Dosimetry

Acta Neuropsychiatr. 2014 Oct 2:1-7. [Epub ahead of print]

The Diagnostic Apathia Scale predicts a dose-remission relationship of T-PEMF in treatment-resistant depression.

Bech P1, Lunde M1, Lauritzen L1, Straasø B1, Lindberg L1, Vinberg M2, Undén M1, Hellström LC3, Dissing S4, Larsen ER5.

Author information

  • 11Psychiatric Research Unit,Psychiatric Centre North Zealand,Copenhagen University Hospital,Hillerød,Denmark.
  • 22Department of Psychiatry,Psychiatric Centre Copenhagen,Copenhagen University Hospital,Copenhagen,Denmark.
  • 33Psychiatric Research Unit,Psychiatric Centre Copenhagen,Copenhagen University Hospital,Copenhagen NV,Denmark.
  • 44Department of Cellular and Molecular Medicine,Panum institute,University of Copenhagen,Copenhagen,Denmark.
  • 55Department of Affective Disorders,Mood Disorders Research Unit,Aarhus University Hospital,Aarhus,Denmark.

Abstract

OBJECTIVE:

The aim of this study was to evaluate the predictive validity of the apathy subsyndrome in patients with therapy-resistant depression in the dose-remission study with transcranial pulsating electromagnetic fields (T-PEMF).

METHODS:

The apathy subsyndrome consists of the symptoms of fatigue, concentration and memory problems, lack of interests, difficulties in making decisions, and sleep problems. We evaluated 65 patients with therapy-resistant depression. In total, 34 of these patients received placebo T-PEMF in the afternoon and active T-PEMF in the morning, that is, one daily dose. The remaining 31 patients received active T-PEMF twice daily. Duration of treatment was 8 weeks in both groups. The Hamilton Depression Scale (HAM-D17) and the Bech-Rafaelsen Melancholia Scale (MES) were used to measure remission. We also focused on the Diagnostic Apathia Scale, which is based on a mixture of items from the MINI and the HAM-D17/MES.

RESULTS:

In patients without apathy, the remission rate after T-PEMF was 83.9% versus 58.8% in patients with apathy (p≤0.05). In patients without apathy receiving one active dose daily 94.4% remitted versus 50% for patients with apathy (p≤0.05). In patients without apathy who received two active doses 69.9% remitted versus 66.7% for patients with apathy (p≤0.05).

CONCLUSION:

Taking the baseline diagnosis of the apathy syndrome into consideration, we found that in patients without apathy one daily dose of T-PEMF is sufficient, but in patients with apathy two daily doses are necessary. Including the apathy syndrome as predictor in future studies would seem to be clinically relevant.

 
Acta Neuropsychiatr. 2014 Oct;26(5):272-9. doi: 10.1017/neu.2014.5.

Dose-remission of pulsating electromagnetic fields as augmentation in therapy-resistant depression: a randomized, double-blind controlled study.

Straasø B1, Lauritzen L1, Lunde M1, Vinberg M2, Lindberg L1, Larsen ER3, Dissing S4, Bech P1.

Author information

  • 11Psychiatric Research Unit,Psychiatric Centre North Zealand,Copenhagen University Hospital,Hillerød,Denmark.
  • 22Department of Psychiatry,Psychiatric Centre Copenhagen,Copenhagen University Hospital,Denmark.
  • 33Department of Affective Disorders,Mood Disorders Research Unit,Aarhus University Hospital,Denmark.
  • 44Department of Cellular and Molecular Medicine,Panum Institute,University of Copenhagen,Copenhagen,Denmark.

Abstract

OBJECTIVE:

To evaluate to what extent a twice daily dose of Transcranial Pulsating ElectroMagnetic Fields (T-PEMF) was superior to once daily in patients with treatment-resistant depression as to obtaining symptom remission after 8 weeks of augmentation therapy.

