prac qs ni justine Flashcards
(86 cards)
1
Q
- instruments are designed to detect or measure radiation
- Those designed detection generally operate in pulse or rate mode.
A
RADIATION DETECTION AND MEASUREMENTS
2
Q
Radiation is indicated by ticking, chirping, or beeping.
A
PULSE MODE
3
Q
instruments response is measured in mR/hr or R/hr
A
RATE MODE
4
Q
designed to measure the intensity of radiation usually operate in the integrate mode- they accumulate with a total exposure of mR or R
A
DOSIMETRY
5
Q
dosimetry measuring device is called
A
dosimeters
6
Q
earliest radiation detection device, still the primary means of radiation detection measurements
A
photographic emulsion
7
Q
TWO PRINCIPAL APPLICATION OF FILM IN DIAGNOSTIC IMAGING
A
- making a radiograph
- Film is used as personnel radiation monitor-film badge
8
Q
As radiation passes through gas, it ionizes atoms of gas in it’s path, then electrons released in ionization are detected as signal proportional to the radiation intensity
A
GAS-FILLED DETECTORS
9
Q
Occurs when a flash of light is emitted from the absorption of ionizing radiation. The amount of light emitted is proportional to the amount of energy absorbed by a material.
A
SCINTILLATION DETECTORS
(crystals and scintillance)
10
Q
Also known as survey meter
(most common)
A
IONIZATION CHAMBER
11
Q
- useful in their ability to detect the difference between alpha and beta radiation.
- sensitive instrument that are used in stationary laboratory instruments for the assay of small quantities of radioactivity
A
PROPORTIONAL COUNTERS
12
Q
Useful in detecting impurities especially in nuclear medicine facility
A
GEIGER-MULLER COUNTERS
13
Q
added to the filling gas of Geiger-Muller to return the counter after the first ionizing event to it’s original condition. (xenon)
A
QUENCHING AGENT
14
Q
SCILLIATION DETECTORS
A
- THERMO LUMINESCENT DOSIMETER (TLD)
- OPTICALLY STIMULATED LUMINESCENCE (OSL)
- POCKET DOSIMETER
15
Q
✓ MOST ACCURATE
✓ USES LITHIUM FLOURIDE (LiF)
✓ CAN MEASURE AS LOW AS
10mrad-10 rad
A
THERMO LUMINESCENT DOSIMETER (TLD)
16
Q
✓ MOST SENSITIVE
✓ USES ALUMINUM OXIDE
✓ CAN MEASURE AS LOW AS 1mrad
A
OPTICALLY STIMULATED LUMINESCENCE (OSL)
17
Q
✓ PROVIDES IMMEDIATE READING
✓ ALSO KNOWN AS PEN DOSIMETER
✓ CAN MEASURE 0-200mR
A
POCKET DOSIMETER
18
Q
- LEAST ACCURATE
- CAN MEASURE DOSES >10mR
- Filters: Aluminum and Copper
- Common causes of film fog HIGH temperature = HIGH humidity
And more than 1 month of use. - ONLY device that can provide permanent record of the dose.
A
FILM BADGE
19
Q
Radionuclide production can happen in two ways:
A
Natural and Artificial
20
Q
A type of radionuclide production wherein it is produced by particle bombardment or electromagnetic irradation.
A
- Artificial
21
Q
What are the types of artificial radionuclide production?
A
- Nuclear Fission
- Neutron bombardment
- Charged particle bombardment
- Radionuclide generator systems
22
Q
units that contain radioactive parent nuclide with relatively long half-life that decays to a short lived daughter nuclide.
A
Generator
- An example of this is Mo-99 to Tc 99m Generator
23
Q
Type of radionuclide production where nuclear reactions occur spontaneously. They have relatively long half-lives and heavy toxic elements
A
natural
24
Q
Mo-99 is produced by the fission of ____
A
- U-135 (fission moly)
- It is chemically purified and passed on to an anion exchange column composed of alumina (Al3O3) where molybdate ions are bound firmly.
25
Mo-99 is converted to _____. It is where it is milked or eluted by drawing sterile saline through the column vial.
