Albannay, Mohammed

Ardenkjær-Larsen, Jan Henrik

Capozzi, Andrea

Møllesøe Vinther, Joachim

Online Research Database In Technology

                       General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.  • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal   If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.     Downloaded from orbit.dtu.dk on: Apr 10, 2018Low RF-field strength cross polarization combined with photo-induced non-persistentradicals for clinically applicable dDNPMøllesøe Vinther, Joachim; Capozzi, Andrea; Albannay, Mohammed; Ardenkjær-Larsen, Jan HenrikPublication date:2017Document VersionPublisher's PDF, also known as Version of recordLink back to DTU OrbitCitation (APA):Møllesøe Vinther, J., Capozzi, A., Albannay, M., & Ardenkjær-Larsen, J. H. (2017). Low RF-field strength crosspolarization combined with photo-induced non-persistent radicals for clinically applicable dDNP. Poster sessionpresented at EUROMAR 2017, Warsaw, Poland.Ændre størrelse  på overskriften  Klik på ‘Forøge indryk‘  for at få større overskrift Klik på  ‘Formindsk indryk’  for at gå tilbage     Ændre størrelse  på Manchet, Mellemrubrik og Brødtekst  Klik en gang på  ‘Forøge indryk‘ for at få mindre Manchet  Klik 2.gang på ‘Forøge indryk‘ for at få Fed mellemrubrik 35 pkt Klik 3.gang på ‘Forøge indryk‘ for at få Regular brødtekst 35 pkt Klik 4.gang på ‘Forøge indryk‘ for at få Fed mellemrubrik 18 pkt Klik 5.gang på ‘Forøge indryk‘ for at få Regular brødtekst 18 pkt Klik på ‘Formindsk  indryk’ for at gå tilbage Low RF-field strength cross polarization combined with photo-induced non-persistent radicals for clinically applicable dDNP Work in progress  Joachim M. Vinther1, Andrea Capozzi1, Mohammed M. Albannay1, Jan Henrik Ardenkjær-Larsen1,2 1Center for Hyperpolarization in Magnetic Resonance, Department of Electrical Engineering, Technical University of Denmark, Kgs. Lyngby, Denmark. 2GE Healthcare, Brøndby, Denmark. Cross Polarisation for SPINlab-like polarisers using non-persistent radicals is demonstrated. The efficiency of the transfer from protons to carbon is modest at the currently achievable low B1 fields of 4-5 kHz still yielding 13C polarisation levels up to 15 %. Based on the presented results, we foresee polarisation levels superior to direct 13C DNP in our next generation of double-tuned probes incorporating local tune and match.   Abstract We demonstrate the possibility of 1H Dynamic Nuclear Polarization followed by cross polarization to carbon (DNP-CP) using a modified low cost benchtop console (Kea2) equipped with an external amplifier (Tomco) and a SPINlab-like dissolution DNP polarizer i.e. using the same fluid path and allowing for hyperpolarisation of a full human dose. Cross polarisation (CP) using Laboratory Frame De- and Remagnetisation1  (LAFDR) was found superior to alternative sequences at the limited B1 fields employed. Faster build-up rates compared to 13C DNP are demonstrated using TEMPOL (4-Hydroxy-2,2,6,6-tetramethylpiperidine 1-oxyl) and DNP-CP 13C polarisations up to 15 % are achieved using non-persistent UV-induced radicals.  Introduction Dissolution Dynamic Nuclear Polarization (dDNP) is used to enhance the MR signals in imaging by factors of 10,000 2 paving the road for metabolic MR studies. However, the polarization build-up on 13C typically takes tens of minutes to hours, significantly lowering the versatility and throughput. Recently, studies have shown the possibility of speeding up the process by polarizing 1H, which has a faster build-up, followed by polarization transfer to e.g. 13C.3  However, strong B1 fields and small sample volumes are used, which makes the technique incompatible with clinical dDNP-MRI. Moreover, for clinical use, and in general to eliminate the relaxation effect, the radical essential for DNP needs to be removed during dissolution. Use of pyruvic acid (PA) non-persistent photo-induced radicals for dDNP has been demonstrated to solve this issue4 and recently polarization build-up on protons with tDNP~690 s and 70 % polarization has been presented5.   Results The efficiency of DNP-CP depends on the build-up rate and final polarisation achieved on protons as well as the transfer efficiency of the CP sequence. 1. For B1≤5 kHz LAFDR (fig. B) was found to outperform other CP sequences (data not shown). 2. On the TEMPOL containing sample, DNP-CP using optimised LAFDR outperforms 13C DNP for build-up times < 1 hour, and 20% 13C polarisation was achieved in only 20 min (fig. C). 