12.09.2018

Old Law and a New Paradigm in Magnetic Resonance Imaging Thermometry – seminar


Academic Centre for Materials and Nanotechnology invites for a special seminar that will be held on 12th September,  2018, at 11.00 am.

A lecture titled “Old Law and a New Paradigm in Magnetic Resonance Imaging Thermometry” will be given by PhD Janusz H. Hankiewicz (University Colorado Colorado Springs, USA).

Venue: Kawiory 30 Street, building D-16, auditorium room (1.02A)

An abstract of the lecture

Temperature is one of the fundamental parameters reflecting the biological status of the body and individual tissues. Clinical studies have indicated that localized temperature measurements could be a useful method for the detection of a variety of health problems including certain tumors and inflammations. Precise determination of tissue temperature is also important in different medical interventional procedures such as hyperthermia treatment and thermal ablation. Additionally, temperature mapping is critical for monitoring the temperature rise of tissue caused by fast switching magnetic gradients and radio-frequency pulses around metallic medical implants during standard magnetic resonance imaging (MRI). Conventional thermometry is usually invasive, allows only single point temperature measurements, and may interfere with therapeutic and imaging instruments. The ability to do in-vivo monitoring of temperature in three dimensions is thus important for both diagnosis and treatment of patients. A minimally invasive magnetic resonance thermometry that produces high thermal, spatial and temporal resolution temperature maps superimposed on anatomical images within the targeted tissue would address these limitations. At present, no non-invasive method exists to provide reliable temperature measurements, requiring critical procedures and safety decisions to be made with no real-time temperature feedback. Magnetic resonance thermometry has previously been attempted. Earlier studies were based on temperature sensitive MRI parameters such as proton resonance frequency, diffusion coefficient, nuclear relaxation times, magnetization transfer, proton density and temperature-sensitive contrast agents. Currently used temperature-sensitive contrast agents include paramagnetic thermo-sensitive liposomes containing gadolinium or manganese compounds and paramagnetic lanthanide complexes. The methods mentioned above have significant drawbacks.

I will present a new method of temperature measurement using MRI that has recently been demonstrated [1,2,3]. This method uses a new type of temperature-sensitive contrast agent and could ultimately be used within human, animals and materials. Key idea is that magnetic particles embedded in, or near, the tissue will create a local dipole magnetic field that will modulate (statically or dynamically) the homogeneity of the main static magnetic field of the MRI scanner, consequently shortening the nuclear relaxation times of the tissue. If the magnetization of the particle changes as the temperature is changed, the results are temperature dependent. We have already shown that micron sized magnetic particles can produce temperature-dependent MRI image. We anticipate the new contrast operating in the range of 30oC to 45oC with accuracy 1oC.

1. Hankiewicz, J.H., Celinski, Z., Stupic, K.F., Anderson, N.R., and Camley, R.E. 2016 Ferromagnetic Particles as Magnetic Resonance Imaging Temperature Sensors. Nature Communications. Published on line August 9th. DOI: 10.1038/ncomms12415.

2. Hankiewicz J.H., Alghamdi N., Hammelev N.M., Anderson N.R., Camley R.E., Stupic K.F., Przybylski M., Zukrowski J., and Celinski Z. (2017) Zinc Doped Copper Ferrite Particles as Temperature Sensors for Magnetic Resonance Imaging. AIP Advances, 7. 5670-5676. DOI:10.1063/1.4973439.

3. Alghamdi, N.A., Hankiewicz, J.H., Anderson, N.R., Stupic, K.F., Camley, R.E., Przybylski, M., Żukrowski, J., and Celinski, J. (2018) “Development of Ferrite-Based Temperature Sensors for Magnetic Resonance Imaging: Study of Cu1-xZnxFe2O4” Physical Review Applied 9. 054030 -054040. Published on line 21 May 2018. DOI: 10.1103/PhysRevApplied.9.054030