Tc-99m
26
also known as a Cow generator
Mo-99 to Tc-99m Generator
27
Other examples of generators are
- Tin110 to Indium-110 generator
- Strontium-82 to zRubidium-82 generator
- Germanium-82 to Gallium-82 generator
28
circular device in which charged particles such as protons and alpha particles are accelerated in a spiral path in a vacuum
cyclotron
29
type of radionuclide used in cardiac PET
type of radionuclide used in cardiac PET
30
Components of a Cyclotron?
- Magnetic field
- Electric field
- Dees
- Deflector
- Target
31
Type of radionuclide used in Neuroendocrine PET
Gallium-82
32
In a cyclotron: It accelerates proton by providing high-kinetic energy
electric field
33
Composed of fuel rods that are inherently unstable (Uranium) which undergo fission. In this process 2-3 fast neutrons and 200MeV heat are released.
reactors
34
In a cyclotron: two half of the circle where the proton is accelerated
dees
35
In a reactor, it slows fast neutrons making it thermal neutrons.
moderator
36
In a cyclotron: Directs the particles out through a window in the cyclotron to strike in the target
deflector
37
In a reactor, it absorbs the neutrons in the reactor controlling the speed of reaction
cadium control rods
38
In a reactor, what are the 2 means of production?
fission
neutron capture
39
In a cyclotron: It is responsible for teering the protons in spiral motion
Magnetic field
40
A reactor is composed of fuel rods that are inherently unstable (Uranium) which undergo fission. In this process ___fast neutrons and ____s heat are released.
2-3
200MeV
41
What are the characteristics of an ideal radionuclide?
- Pure gamma emitter- no particulate radiation
- Sufficient photon energy: 100-300keV to allow attenuation and detecton
- Minutes to hours half-life
- HVL should be around organ dimension
- Monoenergetic
42
In a cyclotron: Material to be bombarded by the proton. After bombardment, 2 neutrons are directed from the nucleus
Target
43
Tc-99m is a metastable element discovered in _____ by ___ and ____ from a sample of Mo-98 that has been irradiated by neutrons and deutrons. It is pure gamma emitter
- 1937
- Carlo Perrier
- Emilio Serge
44
What is the half-life and energy of Tc-99m?
- 6hrs (baligtadin ang “9”, so 6)
- 140keV (98.6%)
45
What are the quality control measures done to assess radionuclides?
- RCR
- Radionuclidic purity:< 0.5
- Chemical Purity: < 10
- Radiochemical Purity: 95%
46
Quality Control: It is the fraction of wanted vs unwanted chemical in the preparation. Ensures that the presence of Al2O3 in the eluate is as low as possible. What is the standard range?
- Chemical Purity
- <10ug/ml (Aurin tricarboxylic acid is used for colorimetric spot testing)
47
It is called an excited state of a nucleus with measurable lifetime (isomeric state)
- Metastable
48
What are the localization mechanisms?
- DPACCC
- Diffusion - Bone scanning using diphosphonates
- Phagocytosis - radicolloids imaging of spleen liver and bone marrow
- Active transport - thyroid uptake scanning with iodine
- Compartmental localization - Blood pool scanning with human serum albumin or RBC
- Capillary blockade - Lung scan using microaggregates
- Cell Sequestration - Spleen scan with damaged RBC
49
Quality Control: fraction of total asctivity in a form of desired radionuclide for Tc99m generator, there should be less Mo-99 in the element. What is it? What is the standard range?
- Radionuclidic Purity
- Standard: <0.5uCi Mo-99/mCi Tc-99m
50
Steps in preparation for radiopharmaceutical
- Sterilization
- Addition to anti-microbial preservatives
- Compounding
- Labeling
- Radiation Shielding
51
Are instruments designed to detect or measure radiation. Generally operate in pulse or rate mode
Radiation detection and measurements
52
Quality Control: Fraction of total radioactivity in desired chemical form. Ensures that the expected valence state is +7
- Radiochemical Purity
- Standard: 95% of Tc-99m in +7 valence state
53
After 1 month of use of a film badge, what are the common causes of film fog?
- Increased temperature and humidity
54
USES LITHIUM FLOURIDE (LiF). CAN MEASURE AS LOW AS 10mrad-10 rad
- TLD
- Lithium-Luminescent
55
This provide immediate reading of radiation
- Pocket dosimeter
56
USES ALUMINUM OXIDE. CAN MEASURE AS LOW AS 1mrad
- OSL
- Oxide- OSL
57
____ detects photon emitted from radioactive gamma decay and determines the two-dimensional location o the decay. It also detects gamma rays from radiopharmaceutical and to build them up into an image.
