Nuclear - Test Review Flashcards

Question

What is the effective annual dose limit for the public, infrequent exposure?

Answer 1

**1 mSv (100 mRem or 0.1 Rem)**

Answer 2

**ischemia** * patients are imaged a while after stress so the EF recovers

Answer 3

**radiotracer half-life** * shorter half life --\> lower Sv * don't pick lower mCi administered

Answer 4

**Tc99m Sestamibi**

Answer 5

someone must receive it

Answer 6

**Tc99m (Sestamibi)**

Answer 7

**0.111** I₁(d₁)² = I₂(d₂)² 1 = I₂(9) 1 / 9 = I₂ I₂ = 0.1111 * **Inverse square law** * intensity (exposure, I₁) = 1 / d² * I₁(d₁)² = I₂(d₂)²

Answer 8

**I₁ (d₁)² = I₂ (d₂)²**

Answer 9

**mitochondria**

Answer 10

ionization chamber

Answer 11

**papillary muscle**

Answer 12

overestimated LVEF

Answer 13

progressive disease of the RI ## Footnote \*\*\*Diagonal not a choice

Answer 14

**coronary angiogram**

Answer 15

uniform labeling of the blood pool

Answer 16

at the face of the collimator

Answer 17

when activity is **similar to background radiation**

Answer 18

one with the highest frequency allowed

Answer 19

* Sensitivity and Counts --\> remain the same * Resolution --\> **decreases**

Answer 20

Stannous pyrophosphate given **~20 minutes** prior to Tc99m pertechnetate

Answer 21

Paradoxical septal motion prior open heart surgery

Answer 22

**Post-referral bias** * occurs when patients with abnormal stress test results are referred to cardiac catheterization at a higher rate than are patients with normal stress test results

Answer 23

1. O15 2. N13

Answer 24

* Perfusion abnormalities * Diastolic Dysfunction * Strain abnormalities * Systolic dysfunction * EKG abnormalities * Angina

Answer 25

Infarct; Ischemia; Stunning; **Area at risk**.???

Answer 26

**Linear scale**

Answer 27

* gradual changes in uptake are seen better than when using sigmoidal (nonliear scales) * small defects may be missed

Answer 28

regions with lower count density (RV) * not used for evaluation of regional differences in LV tracer uptake

Answer 29

**Partial volume averaging** * basis of assessing thickening of myocardial segments is based on the brightening between end-diastolic to end-systolic images related to partial-volume effect reflective of the limitations of spatial resolution of the gamma camera * This results in relative increase in count intensity manifested as brightening used by different vendor programs to quantitate degree of thickening

Answer 30

**lower cost** * END study * showed that cost was significantly reduced in those who underwent cath-only based on MPI results * direct catheterization group --\> * same mortality * higher cost

Answer 31

**5 minutes** * maximum vasodilation of dipyridamole is 287 +/- 101 seconds * radiotracer injection should not be injected until 3-5 minutes following dipyridamole injection

Answer 32

* **Clinician feedback regarding performance** * Clinical decision support tools * probably the most powerful

Answer 33

**decrease the counts per frame** * because the set number of counts are divided into double the number of frames * there is a decrease in the counts per frame

Answer 34

* Temporal resolution --\> **increase** * ****more points sampled over a period of time * Spatial Resolution --\> **unchanged** * Counts per frame --\> **decrease** * ****set number of counts divided by a double number of frames * Ejection fraction --\> **increase**

Answer 35

**discharge and plan elective outpatient stress imaging** * Resting images --\> no perfusion defects * while having active chest pain --\> nonischemic etiology

Answer 36

**ERASE** * normal perfusion --\> very low event rate * can be safely and quickly triaged for discharge

Answer 37

* Collimator --\> **Low-energy, High-Resolution (LEHR) collimator** * Seconds per step --\> **20s / step** * Energy window on PHA --\> **20% energy window** * Frames per cardiac cycle --\> **8 frames per cardiac cycle**

Answer 38

**cardiac catheterization** * SPECT: perfusion abnormalities in septum from base to apex * likely proximal LAD disease * Exercise capacity good but EKG changes of ischemia * patient training for a high-intensity event

Answer 39

**24 hours** * half-life = 6 hours * 4 half lives = 24 hours * this number of half-lives should elapse between studies with similar tracers

Answer 40

**B - 49 yo DM male with atypical CP and CAC \> 100** * appropriate to perform a seqeuential stress RNI for those patients with a prior abnormal CCT calcium and agtston \> 100

