Final Report Summary - COSMA (COHERENT OPTICS SENSORS FOR MEDICAL APPLICATIONS)
The project “Coherent Optics Sensors for Medical Applications” has been proposed to transfer the competences of the participating groups towards the study, design and realization of a new class of sensors, based only on Laser Spectroscopy and Quantum Optics and aimed to the detection of faint signals of medical diagnostics interest. The collaboration was formed by 10 teams from Armenia, Bulgaria, India, Israel, Italy, Poland, Russia, United Kingdom, USA.
The advantages of such a kind of systems are their non invasive character, the possible compactness and portability, the very nice sensitivity, the limited costs, if compared with what is in use in the hospitals for the same aims.
The main type of sensors are called Optical Atomic Magnetometers (OAMs), because they are able to measure by optical methods tiny magnetic fields, as for example the signals generated by our heart, while other, similar sensors can detect what is associated to a Nuclear Magnetic Resonance (NMR) effect. The main problem is to find the desired magnetic source in between a very high “noise” given by spurious fields.
An original approach has been favored, in such a way to create a magnetic shielding that consists of compensating rather than screening everything but the “needle in a haystack”. This choice eliminates the need for an expensive mu-metal (special screening material) isolated room, which would make a large scale diffusion of OAMs in hospitals difficult. From this point of view, we hope to persuade doctors of the importance of our findings, especially of the complementary information they can get by applying this technology on a widespread number of cases.
The project has produced several types of OAMs, together with an intense research activity on the basic principles of them, in order to pave the way to a better theoretical and experimental comprehension of the related physical phenomena and to the parameters to be controlled and checked.
University College of London (UCL) team has published the innovative idea and the practical realization of a system which combine magnetic induction tomography and the unmatched performance of atomic magnetometers. In the paper, imaging of conductive objects is performed at room temperature, in an unshielded environment and without background subtraction. Conductivity maps of target objects exhibit not only excellent performance in terms of shape reconstruction but also demonstrate detection of sub-millimetric cracks and penetration of conductive barriers. In a later Scientific Report, the same team presents the application of such a device to Atrial Fibrillation (one of the major sources of heart problems) investigation. The flexibility of the system makes it promising also for application in other fields, such as neurology and oncology.
Jagiellonian (Krakow) and Berkeley (California) University teams have developed a new type of OAM with a better sensitivity for higher magnetic fields, in a range of amplitudes where the standard systems have much smaller responses.
In Siena, the local group together with people from Sofia (Institute of Electronic of the Bulgarian Academy of Sciences, IEBAS) and Yerevan (Institute for the Physical Research, IPR) have investigated both low field NMR in molecules, have built a dual arm differential OAM, and have constructed a broad use compact magnetometer for the measurement of not only the amplitude of the field, but also for the identification of its direction in space.
For the more general physics understanding, IPR, IEBAS and Israelian (Bar Ilan Univ., BIU) teams have studied more carefully the process that is at the basis of the previous applied results: in particular, they have identified a new coherent process in alkali atoms that makes the magnetic field measurements more precise and is applicable in a large range of values.
In order to go towards a size reduction of these photonics sensors, researchers from IEBAS, IPR, BIU, and the University of Calcutta (UC) have investigated the coherent effects in alkali vapors confined in nanometric and micrometric thick optical cells, a very special tool created in the Armenian group several years ago.
With reducing the dimensions of the cells, the amplitude of the signals decreases and we have to try to compensate this lack of information by some trick. A possible way is to increase the atomic density either with temperature, using special high temperature anti-relaxation coatings, or by the effect named light induced atomic desorption (LIAD). LIAD is a non-thermal process in which atoms adsorbed at a surface of optical cells are released under illumination by any light (a LED, a lamp, even at very low power). In a common UniSi-IEBAS-UC work, the dependence of the shape of the absorption spectra in Rb on illumination by a blue light was measured and analysis of the influence of the LIAD effect was done. The first experimental observation of atomic spin randomization of Rb atoms released by LIAD was demonstrated.
The advantages of such a kind of systems are their non invasive character, the possible compactness and portability, the very nice sensitivity, the limited costs, if compared with what is in use in the hospitals for the same aims.
The main type of sensors are called Optical Atomic Magnetometers (OAMs), because they are able to measure by optical methods tiny magnetic fields, as for example the signals generated by our heart, while other, similar sensors can detect what is associated to a Nuclear Magnetic Resonance (NMR) effect. The main problem is to find the desired magnetic source in between a very high “noise” given by spurious fields.
An original approach has been favored, in such a way to create a magnetic shielding that consists of compensating rather than screening everything but the “needle in a haystack”. This choice eliminates the need for an expensive mu-metal (special screening material) isolated room, which would make a large scale diffusion of OAMs in hospitals difficult. From this point of view, we hope to persuade doctors of the importance of our findings, especially of the complementary information they can get by applying this technology on a widespread number of cases.
The project has produced several types of OAMs, together with an intense research activity on the basic principles of them, in order to pave the way to a better theoretical and experimental comprehension of the related physical phenomena and to the parameters to be controlled and checked.
University College of London (UCL) team has published the innovative idea and the practical realization of a system which combine magnetic induction tomography and the unmatched performance of atomic magnetometers. In the paper, imaging of conductive objects is performed at room temperature, in an unshielded environment and without background subtraction. Conductivity maps of target objects exhibit not only excellent performance in terms of shape reconstruction but also demonstrate detection of sub-millimetric cracks and penetration of conductive barriers. In a later Scientific Report, the same team presents the application of such a device to Atrial Fibrillation (one of the major sources of heart problems) investigation. The flexibility of the system makes it promising also for application in other fields, such as neurology and oncology.
Jagiellonian (Krakow) and Berkeley (California) University teams have developed a new type of OAM with a better sensitivity for higher magnetic fields, in a range of amplitudes where the standard systems have much smaller responses.
In Siena, the local group together with people from Sofia (Institute of Electronic of the Bulgarian Academy of Sciences, IEBAS) and Yerevan (Institute for the Physical Research, IPR) have investigated both low field NMR in molecules, have built a dual arm differential OAM, and have constructed a broad use compact magnetometer for the measurement of not only the amplitude of the field, but also for the identification of its direction in space.
For the more general physics understanding, IPR, IEBAS and Israelian (Bar Ilan Univ., BIU) teams have studied more carefully the process that is at the basis of the previous applied results: in particular, they have identified a new coherent process in alkali atoms that makes the magnetic field measurements more precise and is applicable in a large range of values.
In order to go towards a size reduction of these photonics sensors, researchers from IEBAS, IPR, BIU, and the University of Calcutta (UC) have investigated the coherent effects in alkali vapors confined in nanometric and micrometric thick optical cells, a very special tool created in the Armenian group several years ago.
With reducing the dimensions of the cells, the amplitude of the signals decreases and we have to try to compensate this lack of information by some trick. A possible way is to increase the atomic density either with temperature, using special high temperature anti-relaxation coatings, or by the effect named light induced atomic desorption (LIAD). LIAD is a non-thermal process in which atoms adsorbed at a surface of optical cells are released under illumination by any light (a LED, a lamp, even at very low power). In a common UniSi-IEBAS-UC work, the dependence of the shape of the absorption spectra in Rb on illumination by a blue light was measured and analysis of the influence of the LIAD effect was done. The first experimental observation of atomic spin randomization of Rb atoms released by LIAD was demonstrated.