Gamma camera
58
Gamma camera is developed by _____ at Donner Lab, in Berkley California (1950)
- Hal O. Anger
- Anger gamma scintillation camera, most common nuc imaging device.
59
What are the basic components of a gamma camera?
- Gantry
- Collimator
- Detector
60
Device used to form a relationship bet the original photon position and the position of the subsequent detection in the gamma camera
gamma camera collimator
61
___ inch thick of slab of lead used in collimator. the lead in between each hole is called a ____
- 0.5-2 inch thickness.
- septum
62
_____ design of the gantry is flexible option for small single detector system since it allows manual positioning by virtue of a counter balance mechanism, which offset the wight of the detector. Dualhead and triple head system requires a more sturdy ring gantry with robotic movement of the detector.
Cantilever
63
Is used to support and move the detector.
GANTRY
64
Types of gamma camera collimators:
- Parallel holes
- Diverging
- Converging
- Pinhole
- Fan beam collimator
65
Thick, conical collimators with a single ____mm hole in the bottom. Magnifies or minifies depending on the distance of the object from the collimator
- Pinhole collimator
- 2-5mm
66
Consist of an array of tapered holes that aim at a point at some distance in front of the colli. The image presented is magnified version.
- Converging collimators.
67
Consists of an array of _____ perpendicular to the crystal face, and thus presents a real size image to the crystal face.
- Parallel hole
68
Essentially up-side down converging collimators. Image is minified version of the real object presented to the crystal face
- Diverging collimator
69
Combination of parallel hole collimator and a converging collimator
- Fan beam collimator
70
device that record the spatial distribution and radioactivity and its change over time. It contains components that convert energy of the photons first into light and then into electrical signal.
detector
71
refers to the efficiency of the collimator
- Senstivity
- Greater hole, inc sensitivity. Vice versa
72
What is the seq of image conversion with PM tubes?
Photon signal> Dadaan sa sodium iodid crystal to convert to light> light guide> PM tubes (light ay maaamplify then converted to electron to electric signal> punta sa electronic circuits.
73
The ____ is a device for converting EMR in the form of gamma rays into a VISIBLE LIGHT. Scintillates give off light when high energy photons interact with it.
Crystal
73
- Converts the light produced in the scintillation into an electric signal
- Accelerating dynodes used to amplify electrical signal from photocathode
PMT (photomultiplier tube)
74
What are some crystals used in scintillation camera?
- Sodium Iodide- Thalium Activated
- Cesium Fluoride (CsF)
- Bismuth Germinate (BGO)
- Barium Fluoride (used in PET scanner)
75
hygroscopic material, which is hermitically sealed against moisture to prevent yellowing.
NaI (TI)
76
PMT has _____ that converts light photon into an electron.
photocathode
77
____ in PMT amplify the electrical signal from photocathode
accelerating dynodes
78
In PMT, for every ___ light photons that reach the cathode, one electron is ejected by photoelectric effect
7-10
79
allows the operator to either set the upper and lower energy limits or set peak energy level and associated window.
PHA
80
For each dynodes, the number of electrons is multiplied by a factor of____
- 3-4
- The electrons are collected by the anode to form the final electrical signal from the PMT, and are directed into a preamplifier circuit, which forms and shapes a pulse that is further amplified by a LINEAR AMPLIFIER from a few millivolts to a few volts.
81
The size of electric signal in PMT depends on
- The number of light photons which reach the cathode, depending on the gamma ray energy.
- Light voltage applied to PMT
82
It is an electronic device used to determine which portion of the detected spectrum is used to create images. It can be set to select energies to be counted, and reduce the number of Compton scatter photons
in the image
- Pulse Height analyzer (PHA)
83
It determines the acceptable range of energies around the peak for subsequent counting. Wider___, means more photons accepted and produce images in a shorter time but might degrade image quality.
window
84
responsible for counting the number of detected gamma ray which falls inside the PHA window
scaler and timer
86
most common nuclear imaging device
gamma camera
