Lecture 21: Intro to Nuclear Medicine and Radioactivity Review

What imaging modalities are included in nuclear medicine?

PET and SPECT

What modality was used to take this image?

PET or SPECT; there is little anatomical detail and there shows uptake of radiotracer

Where does the signal comes from for PET and SPECT?

source of signal comes from the radiotracer

Why is PET and SPECT used?

highlights functionality and uptake of specific chemicals

What PET tracer is mostly commonly used?

[18F]FDG

Why is glucose significant?

Why does [18F]FDG get trapped in cells unlike glucose?

Why does the brain light up with [18F]FDG?

the brain is a highly glucose metabolizing organ

How much dose is generally received from PET and SPECT?

When was Tc-99m discovered?

1938

What is considered the golden age of nuclear medicine?

1930s

When did Tc-99m start being used for imaging?

1964

Why was the development of PET imaging a long process?

There needs to FDA approval for the scanner AND the radiophamaceutical

What is the benefit of a whole-body PET scan?

higher sensitivity leads to less radiotracer injected leading to less dose

Why is eV used over the joule?

we are working with really itty bitty energies

What is an AMU?

one twelfth of a C-12 atom (1 AMU = 1 g/mol)

A container contains approximately 18 grams of water. How many moles of water does the container contain?

~ 1 mol

How many atoms are in 1 mole?

6.022 × 10²³

How is molarity defined?

the amount of moles in a compound or element per liter of solution

ppm

1 part of substance per 10^6 parts solution

Molar Activity

amount of activity per amount of radiopharmaceutical (MBq/nmol)

How is mass and energy related?

E=mc²

How many MeV/c² per u?

931.464 MeV/c²

What is the rest mass of an electron?

511 keV/c²

How is the binding energy (or mass deficiency) calculated?

total mass of atom minus the mass of individual constituents

Why does the binding energy per nucleon matter?

The bigger the ratio, the more stable an atom is

isotope

same proton number

isotone

same number of neutrons

isobar

same number of A (protons+neutrons)

isomer

excited nuclear state of a specific nuclide

Is β- emitters above or below the line of stability?

below

Are EC/β+ emitters below or above the line of stability?

Above

Beta decays result in nuclides that are iso (topes, tones, or bars)?

isobars

Mass excess

Δ = (m-A)c²

What is the mass excess for C-12?

0 MeV

Q-value

mass before - mass after

Do exergonic or endergonic reactions have a negative Q-value?

endergonic

What is the Q-value for β- decay?

Q = [m(parent)-m(daughter)]c²

Q-value for positron decay

Q = [m(parent)-m(daughter)-2me]c²

Q-value for electron capture?

Q = [m(parent)-m(daughter)]c² - EB