Nucs Cara flashcards
(224 cards)
1
Q
What is the appropriate protocol for receiving radioactive packages?
A
Survey and wipe test within 3 hours of receipt during workhours or from begining of business opening
2
Q
What is the (external) wipe test limit?
A
2200 dpm/100cm^2 (6600 dpm/300cm^2)
3
Q
What are the handling requirements for radioactive white I package label and what are its radiation limits?
A
No special handling; Surface < 0.005 mSv/hr (0.5 mrem/hr); 0 @ 1 meter
4
Q
What are the handling requirements for radioactive yellow II package label and what are its radiation limits?
A
Special handling; surface < 0.5 mSv/hr (50 mrem/hr); < 0.01 mSv/hr (1 mrem/hr) @ 1 meter
5
Q
What are the handling requirements for radioactive yellow III package label and what are its radiation limits?
A
Special handling; surface > 0.5 mSv/hr but < 2 mSv/hr (200 mrem/hr); < 0.1 mSv/hr (10 mrem/hr) @ 1 meter
6
Q
On a radiation package, what deos TI stand for?
A
Transportation Index
7
Q
What does TI measure/how is it measured?
A
Dose rate at the time of shipping measured with a G-M counter representing number of mrem/hr @ 1 meter
8
Q
Which radioactive package label does NOT have a TI listed?
A
White I because TI will be zero
9
Q
A yellow III package indicates a TI of at least how much radiation?
A
> 0.01 mSv/hr (or 1 mrem/hr) @ 1 meter
10
Q
How long must records be kept for regulatory purposes?
A
Licensee must keep radiation protection program records for 3 years
11
Q
What is the occupational radiation dose limit for a radiation worker?
A
50 mSv/year
12
Q
What is the dose limit for a fetus in a radiation worker?
A
5 mSV during term (or 0.5 mSv/month)
13
Q
What is the lens radiation dose limit?
A
150 mSv/year (more updated limit is 20 mSv/year)
14
Q
What is the extremity and single organ radiation dose limit?
A
500 mSv/year
15
Q
What is the nonoccupational/general public radiation dose limit for frequent and infrequent exposures?
A
Frequent: 1 mSv/year (or 0.02 mSv/hr). Infrequent: 5 mSv/year
16
Q
What is an unrestricted area?
A
Area not controlled by radiation safety officer due to low levels of radiation; Examples include the waiting room, file room, office, nonradiation lab
17
Q
What are the different levels of restricted areas?
A
Radiation area, high radiation area, and very high radiation areas
18
Q
What is the dose limit in an unrestricted (uncontrolled) area?
A
Must be < 0.02 mSv/hr (and < 1mSv/7 consecutive days; or < 5 mSv/year) => Think frequent general public radiation exposure limits
19
Q
What is a restricted area?
A
Occupational exposure area under supervision by the radiation protection officer due to certain levels of radiation exposure
20
Q
What is the dose threshold for a restricted (controlled) area?
A
> 0.02 mSv/hr (and > 1 mSv/7 consecutive days or 50 mSv/yr) => Think occupational radiation exposure limits
21
Q
What radiation level defines a “radiation area”?
A
Possible excess of 0.05 mSv/hr @ 30 cm
22
Q
What radiation level defines a “high radiation area”?
A
Possible excess of 1 mSv/hr @ 30 cm
23
Q
When are personal dosimeters needed?
A
Used on individuals who are likely to receive in excess of 10% of the allowable occupational dose limits.
24
Q
What does CFR 19 cover?
A
Inspections
25
What does CFR 20 cover?
Radiation worker protection
26
What does CFR 35 cover?
Medical uses of radioisotopes
27
What detector is sensitive but cannot handle high radiation doses?
Geiger-Mueller counter
28
How often should a Geiger-Muller counter be calibrated?
Annually
29
What is the max dose of a Geiger-Mueller counter can reliably detect?
100 mR/hr
30
What does a Geiger-Mueller counter detect?
Alpha, beta, gamma, etc. radiation
31
How does an ionization chamber differ from a G-M counter?
An ionization chamber can handle higher radiation levels
32
In what setting is a well-counter used, which has a mid-level sensitivity between G-M and ionization chamber and is therefore good for medium amounts of radiation?
