Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New Mini-sensor Measures Magnetic Field of the Brain

29.05.2012
Successful test at PTB of optical magnetometer with potential applications in brain imaging for neurological diagnostics and in basic research.

In future a new magnetic sensor the size of a sugar cube might simplify the measurement of brain activity. In the magnetically shielded room of Physikalisch-Technische Bundesanstalt (PTB) the sensor has passed an important technical test: Spontaneous as well as stimulated magnetic fields of the brain were detected.


Magnetic sensor the size of a sugar cube with electrical and optical lines.
Foto: PTB/NIST

This demonstrates the potential of the sensor for medical applications, such as, the investigation of brain currents during cognitive processes with the aim of improving neurological diagnostics. The main advantage of the new sensor developed by NIST in the USA over the conventionally used cryoelectronics is its room temperature operation capability making complicated cooling obsolete. The results have recently been published in the journal "Biomedical Optics Express".

The magnetic field sensor is called Chip-scale Atomic Magnetometer (CSAM) as it uses miniaturized optics for measuring absorption changes in a Rubidium gas cell caused by magnetic fields. The CSAM sensor was developed by NIST (National Institute of Standards and Technology), which is the national metrology institute of the USA. In this cooperation between PTB and NIST each partner contributes his own particular capabilities. PTB’s staff has long standing experience in biomagnetic measurements in a unique magnetically shielded room. NIST contributes the sensors, which are the result of a decade of dedicated research and development.

Up to now the measurement of very weak magnetic fields was the domain of cryoelectronic sensors, the so called superconducting quantum interference device (SQUID). They can be considered as the „gold standard“ for this application, but they have the disadvantage to operate only at very low temperatures close to absolute zero. This makes them expensive and less versatile compared to CSAMs. Even though at present CSAMs are still less sensitive compared to SQUIDs, measurements with a quality comparable to SQUIDs, but at lower costs, might eventually become reality. Due to the cooling requirements, SQUIDs have to be kept apart from the human body by a few centimeters. In contrast to that, CSAMs can be attached closely to the human body. This increases the signal amplitude as the magnetic field from currents inside the human bodydecays rapidly with increasing distance.

An important application is the measurement of the magnetic field distribution around the head, which is called magnetoencephalography (MEG). It enables the characterization of neuronal currents. Such investigations have gained importance during the last few years for neurologists and neuroscientists. Objective indicators of psychiatric disorders as well as age dependent brain diseases, are urgently needed for the support of today’s clinical diagnostics.

Already in 2010 scientists from NIST and PTB had successfully tested the performance of an earlier version of the present CSAM by measurements of the magnetic field of the human heart. For the present study the sensor was positioned about 4 mm away from the head of healthy subjects. At the back of the head, the magnetic fields of alpha waves were detected, a basic brain rhythm which occurs spontaneously during relaxation. In another measurement the brain fields due to the processing of tactile stimuli were identified. These fields are extremely weak and the CSAM result was validated by a simultaneous MEG measurement relying on the established SQUID technology. if/ptb

Press Release of NIST
http://www.nist.gov/pml/div688/brain-041912.cfm
Original Publication
• T. Sander-Thömmes, J. Preusser, R. Mhaskar, J. Kitching, L. Trahms, S. Knappe: Magnetoencephalography with a Chip-Scale Atomic Magnetometer. Biomedical Optics Express Vol. 3 Issue 5, pp.981-990 (2012)

http://www.opticsinfobase.org/boe/issue.cfm?volume=3&issue=5

• PTB-NIST-Experiment of 2010:
S. Knappe, T.H. Sander, O. Kosch, F. Wiekhorst, J. Kitching and L. Trahms. Cross-validation of microfabricated atomic magnetometers with SQUIDs for biomagnetic applications. Applied Physics Letters. 97, 133703 (2010); doi:10.1063/1.3491548. Online publication: Sept. 28, 2010.
Contact
Dr. Tilmann Sander-Thömmes, PTB Working Group 8.21 Biomagnetism,
Phone ++49 (30) 3481-7436, E-mail: tilmann.sander-thoemmes@ptb.de

Imke Frischmuth | PTB
Further information:
http://www.ptb.de/index_en.html

More articles from Medical Engineering:

nachricht PET identifies which prostate cancer patients can benefit from salvage radiation treatment
05.12.2017 | Society of Nuclear Medicine and Molecular Imaging

nachricht Designing a golden nanopill
01.12.2017 | University of Texas at Austin, Texas Advanced Computing Center

All articles from Medical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

Im Focus: Successful Mechanical Testing of Nanowires

With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong

Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...

Im Focus: Virtual Reality for Bacteria

An interdisciplinary group of researchers interfaced individual bacteria with a computer to build a hybrid bio-digital circuit - Study published in Nature Communications

Scientists at the Institute of Science and Technology Austria (IST Austria) have managed to control the behavior of individual bacteria by connecting them to a...

Im Focus: A space-time sensor for light-matter interactions

Physicists in the Laboratory for Attosecond Physics (run jointly by LMU Munich and the Max Planck Institute for Quantum Optics) have developed an attosecond electron microscope that allows them to visualize the dispersion of light in time and space, and observe the motions of electrons in atoms.

The most basic of all physical interactions in nature is that between light and matter. This interaction takes place in attosecond times (i.e. billionths of a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Midwife and signpost for photons

11.12.2017 | Physics and Astronomy

How do megacities impact coastal seas? Searching for evidence in Chinese marginal seas

11.12.2017 | Earth Sciences

PhoxTroT: Optical Interconnect Technologies Revolutionized Data Centers and HPC Systems

11.12.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>