Where’s the Physics in Medicine? Richard Watts Director of MR Research, Van der Veer Institute Dept. of Physics and Astronomy University of Canterbury 6th July 2009, NZIP

Therapy Diagnostic Imaging Therapy MRI Nuclear Imaging X-Ray 6th July 2009, NZIP

X-Ray Imaging Contrast: Density, Atomic Number source Object Detector December 22nd, 1895 Wilhelm Roentgen “Builder survives nailgun accident” Phil and Anthony Butler, UC and MARS Bioimaging

Pneumoencephalography Pneumoencephalogram from Moore et al (1935) 'Encephalographic studies in mental disease' - American Journal of Psychiatry 6th July 2009, NZIP

Medipix – Spectroscopic X-ray Imaging (CERN) Separate Density and Atomic Number “Colour X-ray Imaging” 6th July 2009, NZIP

Computed Tomography (CT) 3D X-Ray Imaging 6th July 2009, NZIP

Computed Tomography (CT) 3D X-Ray Imaging 6th July 2009, NZIP

Computed Tomography (CT) 3D X-Ray Imaging Prototype MARS Spectroscopic CT scanner 6th July 2009, NZIP CT Scanner rotating

Nuclear Imaging, Gamma Camera (1957) Contrast: Concentration of radiopharmaceutical 6th July 2009, NZIP

Radiopharmaceuticals for Nuclear Imaging Parent Decay Mode Half-life Daughter Decay Product 69Ge Germanium EC 271 days 68Ga Gallium β+, EC 68 min 68Zn Zinc 81Rb Rubidium 4.5 hr 81mKr Krypton IT 13.5 s 81Kr 82St Strontium 25.5 days 82Rb β+ 75 s 82Kr 99Mo Molybdenum β- 67 hr 99mTc Technetium 6 hr 99Tc EC = Electron capture, IT = Isometric transition 6th July 2009, NZIP

Single Photon Emission Computed Tomography, SPECT 3D Nuclear Imaging 6th July 2009, NZIP Bushberg, Essential Physics of Medical Imaging

Positron Emission Tomography (PET) 6th July 2009, NZIP 18F-FDG, T1/2 ~ 2 hours

Magnetic Resonance Imaging, (n)MRI “You know, what these people do is really clever. They put little spies into molecules and send radio signals to them, and then they have to radio back what they are seeing.” Niels Bohr Hydrogen Nuclei are aligned by a big Magnetic Field Resonant frequency given by Larmor equation Nuclei absorb radiofrequency energy at that frequency and then re-emit energy Magnetic field gradient coils allow the field (and resonant frequency) to vary with location in x,y,z – Imaging 6th July 2009, NZIP

Guess who? 6th July 2009, NZIP

Structural Brain Imaging with MRI T2 FLAIR Apparent Diffusion Coefficient Fractional Anisotropy T2* 6th July 2009, NZIP

Functional MRI of Language – Passive Listening, Rhyming Magnetic properties of oxyhemoglobin and deoxyhemoglobin L. Pauling and C. Coryell, PNAS USA 22:210-216 (1936) 6th July 2009, NZIP

Normal tissue complication probability Tumour control probability Radiation therapy Normal tissue complication probability Tumour control probability Cure Response Dose 6th July 2009, NZIP

Linear Accelerator (linac) 6th July 2009, NZIP

Intensity-Modulated Radiotherapy (IMRT) High Dose Region Constrained inverse problem Tumour Inverse planning Optimization Ill-posed problem -> find best trade-off Patient Intensity Modulated Cross - section Beam Profiles 6th July 2009, NZIP Linear Accelerator (linac) Juergen Meyer, UC

Summary Physics has made, and continues to make essential contributions to modern medicine Imaging X-ray imaging (Medipix/MARS) Nuclear imaging MRI (Functional imaging) Radiation therapy Accelerator physics Treatment planning, Monte Carlo modeling “Blue sky” research results in important unexpected technology (e.g. PET) Medical physics Excellent career prospects Using physics to improve health 6th July 2009, NZIP