For wipe tests
33
How does a well counter work?
It s a single photomultiplier tube, i.e. it uses a scintillation crystal.
34
Why do you have to specify what radionuclide is in the dose calibrator?
Some radionuclides have multiple gamma emissions per decay which would alter apparent activity unless the computer expects this
35
How often is dose calibrator constancy assessed?
Daily; max error +/-5%
36
What do you use for contancy testing?
Co-57 (2-5 mCi, 122 keV, 270 day half-life) or Cs-137 (100-200 uCi, 662 keV)
37
How often is dose calibrator linearity assessed?
Quarterly; max error +/-5%
38
What does linearity mean?
Accurate readings over a whole spectrum of activity levels (high to low)
39
How often is dose calibrator accuracy assessed?
Annually; max error +/-5%
40
What is accuracy?
Measuring a dose on the machine gives a reading in mCi equivalent to what the known standard value should read
41
How often is dose calibrator geometry assessed?
Upon repair or when the unit is moved; max error +/-5%
42
What is geometry?
Potential differences in measuring counts in a vial (which is placed at the bottom of the well) versus syringe (in the syringe holder higher up in the well)
43
Do dose calibrators contain sodium iodine scintillation crystals?
No
44
How often is extrinsic gamma camera uniformity assessed?
Daily with a flood
45
What is the upper limit of non-uniformity?
2-5% on a gamma camera or must be \<1% on SPECT
46
What is the difference between intrinsic versus extrinsic uniformity?
Intrinsic is without a collimator; extrinsic is with the collimator.
47
How often is intrinsic uniformity tested?
Weekly with a point source, collimator removed.
48
What do you use to perform uniformity testing?
A Tc-99m water mixture (tank for extrinsic, less common, more problems; syringe "point" source for intrinsic) or a Co-57 flood source (sheet for extrinsic or point source for intrinsic)
49
What are the components that effect uniformity
Detector uniformity of response (intrinsic uniformity), collimator integrity (extrinsic uniformity), and the quality of the analog/digital signal conversions at the camera–computer interface
50
What is the most common non-uniformity artifact in SPECT?
Ring artifact
51
How often is the gamma camera photopeak calibrated?
Daily, automatic on the camera
52
How often is gamma camera spatial resolution and image linearity (not energy linearity) checked?
Weekly
53
What is used to perform weekly spatial resolution and image linearity gamma camera testing?
Quadrant bar phantom between the detector and a Co-57 sheet
54
What is the difference between spatial resolution and image linearity in the context of the quadrant bar phantom test?
Linearity: lines are straight versus spatial resolution: distinguishing individual small lines
55
How often is gamma camera center of rotation testing performed?
Weekly
56
If center of rotation is off, what is a classic resulting artifact?
Donut artifact (360 degree rotation, point source); tuning fork artifact (180 degree rotation)
57
What energy range defines a low energy collimator?
\< 200 keV
58
What radionuclides use a low energy collimator?
Tc-99m, I-123, Xe-133, and Tl-201
59
What energy range defines a medium energy collimator?
200-400 keV
60
What radionuclides use a medium energy collimator?
Ga-67 and In-111
61
What energy range defines a high energy collimator?
\> 400 keV
62
What radionuclides use a high energy collimator?
I-131
63
In comparing high versus low energy collimators, describe the septa height and spacing?
High energy: long thick septa with widely spaced holes (spacing counter balances septa construction preserving some sensitivity); Low energy: short thin septa closely spaced (spacing preserves resolution in light of sensitive septa contruction)
64
What is the most commonly used collimator?
Low energy and high resolution
65
What is the point of a callimator?
Obtain spatial localization
66
In contradistinction, how does PET obtain spatial localization?
Coincident registration
67
How would a collimation defect appear on a gamma camera?
Linear defect
68
Describe the porportionality between the sensitivity of the collimator to spatial resolution of the collimator?
Inversely proportion
69
When might a highly sensitive collimator be important to use?
In short imaging time sequences such as dynamic imaging
70
What is the effect of distance on sensitivity versus spatial resolution?
