NMT 1613
Nuclear Physics
Historical overview
• 1895- Wilhelm Roentgen discovers X-Rays
• 1896-Henri Becquerel discovers radioactivity
• 1889- Marie Curie discovers Radium
• 1913- Georg de Hevesy-developed the tracer
approach
• 1927- first human study
Historical Overview
• 1930’s-invention of a cyclotron
• Post WWII- nuclear reactors were used for
medical radioisotope production
• 1951-1st Rectilinear Scanner
• 1958- Anger Camera (Paul Anger)
• 1960’s-most studies used I-131
• 1964- 99m Tc
Nuclear Medicine Today
• Development of technology and applied
mathematics = SPECT and PET development
• PET imaging and Fusion imaging
• Over 100 different procedures
• Any organ or organ system, psychology,
research
• Radiotherapy/radioimmunotherapy
Quantities vs Units
• Quantity describes WHAT is measured
whereas a Unit describes HOW much.
– Quantity: physical properties and processes eg.
Time and Energy
Fundamental: stands alone (eg time, distance, mass)
Derived: combinations of fundamental quantities
(eg. Energy is k*m2/ sec2)
Scalars:
• Scalar Quantity: a simple physical quantity
that is not changed by coordinate system
rotations or translations (in Newtonian
mechanics)
Example: driving 85 mph
Vectors
• Vectors: have a measurable amount in a
distinct direction
– quantities that have both magnitude and direction
Eg. Driving 85 mph west
English Vs. Metric
English system: inches, foot, pounds, seconds
Metric System: meters, grams (kilograms),
seconds
Basic Conversions
• Distance:
1 inch = 2.5 centimeters
1 foot = .3048 meters (30 cm)
How many centimeters is someone who is 5’7”?
Basic Conversions
• Weight
1 pound = 16 ounces
1 kilogram = 1,000 grams
1 kilogram= 2.2 pounds
Convert 140.5 lbs into kilograms:
In terms of Radiation
Quantity: energy
SI unit: Joule (J)
Traditional Unit: electron volts (eV)
Conversion:
1 Joule = 6.242 x1018 electron volts
1.602 x 10-19 J = 1 eV
What is the energy of 99mTc in Joules?
How about In-111?
In terms of Radiation…..
Quantity: radioactivity
SI unit: Becquerel
Traditional Unit: Curie
Conversion:
1 Bq = 2.703 x 10-11 curies
3.7 x 1010 Bq = 1 Ci
37 MBq = 1 mCi
1 Ci = 1000 mCi
Becquerel: the activity of
a quantity of
radioactive material in
which one nucleus
decays per second. (SI
unit)
radioactivity(in Bq) =
Curie: (traditional unit)
roughly the activity of 1
gram of the radium
isotope 226Ra
1 Ci = 3.7 × 1010 decays
per second
A patient arrives for a bone scan. The dose from the
radiopharmacy is labeled as 925 MBq but the
charting system requires traditional units .
How many Curies is this?
How many mCi?
37 MBq = 1 mCi
In terms of Radiation:
Practical units of Measure
Quantity: Absorbed Dose-amount of energy
deposited as radiation interacts with matter
SI units: Grays
Traditional Units: rad (radiation absorbed dose)
Conversion:
1 gray (Gy) = 100 rads
1x 10-2 Gy = 1 rad
Gray: amount of radiation required to deposit 1
joule of energy in 1 kilogram of any kind of matter
(J/kg)
rad: corresponding traditional unit.
0.01 J deposited per kg. 100 rad = 1 Gy.
Conversion:
1 gray (Gy) = 100 rads
1x 10-2 Gy = 1 rad
You know that an average absorbed dose to the
bladder for a patient receiving 10 mCi 99m TcMag3 is 263 rads.
How much of the dose is absorbed when
measures in Gy’s?
In Terms of Radiation:
Practical units of Measure
Quantity: Dose Equivalent
- Equal doses of radiation result in different
amounts of damage to living tissue
- Measure of biologic effect of radiation
- Product of the absorbed dose in rads and
weighting factors.
