Marvin Ziskin - Academia.edu (original) (raw)
Papers by Marvin Ziskin
We conducted a double-blinded, randomized, cross-over, prospective trial to evaluate the pain rel... more We conducted a double-blinded, randomized, cross-over, prospective trial to evaluate the pain relief effect of milli- meter waves (MW) under experimental conditions. The cold pressor test was used as a model of tonic aching pain. Twelve healthy male volunteers were exposed to an ac- tive medical MW generator and to a disabled sham gener- ator with at least 24 h
2008 33rd International Conference on Infrared, Millimeter and Terahertz Waves, 2008
The main purpose of this paper is to provide numerical and experimental dosimetry data for in vit... more The main purpose of this paper is to provide numerical and experimental dosimetry data for in vitro bioelectromagnetic experiments at millimeter waves. Numerical field-based and experimental temperature-based approaches were implemented in order to determine the average specific absorption rate (SAR) values in typical biological samples commonly used in bioelectromagnetic studies. It was shown that for frequencies ranging from 42 to
Ultrasound in Medicine & Biology, 2001
The potential risk of ultrasonography resulting in adverse biologic effects is particularly impor... more The potential risk of ultrasonography resulting in adverse biologic effects is particularly important in neurosonographic applications of diagnostic ultrasound in medicine. Key issues relate to the likelihood of producing bioeffects from the level of acoustic output emitted from modern diagnostically powerful ultrasound equipment. Important elements in the assessment of risk include the sensitivity of the tissue structures under examination, the standards of practice in clinical use and the presence of biologic effects identified from laboratory experimentation or from human studies. The World Federation for Ultrasound in Medicine and Biology continues to support activities related to evaluating bioeffects and safety of ultrasound. This paper includes extracts of some of the presentations given during the latest safety meeting, a mini-symposium on "ultrasound and the developing fetal central nervous system" held in conjunction with the WFUMB Congress in May 2000. The speakers covered topics ranging from physics of estimating heating from ultrasound equipment in clinical use to actual measurement of ultrasound-induced intracranial temperature increases in animal fetuses. Finally, some practical scanning strategies were proposed to minimise risk of adverse outcome in various clinical neurosonographic practices.
Ultrasound in Medicine & Biology, 1990
This patient study was based on the observation of characteristic intimal lesions in jugular and ... more This patient study was based on the observation of characteristic intimal lesions in jugular and femoral veins removed from dogs a few hours following total hip replacement. The lesions, small localized intimal tears, suggested that smooth muscle and connective tissue, might have dilated beyond the ability of intima to accommodate. Intraoperative venous dilation correlated with the incidence of intimal lesions. It was postulated that surgical trauma resulted in circulating vasoactive substances which caused venous dilation and that dilation of smooth muscle and connective tissue beyond the yield point of intima resulted in intimal rupture. Similar intraoperative dilation and lesions, in patients might predispose to development of deep vein thrombosis (DVT). Total hip (THR) and total knee (TKR) replacement patients were selected for study because: (a) of the high incidence of DVT and (b) blood circulation is present in THR but not in TKR patients during operation. Ultrasound was used to monitor cephalic vein diameter during the perioperative period. Development of DVT postoperatively was compared with intraoperative venous dilation. In THR patients, intraoperative venous dilation ranged from 6%-56%. One of nine patients with dilation -< 17% developed DVT while 12 patients with dilation of >22% developed DVT, giving a correct prediction of 95%. Of four patients in the intermediate range (19%, 20%), two developed DVT and two did not. The sharp demarcation was to be expected because of abrupt rupture of viscoelastic material when the critical point of elongation is exceeded. In TKR patients (with no intraoperative circulation in the operated leg), nine of ll developed DVT, all in the operated leg, but only one had venous dilation >-22%. We suggest that intraoperative ultrasound monitoring promises to identify susceptible patients, making it possible to target prophylaxis to them.
Life Sciences, 2001
In a series of blind experiments, using the cold water tail-flick test (cTFT) as a quantitative i... more In a series of blind experiments, using the cold water tail-flick test (cTFT) as a quantitative indicator of pain, the hypoalgesic effect of a single exposure of mice to low power electromagnetic millimeter waves (MW) was studied. The MW exposure characteristics were: frequency = 61.22 GHz; incident power density = 15 mW/cm2; and duration = 15 min. MW treatment was applied to the glabrous skin of the footpad. Exposure of an intact murine paw to the MW resulted in a statistically significant hypoalgesia as measured in the cTFT. These mice were able to resist cold noxious stimulation in the cTFF more than two times longer than animals from the sham-exposed group. A unilateral sciatic nerve transection was used to deafferent the area of exposure in animals from one of the experimental groups. This surgery, conducted six days before the MW treatment, completely abolished the hypoalgesic effect of the exposure to MW. The results obtained support the conclusion that the MW-skin nerve endings interaction is the essential step in the initiation of biological effects caused by MW. Based on our past and present results we recommend that in order to obtain a maximum therapeutic effect, densely innervated skin areas (head, hands) need to be used preferentially for exposure to MW in clinical practice.