3. Using [1-13C]PA as the substrate for non-persisting radicals gives a too narrow EPR-line for efficient 1H DNP resulting in poor DNP-CP performance (fig. D). 4. Introduction of hyperfine coupling to the unpaired electron by 13C labelling in position 2 increases the EPR linewidth yielding fast 1H DNP build-up, but a polarisation of only 18 %, and therefore still inefficient DNP-CP (fig. E). 5. Deuterating the methyl group of PA increases the 1H DNP polarisation to 62 % and maintains the efficiency of CP. This yields a final 13C polarisation of 15% after CP (fig. F).  Acknowledgements This project has received funding from Innovation Fund Denmark and from Danish National Research Foundation (DNRF124).  References 1 Lee, J.-S. and Khithrin, A.K. Adiabatic cross-polarization via intermediate dipolar-ordered state. J. Magn. Reson. 177,152–154, 2005; Batel, M. et al. Cross-polarization for dissolution dynamic nuclear polarization. Phys.Chem.Chem.Phys. 16, 21407, 2014. 2 Ardenkjaer-Larsen, J. H. et al. Increase in signal-to-noise ratio of > 10,000 times in liquid-state NMR. Proc. Natl. Acad. Sci. U. S. A. 100, 10158–10163, 2003. 3 Batel, M. et al.. Dissolution dynamic nuclear polarization efficiency enhanced by Hartmann–Hahn cross polarization. Chem. Phys. Lett. 554:72-76, 2012. Bornett, A. et al. Boosting Dissolution Dynamic Nuclear Polarization by Cross Polarization. J. Phys. Chem. Lett. 4, 111−114, 2013. 4 Eichhorn, T. R. et al., Hyperpolarization without persistent radicals for in vivo real-time metabolic imaging. PNAS,110:18064–18069, 2003. 5 Capozzi, A. et al., Preparation of Radical-Free Hyperpolarized Water using Photo-induced non-persistent Radicals on a “SpinLab-like” dissolution-DNP Polarizer. Abstract from 58th Experimental Nuclear Magnetic Resonance Conference, Asilomar, United States, 2017. 1:1 1-13C-pyruvic acid, H2O; 5 min UV-irradiation ~ 40mM 010 2 4 6 813C polarisation (a.u.) Build-up (min) DNP DNP-CP4.5 M [13C]urea in 5:4:1 d5-glycerol, D2O, H2O & 40 mM TEMPOL 13C-DNP: pol = 36% T1 = 53 min  LAFDR: pol = 28% T1 = 11 min  0510152025300 20 40 6013C polarisation (%) Build-up (min) DNP DNP-CP1H-DNP: pol = 72% T1 = 7 min  024681012140 20 40 60 80 10013C polarisation (%) Build-up (min) DNP DNP-CP1:1 [2-13C]pyruvic acid, H2O; 5 min UV-irradiation ~ 40mM 13C DNP: pol = 12% T1 = 25 min LAFDR: pol = 5% T1 = 15 min 1H DNP: pol = 18% T1 = 9 min 1:1 [2-13C,D3]pyruvic acid, H2O; 5 min UV-irradiation ~ 40mM D3C 051015202530350 10 20 3013C polarisation (%) Build-up (min) DNP DNP-CP13C DNP: pol = 38% T1 = 19 min LAFDR: pol = 17% T1 = 15 min 1H DNP: pol = 62% T1 = 14 min Read pulse 1H (285.5 MHz) 13C (71.8 MHz) Methods 1H DNP 13C CP mins msecs UV CP by Laboratory Frame De- and Remagnetisation (LAFDR) Overview DNP-CP using UV-induced radicals with broadened linewidth due to hyperfine coupling DNP-CP using TEMPOL as radical DNP-CP using UV-induced radicals Experimental results Conclusion and Outlook We have demonstrated DNP-CP on a clinical-compatible SPINlab-like polariser using a low-cost benchtop console equipped with an external amplifier. Moreover, the technique has been combined with non-persistent UV-induced radicals. At the current state, with B1≤5 kHz, direct 13C DNP still out-performs the DNP-CP. However, the goal is to implement local tuning of the probe to achieve sufficient B1 fields to increase the transfer efficiency. We expect that sufficiently strong B1 fields are achievable for this setup to outperform direct 13C DNP both with respect to build-up rates and polarisation levels. DNP hrs A B E C F D Method Samples are frozen to small beads in liquid-nitrogen, UV-irradiated for 5 min and kept below 190K until cooled to 1 K in the polariser. Microwave power and frequency as well as modulation were optimised for DNP.  Amplitudes, frequency-sweeps and pulse lengths were optimised for CP. DNP-CP were evaluated by sweeping the build-up time measuring the 13C-DNP, destroying the 13C polarisation, transferring proton polarisation and measuring the resulting 13C polarisation. 

Low RF-field strength cross polarization combined with photo-induced non-persistent radicals for clinically applicable dDNP

http://orbit.dtu.dk/ws/files/142082463/poster_jmv_v2.pdf

Low RF-field strength cross polarization combined with photo-induced non-persistent radicals for clinically applicable dDNP

Abstract

Similar works

Full text

Available Versions

Online Research Database In Technology