Answer 41

**Partial volume effects** * Hayat et al. study * patients with LBBB + no CAD --\> reduced septal thickness and thickening compared to posterior wall * resting MBF was preserved * **partial volume effects** + limited spatial resolution of SPECT (10-12mm) --\> areas with end-diastolic thickness \< 10 mm show perfusion defects * as the count intensity changes in systole dictates thickening assessment, asymmetric reductions in septal thickening during systole observed in LBBB reduced recovery coefficients of detected counts --\> accounts for the septal defect at rest unrelated to HR

Answer 42

* Exercise --\> **reversible** septal defect * HR related decrease in blood flow * Vasodilator --\> **fixed** septal defect * partial volume effects + decreased spatial resolution

Answer 43

**Incidence of diaphragmatic attenuation** * likely due to higher resolution of the cameras and artifact associated with breathing * respiratory gating has been shown to help

Answer 44

* ATTR --\> **Tc99m pyrophosphate (PYP)** * AL --\> **F18 florbetapir** * ****taken up by both AL and ATTR amyloid but cannot distinguish between the two

Answer 45

**coronary arterioles** * most responsive as they possess smooth muscle * venules have less vasodilatory capacity and capillaries do not possess smooth muscle

Answer 46

* at rest approximately **90% of myocardial blood volume is in capillaries** and * **capillary resistance** is the primary determinant of coronary vascular resistance * Perfusion defects (on SPECT) are primarily felt to be related to elevation of capillary resistance and reduction in myocardial blood volume at the capillary level * This leads to reduced isotope uptake due to capillary decruitment, which happens in response to epicardial coronary stenosis

Answer 47

**C - 55 yo woman, BMI 44, no cardiac history, new SOB** * 2 day protocol is best used in the patient with large body habitus where high-dose stress-and-rest imaging could provide image quality for diagnostic purposes * mainly reserved for large BMI

Answer 48

**B - 2 day high-dose stress, high-dose rest exercise MPI** * No limitations for exercise * Imaging is appropriate --\> baseline ST, T changes * High BMI ( **\> 35** ) --\> 2-day high/high is protocol is recommended

Answer 49

**D - asymptomatic woman with anomalous RCA from left cusp with interarterial course** * interarterial course --\> high risk for sudden death * recommend evaluating for provocable ischemia with imaging

Answer 50

**no testing** * chronic stable angina + mild ischemia (on SPECT) + no change in symptomatology --\> **continue medical management**

Answer 51

**D - 70 yo male with typical angina, weighs 320 lbs** * stress imaging is usually performed on day 1, so rest imaging can be avoided if the stress study is normal * patients with prior MI, known CAD, LV dysfunction are not optimal candidates for stress-first imaging given expected higher frequency of abnormal test results

Answer 52

**\> 250 pounds and/or BMI \< 35 (generally)**

Answer 53

if normal --\> can avoid rest imaging

Answer 54

* prior MI * known CAD * LV dysfunction \*\*\*\*not optimal candidates for stress-first imaging given expected higher frequency of abnormal test results

Answer 55

* SPECT findings: * **marked flattening of the septum (Movahed's sign)** --\> related to RV/LV interdependence * **RV strain** * no significant LV perfusion defects * **CT scan of chest**

Answer 56

**partial volume effect** * there is a relatively linear relationship between myocardial counts and thickening --\> time activity curve of the myocardium is essentially a thickening curve * The low fidelity curve derived from 8-16 time points is transformed into a continuous thickening curve by Fourier transformation * Phase analysis of curves derived from different myocardial regions is then used to measure dyssyncrhony (regional variation in mechanical activation).

Answer 57

**H/M \< 1.60**

Answer 58

**cost of CZT SPECT technology** * up front hardware cost is greater than traditional cameras * higher efficiency and speed of imaging likely makes this approach more cost effective

Answer 59

* Higher energy efficiency * Higher sensitivity * Higher spatial resolution * similar to PET * Ability to perform ultra low-dose imaging protocols * high diagnostic accuracy for detection of CAD in morbidly obese patients

Answer 60

**60 seconds**

Answer 61

**depth-dependent image blurring** * by decompensating for the loss of resolution with increasing depth from the face of a parallel-hole collimator

Answer 62

**Avoid ramp filter artifact** * ramp filter is not applied in iterative reconstruction

Answer 63

* uses image-modeling physics to update image reconstruction and * considers depth-dependent loss of resolution and scatter

Answer 64

* Bronchoconstriction * CVA (stroke) * Seizures * Myocardial ischemia * A-fib / A-flutter * SA / AV nodal block * Hypersensitivity (including anaphylaxis) * Hypotension * Hypertension