METHODS:

A self-treatment set-up of the T-PEMF device was used allowing self-administration by patients in own homes. All patients were treated for 30 min per T-PEMF session. The antidepressant medication the patients were receiving at baseline remained unchanged during the trial. The patients were randomised to either one T-PEMF dose (active dose in the morning and sham in the afternoon) or two T-PEMF doses (active dose both morning and afternoon) in a double-blind procedure. A score of 7 or less on the Hamilton Depression Scale (HAM-D17) was the criterion of remission.

RESULTS:

In total 34 patients received active T-PEMF once a day and 31 patients twice daily. After 5 weeks of therapy remission was obtained in 26.5% and 32.3% on one dose and two doses of T-PEMF, respectively. After 8 weeks the rate of remission was 73.5% and 67.7%, respectively. The side effects as measured by the Udvalget for Kliniske Undersøgelser scale showed a better toleration of the antidepresssive medication in both treatment groups, which was reflected by the WHO-5 well-being scale with increased scores in both groups of patients.

CONCLUSION:

The high remission rate obtained by the T-PEMF augmentation was not a dose effect (one versus two daily T-PEMF sessions) but was explained by the extension of the treatment period from 5 to 8 weeks.

Evid Based Complement Alternat Med. 2009 Jun;6(2):133-9. Epub 2007 Oct 4.

Static magnetic field therapy: a critical review of treatment parameters.

Colbert AP, Wahbeh H, Harling N, Connelly E, Schiffke HC, Forsten C, Gregory WL, Markov MS, Souder JJ, Elmer P, King V.

Helfgott Research Institute, National College of Natural Medicine, 049 SW, Porter Street, Portland, OR 97291, USA. acolbert@ncnm.edu

Abstract

Static magnetic field (SMF) therapy, applied via a permanent magnet attached to the skin, is used by people worldwide for self-care. Despite a lack of established SMF dosage and treatment regimens, multiple studies are conducted to evaluate SMF therapy effectiveness. Our objectives in conducting this review are to:(i) summarize SMF research conducted in humans; (ii) critically evaluate reporting quality of SMF dosages and treatment parameters and (iii) propose a set of criteria for reporting SMF treatment parameters in future clinical trials. We searched 27 electronic databases and reference lists. Only English language human studies were included. Excluded were studies of electromagnetic fields, transcranial magnetic stimulation, magnets placed on acupuncture points, animal studies, abstracts, posters and editorials. Data were extracted on clinical indication, study design and 10 essential SMF parameters. Three reviewers assessed quality of reporting and calculated a quality assessment score for each of the 10 treatment parameters. Fifty-six studies were reviewed, 42 conducted in patient populations and 14 in healthy volunteers. The SMF treatment parameters most often and most completely described were site of application, magnet support device and frequency and duration of application. Least often and least completely described were characteristics of the SMF: magnet dimensions, measured field strength and estimated distance of the magnet from the target tissue. Thirty-four (61%) of studies failed to provide enough detail about SMF dosage to permit protocol replication by other investigators. Our findings highlight the need to optimize SMF dosing parameters for individual clinical conditions before proceeding to a full-scale clinical trial.

Gig Sanit. 2009 Jan-Feb;(1):72-6.

Criterion for the hygienic standardization of exposure to infrequent ultra-short electromagnetic pulses.

[Article in Russian]

Gavrish NN, Ushakov IB, Pokhode? LV, Rubtsova IB, Pal'tsev IuP.

Abstract

The authors provide evidence for the estimated density of an inducted current as a criterion for the hygienic standardization of exposure to infrequent electromagnetic pulses of nanosecond duration, which are generated by test discharge units. The adverse effect threshold for the pulse has been determined and its maximum accessible action of the units on the staff established. Reference guidelines for electromagnetic safety of workers engaged in the pulsed fields have been developed and approved.

Radiat Prot Dosimetry. 2003;106(4):333-40.

50-60 Hz electric and magnetic field effects on cognitive function in humans: a review.

Crasson M.

