Introduction to Modern Medical Imaging Allen T. Newton, Ph.D. Institute of Imaging Science, Department of Radiology Vanderbilt University PAVE 2014

Medical Imaging The goal is to better visualize structure or function in the living or non-living organism, animal or human Involves collaborations with mathematicians, physicists, engineers, chemists and biologists Work with physicians to meet their diagnostic and treatment evaluation needs Look at a couple of key components of medical imaging Look at some examples from MRI, ultrasound, CT

Imaging Science Physics Chemistry Biology Medicine Computer Science Math Engineering

Physicist/engineer (PhD) 4 yrs of college 5-7 yrs of graduate school Radiologists (MD) 4 yrs of college 4 yrs of medical school Physicist/engineer (PhD) 4 yrs of college 5-7 yrs of graduate school improve interpret Medical Imaging Then, to end the lecture, the final message is the definition of imaging science. We can guide them into helping us define imaging science since through the lecture we have showed them that its is a multidisciplinary science, and we can name all or most of the different fields of science that have a role in imaging, I believe that we have a slide for that, and that imaging can be use for research and for medical purposes. create Technologists (RT) 2-4 yrs of college 2 yrs of technical school

How do we make medical images? X-ray images are made using x-rays, which are waves like radiowaves or ultraviolet light but with higher frequency and smaller wavelength. http://www.andor.com/image_lib/lores/introduction

Magnetic Resonance Imaging (MRI) The Major Imaging Modalities Magnetic Resonance Imaging (MRI) X-ray Imaging Computed Tomography (CT) Positron Emission Tomography (PET) Ultrasound (US)

X-ray Imaging The Major Imaging Modalities Magnetic Resonance Imaging (MRI) X-ray Imaging Computed Tomography (CT) Positron Emission Tomography (PET) Ultrasound (US)

Computed Tomography (CT) The Major Imaging Modalities Magnetic Resonance Imaging (MRI) X-ray Imaging Computed Tomography (CT) Positron Emission Tomography (PET) Ultrasound (US)

Positron Emission Tomography (PET) The Major Imaging Modalities Magnetic Resonance Imaging (MRI) X-ray Imaging Computed Tomography (CT) Positron Emission Tomography (PET) Ultrasound (US)

So, you are playing soccer… … you collide with another player, and collapse in pain on the ground You have pretty intense pain in your lower left leg How bad is it and how do we find out?

So, you go to the Emergency Room… … and the attending physician orders an X-ray of your injured leg What are they looking for? What will the X-ray show?  The X-ray shows a bad break in your tibia General Message: What is the problem? Can imaging solve the problem? How? Image adapted from http://www.gentili.net/image.asp

Spatial Resolution 32x32, 7.5 mm2 64x64, 3.75 mm2 128x128, 1.87 mm2

Spatial resolution 7T MRI, 0.6x0.6x1.0 mm3 resolution

Contrast

A Magnetic Resonance Imaging Scanner

Magnetic Resonance imaging Can generate 2D and 3D views in any plane Uses no ionizing radiation Extremely versatile modality Spatial resolution: humans~100, animals~25 microns Coronal Sagittal Axial

Magnetic Resonance imaging

Magnetic Resonance imaging MRI showing blood vessels in brain

Assessing brain white matter tracks Magnetic Resonance imaging Assessing brain white matter tracks Bright in coherent white matter Darker where 1) Fibers diverge/cross, or 2) No preferred orientation Orientation is color code by direction  Red = Right/Left  Green = Anterior/Posterior  Blue = Superior/Inferior Reveals structure within white matter Adam Anderson, Ph.D. 20

Finding white matter tracks Magnetic Resonance imaging Finding white matter tracks  Establishes connections between different brain regions Adam Anderson, Ph.D. 21

Some examples from cancer imaging

Signal Intensity time courses MRI in cancer imaging Signal Intensity time courses 3D rendering of tumor anatomical MRI

X-rays in cancer imaging, 1/2 Mammogram displaying calcification, increased density Mrs. Röntgen's hand, the first X-ray picture of the human body ever taken

X-rays in cancer imaging, 2/2 Standard radiography yields a 2-D projection of a 3D object, whereas CT allows for true 3-D image acquisition CT acquires a series of projections from many angles around the subject; each set of projections is then reconstructed via a “backprojection” algorithm Developed by Sir Godfrey Houndsfield, won 1972 Nobel Prize in Medicine/Physiology Spatial resolution: humans~200 microns, animals~35 micron Munden, et al, Radiology, 2005; 237:803-18 www.radiologyinfo.org/

PET in cancer imaging, 1/2 Some radioactive isotopes (18F, 15O, etc) emit positrons: Such elements can be incorporated into metabolically relevant compounds Emitted positron encounters electron, they annihilate leaving 2 photons traveling in opposite directions which are measured by ring of detectors Images generated using very similar computations as in CT Spatial resolution: humans and animals ~2 mm Most common PET tracer is FDG (flourodeoxyglucose), a glucose analog 18FDG (blood) (tissue) 18FDG-6-PO4 (cells) X

PET in cancer imaging, 2/2 CT PET CT/PET Dominique Delbeke www.breastcancer.org Dominique Delbeke CT PET CT/PET

This week Today: Overview Tuesday: X-Ray & Computed Tomography (CT) Wednesday: Ultrasound, SPECT, PET Thursday: MRI Friday: fMRI lab !!!!!!