ST:2

Question 1

Static bone imaging is routinely performed how long after tracer administration to an adult?
(a)30 min

(b) 1 hr
(c) 2-3 hr
(d) 24 hr
(e) 48 hr

Answer 1

(c) Static bone imaging performed with a labeled diphosphonate compound is routinely performed 2-3 hr after tracer administration.

Question 2

Which of the following structures normally does NOT appear as areas of increased activity on the bone images of adults?
(a)phalanges

(b) glenoid fossa
(c) sternoclavicular joints
(d) vertebrae column
(e) anterior iliac crests

Answer 2

(a) On bone images of adults, areas of normally increased tracer activity include all those listed, as well as the sacroiliac, hip, and acromioclavicular joins and vertebral column.

Question 3

Which of the following conditions is visualized on a bone image as a photopenic area?
(a)fracture of the vertebrae column

(b) tracer infiltration
(c) acute myocardial infarction
(d) osteomyelitis
(e) attenuation

Answer 3

(e) A photopenic area is one in which a smaller number of photons is visualized - a “cold” spot. A material that absorbs photons may cause an attenuation artifact - an area of falsely decreased tracer concentration. Jewelry, pocket contents, belt buckles, prostheses, and pacemakers are examples of objects that commonly cause photopenic areas on bone images. Tracer concentration is increased in the area of dose infiltration, acute myocardial infarction, and osteomyelitis.

Question 4

It is safe to block a portion of the pulmonary circulation with MAA particles in patients with suspected pulmonary emboli because the:
(a)number of injected particles is too small to cause harm

(b) particles are made from albumin isolated from human serum
(c) particles are rapidly phagocytized by lung macrophages
(d) number of injected particles blocks only a small number of precapillary arterioles
(e) albumin is denatured before it is made into particles

Answer 4

(d) Less than 1% of the precapillary arterioles are blocked with the MAA particles; therefore, there is no adverse effect on the patient.

Question 5

A nebulizer is used to administer which of the following lung ventilation radiopharmaceuticals?
(a)[81mKr]gas

(b) [133Xe]gas
(c) [99mTc]pentetate
(d) [99mTc]macroaggregated albumin
(e) [99mTc]pertechnetate

Answer 5

(c) A nebulizer is a device that uses ultrasound or pressure to create airborne (aerosol) particles from a liquid. [99mTc]pentetate (DTPA) is introduced into the nebulizer in liquid form. When the nebulizer is activated, the liquid is converted into small radioactive droplets that are inhaled by the patient through tubing connected to the nebulizer.

Question 6

Which of the following radiopharmaceuticals may be used to image acute deep vein thrombosis in the lower extremities?
(a)[99mTc]sulfur collid

(b) [99mTc]macroaggregated albumin
(c) [131I]iobenguane
(d) [111In]oxyquinoline
(e) [99mTc]arcitumomab

Answer 6

(b) [99mTc]MAA is used to image acute deep-vein thrombosis in the lower extremities.

Question 7

In performing radionuclide venography with [99mTc]MAA, the radiopharmaceutical is administered at what site?
(a)dorsal veins on top of each foot

(b) either femoral vein
(c) metacarpal vein
(d) either basilica vein
(e) antecubital area of either arm

Answer 7

(a) The tracer is introduced into the deep venous system of the legs. Therefore, the tracer is administered into the dorsal vein of each foot.

Question 8

After total thyroidectomy, total-body imaging with radioiodine normally will demonstrate tracer concentration in which of the following areas?
(a)liver, lungs, and bones

(b) salivary glands, stomach, and bladder
(c) liver, salivary glands, stomach, and lungs
(d) bladder, liver, and brain
(e) GI tract, bladder, and bones

Answer 8

(b) The salivary glands and saliva in the mouth, the gastric mucosa and its secretions into the intestine, and the urinary bladder are sites that normally concentrate radioiodine. Concentrations in other sites indicate areas of functioning thyroid metastases.