University of Liege, Psychoneuroendocrinology Unit, B-35, B-4000 Liege, Belgium. mcrasson@ulg.ac.bl

Abstract

This paper reviews the effect of 50-60 Hz weak electric, magnetic and combined electric and magnetic field exposure on cognitive functions such as memory, attention, information processing and time perception, as determined by electroencephalographic methods and performance measures. Overall, laboratory studies that have investigated the acute effects of power frequency fields on cognitive functioning in humans are heterogeneous, in terms of both electric and magnetic field (EMF) exposure and the experimental design and measures used. Results are inconsistent and difficult to interpret with regard to functional relevance for possible health risks. Statistically significant differences between field and control exposure, when they are found, are small, subtle, transitory, without any clear dose-response relationship and difficult to reproduce. The human performance or event related potentials (ERPs) measures that might specifically be affected by EMF exposure, as well as a possible cerebral structure or function that could be more sensitive to EMF, cannot be better determined.

Radiat Prot Dosimetry. 2003;106(4):349-56.

Dosimetry considerations in the head and retina for extremely low frequency electric fields.

Taki M, Suzuki Y, Wake K.

Department of Electrical Engineering, Tokyo Metropolitan University 1-1, Minami-osawa, Hachioji, Tokyo 192-0397, Japan. taki@eei.metro-u.ac.jp

Abstract

Magnetophosphenes are investigated from the viewpoint of electromagnetic dosimetry. Induced current density and internal electric fields at the threshold of perception are estimated by analytical and numerical calculations, assuming different models. Dosimetry for electrophosphenes is also discussed and compared with that for magnetophosphenes. The distribution of current density and internal electric fields is consistent with the experimental observation that flashing sensations reach their greatest intensity at the periphery of the visual field, for both electro and magnetophosphenes. The estimated thresholds in internal electric fields are consistent for magnetophosphenes and for electrophosphenes, respectively. The magnitudes of the thresholds, however, differ by about 10-fold. The thresholds in induced current density are critically dependent on the conductivity of the eye assumed for the calculations. The effect of thin membrane structure is also discussed with regard to the difference between electric field and magnetic field exposures.

Fiziol Zh. 2003;49(2):13-24.

Specific and non-specific electromagnetic irradiation effects on biological objects.

[Article in Ukrainian]

Berezovs'ky? VIa.

A.A. Bogomoletz Institute of Physiology, NAS of Ukraine, Kiev.

Abstract

There are the pecularities of the biophysical influence of the ultraviolet, light and infra-red irradiation in connection with their frequent and energetic characteristics. The specific resonant and non-specific heating effects are educed (distinguished). [table: see text] It is shown that the radial area of electromagnetic spectrum corresponding to the non-ionising. Sun irradiation, contains the evolutionary fixed molecular mechanisms of the energy acception activizing biochemical and biophysical metabolic reactions. The living beings, deprived of heliofugal influences (cave and deep-watered specimen objects) reached only the primitive development stages. The dosed wage of the non-ionising radiation generators in the clinic medicine promotes the restoration of the self sanogenic mechanisms and deficit restoration of the natural influences caused by the contemporary human being's mode of life changes.

Indian J Biochem Biophys. 1999 Oct;36(5):337-40.

Effect of amplitude modulated RF radiation on calcium ion efflux and ODC activity in chronically exposed rat brain.

Paulraj R, Behari J, Rao AR.

School of Environmental Sciences, Jawaharlal Nehru University, New Delhi.

Abstract

The effect of exposing rats to amplitude modulated radiofrequency radiation (112 MHz modulated to 16 Hz) during development and growth has been examined. Wistar rats (35 days old) when exposed at above frequency at the power level 1.0 mW/cm2 (SAR, 0.75 W/kg) for 35 days showed enhanced ornithine decarboxylase activity and Ca2+ efflux in brain indicating potential health hazards due to exposure.

Bioelectromagnetics. 1996;17(3):195-208.

Radio frequency electromagnetic exposure: tutorial review on experimental dosimetry.