Ultrasound in Medicine & Biology, 1997
Mammalian tissues have differing sensitivities to damage by physical agents such as ultrasound. T... more Mammalian tissues have differing sensitivities to damage by physical agents such as ultrasound. This article evaluates the scientific data in terms of known physical mechanisms of interaction and the impact on pre-and postnatal tissues. Actively dividing cells of the embryonic and fetal central nervous system are most readily disturbed. As a diagnostic ultrasound beam envelopes a small volume of tissue, it is possible that the effects of mild disturbance may not be detected unless major neural pathways are involved. There is evidence that ultrasound can be detected by the central nervous system; however, this does not necessarily imply that the bioeffect is hazardous to the fetus. Biologically significant temperature increases can occur at or near to bone in the fetus from the second trimester, if the beam is held stationary for more than 30 s in some pulsed Doppler applications. In this way, sensory organs that are encased in bone may be susceptible to heating by conduction. Reports in animals and humans of retarded growth and development following frequent exposures to diagnostic ultrasound, in the absence of significant heating, are difficult to explain from the current knowledge of ultrasound mechanisms. There is no evidence of cavitation effects occurring in the soft tissues of the fetus when exposed to diagnostic ultrasound; however, the possibility exists that such effects may be enhanced by the introduction of echo-contrast agents. 0 1997 World Federation for Ultrasound in Medicine & Biology.
Ultrasound in Medicine & Biology, 2000
Modern sophisticated ultrasonographic equipment is capable of delivering substantial levels of ac... more Modern sophisticated ultrasonographic equipment is capable of delivering substantial levels of acoustic energy into the body when used at maximum outputs. The risk of producing bioeffects has been studied by international expert groups during symposia supported by the World Federation for Ultrasound in Medicine and Biology (WFUMB). These have resulted in the publication of internationally accepted conclusions and recommendations. National ultrasound safety committees have published guidelines as well. These recommendations and safety guidelines offer valuable information to help users apply diagnostic ultrasound in a safe and effective manner. Acoustic output from ultrasound medical devices is directly regulated only in the USA and this is done by the Food and Drug Administration (FDA). However, there is also a modern trend towards self-regulation which has implications for the worldwide use of diagnostic ultrasound. It has resulted in a move away from the relatively simple scheme of FDA-enforced, application-specific limits on acoustic output to a scheme whereby risk of adverse effects of ultrasound exposure is assessed from information provided by the equipment in the form of a real-time display of safety indices. Under this option, the FDA allows a relaxation of some intensity limits, specifically approving the use of medical ultrasound devices that can expose the fetus or embryo to nearly eight times the intensity that was previously allowed. The shift of responsibility for risk assessment from a regulatory authority to the user creates an urgent need for awareness of risk and the development of knowledgeable and responsible attitudes to safety issues. To encourage this approach, it is incumbent on authorities, ultrasound societies and expert groups to provide relevant information on biological effects that might result from ultrasonographic procedures. It is obvious from the continued stream of enquiries received by ultrasound societies that effective dissemination of such knowledge requires sustained strenuous effort on the part of ultrasound safety committees. There is a strong need for continuing education to ensure that appropriate risk/benefit assessments are made by users based on an appropriate knowledge of the probability of biological effects occurring with each type of ultrasound procedure. The primary purpose of this paper is to draw attention to current safety guidelines and show the similarities and areas of general agreement with those issued by the parent ultrasound organisation, the WFUMB. It is equally important to identify gaps in our knowledge, where applicable.
