NUCMED - PRELIM L2 Flashcards
The time after which 50% of the atoms in a
sample undergo disintegration
Half-Life
Initial Activity is equivalent to how many cpm ?
32,000 cpm
After two half-lives, cpm will be at
8,000 cpm
After one half-life, cpm will be at
16,000 cpm
After three half-lives, cpm will be at
4,000 cpm
The formula for the calculation of the amount of radioactivity remaining after a given time is:
Nt = N0 x (0.5) number of half-lives
The half life of Technetium-99m is equivalent to
6.02 hours
N0 stands for
Initial Activity at Time
The half-life of Cobalt 60 is equivalent to
5.271 Years
The half-life of Iodine-131 is equivalent to
8.04 Days
Radioactive decay may be determined with what formula ?
A(t) = A0e-λt
e is called as _______ and is equivalent to _____
- Euler’s Number
- 2.718
The overall decay constant is derived by dividing _______ with the half-life of the radioactive source
0.693
t stands for _______
Elapsed Time
This is a useful parameter for calculating the
cumulated activity in the source organ in
internal dosimetry, for the actual lifetimes of individual atoms in a sample are different
Average Life
In many cases, the daughter element is also
radioactive and immediately starts disintegrating after its formation
Radioactive Equilibrium
This is the ejection of electrons from the target atoms
Ionization
The fractional reduction in the beam per unit thickness as determined by a thin layer of the absorbing material
Linear Attenuation Coefficient
The thickness of absorbing material
necessary to reduce the x-ray intensity to half of its original value
Half-Value Layer
What are the five (5) materials that may be used for measurement of HVL
- Aluminum
- Copper
- Lead
- Brick
- Concrete
(Air-Con-Lang-Ba-Cold ?)
There is no energy transfer and no ionization, but there is a change in the direction of the x-ray without a change in its energy
Coherent Scattering
Coherent Scattering may be also called as _______ or ______
- Classical Scattering
- Thompson Scattering
Coherent Scattering contributes slightly to the _____ of an image that reduces image contrast
General Graying
The incident x-ray interacts with an
outer-shell electron and ejects it from the
atom, thereby ionizing the atom. They produce a uniform optical density on the
screen-film radiograph and uniform intensity on the digital image receptor that results in reduced image contrast
Compton Scattering
The x-ray is not scattered, but it is totally
absorbed. The photoelectron escapes with kinetic energy equal to the difference between the energy of the incident x-ray and the binding energy of the electron.
Photoelectric Effect
What type of x-rays are produced after a photoelectric interaction ?
Characteristic X-rays
If an incident x-ray has sufficient energy, it
may escape interaction with electrons and
come close enough to the nucleus of the atom to be influenced by the strong nuclear field
Pair Production
This is used to the diagnosis and treatment of human diseases
Radiopharmaceutical
X-rays with energy above approximately 10
MeV can escape interaction with electrons
and the nuclear field and be absorbed directly by the nucleus. When this happens, the nucleus is raised to an excited state and instantly emits a nucleon or other nuclear fragment.
Photodisintegration
These have the ability to image endogenous ligands such as peptides and antibodies, and also can measure relatively snow kinetic processes due to relatively long half-life of commonly used isotopes duly approved by the FDA
SPECT Tracers
______and ______radiopharmaceuticals have a wide acceptance in molecular imaging,
biomedical research disciplines, and drug
development.
SPECT and PET
This is a quality of an ideal pharmaceutical wherein it should not exceed the time assigned to complete the study, also capable of providing a smaller radiation dose to the organ
Short Half-Life
An ideal pharmaceutical for diagnostic procedures must be made from gamma radiation by electron capture or isomeric transition with energy between ____ and _____ keV
30 and 300
______, _____, and _____ electron emitters
are used because of their high linear
energy transfer, which leads to maximum exposure and damage of the target cells
Alpha, Beta, and Auger
This should be as large as possible because the agent with better target uptake is a superior imaging agent since the activity from the nontarget areas can interfere with the structural details of the organ imaged
High Target-to-Nontarget Ratio
The rate at which an organ takes up the
administrated radiopharmaceutical
Target Uptake Rate
Radiopharmaceuticals must be cleared from
the blood and background tissue to achieve
better image contrast since organ visualization is better when the background
tissues have less uptake than the target
organ.