Chou CK, Bassen H, Osepchuk J, Balzano Q, Petersen R, Meltz M, Cleveland R, Lin JC, Heynick L.

Department of Radiation Research, City of Hope National Medical Center, Duarte, CA 91010-3000, USA.

Abstract

Radio frequency (RF) dosimetry is the quantification of the magnitude and distribution of absorbed electromagnetic energy within biological objects that are exposed to RF fields. At RF, the dosimetric quantity, which is called the specific absorption rate (SAR), is defined as the rate at which energy is absorbed per unit mass. The SAR is determined not only by the incident electromagnetic waves but also by the electrical and geometric characteristics of the irradiated subject and nearby objects. It is related to the internal electric field strength (E) as well as to the electric conductivity and the density of tissues; therefore, it is a suitable dosimetric parameter, even when a mechanism is determined to be "athermal." SAR distributions are usually determined from measurements in human models, in animal tissues, or from calculations. This tutorial describes experimental techniques that are used commonly to determine SAR distributions along with the SAR limitations and unresolved problems. The methods discussed to obtain point, planar, or whole-body averaged SARs include the use of small E-field probes or measurement of initial rate of temperature rise in an irradiated object.

Bioelectromagnetics. 1994;15(5):447-63.

Dose response study of human exposure to 60 Hz electric and magnetic fields.

Graham C, Cook MR, Cohen HD, Gerkovich MM.

Midwest Research Institute, Kansas City, Missouri 64110.

Abstract

This human exposure study examined the relationship between field strength and biological response and tested whether the exposure levels at which the greatest effects occur differ for different endpoints. Three matched groups of 18 men each participated in two 6 h exposure test sessions. All subjects were sham exposed in one session. In the other session, each group of subjects was exposed at a different level of combined electric and magnetic field strength (low group:6 kV/m, 10 microT; medium group:9 kV/m, 20 microT; and high group: 12 kV/m, 30 microT). The study was performed double blind, with exposure order counterbalanced. Significant slowing of heart rate, as well as alternations in the latency and amplitude of event-related brain potential measures derived from the electro encephalogram (EEG), occurred in the group exposed to the 9 kV/m, 20 microT combined field (medium group). Exposure at the other field strength levels had no influence on cardiac measures and differential effects on EEG activity. Significant decrements in reaction time and in performance accuracy on a time estimation task were observed only in the low group. These results provide support for the hypothesis that humans may be more responsive to some combinations or levels of field strength than to others and that such differences in responsivity may depend, in part, on the endpoint of interest.

Bioelectromagnetics. 1992;Suppl 1:209-35.

Dosimetry of extremely-low-frequency magnetic fields.

Polk C.

Department of Electrical Engineering, University of Rhode Island, Kingston 02881.

Abstract

Extrapolation of quantitative measurements across biological systems requires knowledge of field-organism interaction mechanisms. In the absence of such knowledge, one can only indicate which parameters would be important under some plausible assumptions that still lack experimental proof. In the first part of the paper it is assumed that biological effects of low intensity, extremely low frequency magnetic fields are caused by the electric fields which they induce. It is shown that detailed knowledge of electrical properties on a microscale is important to predict effects that may be due to local current density, electric field strength, surface charge distribution, and mechanical forces. In the second part of the paper, it is shown that all proposed mechanisms for direct interaction between alternating magnetic fields and cells involve also the magnitude and direction of a simultaneously present static magnetic field. Reviewed are "cyclotron resonance," quantum mechanical effects on ions weakly bound to proteins, nuclear magnetic resonance, and recent progress in magneto chemistry dealing with effects of magnetic fields of a few hundred microtesla on chemical reactions that involve free radicals.

Bioelectromagnetics. 1989;10(2):115-28.

Multiple power-density windows and their possible origin.

Blackman CF, Kinney LS, House DE, Joines WT.

Health Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711.