Ultrasound in Medicine & Biology, 2007
Ultrasound in Medicine & Biology, 2007
Skin Research and Technology, 2008
A new non-invasive method for determining the free water content in human skin has been developed... more A new non-invasive method for determining the free water content in human skin has been developed. The method analyzes the reflection of millimeter (mm) wavelength electromagnetic waves. The amount of reflection of mm waves depends on an electrical property (namely, the permittivity) of the skin, and this depends upon the free water content of the various skin layers. The aim of the present study was to use the mm wave reflectometry method for determination of free water content in healthy skin treated with different hydrating substances. Skin lotion, pure water, glycerol, and petroleum jelly (an occlusive substance) were used for hydration of skin. The amount of free water was calculated using the permittivity values of skin layers found from fitting a three layer skin model to measured reflection data. The skin model consisted of (1) the stratum corneum (SC), (2) the viable epidermis plus the dermis, and (3) fat layers. Mm wave reflection was significantly affected by the water content of the thick SC of the palm but not by the very thin SC of the forearm. Treatment of the forearm and palm skin with different hydrating substances produced notable changes of the free water content in the SC, but not in the viable epidermis or dermis. The greatest hydration was produced by pure water and skin lotion, and the lowest by petroleum jelly. However, petroleum jelly produced prolonged retention of water in the SC following its hydration by other moisturizers. The content of free water was found to return to its baseline value after removal of moisturizers in as short a time as 8.3 min. The study shows that mm wave reflectometry can be used as a sensitive technique for the non-invasive determination of water content in living skin.
Life Sciences, 2000
Based on a hypothesis of neural system involvement in the initial absorption and further processi... more Based on a hypothesis of neural system involvement in the initial absorption and further processing of the millimeter electromagnetic waves (MW) signal, we reproduced, quantitatively assessed and compared the analgesic effect of a single MW treatment, exposing areas of skin possessing different innervation densities. The cold water tail flick test (cTFT) was used to assess experimental pain in mice. Three areas of exposure were used: the nose, the glabrous skin of the right footpad, and the hairy skin of the mid back at the level of T5-TlO. The MW exposure characteristics were: frequency = 61.22 GHz; incident power density = lSmW/cm'; and duration = 15 min. The maximum hypoalgesic effect was achieved by exposing to MW the more densely innervated skin areas -the nose and the footpad. The hypoalgesic effect in the LIFT after MW exposure to the murine back, which is less densely innervated, was not statistically significant. These results support the hypothesis of neural system involvement in the systemic response to MW.
Life Sciences, 1998
In our previous studies, exposure of mice to millimeter waves (MW) increased the duration of anes... more In our previous studies, exposure of mice to millimeter waves (MW) increased the duration of anesthesia caused by either ketamine or chloral hydrate, and this effect was blocked by naloxone. To further characterize the biological effects of MW, we have chosen a new animal model of experimental itch. Male Swiss albino mice were injected S.C. in the rostral part of the back with the pruritogenic agent, compound 48/80, with or without naloxone pretreatment. After a 15-min exposure of mice to MW (frequency, 61.22 GHz; incident power density, 15 mW/cm'), the number of scratches of the injected site was counted for 90 min post-injection. MW inhibited the scratching activity of mice by more than 2 times in comparison with the sham-exposed controls (pcO.005). Pretreatment of animals with (-)-naloxone (0.1-1.0 m@g, i.p.) suppressed the antipruritic effect of MW in a dose-dependent manner, while the inactive enantiomer (+)-naloxone at 1 mg/kg did not alter the effect. These results suggest that MW trigger the release of opioids in exposed subjects. 0 1998 Elsevier Science Inc.
Investigative Radiology, 1973
IEEE Transactions on Plasma Science, 2004
... Millimeter Wave Hyperthermia in Mice Imre Szabo, Stanislav I. Alekseev, Geza Acs, Alexander A... more ... Millimeter Wave Hyperthermia in Mice Imre Szabo, Stanislav I. Alekseev, Geza Acs, Alexander A. Radzievsky, Mahendra K. Logani, Vera R. Makar, Oleg R. Gordiienko, and Marvin C. Ziskin, Life Fellow, IEEE ... 2003. [24] SM Todryk, MJ Gough, and AG Pockley, Facets of heat ...
IEEE Transactions on Plasma Science, 2004
Millimeter-wave therapy (MWT) is based on the systemic biological effects resulting from local ex... more Millimeter-wave therapy (MWT) is based on the systemic biological effects resulting from local exposure of skin to low-power electromagnetic waves of millimeter wavelength. The aims of the present study are to quantitatively evaluate hypoalgesic effects of MWT in murine experimental models of acute and chronic neuropathic pain, and to compare them with the previously determined MWT-induced hypoalgesia in an experimental
IEEE Transactions on Microwave Theory and Techniques, 2000
This paper provides extensive dosimetry data for in vitro experiments regarding the biological ef... more This paper provides extensive dosimetry data for in vitro experiments regarding the biological effects of millimeter waves. Two particular frequency ranges have been considered, which are: (1) the 57-64-GHz frequency range dedicated to near-future applications in high-speed wireless communication systems and (2) the discrete frequencies used in millimeter-wave therapy, namely, 42.25, 53.57, and 61.22 GHz. The dielectric properties of keratinocyte cells and culture media were determined using permittivity data of free water and Maxwell's mixture equation. The local specific absorption rate (SAR) distribution within the cell monolayer located in a standard tissue culture plate was computed using the finite-element method and the finite-integration technique. The averaged near-surface SAR for the cell monolayer was determined using both numerical electric-field-based and experimental temperature-based approaches. The SAR was computed taking into account physiological variations of the water content in the keratinocyte cells, as well as variations in the cell monolayer thickness. Experimental and computational results are shown to be in very good agreement.