Sievert (Sv)- more of a
weighted average of the
absorbed dose,
designed to represent
the health effects of
exposure. (SI unit)
also measured in J/kg
Traditional Unit: Roentgen
Equivalent Man (rem)
Conversion:
1 Sv = 100 rems
1 x 10-2 Sv = 1 rem
There has been a radioactive spill in your
department in which a patient was
unnecessarily exposed to radiation and now
you have to determine the amount of
radiation equivalent to that patient receiving
a dose. The dose equivalent of 253 rems has
been determined. What is the dose equivalent
in Sv’s?
In Terms of Radiation:
Fundamental units of Measure
Quantity: Exposure
SI unit: Coulomb/kg of air (C/kg air)
TI unit: Roentgen (R)
Conversion:
1 C/kg air = 3876 Roentgen
2.58 x 10-4 C/kg air = 1 R
Coulombs Law: describes interaction between
electrically charged particles.
Coulomb: unit of electrical charge, charge
transported by a steady current of one
ampere/sec.
Coulomb in kg of air = the amount of radiation
required to create 1 coulomb of charge of
each polarity in 1 kilogram of matter.
- SI unit, measured in C/kg
Roentgen
- traditional unit
- the amount of radiation required to liberate
1 esu of charge of each polarity in 1 cubic
centimeter of dry air.
Conversion:
1 C/kg air = 3876 Roentgen
2.58 x 10-4 C/kg air = 1 R
Atomic Review
Atomic Structure
Bohr Model
Protons (atomic # Z)
•Positively charged
•Located in the nucleus
–Mass = 1.6726 x 10 -27 kg
•All atoms of an element have the same number
of protons, whether they are radioactive or not.
•Dictates position on periodic table and chemical
identity
•Protons and Neutron, and their associated forces,
affect an atom’s radioactive properties
Neutrons
•No charge
•Located in the nucleus
•1800 times as heavy as an electron.
–Mass= 1.6749 x 10 -27 kg
•Neutron + proton = Nucleon
Electrons
•Negatively charged
–Neg. charge of 1.6022 x 10-19 Coulomb
–Mass = 9.109 x 10-31 kg
•Orbit around the nucleus
•Determine atom’s chemical properties
•Less mass
•Higher energy?
Electron Shell Configuration
Sl.No
Electron Shell
Maximum
Capacity
1
K Shell
2 electrons
2
L Shell
8 electrons
3
M shell
18 electrons
4
N shell
32 electrons
ELECTRON VOLT
•Base unit of energy
•Amount of energy acquired by an electron
when accelerated through an electrical
potential of 1V.
Chemical Shorthand
• X= elemental atom
X
• Z= Atomic Number
•# of protons
• N= Neutron Number
• A= Mass Number
•Z + N
•Total number of nucleons
Atomic Shorthand
X = Chemical Symbol
A= Atomic mass
Z= Number of protons
Subtract A-Z to find the number of neutrons.
Mass Unit
•Universal mass unit: equal to ½ the mass of a
Carbon atom
1.66054 x 10 -27 kg
•Atomic Mass Unit (AMU)
1/12 mass of stable Carbon-12 atom
One AMU is about the same as one proton, and
also about the same as one neutron.
One AMU is 1.66x10-27 kg
Vocabulary words
• Valent Electrons: outer electrons that interact to form
molecules
• Valence: is an atom’s ability to lose or gain an e- so that it can
achieve a stable e- configuration. Usually determined by the
number of e- in outermost shell (valence shell)
–Octet Rule: Most stable form of atom. Main-group
elements tend to undergo reactions that leave them with
8 outer shell e-. They react in such a way that they attain
an e- configuration like an inert gas in which the s and p
orbitals are filled in their valence e- shell (ns2np6)
Vocabulary words
•Atom: smallest part of an element with the same
chemical properties. Contains 3 types of elementary
particles: p+, n, e•Element: An element is a fundamental substance that
cannot be chemically broken down any further.
•Molecules :are formed from combinations of elements
•Matter: Molecules make up matter
For Next Week:
• Read chapters 1 and 2 in your Physics book
• Read Math Book pages 26-39
• Homework handout
• Log onto Canvas for this course.