Answer 65

**B - may be appropriate** * based on: * 1-2 clinical risk factors (DM and TIA) * \< 4 METS for the last 12 months * intermediate risk surgery

Answer 66

**30-60 minutes** * cleared by the hepatobiliary system * take 30-60 minutes to reach desired **1:1 heart-to-liver ratio**

Answer 67

**\< 10 minutes** * cleared by the kidneys * must be imaged \< 10 minutes of injection due to redistribution

Answer 68

**reach the desired heart-to-liver ratio faster** * due to redistribution of splanchnic blood flow to skeletal muscles

Answer 69

introduces more scatter and noise

Answer 70

**limited ability to be extracted by the myocardium at high flow rates**

Answer 71

**B** * Tl201 has a more linear relationship with myocardial blood flow and higher tracer uptake than Tc99m with either sestamibi or tetrofosmin

Answer 72

1. O15 2. Tc99m Teboroxime 3. Tl201 4. N13 5. Rb82 6. Tc99m-sestamibi 7. Tc99m-tetrofosmin

Answer 73

**Misregistration**

Answer 74

**cardiac catheterization** * SPECT study: normal * Stress EKG: grossly abnormal * submaximal stress * High risk features on EKG * ST elevation in VR and V1 * chest pain with exertion

Answer 75

**apyrogenicity** * allergic reaction typically caused by the presence of a pyrogen * pyrogens include * proteins or polysaccharide produced from metabolism of microbes

Answer 76

presence of an additional radionuclide that does not cause an immediate reaction but may expose the patient to a significantly high radiation dose

Answer 77

consists of the presence of unwated chemicals * such as aluminum breakthrough from the Mo99 generator * does not cause an immediate reaction

Answer 78

**2 mR/hr** * I₁(d₁)² = I₂ (d₂)² * 32 (1)² = I₂ (2)² * I2 = 32/4 = 8 * 8 mm = 2 HVL (at 4mm) * 8 mR/hr \* 1/2 \* 1/2 = **2 mR/hr**

Answer 79

**decreases by 1** * proton is converted into a neutron (beta+ decay)

Answer 80

**higher frequency filter** * Butterworth is a low pass filter --\> allows low frequency to pass through * noise = high frequency

Answer 81

**Allows high frequency to pass through** * sharpens edges * removes star artifact * may introduce * more noise * ramp filter artifact

Answer 82

Allows low frequencies to pass through * blurs edges * smoothens image

Answer 83

**Resolution decreases** * number of counts --\> unchanged * sensitivity --\> unchanged * field of vision --\> unchanged

Answer 84

* Tl201 --\> **electron capture** * Tc99m --\> **gamma decay**

Answer 85

**110 minutes**

Answer 86

**physical half-life**

Answer 87

1. **Close area and check for self-contamination** 2. Absorbent material over any spill 3. Shield source if possible (only if can be done without further contamination) 4. Close room and lock or secure area 5. Inform radiation safety officer 6. Survey and decontaminate (use mild soap...luke-warm water...surgical sponge)

Answer 88

1. NOTIFY all persons in area a spill has occurred 2. PREVENT - cover with absorben paper 3. CLEAN - using gloves, tongs (remote handling) 4. SURVEY - check spill and personnel 5. RESPORT to RSO

Answer 89

* Tc99m --\> **100 mCi** * Tl201 --\> **100 mCi** * I123 --\> **10 mCi**

Answer 90

conincidence imaging

Answer 91

**saline**

Answer 92

**LVEF = ED counts - ES counts / ED counts - background counts** * LVEF = 15 / 22 = 68%

Answer 93

**Pertechnetate contamination**

Answer 94

* 0.7 - 1.2 mL/min/g * parallels tissue O2 consumption * Myocardial perfusion reserve \> 2 * 1-year risk of cardiac death or MI is significantly lower

Answer 95

**Inducibe ischemia in RCA distribution** * reversible prfusion defect consistent with stress-induced ischemia in the inferior and basal inferoseptal region

Answer 96

**Severe perfusion defect in LAD distribution, with minimal reversibility on the rest images** * Perfusion defects of apical, apical septal, and apical anterior segments * No hypoperfused myocardial regions with enhanced FDG uptake to suggest myocardial hibernation

Answer 97

**Left Cfx** * Perfusion defects * moderately severe lateral wall defect extending from the apex to the midcavity * TID 1.33 - increased * Angiography --\> 70% stenosis in large OM1