Distance does NOT effect sensitivity (despite inverse square law more of the body is included in the detector s field of view so net counts is unchanged); distance DECREASES spatial resolution
71
Where should the collimator-detector be placed in relation to the patient (far or close)?
As close as possible
72
What effect on spatial resolution does moving closer to parallel hole collimator do?
Increases resolution
73
What is star artifact and why does it occur?
Star artifact looks like beams emanating from a hot spot; occurs due to septal penetration of high energy gamma rays due to inappropriately low energy collimator being used, especially happens when imaging I-131 post-treatment thyroid bed
74
What happens when your gamma camera window is too wide?
Terrible image due to image inclusive of scatter
75
What happens when your pulse height analyzer is incorrect?
Too much scatter!
76
What is one advantage of dual head gamma camera?
Decreased scan time
77
What is the advantage of SPECT over planar gamma camera?
Better contrast resolution (due to less overlap of tissues)
78
What is an approximate estimate of the sensitivity of PET in comparison to SPECT?
PET is 10-20x more sensitive
79
Regarding the appearance of the scan, what organs are hotter on the non-attenuation corrected images?
Skin and lungs
80
What is the difference between 2D and 3D PET?
2D excludes scatter using septa in addition to coincident timing; 3D excludes scatter by coincident timing along
81
What is the purpose of time-of-flight in PET?
Improve spatial resolution and contrast
82
What is normalization testing for PET?
Normalizes detectors using point source
83
How often is normalization performed?
Monthly
84
How often does a "blank scan" need to be performed?
Daily
85
What is a "blank scan" used for and how is it performed?
Used to zero the scanner using the scanner s own transmission source; nothing is in the scanner when it s performed
86
How are SUV values effected in an obese person?
SUV values are falsely high, i.e overestimated. Using lean body mass can be used to overcome this limitation
87
In the case of truncation of CT data due to an extremely large person partially outside the field of view, how will this effect SUV?
Falsely lower SUVs, in contradistinction to the above abberation in SUV
88
What is the effect of when an FDG-PET scan is performed, i.e. time since injection of FDG?
Increasing SUV values over time when scanned later (e.g. @ 1 hour SUVs will be lower than @ 2 hours; increases to a point obviously limited by half-life)
89
What is the molybdenum breakthrough limit in a molybdenum-technetium generator?
0.15 uCi Mo/1 mCi Tc at the time of administration (amount of Mo @ time of elution does NOT matter); holds true also for 0.15 kBq Mo/1 MBq Tc
90
Which is assessed for first in Mo breakthrough testing, Mo or Tc?
Molybdenum
91
What are the gamma emmisions of Mo?
181, 740, 780 keV
92
When is Mo breakthrough measured?
With EVERY generator elution; due to longer Mo half-life in comparison to Tc, an elution that is Mo breakthrough compliant may no longer be compliant @ the time of administration, hence why time of administration is key in this regulation
93
What are the radiochemical purities mandated?
\>95% for Tc-pertechnetate, \>92% for Tc-MAA and \>91% for other Tc agents
94
How do you test for radiochemical purity?
Thin Layer Chromatography
95
What does TLC detect?
Free tecnetium
96
Where is the free tech on TLC?
Front on the acetone and origin on saline
97
What is a stannous ion?
Tin (II)
98
What is a stannous ion used for?
To reduce free pertechnetate from +7 valence state at elution to a lower valence state to allow binding of the radionuclide to a chemical
99
How do unwanted radiochemical impurities occur?
Insufficient stannous ion (Tc not reduced sufficiently), accidental air injection (stannous ion is oxidized to stannic ion by oxygen or sometimes water) or exposure to saline preservatives (hydrolyzed-reduced Tc)
100
What has to happen before Tc-99m can be conjugated to RBC?
It must be reduce with stannous ion, also called tinning
101
How can EXCESS stannous ion appear?
For example, unexpected liver activity in a bone scan
102
What does pyrogen testing assess for and how it is performed?
Endotoxin impurities tested by limulus amebocyte lysate test
103
What is the aluminum breakthrough limit for an elution of Tc-99m?
Must be \<10 ug/mL, performed on every elution
104
Aluminum testing is what kind of purity?
Chemical
105
What test is performed when doing chemical purity testing for Al?
pH
106
What causes clumped hot spots in the lungs on a liver/spleen (sulfur colloid) scan?