IEEE Transactions on Biomedical Engineering, 2000
Earlier publications demonstrated that 0.9 GHz microwave exposure induced notable changes of the ... more Earlier publications demonstrated that 0.9 GHz microwave exposure induced notable changes of the conductivity of modified bilayer lipid membranes (BLM) formed in holes in thin Teflon film (TF). The aims of this study were: 1) to perform detailed calculations of the microwave field distributions in holes formed in TF, using the finite-difference time-domain technique and 2) to model microwave heating of the hole under the conditions used in the BLM experiments but in the absence of BLM in the hole. We found that with the E-field oriented perpendicular to the TF plane the local-specific absorption rate in holes increased significantly. The increase became larger with increasing electrolyte concentration and with decreasing diameter of the hole and frequency. The calculated temperature elevations in the hole were in good agreement with those determined experimentally. These findings allowed us to conclude that the microwave effects on BLM conductivity reported previously resulted mostly from the enhanced absorption of microwave energy by the membrane-forming holes and subsequent local temperature elevation in the holes.
IEEE Transactions on Biomedical Engineering, 2001
Specific absorption rate (SAR) distributions in the vicinity of a thermocouple or air bubble in w... more Specific absorption rate (SAR) distributions in the vicinity of a thermocouple or air bubble in water and in the presence of hair or sweat duct in skin were calculated using analytical and two-dimensional impedance methods. The objects were exposed to uniform 42.25 GHz plane electromagnetic fields. Insertion of a 0.1-mm thermocouple or similarly sized air bubble into water produced a strong localized disturbance of the otherwise uniform SAR distribution. However, the average of SAR values immediately surrounding the thermocouple was close to the undisturbed uniform average SAR. This allows measuring the average SAR during exposure of both unbounded and bounded media using calibrated small thermocouples (up to 0.1 mm). The SAR distribution in the vicinity of a hair was qualitatively similar to that produced by an air bubble. The maximal value of SAR was more than three times higher than the overall average SAR value in the skin. Sweat ducts produced a smaller disturbance of the millimeter-wave (mm-wave) field.
Ultrasound in medicine …, 1994
This overview of bioeffects of ultrasound presents some key aspects of selected papers dealing wi... more This overview of bioeffects of ultrasound presents some key aspects of selected papers dealing with biophysical end-points. Its purpose is to establish a basis for exposure and dosimetric standards for medical ultrasonic equipment. It is intended to provide essential background resource material for the medical/scientific community, and more specifically for scientific working groups. This document was prepared by members of the Safety Committee of the World Federation for Ultrasound in Medicine and Biology. It was produced as a resource document in response to a request for information by Working Group 12 (Ultrasound exposure parameters) of the International Electrotechnical Commission Technical Committee 87, Ultrasonics. IEC TC 87, WG12 is the working group responsible for generating international standards for the classification of equipment by its acoustic fields based on safety thresholds. Our paper is intended to update and supplement information on the thermal mechanism provided in the publication, "WFUMB Symposium on Safety and Standardisation in Medical Ultrasound: Issues and Recommendations Regarding Thermal Mechanisms for Biological Effects of Ultrasound" (WFUMB 1992). It also provides an overview of trends in research into nonthermal mechanisms as a prefiminary to the next WFUMB Symposium on Safety of Medical Ultrasound when this subject will be examined in detail by a select group of international experts. The WFUMB-sponsored workshop will take place in Utsunomiya, Japan during ll-15th July, 1994. The purpose of the meeting is to evaluate the scientific literature and to formulate internationally accepted recommendations on the safe use of diagnostic ultrasound that may be endorsed as official policy of the WFUMB. It should be noted that the current publication is not intended for review or endorsement as an official WFUMB document. It is produced as a scientific paper by individuals who are members of the WFUMB Safety Committee, and it therefore represents the opinions of the authors. Nevertheless, during the preparation of this document, contributions were received from members of the International Electrotechnical Commission Technical Committee 87 as well as many other individual experts, and the authors sincerely acknowledge their support.
