Richard Laforest is a researcher specializing in Clinical Nuclear Medicine, Positron Emission Tomography, and Multi-Modality Small Animal Imaging.

PET is a noninvasive imaging technique that allows measurement of the concentration of radiotracers in the body of a living subject. Recent technological advances in detector design have allowed the construction of higher resolution tomographs for imaging radiopharmaceuticals in small laboratory animals, thus opening new areas of research of the brain, tumors, preclinical evaluation of new radiopharmaceuticals as well as gene expression and gene therapy.

The coregistration of functional images and anatomical images from MRI or CT allows for precise localization of activity distribution within the body of a living animal. Anatomical information, in conjunction to PET, can also be used for organ or tumor size determination. Knowing the exact size of an organ or tumor allows correction of the measured activity concentration for partial volume effects and will be used to improve the radiation dosimetry calculation. This will be especially crucial with nonstandard isotopes where partial volume effects are larger.

In addition to the common positron emitting isotopes used in nuclear medicine such as C-11, N-13, and O-15 and F-18, this laboratory is involved in the production of nonconventional radionuclides for PET imaging. Some of these isotopes are characterized by a longer half-life, allowing longitudinal studies on the same animal with a single injection of radiopharmaceuticals. Radiopharmaceutical kinetics can, thus, be studied on the same animal by successful PET imaging over several hours or days. Unfortunately, non-tandard isotopes decay with the emission of a high-energy positron and emit other concurrent gamma rays. Higher energy positron will travel longer distances from the point of emission in matter before annihilating. This will reduce the imaging performance by degrading the spatial resolution. Also, the emission of concurrent gamma rays will strongly affect the counting ability of the imaging device. Evaluation of these isotopes is thus mandatory before accurate quantitation can be achieved, both in small animal and human PET cameras. Improvement of imaging techniques is being investigated.

PET is an important noninvasive imaging technique and has become an accepted clinical tool in nuclear medicine. In particular PET imaging with [F-18]-Fluoro-2-deoxyglucose [FDG] for staging and localization of malignant cancerous tumors is now routinely performed. Nonetheless, significant advances in camera design and image reconstruction algorithms have been achieved recently, and efforts are being made to improve the overall utility of PET imaging and to develop new applications, notably in the areas of radiation treatment planning and cardiology.

1. Dosimetry of 60,61,62,62Cu-ATSM: A hypoxia Imaging agent for PET. R.Laforest, F.Dehdashti, J.S. Lewis, S.W. Schwarz, Eur. Jour. Nucl. Med. (2004)
2. Production, Processing, and MicroPET Imaging of Titanium-45, Amy L. Vâvere, Richard Laforest, Michael J. Welch, Nucl. Med. Biology, (2004).
3. Performance Evaluation of the microPET®-Focus™: a third generation microPET scanner dedicated to animal imaging, Yuan-Chuan. Tai, Ananya Ruangma, Douglas Rowland, Stefan Siegel, Danny F. Newport, Patrick L. Chow, Richard Laforest*, accepted in Jour. Nucl. Medicine, July 2004.
4. In Vivo Assessment of Tumor Hypoxia in Lung Cancer with 60Cu-ATSM, Farrokh Dehdashti, Mark A. Mintun, Jason S. Lewis, Jeffrey Bradley, Ramaswamy Govindan, Richard Laforest, Michael J. Welch, Barry A. Siegel, Jour. Nucl. Med. 30-6 (2003) 844-850.
5. Preparation of 66Ga- and 68Ga-labeled Ga(III)-Deferoxamine-Folate as Potential Folate-Receptor-Targeted PET Radiopharmaceuticals. Carla J. Mathias, Michael R. Lewis, David E. Reichert, Richard Laforest, Terry L. Sharp, Zhen-Fan Yang, David J. Waters, Paul W. Snyder, Philip S. Low, Michael J. Welch, and Mark A. Green , Nucl. Med. Biol. 30-7 (2003) 725-731
6. Delineation of Hypoxia in Canine Myocardium Using PET and Copper(II)-Diacetyl-bis(N4-Methylthiosemicarbazone), J. S. Lewis, P. Herrero, T.L. Sharp, J.A. Engelbach, Y. Fujibayashi, R. Laforest, A. Kovacs, R.J. Gropler, M.J. Welch, Jour. Nucl. Med. 43 (2002) 1557-1569.
7. Physiologic FDG-PET three-dimensional brachytherapy treatment planning for cervical cancer. Malyapa RS, Mutic S, Low DA, Zoberi I, Bosch WR, Laforest R, Miller TR, Grigsby PW. Int J Radiat Oncol Biol Phys. 2002 Nov 15;54(4):1140-6.
8. Production and purification of gallium-66 for preparation of tumor-targeting radiopharmaceuticals, Lewis MR, Reichert DE, Laforest R, Margenau WH, Shefer RE, Klinkowstein RE, Hughey BJ, Welch MJ. Nucl Med Biol. 2002 Aug;29(6):701-6.
9. PET-guided three-dimensional treatment planning of intracavitary gynecologic implants. Mutic S, Grigsby PW, Low DA, Dempsey JF, Harms WB, Laforest R, Bosch WR, Miller TR. Int J Radiat Oncol Biol Phys. 2002 Mar 15;52(4):1104-10.