Too much aluminum in the Tc-99m
107
When is 95% maximum activity for Mo/Tc generator reached?
24 hours after last elution
108
What does equilibrium mean with regard to a parent/daughter isotope?
When the activity of the daughter is equal to the parent
109
What is transient equilibrium?
When the half-life of daughter \< parent. For example, in the case of Mo/Tc generator, transient equilibrium is reached in 4 half-lives. Activity of the daughter slightly exceeds parent @ equilibrium in a "transient equilibrium" relationship. At this point, both start to slightly decrease in activity.
110
What is secular equilibrium?
Half-life of daughter \<\<\< parent, so the activity of the daughter approaches the parent and stays level
111
What is effective half-life, how is it calculated and how does it compare to physical or biologic half-lives?
Accounts for both physical and biologic half-lives; 1/Te=1/Tp+1/Tb; Te is always less than the smaller of either Tp or Tb.
112
Which are usually carrier free, isotopes created by neutron bombardment or by cyclotron production?
Cyclotron produced radionuclides
113
Are fission products known for being carrier free?
Yes
114
How do isotopes differ from one another?
Same protons but different neutrons
115
How do isomers differ?
Different energy, but same number of protons and neutrons
116
How do isotones differ?
Same number of neutrons but different protons and different atomic number
117
How do isobars differ?
Same atomic number (protons + neutrons) but different numbers of protons and different numbers of neutrons
118
What is the most a dose can differ from the prescribed radioactive dose?
20% (10% in some agreement states)
119
What qualifies as a medical event and needs to be reported?
1) Wrong patient, wrong radiopharmaceutical, wrong route, wrong dose (\>20%) or dose to wrong site of body resulting in \>50% excess to the body part than otherwise expected for appropriate administration AND (must ALSO result in) 2) HARM to the patient, i.e. a whole body dose \> 50 mSv or organ/extremity dose \> 500 mSv
120
If the "harm to the patient" dose levels are not met, what then?
It is a recordable but not reportable event
121
What do you have to do in a medically reportable event?
Call the referring doctor, call the NRC/state if agreement state, call the patient, write a letter to the NRC within 15 days
122
What do you have to do for a recordable event?
Keep record for 3 years; institutional review
123
How many days are given to submit a written report to the NRC when a medical event occurs?
15 days
124
What is a MINOR spill?
\< 100 mCi of Th-201 or Tc-99m; \< 10 mCi Ga-67, In-111, I-123; \< 1 mCi I-131
125
What is a MAJOR spill?
\> 100 mCi of Th-201 or Tc-99m; \> 10 mCi Ga-67, In-111, I-123; \> 1 mCi I-131
126
What do you have to do for a minor spill?
Clean it up
127
What do you have to do for a major spill?
Don t clean it up; Call the radiation safety officer
128
How long do you have to keep radioactive waste?
Approximately 10 half-lives i.e. when indistinguishable from background radiation
129
What is the frequency of an ambient radiation survey?
Daily, end of the work day
130
Name two radionuclides made with generators?
Tc-99m and Rb-82
131
When is a writtern directive from the authorized user required?
Anytime \>30 uCi of I-131 is administered or any therapeutic radioactive material
132
Written instructions are given to a patient after being dosed with I-131 given the possible radiation exposure to others with the goal of the patient keeping exposure to others below certain threshold to the general public. What is this level?
Written instructions given to the patient on avoiding others if the potential exists for an exposure in excess of 1 mSv to the general public.
133
What are the threshold levels for release after therapeutic I-131 administration?
The patient may be released when any one is met 1) A calculated level of potential exposure to other people is \< 5 mSv to any individual 2) Actual activity measures \< 0.07 mSv/hr @ 1 meter (\< 7 mrem/hr) measure by a G-M counter or 3) An oral dose of \< 33 mCi was administered.
134
Are outpatients actually measured before they leave our department?
Not if the expected (calculated) exposure is \< 5mSv to any individual
135
Is there a dose limit to the caregiver of an individual who received I-131?
No regulated dose limit for caregiver, only that which does not cause health problems.
136
On average, how much higher is a retreatment dose of I-131 in comparison to the initial dose?
