What is Radiation? • Propagation of energy through matter or space in the form of • Particles (e-, β±, proton, α, neutron, etc.) or • Photons(X-ray, γ-ray, synchrotron light, etc.) e- 6 MeV hν 6 MV
Types of Radiation Directly ionizing (charged particle) direct Coulomb interaction with orbital e- of atoms Ionizing Indirectly ionizing (neutral particle) 1st: release charged particle (photon > e-, e+, neutron > proton or heavier ions) 2nd: direct Coulomb interaction between released charged particle and orbital e- of atoms Radiation heat, radio- or microwaves, or visible, infrared, or ultraviolet light Non-ionizing
Energy Absorbed into Body CT Scan Sauna Body temperature rise from 36.4 C° to 36.5 C° 0.1 C° × 4.184 J/ C°/g = 418.4 J/kg ≠ 418.4 Gy One chest CT scan 30 mGy = 30 × 10-3 J/kg = 0.03 J/kg = 0.03 Gy
What is Radioactivity? • Radiation emissions as the result of the spontaneous transmutation of one element to another (element or state)
Discovery of Radiation On the evening of November 8, 1895
Discovery of Radioactivity February 26, 1896
X-ray quickly in clinical use A woman (50 yrs) with recurrent breast cancer 18 daily 1-hour irradiation Imaging: 1896 – Mihajlo I. Pupin in New York City Therapy: 1896- Emil H. Grubbé in Chicago
Radiotherapy Timeline • Co-60 Teletherapy • Low Energy LINAC • Betatron • 100-400 keV X-rays • Rotational Therapy • Radium Brachytherapy 1895 1950 1965 • Computer Tomography • High Energy LINAC • Ir-192, Cs-137 Brachytherapy 1980 2000 • PET-CT, MR-PET, Dual energy CT • IMRT with MLC, Inverse Plans • Image-Guided Radiotherapy • Targeted therapy • Proton and C-ion therapy • Popular CT, MRI Scanners • 3D RT Planning • Accurate Dosimetry • Computer remote afterloader
A Bit History Roentgen (1901): Discovery of X-rays Becquerel & Curie’s (1903): Discovery of radioactivity William Bragg(1915): Discovery of Bragg Peak Willem Einthoven (1924): Invention of Electrocardiogram E. O. Lawrence (1939): Invention of cyclotron Hounsfield & Cormack (1979): Invention of CTLauterbur & Mansfield (2003): Invention of MRI
1895 X-ray Wilhelm KonardRöntgen 1896 Natural radioactivity Antoine-Henri Becquerel 1897 Electron Joseph John Thomson 1898 Radium-226 Pierre & Marie Curie 1903 Bragg peak William Henry Bragg 1905 Photoelectric effect Albert Einstein 1906 Characteristic x-ray Charles G. Barkla 1911 Electron charge Robert Millikan 1913 Model of hydrogenNeils Bohr 1916 W-filament of x-ray tube William D. Coolidge 1919 Proton Ernest Rutherford 1922 X-ray scattering Arthur H. Compton 1926 Quantum mechanics Erwin Schrodinger 1931 Cyclotron Ernest O. Lawrence 1932 Neutron James Chadwick 1932 Positron Carl D. Anderson 1934 Artificial radioactivityIrène Joliot-Curie, Frédéric Joliot 1940 Betatron Donald W. Kerst 1942 Controlled nuclear fissionEnrico Fermi 1946 Nuclear magnetic resonance Felix Bloch, Edward Purcell 1951 Cobalt-60 machine Harold E. Johns 1968 Gamma Knife Lars Leksell 1971 Computer Tomography Godfrey Hounsfield, Alan Cormack 1973 Magnetic resonance imaging Paul C. Lauterbur, Peter Mansfield Milestones in Modern Physics & Radiological Sciences
Radiological Sciences • is a perfect and long-standing example of translational research where basic experimental & theoretical discoveries are rapidly implemented into benefiting humanity through improving procedures in diagnosis and treatment of disease • Medical Radiation Physics is an outstanding branch of it
1908년 대한의원 완공 1911년X-선 장치 설치: 정형외과 륀트겐실 ▶우측에서 본 병원 전경지 ▶본 관 (시계탑) 대한의원 총독부의원 Courtesy of Prof. Chung, J. K.
1940년 방사선의학 강좌 경성제국대학 의학부 Courtesy of Prof. Chung, J. K.
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