We conducted a double-blinded, randomized, cross-over, prospective trial to evaluate the pain rel... more We conducted a double-blinded, randomized, cross-over, prospective trial to evaluate the pain relief effect of milli- meter waves (MW) under experimental conditions. The cold pressor test was used as a model of tonic aching pain. Twelve healthy male volunteers were exposed to an ac- tive medical MW generator and to a disabled sham gener- ator with at least 24 h
2008 33rd International Conference on Infrared, Millimeter and Terahertz Waves, 2008
The main purpose of this paper is to provide numerical and experimental dosimetry data for in vit... more The main purpose of this paper is to provide numerical and experimental dosimetry data for in vitro bioelectromagnetic experiments at millimeter waves. Numerical field-based and experimental temperature-based approaches were implemented in order to determine the average specific absorption rate (SAR) values in typical biological samples commonly used in bioelectromagnetic studies. It was shown that for frequencies ranging from 42 to
Ultrasound in Medicine & Biology, 2001
The potential risk of ultrasonography resulting in adverse biologic effects is particularly impor... more The potential risk of ultrasonography resulting in adverse biologic effects is particularly important in neurosonographic applications of diagnostic ultrasound in medicine. Key issues relate to the likelihood of producing bioeffects from the level of acoustic output emitted from modern diagnostically powerful ultrasound equipment. Important elements in the assessment of risk include the sensitivity of the tissue structures under examination, the standards of practice in clinical use and the presence of biologic effects identified from laboratory experimentation or from human studies. The World Federation for Ultrasound in Medicine and Biology continues to support activities related to evaluating bioeffects and safety of ultrasound. This paper includes extracts of some of the presentations given during the latest safety meeting, a mini-symposium on "ultrasound and the developing fetal central nervous system" held in conjunction with the WFUMB Congress in May 2000. The speakers covered topics ranging from physics of estimating heating from ultrasound equipment in clinical use to actual measurement of ultrasound-induced intracranial temperature increases in animal fetuses. Finally, some practical scanning strategies were proposed to minimise risk of adverse outcome in various clinical neurosonographic practices.
Ultrasound in Medicine & Biology, 1990
This patient study was based on the observation of characteristic intimal lesions in jugular and ... more This patient study was based on the observation of characteristic intimal lesions in jugular and femoral veins removed from dogs a few hours following total hip replacement. The lesions, small localized intimal tears, suggested that smooth muscle and connective tissue, might have dilated beyond the ability of intima to accommodate. Intraoperative venous dilation correlated with the incidence of intimal lesions. It was postulated that surgical trauma resulted in circulating vasoactive substances which caused venous dilation and that dilation of smooth muscle and connective tissue beyond the yield point of intima resulted in intimal rupture. Similar intraoperative dilation and lesions, in patients might predispose to development of deep vein thrombosis (DVT). Total hip (THR) and total knee (TKR) replacement patients were selected for study because: (a) of the high incidence of DVT and (b) blood circulation is present in THR but not in TKR patients during operation. Ultrasound was used to monitor cephalic vein diameter during the perioperative period. Development of DVT postoperatively was compared with intraoperative venous dilation. In THR patients, intraoperative venous dilation ranged from 6%-56%. One of nine patients with dilation -< 17% developed DVT while 12 patients with dilation of >22% developed DVT, giving a correct prediction of 95%. Of four patients in the intermediate range (19%, 20%), two developed DVT and two did not. The sharp demarcation was to be expected because of abrupt rupture of viscoelastic material when the critical point of elongation is exceeded. In TKR patients (with no intraoperative circulation in the operated leg), nine of ll developed DVT, all in the operated leg, but only one had venous dilation >-22%. We suggest that intraoperative ultrasound monitoring promises to identify susceptible patients, making it possible to target prophylaxis to them.
Life Sciences, 2001
In a series of blind experiments, using the cold water tail-flick test (cTFT) as a quantitative i... more In a series of blind experiments, using the cold water tail-flick test (cTFT) as a quantitative indicator of pain, the hypoalgesic effect of a single exposure of mice to low power electromagnetic millimeter waves (MW) was studied. The MW exposure characteristics were: frequency = 61.22 GHz; incident power density = 15 mW/cm2; and duration = 15 min. MW treatment was applied to the glabrous skin of the footpad. Exposure of an intact murine paw to the MW resulted in a statistically significant hypoalgesia as measured in the cTFT. These mice were able to resist cold noxious stimulation in the cTFF more than two times longer than animals from the sham-exposed group. A unilateral sciatic nerve transection was used to deafferent the area of exposure in animals from one of the experimental groups. This surgery, conducted six days before the MW treatment, completely abolished the hypoalgesic effect of the exposure to MW. The results obtained support the conclusion that the MW-skin nerve endings interaction is the essential step in the initiation of biological effects caused by MW. Based on our past and present results we recommend that in order to obtain a maximum therapeutic effect, densely innervated skin areas (head, hands) need to be used preferentially for exposure to MW in clinical practice.