Tracer Excretion
The most common excretion route is _______
Renal Clearance
The ideal radiopharmaceutical should be cost effective, inexpensive, and readily available in any nuclear medicine facility
Availability
What are the 2 Major Principles of a Nuclear Reactor:
- Neutrons Induce Fission in the Fissile Material Constructing the Fuel Rods of the Reactor
- Number of Neutrons Released in that Fission Reaction is About Two or Three Neutrons with a Mean Energy of 1.5 MeV
Naturally occurring radionuclides cannot be
employed for medical diagnosis because of
their long half-lives, which warrant the need
for production of other radionuclides that can be safely used for medical applications.
Radiopharmaceutical Production
Produces a wide range of nuclear medicine
radiopharmaceuticals, especially those with
short half-lives
Cyclotron
______ are placed between the two poles of
a magnet so that the ion beam is constrained within a circular path inside of it
Dees
The Cyclotron was built in ______ by _______
- 1930
- Ernest Orlando Lawrence
The _____________ originate at the ion source at the center of the cyclotron, and as they spiral outward in the dees, they acquire
increasing energy for each passage across
the gap of the dees
Beam Particles
The first commercial radionuclide generator
was produced in the United States in the ______ at the ________
- 1960’s
- Brookhaven National Laboratories
These are “parent daughter systems involving a long-lived parent radionuclide that
decays to short half-life daughter” and is called a generator because of its ability to generate continuously a relatively short-lived daughter radionuclide.
Generator-Produced Radionuclides
These are generated by the
decay of the parent radionuclide until either a
transient or secular equilibrium is reached.
Daughter Radionuclides
This is the most commonly used radionuclide generator in nuclear medicine practice worldwide since its first commercial introduction in 1965.
99Mo-99m TC Generator
This is formed by a glass or plastic column fitted at the bottom with a filtered disk
Generator
This radiopharmaceutical is mainly for lung ventilation scans and for the assessment of cerebral blood flow
Xenon-133
This radiopharmaceutical’s most common application are in labelling blood cells for imaging inflammatory processes, thrombi, and proteins
Indium-111
It was approved for the treatment of patients
with relapsed or refractory, low-grade or follicular B-cell NHL
111In-and-90Y Ibtritumomab Tiuxetan (Zevalin)
Radiopharmaceutical used for liver imaging
90Y-Labeled Microspheres
The name Technetium was derived by the scientist _______ from the ______ word _______ which means _______
- Mendeyelev
- Greek
- “Technetos”
- Artificial
It is a transient metal that exists in many oxidation states, and can combine with a variety of electron-rich compounds
Technetium-99m
Technetium-99m partners with _____% of all nuclear medicine procedures
85 %
This is eluted from the
99m Tc99Mo generator with sterile isotonic saline
99mTc-Sodium Pertechnetate
The commonly used diphosphonate compounds are:
- Methylene Diphosphonate
- Hydroxymethylene Diphosphonate
Used to diagnose renal infection in children and in morphological studies of the renal cortex.
99mTc Dimercaptosuccinic Acid
It was introduced initially under the brand name Cardiolite as a technetium-based radiopharmaceutical to replace Tl-201 in myocardial perfusion imaging.
99mTc Methoxyisobutyl Isonitrile
Used in the diagnosis of myocardial perfusion
abnormalities in patients with coronary artery
disease.
99m Tc Tetrofosmin
The radiopharmaceutical of choice for lung perfusion scan with ventilation scan to
exclude pulmonary embolism.
99m Tc Macroaggregated Albumin
Primarily used in brain perfusion imaging,
although it is used for leukocyte labeling
substituting
111 In-oxine.
99m Tc Hexamethylpropylene Amine Oxime
Used for pulmonary perfusion scintigraphy and determination of right-to-left shunts
99m Tc Human Serum Albumin Microspheres
What are the four (4) uses of Sulfur Colloid:
- Bone Marrow
- Spleen Scintigraphy
- Liver Scintigraphy
- Lymphoscintigraphy
