units

Short-wave diathermy (SWD) is a form of radiofrequency (RF) radiation, operating at 27.12 MHz, that is used therapeutically by physiotherapists. Although this form of therapy is widely available, the management of the equipment is not often addressed by either physiotherapists or by medical physics/clinical engineering. A quality control protocol for SWD units, examining power output and electrical and mechanical condition, was developed and applied to 20 units used in clinical practice. In addition, an environmental assessment of where the units were used was also included. Results showed that the power output was generally stable (coefficient of variation range 0-8.8%) and reproducible (coefficient of variation range 0-6.8%). When the outputs from 12 similar units were compared, it was found that the relationship between the units' intensity settings and power output measurements was non-linear. Two units with mechanical timers were found to have inaccuracies that could contribute, under a 'worst-case' scenario, to a dosage error of up to 45%. Environmental analysis found that all treatment plinths in use contained metal parts, which could constitute a fire hazard, and no department examined was equipped with an RF screened room, a facility that would ensure that other persons in the vicinity were not exposed to excessive stray radiation.

[The role of control over microcirculation in millimetric wave therapy of acute destructive pancreatitis]

Microcirculatory reaction to millimetric waves (5.6, 7.1 and 4.9 mm) was studied in 78 patients with acute destructive pancreatitis using laser doppler flowmetry. The 4.9 mm waves proved most effective. As such waves have a normalizing effect on capillary blood flow, they can be used at early stages of the disease. The method allows control of individual reaction of the patient to millimetric waves and, therefore, facilitates the decision on its application.

Use of a transurethral microwave thermotherapeutic device with permanent pacemakers and implantable defibrillators

OBJECTIVE

To determine whether a device (Urologix Targis system) used for transurethral microwave treatment interferes with sensing, pacing, and arrhythmia detection by permanent pacemakers and implantable cardioverter-defibrillators (ICDs).

METHODS

We tested 13 pacemakers in both bipolar and unipolar sensing configurations and 8 ICDs in vitro. Pacemakers and ICDs were programmed to their most sensitive settings. Energy outputs of the microwave device were typical of those used clinically. The probe of the microwave device was anchored 1.2 cm from the pacemaker or ICD being tested.

RESULTS

No sensing, pacing, or arrhythmic interactions were noted with any ICD or any pacemaker programmed to the bipolar configuration. One pacemaker (Guidant Vigor 1230) showed intermittent tracking when programmed to the unipolar configuration.

CONCLUSIONS

Most patients with permanent pacemakers or ICDs can safely undergo transurethral microwave therapy using the device tested. Pacemakers and ICDs should be programmed to the bipolar configuration (if available) during therapy. The pacemaker or ICD should be interrogated before and after therapy to determine whether programming changes occurred as a result of treatment. However, our findings suggest that this is unlikely.

Focussed extracorporeal pyrotherapy: experimental results

A new device made of piezoelectric ceramic placed in a semispherical dish and focussed at 320 mm was developed in order to generate heat and cavitation responsible for coagulative necrosis of deep tissues. The target to be treated is located with a central ultrasound probe of 3.5 MHz. In vitro studies with polyurethane phantoms showed that the ultrasound melted a surface of 2 x 12 mm within 1 s. The temperature recorded at the focus was 270 degrees C. In tissue samples (prostate cancer and benign prostate hyperplasia), the temperature rose to 85 degrees C in vitro and a hyperechoic zone appeared at the focus during shots. In vivo 8-mm plastic spheres, introduced surgically into the bladder of pigs, were melted by repeat shots without burning of crossed tissues. These studies were performed in the kidney and the liver. Autopsy performed on day 0 showed congestion, autopsy performed between day 6 and day 11 showed necrosis, whereas at 3 months the focussed area was fibrosed. This technique, which we called 'focussed extracorporeal pyrotherapy', combines phenomena of cavitation and high heat at the focus. Prostate tumors, bladder tumors, kidney tumors and liver metastases are potential indications for pyrotherapy.

