Featured Research

from universities, journals, and other organizations

Magnetic field measurements of the human heart at room temperature

Date:
December 26, 2009
Source:
Physikalisch-Technische Bundesanstalt (PTB)
Summary:
A new optical sensor was successfully tested in the "magnetically best shielded room on Earth." The sensor does not need advanced cooling and is very small. Its suitability was proven for biomagnetic measurements in the picotesla range. So, magnetocardiographic measurement devices -- to be used as a supplement or an alternative to the ECG -- could become simpler and less expensive.

The "most magnetically quiet room on earth" is on the PTB site in Berlin.
Credit: Image courtesy of Physikalisch-Technische Bundesanstalt (PTB)

The "magnetically best shielded room on earth" has the size of an apartment block and is located on the site of the Physikalisch-Technische Bundesanstalt (PTB), Institute Berlin. Magnetic fields such as that of the earth are kept out here as effective as nowhere else. Such ideal conditions allow to measure the tiny magnetic fields of, e.g., the human heart.

This was the motivation for the American National Institute of Standards and Technology (NIST) to ask PTB to jointly test a newly developed optical magnetic field sensor. It is based on a physical principle very different from SQUIDs, which are usually applied for biomagnetic field measurements. The optical sensor does not need advanced cooling and has the size of a lump of sugar. A high-quality measurement of the human heart signal was demonstrated using this optical sensor. The sensor's suitability was thus proven for biomagnetic measurements in the picotesla range. In future magnetocardiographic measurement devices -- to be used as a supplement or an alternative to the ECG -- could become simpler and less expensive.

Up until now one had to cool as much as one could for biomagnetic measurements. This was necessary as SQUIDs, superconducting quantum interference devices, work optimally at -269 degrees Celsius and can only then fulfil their purpose of measuring tiny magnetic fields. SQUIDs are the best suited sensors to record the magnetic fields arising during the electrical activity of the human heart. A magnetocardiogram (MCG) can be compiled supplementing a conventional electrocardiogram (ECG). (The same applies to the magnetoencephalogram, MEG, which is a recording of the magnetic field of the brain.) Yet to use SQUIDs requires well-shielded rooms and complicated cooling systems. The latter might become obsolete in the future if the optical magnetometer developed by NIST continues to fulfil expectations.

The optical sensor is a byproduct of the development of miniaturized atomic clocks, one of NIST's current key research areas. As biomagnetic research is not established at NIST, the scientists turned to their colleagues at PTB in Berlin. PTB is one of the few metrological state institutes in the world with a large scale biomedical research program. The combination of highly advanced equipment such as the magnetically shielded room (BMSR-2) with the experience in testing new sensors on human subjects made PTB the ideal partner for NIST.

Using the optical magnetometer PTB experts measured the magnetic field of the human heart and relaxation curves of magnetic nanoparticles. Both are important routine laboratory measurements normally applying SQUIDs. For a direct comparison of the results, SQUID reference data were recorded simultaneously with the optical magnetometer using the multichannel SQUID device installed in the BMSR-2.

The impressive quality of the data obtained confirms the suitability of these optical micromagnetometers in the picotesla range. This is the range for magnetic field measurements of the heart, but further improvements are needed to measure the even tinier fields of the human brain. Compared to SQUIDs, the optical sensors exhibited -- as expected -- a significantly higher noise level. The distinct advantage of these sensors lies, however, in their small design (< 1 cm3). This allows them to be installed at a small distance from the magnetic source in order to increase the signal strength. The room temperature operation of the sensor and its small size will allow a much simpler system design compared to other sensor types suitable for this measurement range. The fabrication of the sensor by use of microsystem technology could enable simple and cost-effective mass production. NIST plans the development of a multichannel system on the basis of the existing technology. Further tests of these sensors at PTB are planned.


Story Source:

The above story is based on materials provided by Physikalisch-Technische Bundesanstalt (PTB). Note: Materials may be edited for content and length.


Cite This Page:

Physikalisch-Technische Bundesanstalt (PTB). "Magnetic field measurements of the human heart at room temperature." ScienceDaily. ScienceDaily, 26 December 2009. <www.sciencedaily.com/releases/2009/12/091211131520.htm>.
Physikalisch-Technische Bundesanstalt (PTB). (2009, December 26). Magnetic field measurements of the human heart at room temperature. ScienceDaily. Retrieved July 29, 2014 from www.sciencedaily.com/releases/2009/12/091211131520.htm
Physikalisch-Technische Bundesanstalt (PTB). "Magnetic field measurements of the human heart at room temperature." ScienceDaily. www.sciencedaily.com/releases/2009/12/091211131520.htm (accessed July 29, 2014).

Share This




More Matter & Energy News

Tuesday, July 29, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Climate Change Could Cost Billions, According To White House

Climate Change Could Cost Billions, According To White House

Newsy (July 29, 2014) A report from the White House warns not curbing greenhouse gas emissions could cost the U.S. billions. Video provided by Newsy
Powered by NewsLook.com
Stranded Whale Watching Boat Returns to Boston

Stranded Whale Watching Boat Returns to Boston

Reuters - US Online Video (July 29, 2014) Passengers stuck overnight on a whale watching boat return safely to Boston. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
Baluchistan Mining Eyes an Uncertain Future

Baluchistan Mining Eyes an Uncertain Future

AFP (July 29, 2014) Coal mining is one of the major industries in Baluchistan but a lack of infrastructure and frequent accidents mean that the area has yet to hit its potential. Duration: 01:58 Video provided by AFP
Powered by NewsLook.com
Easier Nuclear Construction Promises Fall Short

Easier Nuclear Construction Promises Fall Short

AP (July 29, 2014) The U.S. nuclear industry started building its first new plants using prefabricated Lego-like blocks meant to save time and prevent the cost overruns that crippled the sector decades ago. So far, it's not working. (July 29) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins