CHM3930 Lecture Notes - Lecture 10: Ionizing Radiation, Nuclear Reactor, Radiochemistry
20 Jun 2018
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Week 10 -Fluorine-18 Radiochemistry and Radiopharmaceuticals
Nuclear reactor: Isotopes made through neutron radiation
Cyclotrons: Isotopes made with proton radiation
Lots of radionucleotides
oNeutron deficient
– Particle accelerator produced
– β+ emission or electron capture
– Higher proton number than neutron number
oNeutron rich
– Reactor produced
– β- emission -high energy electron
– Lower proton number to neutron number
Fluorine 18
oNeutron deficient
oPET imaging
Types of radio pharmaceuticals
oImaging-based -target cells, and used to show where cells are
oTherapeutic – deliver the dose/ attack cells
Types of Ionising radiation
oAlpha particles
– Helium nucleus
– Two protons and two neutrons
– High energy
– Large
– Very damaging
– Can be shielded by paper
oBeta particles
– High energy electron or a positron
– Lower energy than alpha, but still damaging
– Can be shielded by plastic
find more resources at oneclass.com
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oGamma particles
– Behave like rays
– High energy electromagnetic waves
– Need several layers of lead to shield from gamma rays
oNeutrons
– High energy neutron particle
– Need thick layer of concrete to shield
Units of Ionising radiation
oThe becquerel (Bq)
– 1Bq = 1 disintegration per second
oThe curie (Ci)
– 1 Ci = 37 billion disintegrations per second
– 1 Ci = 3.7 x 1010 Bq = 37 GBq
oThe gray (Gy)
– Absorbed dose units
– 1 Gy =1 J/Kg
– 6-10 Gy (fatal) = chemical energy of 20mg of sugar
oThe sievert (Sv)
– Dose equivalent units
– 1 Gy = 1 Sv (for gamma radiation, electrons and photons)
– 1 Gy = 20 Sv (for alpha particles)
– 1 Gy = 30 Sv (for neutrons)
– 6-10 Sv -acute radiation sickness and probable death
Exposure to Ionising radiation
oThe average Australian has 1500 μSv per year
oGet more at sea level than at high altitudes
oRadiation industry workers have a limit of 20,000 μSv per year
– Don’t have an increased risk of cancer
– If more, then they must take 6 months off
Positron Emission Tomography (PET scans)
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Nuclear reactor: isotopes made through neutron radiation. Higher proton number than neutron number: neutron rich. Types of radio pharmaceuticals: imaging-based -target cells, and used to show where cells are, therapeutic deliver the dose/ attack cells. Can be shielded by paper: beta particles. Lower energy than alpha, but still damaging. Can be shielded by plastic: gamma particles. Need several layers of lead to shield from gamma rays: neutrons. Need thick layer of concrete to shield. Units of ionising radiation: the becquerel (bq) 1bq = 1 disintegration per second: the curie (ci) 1 ci = 37 billion disintegrations per second. 1 ci = 3. 7 x 1010 bq = 37 gbq: the gray (gy) 6-10 gy (fatal) = chemical energy of 20mg of sugar: the sievert (sv) 1 gy = 1 sv (for gamma radiation, electrons and photons) 1 gy = 20 sv (for alpha particles) 1 gy = 30 sv (for neutrons) 6-10 sv -acute radiation sickness and probable death.