Answer 98

**D - Dual-isotope Tl201 / Tc99m** * Tl 201 given in 3-4 mCi dose with 72 hour half life --\> **~27 mSv of radiation** * other 3 choices will give radiation exposure of \< 15 mSv * MDCT may be as low as 1-2 mSV

Answer 99

**Pericardial Effusion** * lateral and right ventricular halo surrounding the heart on the projection image and can be seen on the HLA image * distended stomach bubble below the heart *

Answer 100

distended stomach bubble below the heart --\> * usually result of giving the patient fluids to get greater separation between the inferior wall and gastric/intestinal activity that may be close to the heart

Answer 101

* **Tc99m pyrophosphate** * retained in areas of healing infarction * has been used to detect infarcts 3-7 days old * **Tc99m Myoscint** * antibody directed to myosin that is exposed following acute damage * detects earlier than Tc99m PYP * **I-123 BMIPP** * fatty acid analog that is not taken up in areas of infarction due to cell damage * areas surrounding ischemia at the the time of infarction also fail to use fatty acids and may overestimate the area of actual infarction

Answer 102

**in vitro** * image shows excellent delineation of the ventricular blood volumes with very low background activity * Based on excellent image quality, "in vitro" method is likely to give the best results and is the best answer

Answer 103

**Stress treadmill EKG** * Low pre-test probability --\> could argue no testing needs to be done * Stress EKG avoids risk of radiation and contrast reactions

Answer 104

**Abnormal due to CFx ischemia** * Images: * moderate perfusion defect involving the entire inferior and inferolateral wall * Angiography: * LIMA-LAD: patent * SVG-CFx: **severe disease** * SVG-RCA: **occluded**

Answer 105

**RCA and CFx infarct and ischemia** * Images: * severe fixed perfusion defect in the inferior and inferolateral wall * reversible peri-infarct ischemia as depicted by semi-quantitative analysis

Answer 106

**No further studies are indicated** * excellent functional capacity * MPI images: * no evidence of ischemia or infarcts * Semi-quantitative analysis of rest/stress images below

Answer 107

**LVEF \< 20%** **extensive remodeling**

Answer 108

* **reasonable test to evaluate for hibernating myocardium** * **better positive and negative predictive value when compared to Tl201 rest/redistribution**

Answer 109

**no advantage of one test over the other** * MA (3,088 patients) * no statistically significant difference in prediction of survival benefit with revascularization was detected between testing methods * Improvement in survival was a function of: * **size of viable myocardium** * **degree of LV dysfunction**

Answer 110

* Higher risk for development of CAD * CV disease is the leading cause of mobidity and mortality in diabetics * Myocardial ischemia is more likely to be silent in diabetics * Diabetic patients who sustain a MI are at higher risk for mortality than nondiabetic patients

Answer 111

**higher CAC score and higher mortality in patients with DM vs. non-DM**

Answer 112

**very low and similar event rates at 5 years** * no further risk stratification is needed * similar in patients with and without DM

Answer 113

**bluted heart rate response compared to patients without DM** * attributed to cardiac autonomic neuropathy

Answer 114

**direct relationship between blood sugar level and HRR**

Answer 115

* increase in the risk of heart failure progression * increased incidence of diastolic dysfunction * increased presence of silent ischemia * impaired myocardial flow reserve

Answer 116

* calcium deposition is a late phenomenon in the atherosclerotic process * reflection of earlier soft plaque rupture and subsequent healing * **High specificity:** indicator of plaque burden * **correlates well with extent of atherosclerotic plaque burden** * **Poor sensitivity**

Answer 117

* CAC provides incremental value for favorable or unfavorable risk stratification as compared to traditional risk factors like FRS * MESA study * this concept has been validated in ethnic minorities * **CAC = 0** * **predicts very low event rates irrespective of other risk factors**

Answer 118

* CAC \> 1,000 --\> **25%** * MPI - very abnormal --\> **7.5%** **\*\*\*\***symptomatic or asymptomatic patients

Answer 119

**complementary in multiple studies** * **normal SPECT MPI** have low event rate irrespective of their calcium score * high risk MPI SPECT + high CAC --\> **mortality 42%** * compared to 30% when only one abnormal

Answer 120

* \< 100 --\> **no events** * \> 400 and \< 1000 --\> **2.9x the event rate for CAC \> 400** * \> 1000 --\> **event rate \> 10%**

Answer 121

* Caffeine * Aminophylline * Theophylline * Dipyridamole * L-arginine (nitrate precursor)

Answer 122

* decrease duration of side effects * decrease liver activity * improve sensitivity to detect ischemia * **provide incremental information about functional capacity**

