Three Licentiate of Technology Degrees Completed at the RGI
Jafar Keshvari 25.4.1997. "An Eccentric Spherical Model with Analytical - Mathematical
Method to Study DC Potential Distribution around the Eye."
Pasi Kauppinen 25.4.1997 "Measurement Properties of Impedance Cardiography -
FDM Computer Model Studies."
Tomi Kauppinen 13.6.1997. "Comparison between Iteration and Back-projection
based on Emission Tomography Reconstruction Methods."
Survey of Persons having
Studied Biomedical Engineering at the RGI since 1976
We make a survey of those persons who have studied Biomedical Engineering at RGI
since 1976. Their total number is 275. The review's purpose is to find out
how fast the persons were employed
the type of the persons' employer
location of the employer
position and duties of the persons
how their education meets their duties
general comments and feedback.
We received replies from 206 persons (75%). Of those who replied, almost one half is working
related to the field of biomedical engineering. The other half is working mainly in electronics and
Half of the persons got their job from Tampere Region. Half of the rest got a job from Helsinki
Region, half of the rest from Turku. And the rest were scattered throughout the world.
The total numbers of various theses and degrees made at the RGI since 1976 are:
M.Sc.(Eng.) 140; Lic.Tech.18; Dr. Tech. 6; Ph.D. 1 and in addition: M.D. 2.
The survey is being performed by Lic. Tech.
Jari Viik. Detailed results will be published as Reports of the RGI, both Finnish and
English editions. The report may be subscribed from the Institute Secretary
It will also be available on the Web at the www.rgi.fi/www/reports/survey/index.htm.
Survey on Clinical Studies Comparing the Diagnostic Performance of
EEG and MEG
The RGI has made a survey of clinical studies comparing the diagnostic performances of
EEG and MEG. The motivation for this came from our theoretical work, where we compared the
sensitivity distributions of EEG and MEG in a spherical model:
J. Malmivuo, V. Suihko and H. Eskola: "Sensitivity Distributions of EEG and MEG Measurements."
IEEE TBME 44/3, 1997, pp. 196-208. (See also RGI News,
Vol. 2, No 1. 15.03.1995.)
In this work we published two results which contradict the general ideas about the properties
of EEG and MEG:
1) It is believed that because the skull is transparent to magnetic fields, the MEG should be
spatially more accurate than the EEG.
By using the half-sensitivity volume concept we found that planar gradiometer MEG has
about the same spatial resolution as the EEG. MEG using axial gradiometer is an order of magnitude
worse in spatial resolution.
2) It is believed that the MEG measures a source complementary to the EEG.
In 1987 we published the sensitivity distributions of axial and planar gradiometers
(J. Malmivuo, J. Puikkonen, "Sensitivity Distribution of Multichannel MEG Detectors",
in Abstr. 6th Internat. Conf. Biomagnetism, Tokyo, 1987). This article demonstrates that
the sensitivity distribution of planar gradiometer MEG closely resembles that of EEG.
Thus the planar gradiometer MEG does not detect a source complementary to that of the EEG.
In addition to these two results, four other features of the MEG are not very favorable:
3) In the MEG there is no need to fix the electrodes on the patient's scalp.
This benefit is marginal. Today, in EEG recording, a specific electrode cap is used
which enables some 100 electrodes to be attached within 10 to 15 minutes. When using
two electrode caps, electrodes can be attached to one patient while another patient is
measured. Furthermore, the electrode cap gives rather good freedom for the patient to move
the head. The MEG dewar fixes the patient's head to a certain position and orientation.
Today, MEG manufacturers provide an option to measure the EEG simultaneously
with the MEG. Thus the EEG-electrodes are also fixed when using the MEG.