Abstract

We have previously reported that in vitro exposure of chick forebrain tissue to 50-MHz radiofrequency (RF) electromagnetic radiation, amplitude modulated (AM) at 16 Hz, would enhance the efflux of calcium ions within only two power-density ranges: one from 1.44 to 1.67 mW/cm2, and the other including 3.64 mW/cm2. No effect on efflux occurred at 0.37, 0.72, 2.17, and 4.32 mW/cm2. We confirmed and extended these results by testing at another set of power densities, which included the range of the previous study. Forebrain tissue from 1-7-day-old chickens was labeled in vitro with radioactive calcium ions (30 min, at 37 degrees C), rinsed, placed in a physiological salt solution, and then exposed for 20 min to 50-MHz radiation, AM at 16 Hz, in a transverse electric and magnetic field (TEM) cell maintained at 37 degrees C. The solution was then assayed for radioactive calcium activity. A power-density series was tested. An enhanced efflux of calcium ions was found at 1.75, 3.85, 5.57, 6.82, 7.65, 7.77, and 8.82 mW/cm2; no change was observed at 0.75, 2.30, 4.50, 5.85, 7.08, 8.19, 8.66, 10.6, and 14.7 mW/cm2. Power density is converted to specific absorption rate (SAR) by 0.36 mW/kg per mW/cm2. Even the highest SAR tested (0.005 W/kg) is much too low to result in generalized heating of the sample and thus to be the underlying cause of the enhanced response. A hypothetical mechanism is proposed involving dynamic systems that may account for the power-density dependency as well as for part of the frequency dependency observed with both modulated RF radiation and extremely-low-frequency (ELF) fields.

Med Phys. 1992 Jul-Aug;19(4):1089-98.

Human exposure to 4.0-Tesla magnetic fields in a whole-body scanner.

Schenck JF, Dumoulin CL, Redington RW, Kressel HY, Elliott RT, McDougall IL.

General Electric Corporate Research and Development Center, Schenectady, New York 12301.

Abstract

Details are given for the design, construction, properties, and performance of a large, highly homogeneous magnet designed to permit whole-body magnetic resonance imaging and spectroscopy at 4 T. The magnet has an inductance of 1289 H and a stored energy of 33.4 MJ at rated field. The health of a group of 11 volunteers who had varying degrees of exposure to this field was followed over a 12-month period and no change that could be associated with this exposure was detected. A mild level of sensory experiences, apparently associated with motion within the field of the magnet, was reported by some of the volunteers during some of their exposures. A questionnaire regarding sensory effects associated with magnetic resonance scanners and possibly caused by the static magnetic field of these instruments, was given to nine respondents who had experience within both 1.5-T scanners and this 4-T scanner and to another group of 24 respondents who had experience only within 1.5-T scanners. For the sensations of vertigo, nausea, and metallic taste there was statistically significant (p less than 0.05) evidence for a field-dependent effect that was greater at 4 T. In addition, there was evidence for motion-induced magnetophosphenes caused by motion of the eyes within the static field. These results indicate the practicality of experimental whole-body body scanners operating at 4 T and the possibility of mild sensory effects in humans associated with motion within a static magnetic field. The results also indicate the likelihood of a wide margin of safety for the exposure of noncompromised patients to the static fields of conventional magnetic resonance scanners operated at 1.5 to 2 T and below.

Radiat Res. 1987 Jan;109(1):19-27.

Effect of amplitude-modulated 147 MHz radiofrequency radiation on calcium ion efflux from avian brain tissue.

Albert EN, Slaby F, Roche J, Loftus J.

Abstract

Cerebral cortex tissue slices and cerebral hemispheres prepared from Gallus domesticus chicks were exposed to 147 MHz radiofrequency radiation, amplitude modulated at 16 Hz and applied at a power density of 0.75 mW/cm2, to determine the effect of such exposure of 45Ca2+ efflux from the avian brain tissue. Statistical analysis of these data demonstrates that such exposure has no significant effect on 45Ca2+ efflux.