Answer 123

**Second-degree AV block (4.1%)** * Hypotension (1.8%) * 3rd-degree AV block (0.8%) * Bradycardia (0.2%)

Answer 124

**Chest Pain (20%)**

Answer 125

**Filtered back projection** * use of a ramp filter during filtered back projection reconstruction will result in decreased counts in the wall of the LV closest to the hot area

Answer 126

will lessen the effect of a hot liver or loop of bowel

Answer 127

correction for the loss of resolution the further an object is from the detector * should not influence the counts in an area

Answer 128

* correction for the overrepresentation in counts due to misregistration of counts coming from a hot area close to the heart * will decrease the total counts in the inferior wall

Answer 129

**1-day rest/stress in an obese female patient** * scaling or normalization artifacts occur with greater frequency in **low-count studies** using fixed threshold filtering during reconstruction * **obese patients have greater attenuation resulting in lower counts**, and this effect is greater when doing 1-day studies with split doses as opposed to 2-day studies when equal and higher doses are gien * females have greater anterior wall attenuation due to the presence of breast tissue --\> most likely to result in normalization problems or the creation of hot spots

Answer 130

**Greatest uniformity** * center generally has the greatest unifromity of crystal and PMT's * at the edges of the field, light leaks due to poor contact between the PMTs and the crystal

Answer 131

**not affected - all are generally uniform across the field of view**

Answer 132

**CZT - highest response rate for SPECT** \*\*\*BGO and LSO used in PET

Answer 133

* type of stress * protocol used * gender (or size of the LV)

Answer 134

* Older systems: * Exercise TID --\> **1.14** * Vasodilator TID --\> **1.23** * New (CZT camera) system: * Exercise TID --\> **1.16** * Vasodilator TID --\> **1.29**

Answer 135

* Small FOV cameras * **\> 3,000,000 counts** * Large FOV cameras * **\> 5,000,000 counts**

Answer 136

**quarterly**

Answer 137

**weekly**

Answer 138

**quarterly**

Answer 139

**half-life \< 120 days** * Tc99m, Tl201, F18, Mo99, **Sr89**

Answer 140

**annually** * to ensure that the meter responds appropriately to radiation

Answer 141

**daily** * verifies that the instrument responds to a radioactive **source**

Answer 142

**3 working hours** * should be surveyed and wipe tested withiin 3 hours of receipt if during normal working hours

Answer 143

**surveyed and wipe tested within 3 hours of the next business day**

Answer 144

**collimator (using a)**

Answer 145

**sheet source**

Answer 146

**point souce (without a collimator)**

Answer 147

**at the end of each working day**

Answer 148

they are excreted into the duodenum where they cause scatter if they are close to the heart

Answer 149

**soda** * increases intestinal motility or push the loops of bowel toward the pelvies when the patient is supine during acquisition and gravity causes layering * Food, water and coffee have greater attenuation thatn carbonated beverages (**mixture of liquid and gas causes less attenuation**)

Answer 150

**cancel testing** * diagnose and manage A-fib prior to stress testing * based on patient safety and lack of diagnostic accuracy as there is not a true baseline blood flow measurement * Rest/stress studies should be performed under the same conditions

Answer 151

usually normal * Patients with DM and known CAD --\> may represent higher risk * High risk --\> consider LHC * Low risk --\> medical management

Answer 152

* Hypertension with LVH * especially hypertensive BP response to stress * Differences in HR between rest and stress acquisition * Technical factors related to differences in acquisition, slice selection, tracer doses

Answer 153

**C - Stress Echo** * exercise with nuclear imaging is not the best test due to low specificity associated with **exercise-induced septal perfusion defects** * PET study will give the **lowest radiation exposure** but exercise may still be a problem

Answer 154

**C - insist on repeat imaging** * repeating the study is the best method to get accurate results * already exposed to radiation dose * interpreting the study will not be diagnostic based on the large distance moved * it is not possible to correct for side-to-side or horizontal motio

Answer 155

decreases the total counts

Answer 156

**single-headed small field of view** * Single-headed, SFOV * not generally utilized for SPECT due to long acquisition times * but provide **greatest flexibility for angulation in MUGA studies** * Single-headed, LFOV * extends too far toward the abdomen to allow angulation * Dual-headed systems do not allow optimal positioning of the camera head relative to the patient that permits the best septal view LAO * most are in a fixed 90-degree configuration and do not allow caudal tilt angulation, this limits the rotation

Answer 157

**transmural ischemia** * ST elevations can localize territory of ischemia * **ST depressions --\> do not localize**

Nuclear - Test Review Flashcards

(185 cards)