50% higher
137
When is recombinant TSH used (thyrogen)?
Pre-treatment with I-131 to prime uptake
138
What radiotracers can you use to perform thyroid imaging?
Tc-99m pertechnetate and I-123; I-131 less commonly but done sometimes in preparation for; imaging is always does after I-131 treatment which uses the gamma rays emitted by I-131
139
How does the thyroid treat Tc-pertechnetate versus Iodine?
Technetium pertechnetate is trapped but not organified; Iodine is trapped and organified.
140
What is normal thyroid uptake on I-123 or I-131?
10-30% @ 24 hours
141
What scan most effectively images medullary thyroid CA?
In-111 pentetriotide (and second to that FDG-PET)
142
What is suspected if you see brain or kidneys in the perfusion portion of a V/Q scan?
Right to left shunt is present (in the heart or lungs)
143
What radiopharmaceuticals can be used for V/Q?
Xe-133 gas or Tc-99m DTPA for ventilation; Only Tc-99m MAA for perfusion.
144
With what radiotracer can you do ventilation washout imaging?
Only Xenon
145
What criteria are used to assess V/Q scans for PE?
Modified PIOPED II
146
How do you diagnose a PE using the modified PIOPED II criteria?
Using the modified PIOPED II criteria, two or more large V/Q mismatches are needed to make a determination of PE present. There are limited specific criteria used to make a determination of PE-absent (very low probability or a normal scan). All other findings are nondiagnostic.
147
What renal agents are used for functional imaging and what are used for structural imaging?
DTPA and MAG3 for function; DMSA for structure
148
What is the appearance of pyelonephritis on a renal scan?
Perfusion on a functional renal scan can be normal; focal or diffuse photopenic defect may be seen in structural renal imaging
149
How will ATN appear on functional renal imaging?
Normal perfusion but poor excretion
150
When is lasix given and why?
20 minutes into a functional renal scan in the setting of retained tracer in the renal pelvis (i.e. obstruction versus dilated collecting system)
151
Why is an ACEi given in specific renal scans?
To assess for renal artery stenosis
152
What would be seen in an ACEi provocation renal scan?
Delayed perfusion of a kidney with prolonged retention
153
Describe the liquid gastric emptying curve.
Liquid empties exponentially
154
What is the cause of a medially displaced liver from the ribs on sulfur-colloid scan?
Ascites usually in the setting of chronic liver dysfunction (cirrhosis)
155
Name the intrathecal radiotracers.
In-111 DTPA or Tc-99m DTPA.
156
Which is preferred, an exercise or pharmacologic stress test?
Exercise
157
What medications can be used in a pharmacologic stress test?
Vasodilators (dipyridamole, adenosine, or regadenson) or dobutamine
158
What are the contraindications to vasodilator stress tests?
Severe obstructive airway disease, high-grade heart block (2nd- or 3rd-degree atrioventricular (AV) block without a pacemaker or sick sinus syndrome), arterial hypotension, recent caffeine ingestion, or dipyridamole or theophylline containing medications.
159
What are the contraindications for dobutamine stress tests?
Cardiac issues (e.g. critical aortic stenosis, hypertrophic cardiomyopathy, uncontrolled hypertension, uncontrolled atrial fibrillation, known severe ventricular arrhythmias) and disorders in potassium homeostasis
160
Concerning vasodilators, what are the indications for stress testing?
Patients who are taking a beta blocker, calcium channel blocker, or have a pacemaker and cannot achieve the required target heart rate (85% of maximum predicted heart rate) should undergo a pharmacologic stress in lieu of an exercise stress.
161
What is dipyridamole?
Inhibits breakdown of adenosine, indirectly causing vasodilatation through prolonging lifespan of endogenous adenosine
162
What is regadenoson?
Selective A2a receptor agonist, which is a vasodilator
163
What is the antedote to adenosine and/or dipyridamole?
Aminophylline (caution: its half-life is shorter than dipyridamole)
164
What is dobutamine?
Beta 1 agonist increasing heart rate and contractility (chronotrope and inotrope)
165
When is dobutamine contraindicated?
Severe aortic stenosis
166
What medication is contraindicated for a dobutamine stress?