Ultrasound in Medicine & Biology, 1997
Mammalian tissues have differing sensitivities to damage by physical agents such as ultrasound. T... more Mammalian tissues have differing sensitivities to damage by physical agents such as ultrasound. This article evaluates the scientific data in terms of known physical mechanisms of interaction and the impact on pre-and postnatal tissues. Actively dividing cells of the embryonic and fetal central nervous system are most readily disturbed. As a diagnostic ultrasound beam envelopes a small volume of tissue, it is possible that the effects of mild disturbance may not be detected unless major neural pathways are involved. There is evidence that ultrasound can be detected by the central nervous system; however, this does not necessarily imply that the bioeffect is hazardous to the fetus. Biologically significant temperature increases can occur at or near to bone in the fetus from the second trimester, if the beam is held stationary for more than 30 s in some pulsed Doppler applications. In this way, sensory organs that are encased in bone may be susceptible to heating by conduction. Reports in animals and humans of retarded growth and development following frequent exposures to diagnostic ultrasound, in the absence of significant heating, are difficult to explain from the current knowledge of ultrasound mechanisms. There is no evidence of cavitation effects occurring in the soft tissues of the fetus when exposed to diagnostic ultrasound; however, the possibility exists that such effects may be enhanced by the introduction of echo-contrast agents. 0 1997 World Federation for Ultrasound in Medicine & Biology.
Ultrasound in Medicine & Biology, 2000
Modern sophisticated ultrasonographic equipment is capable of delivering substantial levels of ac... more Modern sophisticated ultrasonographic equipment is capable of delivering substantial levels of acoustic energy into the body when used at maximum outputs. The risk of producing bioeffects has been studied by international expert groups during symposia supported by the World Federation for Ultrasound in Medicine and Biology (WFUMB). These have resulted in the publication of internationally accepted conclusions and recommendations. National ultrasound safety committees have published guidelines as well. These recommendations and safety guidelines offer valuable information to help users apply diagnostic ultrasound in a safe and effective manner. Acoustic output from ultrasound medical devices is directly regulated only in the USA and this is done by the Food and Drug Administration (FDA). However, there is also a modern trend towards self-regulation which has implications for the worldwide use of diagnostic ultrasound. It has resulted in a move away from the relatively simple scheme of FDA-enforced, application-specific limits on acoustic output to a scheme whereby risk of adverse effects of ultrasound exposure is assessed from information provided by the equipment in the form of a real-time display of safety indices. Under this option, the FDA allows a relaxation of some intensity limits, specifically approving the use of medical ultrasound devices that can expose the fetus or embryo to nearly eight times the intensity that was previously allowed. The shift of responsibility for risk assessment from a regulatory authority to the user creates an urgent need for awareness of risk and the development of knowledgeable and responsible attitudes to safety issues. To encourage this approach, it is incumbent on authorities, ultrasound societies and expert groups to provide relevant information on biological effects that might result from ultrasonographic procedures. It is obvious from the continued stream of enquiries received by ultrasound societies that effective dissemination of such knowledge requires sustained strenuous effort on the part of ultrasound safety committees. There is a strong need for continuing education to ensure that appropriate risk/benefit assessments are made by users based on an appropriate knowledge of the probability of biological effects occurring with each type of ultrasound procedure. The primary purpose of this paper is to draw attention to current safety guidelines and show the similarities and areas of general agreement with those issued by the parent ultrasound organisation, the WFUMB. It is equally important to identify gaps in our knowledge, where applicable.