An evaluation of radiofrequency exposure from therapeutic diathermy equipment in the light of current recommendations

Shortwave and microwave diathermy equipment use by physiotherapy departments in Grampian Region has been studied. Stray electric and magnetic fields close to equipment have been measured and compared with exposure levels recommended by the INIRC and the NRPB. Fields above the recommended whole body levels extend to 0.5-1.0 m from the electrodes and cables for continuous wave (cw) shortwave equipment, and up to 0.5 m for microwave units and pulsed shortwave models. Operators were exposed to local fields above these values for 2 - 3 min during cw shortwave treatments, but rarely exceeded the recommended exposure. However, short localised exposures to high fields, which can occur if the operator moves close to the electrodes or cables, could exceed these limits. Physiotherapists are advised to remain at a distance of at least 1 m during cw treatments, and not to approach within 0.5 m of the electrodes and cables even for a short period.

Pulsed electromagnetic (short-wave) energy therapy

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Continuous short-wave (radio-frequency) diathermy

Continuous shortwave diathermy is the technique of choice when uniform marked elevation of temperature is required in the deep tissues. This heating can be targeted accurately by using an appropriate applicator positioned correctly. SWD also allows superficial structures to be heated selectively, although for this the various methods of surface heating are usually preferable. Sub-acute or chronic conditions respond best to continuous shortwave diathermy which, when used properly, can be as effective as ultrasound. Acute lesions are better treated with pulsed shortwave diathermy. Continuous shortwave diathermy can help to relieve pain and muscle spasm, resolve inflammatory states and reduce swelling, promote vasodilation, increase the compliance of connective tissue, increase joint range and decrease joint stiffness.

Microwave hyperthermia. Principles and quality assurance

This article discusses some of the basic principles involved in the deposition of microwave power in the tissue. Insight is offered into the characteristics of the instrumentation, its limitations, and the necessary quality control needs.

Clinical experience with thermotron RF-8 capacitive heating for bulky tumors: University of Minnesota experience

We conducted a phase I clinical trial of the feasibility of using the Thermotron RF-8, a capacitative heating device utilizing 8-MHz RF, for the treatment of deep-seated and bulky human tumors. Preclinical studies with agar phantoms demonstrated that deep heating can be achieved with this device when the electrode diameters are sufficiently large relative to the thickness of the heated object. In the clinical application of capacitive heating with radiofrequency, excessive heating of subcutaneous tissue has often been a problem. However, this could be minimized by continuous cooling of the subcutaneous fat with a 10 degrees C saline bolus, beginning more than 20 minutes prior to the start of heating. It was often possible to raise the temperature of deep-seated tumors even in obese patients by applying this pre-cooling method. The mean achieved temperature during 30 to 40 minutes of heating was higher than 42 degrees C and 40 degrees C to 42 degrees C in 26% and 50% of 58 tumors treated, respectively. A combination of hyperthermia (four to ten sessions, twice a week) with full-course or a limited dose of radiotherapy resulted in complete tumor remission in 7% of patients, and partial tumor remission in 50% of patients. In the full-course radiotherapy group, 69% of the tumors were judged to show complete or partial regression, and in the low-dose group, 43% of the tumors regressed completely or partially. Histologic examination of many of the tumors that did not regress showed massive necrosis, indicating that tumor size after hyperthermia is not an accurate criterion of the treatment result. Side effects were minimal, and vital sign changes during heating were insignificant. Our data, together with those reported by Japanese investigators, clearly demonstrated that hyperthermia with the Thermotron RF-8 in combination with radiotherapy is useful in treating deep-seated and bulky tumors that fail to respond to conventional treatment modalities.

[Rewarming of humans in deep hypothermia using a short-wave therapy apparatus. Report of 3 cases]

Three cases of successful "rewarming" of low hypothermic patients (below 30 degrees C = 86 degrees F) with a short-wave therapy apparatus (operating frequency 27.12 MHz) and eddy-current electrodes (Diplode) are described. The patients survived without any visible complications such as afterdrop, ventricular fibrillation or burns. This method is simple and not restricted to special hospitals.

Heating patterns produced by shortwave diathermy applicators in tissue substitute models

To be a deep-heating modality, shortwave diathermy applicators have to heat the musculature more than the subcutaneous fat. In this study, commercially available and prototype shortwave diathermy applicators were tested using tissue substitute models which allow rapid thermographic scanning of the initial linear transient temperature rise in the subcutaneous fat and muscle. The specific absorption rates (SAR) of the electromagnetic radiation were calculated throughout the tissues. Great differences were found in the deep-heating capability of these applicators. Some of the applicators heated the subcutaneous fat more than the muscle, while others were more efficient in heating the musculature.