Beta-blockers (would block it s action)
167
How do you reverse dobutamine?
Beta-blockers
168
What is the signficance of normal wall motion with an apparent perfusion defect?
Think something other than ischemia (e.g. artifact like attenuation)
169
Where does the breast classically cause attenutation defects?
Anterior or lateral wall
170
How would left bundle branch block present on a myocardial perfusion test?
Can cause a false-positive reversible septal perfusion defect with exercise; therefore a pharmacologic stress is preferred.
171
What is the reason for an apparent defect when there is adjacent extra-cardiac activity (e.g. inferior wall defect with adjacent liver/bowel activity?
It is the result of filtered back projection using a ramp filter
172
A similar result is seen due to the diaphragm but the diaphragm is not hot unlike liver/bowel. Why does this occur?
Attenuation; overcome by attenuation correction or prone imaging
173
What does transient ischemic dilatation (TID) suggest?
Severe or multivessel disease
174
What is the TID cutoff ratio?
1.4
175
What would be a cause of apparent left ventricular wall divergence toward the apex with an apical defect?
Left ventricular aneurysm
176
Which has less attenuation, Th or Tc cardiac studies?
Tc due to higher energy gamma rays
177
Which requires active transport into cells, Th or Tc cardiac agents?
Th (N/K ATPase pump) versus Tc agents rely on passive diffusion into mitochondria
178
Which needs to be imaged immediately after injection (in the stress portion of a study)?
Th because it redistributes; Tc images acquired 30-90 minutes after (lungs back to nl volume, liver activity cleared but not yet to transverse colon)
179
What does a matched true defect represent on a Tc cardiac study?
Either infarct or hibernating myocardium
180
In a cardiac PET, what does F-18 FDG uptake in an area of absent myocardial perfusion suggest (such as seen previously on Tc-Sestamibi)?
Anaerobic utilization of the radioactive glucose due to viabile myocardium in the setting of hibernating myocardium (i.e. NOT infarct)
181
How do you calculate EF for a MUGA?
(ED counts-ES counts)/(ED counts-background counts) x 100 = %
182
What background activity will make EF falsely HIGH on MUGA?
High background
183
What background activity will make EF falsely LOW on MUGA?
Low background
184
Inclusion of what organ can commonly falsely alter background counts in a MUGA study?
An error can occur if the processing includes counts from the spleen.
185
On a MUGA scan, drawing the background ROI over the spleen will do what?
Falsely elevated EF
186
What classically causes a photopenic halo on a MUGA?
Pericardial effusion
187
What medication is used for cerebrovascular reserve?
Acetazolamide
188
What does an acetazolamide cerebral flow reserve study distinguish?
Vascular versus another cause of dementia
189
How is a balloon occlusion test performed for cerebral flow reserve testing?
The carotid is occluded to evaluate for collateral cerebral blood flow/reserve; if sx occur inject Tc immediately, if no sx occur inject 5 min prior to deflation of the balloon.
190
What two scans are useful in sarcoid?
Ga-67 and FDG-PET
191
What s the sign associated with sarcoid in the chest on Ga-67?
Lambda sign
192
After intraarterial injection of Y-90 theraspheres, what imaging is done?
Brehmstralung liver imaging to evaluate for lung shunt fraction, a potential contraindication to treatment
193
What does Y-90 emit?
Beta particles (negatively charged electrons)
194
What then creates the brehmstralung radiation in a Y-90 Brehmstralung scan?
The electrons by brehmstralung interactions in the patient forming x-rays
195
What scans are helpful in distinguishing CNS toxoplasmosis from CNS lymphoma?
Th-201 and Ga-67: Toxoplasmosis will be cold on Th but hot on Ga (Similar to PCP/PJP); Lymphoma will be hot on Th AND Ga (Unlike Kaposi s which is hot only on Th but cold on Ga).
196
What agent/agents could be used for ictal imaging?
Tc-99m ECD or HMPAO, lipophilic brain agents
197
Which is more sensitive a test, ictal or interictal?
Ictal
198
What might the underlying pathology be when increased soft tissue uptake is seen in the lower extremity (one or both) on a bone scan?
Diffuse lymphedema or IVC obstruction
199
You see a solitary lesion in rib or elsewhere on PET for mets. Is it a met or not?