Kosm Biol Aviakosm Med. 1984 Mar-Apr;18(2):7-22.

Dosimetric aspects in studying the biological action of nonionizing electromagnetic radiation.

[Article in Russian]

Karpov VN, Galkin AA, Davydov BI.

Abstract

In order to clarify mechanisms of biological reactions, it is very important to study the absorption and spatial distribution of the absorbed electromagnetic energy. The procedures and methods of calculating the electromagnetic energy absorption of biological specimens exposed to nonionizing electromagnetic irradiation in a wide frequency range (0-300 GHz) are described. Also presented are formulas and plots to be used in calculating the specific absorption of the dose rate by biological specimens, with the inclusion of resonance absorption, polarization of the incident electromagnetic wave, presence of reflecting surfaces and grounding. The extrapolation of the average energy absorption from one animal species to another and to man is discussed, assuming that spatial and energy distributions are equivalent. The notion of the irradiation quality coefficient is introduced. The magnitudes of the coefficients are given as related to the irradiation frequency and polarization type. A mathematical relation is offered to determine the safety of a complex spectrum of electromagnetic irradiation. The relation takes into consideration different dimensionality of the parameters of the electromagnetic field in the low- and high-frequency ranges.

Bioelectromagnetics. 1980;1(1):35-43.

Induction of calcium-ion efflux from brain tissue by radiofrequency radiation: effect of sample number and modulation frequency on the power-density window.

Blackman CF, Benane SG, Elder JA, House DE, Lampe JA, Faulk JM.

Abstract

Changes have been found in calcium-ion binding to brain tissue exposed in vitro to a specific power density (0.83 mW/cm2) of 147-MHz radiation, amplitude modulated by a 16-Hz sine wave. This report replicates and extends this previous work. To define more precisely the range of effective power densities, two different numbers of samples were treated in a Crawford cell. In one series, four brain tissues were exposed at a time; in the other series, four brain tissues plus six dummy loads were exposed together. While the four-sample configuration produced a narrow power-density window, the ten pseudosample configuration resulted in a broader power-density window. The reason for the sample-number dependence is unresolved, but may be due to interactions between samples and field distortions caused by the close spacing. The ten pseudosample configuration was used to test for the presence and rage of a power-density window at a sinusoidal modulation frequency of 9 Hz. The response curve at 9 Hz was essentially identical to the results for 16-Hz sinewave modulation.

Bioelectromagnetics. 1980;1(3):277-83.

Calcium-ion efflux from brain tissue: power-density versus internal field-intensity dependencies at 50-MHz RF radiation.

Blackman CF, Benane SG, Joines WT, Hollis MA, House DE.

Abstract

In previous experiments changes were found in calcium-ion efflux from chick-brain tissue that had been exposed in vitro to 147-MHz radiation across a specific range of power densities when the field was amplitude modulated at 16 Hz. In the present study, 50-MHz radiation, similarly modulated as a sinusoid, was found to produce changes in calcium-ion efflux from chick brains exposed in vitro in a Crawford cell. Exposure conditions were optimized to broaden any power-density window and to enhance the opportunity to detect changes in the calcium-ion efflux. The results of a power-density series demonstrated two effective ranges: One spanning a range from 1.44 to 1.67 mW/cm2, and the other including 3.64 mW/cm2, which were bracketed by no-effect results at 0.72, 2.17, and 4.32 mW/cm2. peaks of positive findings are associated with near-identical rates of energy absorption: 1.4 microW/g at 147 MHz, and 1.3 microW/g at 50 MHz, which indicates that the enhanced-efflux phenomenon is more dependent on the intensity of fields in the brain than on the power density of incident radiation. In addition, the phenomenon appears to occur at multiples of some, as yet unknown, rate of radiofrequency (RF) energy absorption. Because of the extremely small increments of temperature associated with positive findings (less than 4 X 10(-4) degrees C), and the existence of more than one productive absorption rate, a solely thermal explanation appears extremely unlikely.