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James Gräfe, PhD, MCCPM

416-979-5000 x3405
james.grafe@ryerson.ca

Specialization

Medical Physics, radiation therapy, in vivo trace and toxic metal analysis, in vivo neutron activation analysis, in vivo X ray fluorescence, gadolinium toxicity, innovative nuclear medicine, proton prompt gamma ray, Proton Neutron Gamma-X Detection (PNGXD).

Research

My research revolves around developing innovative techniques in applied nuclear medicine or radiation therapy through experiment and simulation.
A few projects that I am currently working on are:

Proton Neutron Gamma-X Detection (PNGXD): I am currently investigating the potential to image a gadolinium-based contrast agent during proton therapy by neutron activation. More details can be found here: http://www.sciencedirect.com/science/article/pii/S0168583X17306080

In vivo detection of rare earth elements: The use of rare earth elements (REE) is increasing in popularity in both industry and medicine. However, it is often thought that these metals in their free form can be toxic and cause fibrosis, calcium deposition, inflammation, and necrosis to a variety of different organs and tissues. In contrast to this thinking, there is some evidence to suspect a therapeutic effect on bone health from these elements. Gadolinium (Gd), Samarium (Sm), and Lanthanum (La) are three REE of particular interest due to industrial practices, mining, medical applications, and water contamination from anthropogenic activity. Gd-based contrast agents (GBCAs) are the most routinely used contrast agents in magnetic resonance imaging (MRI). La-carbonate is used as a phosphate binder in chronic kidney disease, while other lanthanum based agents have recently been proposed as therapeutic agents for bone resorption disorders. However, with these applications there is the potential for residual amounts of rare earth metals to be deposited in the human body with potential toxic consequences. Increasing evidence is appearing in the literature about Gd deposition in the bone and brain for patients administered a GBCA. Furthermore, Health Canada recommends longer follow-up studies on bone health and bone quality due to residual La from a common La-based drug approved for use in Canada.
This research aims to design non-invasive systems that can measure rare earth metal concentration in the human body using the atomic and nuclear spectroscopic signatures of the REE. This work links trace element concentration with biological effects and/or benefits.

Our latest work was featured on medicalphysicweb: http://medicalphysicsweb.org/cws/article/research/70084

Publications

[1] M.L. Lord*, D.R. Chettle, J.L. Gräfe, M.D. Noseworthy, F. E. McNeill Observed retention of gadolinium in bone using a new non-invasive in vivo biomedical device: results of a small pilot study. Accepted October 2017, Radiology.

[2] Z. Keldani*, M.L. Lord*, F.E. McNeill, D.R. Chettle, J.L. Gräfe, Coherent normalization for in vivo measurements of Gd in bone. Physiological Measurement, 2017 38 1848-1858. See: http://medicalphysicsweb.org/cws/article/research/70084

[3] J. Nguyen*, Z. Keldani*, E. Da Silva, A. Pejovic-Milic, J.L. Gräfe. The feasibility of in vivo detection of lanthanum using a 241Am K X-ray Fluorescence system. Physiological Measurement, 2017 38 1766-1775.

[4] Gräfe,JL. Proton Neutron Gamma-X Detection (PNGXD): An introduction to contrast agent detection during proton therapy via prompt gamma neutron activation. Nuclear Instruments and Methods in Physics Research Section B 2017 407 20-23. http://www.sciencedirect.com/science/article/pii/S0168583X17306080

[5] Gräfe,JL, Owen, J , Villarreal-Barajas, JE, Khan, R. Characterization of a 2.5 MV inline portal imaging beam. Journal of Applied Clinical Medical Physics 2016 17 222-234.

[6] James L. Gräfe, David R. Chettle, and Fiona E. McNeill. In vivo detection of samarium by prompt gamma neutron activation analysis: a comparison between experiment and Monte-Carlo simulation. J. Anal. At. Spectrom., 2015 30 2441-2448 DOI:10.1039/c5ja00352k

[7] Gräfe JL, McNeill FE, Noseworthy MD, Chettle DR. Gadolinium detection via in vivo prompt gamma neutron activation analysis following gadolinium-based contrast agent injection: a pilot study in 10 human participants. Physiological Measurement 2014 35 1861-1872.

[8] Gräfe, JL, Poirier, Y, Jacso, F, Khan, R, Liu, HW, Villarreal-Barajas, JE. Assessing the divergence from the inverse square law for orthovoltage beams with closed-ended applicators. Journal of Applied Clinical Medical Physics 2014 15 356-366.

[9] Gräfe JL, McNeill FE, Chettle DR, Byun SH. Characteristic X ray emission in gadolinium following neutron capture as an improved method of in vivo measurement: a comparison between feasibility experiment and Monte-Carlo simulation. Nuclear Instruments and Methods in Physics Research Section B 2012 281 21-25.

[10] Chamberlain M, Gräfe JL, Aslam, Byun SH, Chettle DR, Egden LM, Webber CE, McNeill FE. In vivo quantification of bone-fluorine by delayed neutron activation analysis: a pilot study of hand bone-fluorine levels in a Canadian population. Physiological Measurement 2012 33 375-384.
[11] Chamberlain M, Gräfe JL, Aslam, Byun SH, Chettle DR, Egden LM, Orchard GM, Webber CE, McNeill FE. The feasibility of in vivo quantification of bone-fluorine in humans by delayed neutron activation analysis: a pilot study. Physiological Measurement 2012 33 243-257. Featured Article.

[12] Gräfe JL, McNeill FE, Byun SH, Chettle DR, Noseworthy MD. The feasibility of in vivo detection of gadolinium by prompt gamma neutron activation analysis following gadolinium-based contrast-enhanced MRI. Applied Radiation and Isotopes 2011 69 105-111.

[13] Gräfe JL, McNeill FE, Byun SH, Chettle DR, Noseworthy MD. A benchmarked MCNP model of the in vivo detection of gadolinium by prompt gamma neutron activation analysis. Nuclear Instruments and Methods in Physics Research Section B 2010 268 2451-2457.

Funding

NSERC
Ryerson University