Ultrasound in Medicine & Biology, 2007
Ultrasound in Medicine & Biology, 2007
Skin Research and Technology, 2008
A new non-invasive method for determining the free water content in human skin has been developed... more A new non-invasive method for determining the free water content in human skin has been developed. The method analyzes the reflection of millimeter (mm) wavelength electromagnetic waves. The amount of reflection of mm waves depends on an electrical property (namely, the permittivity) of the skin, and this depends upon the free water content of the various skin layers. The aim of the present study was to use the mm wave reflectometry method for determination of free water content in healthy skin treated with different hydrating substances. Skin lotion, pure water, glycerol, and petroleum jelly (an occlusive substance) were used for hydration of skin. The amount of free water was calculated using the permittivity values of skin layers found from fitting a three layer skin model to measured reflection data. The skin model consisted of (1) the stratum corneum (SC), (2) the viable epidermis plus the dermis, and (3) fat layers. Mm wave reflection was significantly affected by the water content of the thick SC of the palm but not by the very thin SC of the forearm. Treatment of the forearm and palm skin with different hydrating substances produced notable changes of the free water content in the SC, but not in the viable epidermis or dermis. The greatest hydration was produced by pure water and skin lotion, and the lowest by petroleum jelly. However, petroleum jelly produced prolonged retention of water in the SC following its hydration by other moisturizers. The content of free water was found to return to its baseline value after removal of moisturizers in as short a time as 8.3 min. The study shows that mm wave reflectometry can be used as a sensitive technique for the non-invasive determination of water content in living skin.
Life Sciences, 2000
Based on a hypothesis of neural system involvement in the initial absorption and further processi... more Based on a hypothesis of neural system involvement in the initial absorption and further processing of the millimeter electromagnetic waves (MW) signal, we reproduced, quantitatively assessed and compared the analgesic effect of a single MW treatment, exposing areas of skin possessing different innervation densities. The cold water tail flick test (cTFT) was used to assess experimental pain in mice. Three areas of exposure were used: the nose, the glabrous skin of the right footpad, and the hairy skin of the mid back at the level of T5-TlO. The MW exposure characteristics were: frequency = 61.22 GHz; incident power density = lSmW/cm'; and duration = 15 min. The maximum hypoalgesic effect was achieved by exposing to MW the more densely innervated skin areas -the nose and the footpad. The hypoalgesic effect in the LIFT after MW exposure to the murine back, which is less densely innervated, was not statistically significant. These results support the hypothesis of neural system involvement in the systemic response to MW.
Life Sciences, 1998
In our previous studies, exposure of mice to millimeter waves (MW) increased the duration of anes... more In our previous studies, exposure of mice to millimeter waves (MW) increased the duration of anesthesia caused by either ketamine or chloral hydrate, and this effect was blocked by naloxone. To further characterize the biological effects of MW, we have chosen a new animal model of experimental itch. Male Swiss albino mice were injected S.C. in the rostral part of the back with the pruritogenic agent, compound 48/80, with or without naloxone pretreatment. After a 15-min exposure of mice to MW (frequency, 61.22 GHz; incident power density, 15 mW/cm'), the number of scratches of the injected site was counted for 90 min post-injection. MW inhibited the scratching activity of mice by more than 2 times in comparison with the sham-exposed controls (pcO.005). Pretreatment of animals with (-)-naloxone (0.1-1.0 m@g, i.p.) suppressed the antipruritic effect of MW in a dose-dependent manner, while the inactive enantiomer (+)-naloxone at 1 mg/kg did not alter the effect. These results suggest that MW trigger the release of opioids in exposed subjects. 0 1998 Elsevier Science Inc.
Investigative Radiology, 1973
IEEE Transactions on Plasma Science, 2004
... Millimeter Wave Hyperthermia in Mice Imre Szabo, Stanislav I. Alekseev, Geza Acs, Alexander A... more ... Millimeter Wave Hyperthermia in Mice Imre Szabo, Stanislav I. Alekseev, Geza Acs, Alexander A. Radzievsky, Mahendra K. Logani, Vera R. Makar, Oleg R. Gordiienko, and Marvin C. Ziskin, Life Fellow, IEEE ... 2003. [24] SM Todryk, MJ Gough, and AG Pockley, Facets of heat ...
IEEE Transactions on Plasma Science, 2004
Millimeter-wave therapy (MWT) is based on the systemic biological effects resulting from local ex... more Millimeter-wave therapy (MWT) is based on the systemic biological effects resulting from local exposure of skin to low-power electromagnetic waves of millimeter wavelength. The aims of the present study are to quantitatively evaluate hypoalgesic effects of MWT in murine experimental models of acute and chronic neuropathic pain, and to compare them with the previously determined MWT-induced hypoalgesia in an experimental
IEEE Transactions on Microwave Theory and Techniques, 2000
This paper provides extensive dosimetry data for in vitro experiments regarding the biological ef... more This paper provides extensive dosimetry data for in vitro experiments regarding the biological effects of millimeter waves. Two particular frequency ranges have been considered, which are: (1) the 57-64-GHz frequency range dedicated to near-future applications in high-speed wireless communication systems and (2) the discrete frequencies used in millimeter-wave therapy, namely, 42.25, 53.57, and 61.22 GHz. The dielectric properties of keratinocyte cells and culture media were determined using permittivity data of free water and Maxwell's mixture equation. The local specific absorption rate (SAR) distribution within the cell monolayer located in a standard tissue culture plate was computed using the finite-element method and the finite-integration technique. The averaged near-surface SAR for the cell monolayer was determined using both numerical electric-field-based and experimental temperature-based approaches. The SAR was computed taking into account physiological variations of the water content in the keratinocyte cells, as well as variations in the cell monolayer thickness. Experimental and computational results are shown to be in very good agreement.