Likelihood of a met is 15-20% of cases overall. If it were actually a met, usually it would be in the spine. \< 10% of the time does it represent a met when the solitary lesion is in a rib and usually these are more longitudinally oriented in the rib.
200
Significance of heart activity on bone scan?
amyloidosis, myocarditis, pericarditis, prior myocardial infarction, or previously administered radiopharmaceutical.
201
What scans should be considered in the setting of an orthopedic prosthesis when the ddx is infection versus aseptic loosening?
Tc-99m sulfur colloid (to look for normal marrow, cold in infx), Tc-99m MDP (non-specific for any reactionary change but helpful if totally negative), and Indium-111 (hot in normal marrow or infection, helpful? maybe in septic arthritis)
202
What are distinguishes peri-prothetic infection versus loosening?
Both appear hot on Indium-111 oxime WBC scan, but only aseptic loosening will be hot on Tc-99 sulfur colloid. Bone scan hot in either, so only helpful if cold ruling out both etiologies as source of pain.
203
What does prominent renal cortical activity on a bone scan suggest?
Hemochromatosis
204
What don t you see in a superscan?
Kidneys and bladder (also less soft tissue)
205
What are the causes of a superscan?
Diffuse mets (prostate and breast, skull possibly not as stunningly hot) or metabolic (hyperparathyroidism, Paget s, thyrotoxicosis, and renal osteodystrophy; skull markedly hot)
206
What is Prostacint?
In-111 capromab which is an antibody to PSA, does NOT pick up bone mets, used AFTER bone scan to look for soft tissue mets
207
What are the three radiopharmaceuticals used for therapeutic reasons for bone pain caused by mets?
Sr-82 (Strontium)-Chloride [Metastron, pure beta emitter, high myelotoxicity, 50 DAY half life], Sa-153 (Samarium)-EDTMP [Quadramet, beta and gamma emitter, transient bone marrow suppression, 46 hour half life], and Ra-223 (Radium)-dichloride [Xofigo, alpha emitter and minimal gamma, GI excretion rather than renal, less hematologic toxicity although more diarrhea/nausea/vomiting/bone pain, 64 hour half life]
208
Which therapeutic radiopharmaceutical improves survival?
Ra-223 dichloride
209
Absolute contraindications for treatment with Sr-82 or Sa-153?
For Sr 82-Cl and Sa 152-EDTMP: pregnancy, breast feeding, and GFR \<30, and possibly extensive (superscan level) mets [although this is controversial]
210
What scans are known for having a hot spleen?
In-111 WBC and In-111 pentetriotide scans (Both In-111 scans!)
211
What does renal uptake on a liver/spleen scan suggest?
CHF
212
What does renal transplant uptake on a liver/spleen scan suggest?
Rejection
213
How might renal cancer activity on PET appear?
Variable, can be hypermetabolic but known for being HYPOmetabolic. For instance, an oncocytoma is known for being hot and clear cell RCC is known for being cold.
214
What is peculiar about a lymphoscintigraphy study (i.e. how does it look)?
Co-57 flood source behind patient, soft tissues photopenic, nodes hot
215
What is the radiotracer of choice for neuroblastoma imaging?
I-123 MIBG
216
What is the radiotracer of choice for pheochromocytoma imaging?
I-123 MIBG
217
What is Lugol s solution?
Potassium iodide
218
Why is Lugol s solution given?
To suppress thyroid uptake
219
When is Lugol s solution used?
Prior to I-123 MIBG scan
220
What does a salivagram detect?
Aspiration; a salivagram is DIFFERENT than salivary gland scintigraphy (parenchymal and excretory function of glands)
221
What is dacryscintigraphy?
Tc-99m pertechnetate drops in the eye; normal flow into nasal cavity if nasolacrimal duct not occluded at medial canthus
222
What is the rate of bleeding necessary for detection on angio and on a GI bleeding scan?
Angio: 1 mL/min. Tagged RBC: 0.1 mL/min.
223
At what size should a PET/CT be considered in the evaluation of a solitary solid pulmonary nodule?
\> 8 mm
224
What is the spatial resolution limit of PET?
5-8 mm