IEEE Transactions on Biomedical Engineering, 2000
Earlier publications demonstrated that 0.9 GHz microwave exposure induced notable changes of the ... more Earlier publications demonstrated that 0.9 GHz microwave exposure induced notable changes of the conductivity of modified bilayer lipid membranes (BLM) formed in holes in thin Teflon film (TF). The aims of this study were: 1) to perform detailed calculations of the microwave field distributions in holes formed in TF, using the finite-difference time-domain technique and 2) to model microwave heating of the hole under the conditions used in the BLM experiments but in the absence of BLM in the hole. We found that with the E-field oriented perpendicular to the TF plane the local-specific absorption rate in holes increased significantly. The increase became larger with increasing electrolyte concentration and with decreasing diameter of the hole and frequency. The calculated temperature elevations in the hole were in good agreement with those determined experimentally. These findings allowed us to conclude that the microwave effects on BLM conductivity reported previously resulted mostly from the enhanced absorption of microwave energy by the membrane-forming holes and subsequent local temperature elevation in the holes.
IEEE Transactions on Biomedical Engineering, 2001
Specific absorption rate (SAR) distributions in the vicinity of a thermocouple or air bubble in w... more Specific absorption rate (SAR) distributions in the vicinity of a thermocouple or air bubble in water and in the presence of hair or sweat duct in skin were calculated using analytical and two-dimensional impedance methods. The objects were exposed to uniform 42.25 GHz plane electromagnetic fields. Insertion of a 0.1-mm thermocouple or similarly sized air bubble into water produced a strong localized disturbance of the otherwise uniform SAR distribution. However, the average of SAR values immediately surrounding the thermocouple was close to the undisturbed uniform average SAR. This allows measuring the average SAR during exposure of both unbounded and bounded media using calibrated small thermocouples (up to 0.1 mm). The SAR distribution in the vicinity of a hair was qualitatively similar to that produced by an air bubble. The maximal value of SAR was more than three times higher than the overall average SAR value in the skin. Sweat ducts produced a smaller disturbance of the millimeter-wave (mm-wave) field.
Ultrasound in medicine …, 1994
This overview of bioeffects of ultrasound presents some key aspects of selected papers dealing wi... more This overview of bioeffects of ultrasound presents some key aspects of selected papers dealing with biophysical end-points. Its purpose is to establish a basis for exposure and dosimetric standards for medical ultrasonic equipment. It is intended to provide essential background resource material for the medical/scientific community, and more specifically for scientific working groups. This document was prepared by members of the Safety Committee of the World Federation for Ultrasound in Medicine and Biology. It was produced as a resource document in response to a request for information by Working Group 12 (Ultrasound exposure parameters) of the International Electrotechnical Commission Technical Committee 87, Ultrasonics. IEC TC 87, WG12 is the working group responsible for generating international standards for the classification of equipment by its acoustic fields based on safety thresholds. Our paper is intended to update and supplement information on the thermal mechanism provided in the publication, "WFUMB Symposium on Safety and Standardisation in Medical Ultrasound: Issues and Recommendations Regarding Thermal Mechanisms for Biological Effects of Ultrasound" (WFUMB 1992). It also provides an overview of trends in research into nonthermal mechanisms as a prefiminary to the next WFUMB Symposium on Safety of Medical Ultrasound when this subject will be examined in detail by a select group of international experts. The WFUMB-sponsored workshop will take place in Utsunomiya, Japan during ll-15th July, 1994. The purpose of the meeting is to evaluate the scientific literature and to formulate internationally accepted recommendations on the safe use of diagnostic ultrasound that may be endorsed as official policy of the WFUMB. It should be noted that the current publication is not intended for review or endorsement as an official WFUMB document. It is produced as a scientific paper by individuals who are members of the WFUMB Safety Committee, and it therefore represents the opinions of the authors. Nevertheless, during the preparation of this document, contributions were received from members of the International Electrotechnical Commission Technical Committee 87 as well as many other individual experts, and the authors sincerely acknowledge their support.