Question 9

A parathyroid adenoma will concentrate which of the following radiopharmaceuticals?
(a)[123I]sodium iodide

(b) [99mTc]pertechnetate
(c) [99mTc]sestamibi
(d) [99mTc]pertechnetate or [99mTc]sestamibi
(e) [99mTc]filtered sulfur colloid

Answer 9

(c) Of the radiopharmaceuticals listed, only [99mTc]sestamibi concentrates in parathyroid tissue. A computer subtraction technique using [99mTc]pertechnetate and [201Tl]thallous chloride has been used to image the parathyroids. [99mTc]pertechnetate concentrates in the thyroid, whereas [201Tl]thallous chloride localizes in both thyroid and parathyroid tissue. In this technique, the [99mTc]pertechnetate image is subtracted from the 201Tl image. The resulting image demonstrates 201Tl concentration in the parathyroids.

Question 10

When positioning a patient for an LAO view of a gated equilibrium ventricular function study, tilting the camera detector toward the patient’s feet separates which two structures?
(a)left ventricle and aorta

(b) right ventricular and aorta
(c) left ventricle and left atrium
(d) left and right ventricles
(e) left and right atria

Answer 10

(c) The left atrium is partially hidden by the aorta and pulmonary artery. Tilting the detector caudally and visually brings the left atrium out from under these structures and separates it from the left ventricle.

Question 11

Which tracer is excreted primarily via the hepatobiliary system?
(a)[99mTc]pyrophosphate

(b) [99mTc]exametazime
(c) [99mTc]medronate
(d) [99mTc]sestamibi
(e) [201Tl]thallous chloride

Answer 11

(d) [99mTc]sestamibi is excreted through the hepatobiliary system.

Question 12

A cardiac stress test requires the placement of how many electrodes on the patient’s body?
(a)3

(b) 6
(c) 10
(d) 12
(e) 15

Answer 12

(c) A cardiac stress test requires a 12-lead ECG tracing, which uses 10 electrodes attached to the patient. For exercise testing, the two arm leads are positioned over the left and right supraclavicular areas, the two leg leads go over the left and right lover quadrants of the abdomen, and six chest leads are placed around the heart.

Question 13

Visualization of bone marrow uptake on a [99mTc]sulfur colloid liver/spleen image is most likely the result of which of the following?
(a)improper colloid particle size

(b) insufficient tracer circulation time
(c) overactive pituitary gland
(d) overactive bone marrow
(e) liver dysfunction

Answer 13

(e) Bone marrow uptake is visualized on liver/spleen images when severe liver dysfunction, such as advanced cirrhosis, is present. In such cases, the spleen has a markedly increased concentration of tracer, and the skeleton (ribs, vertebrae, sternum, etc.) is visualized as a result of increased tracer uptake in the bone marrow.

Question 14

During hepatobiliary imaging, which structure will NOT be visualized if cystic duct obstruction is present?
(a)gallbladder

(b) common bile duct
(c) stomach
(d) small intestine
(e) common hepatic duct

Answer 14

(a) If cystic duct obstruction is present, the tracer will be unable to enter the gallbladder. the cystic duct is the passage between the common bile duct and the gallbladder.

Question 15

How long after the administration of [99mTc]pertechnetate does imaging begin for the localization of a Meckel’s diverticulum?
(a)10 min

(b) 15-20 min
(c) 1 hr
(d) immediately
(e) delayed imaging 2-3 hr

Answer 15

(d) For localization of a Meckel’s diverticulum, imaging begins immediately after administration of the tracer.

Question 16

All of the following 99mTc-labeled radiopharmaceuticals may be appropriate for performing a left-to right cardiac shunt examination using the first-pass method EXCEPT:
(a)pertechnetate

(b) thallous chloride
(c) sestamibi
(d) tetrofosmin
(e) pentetate

Answer 16

(b) First-pass cardiac studies to identify or quantify left-to-right shunts are performed with radiopharmaceuticals that can be administered in small volumes of 20-25 mCi. Recommended tracers include [99mTc]pentetate, [99mTc]sestamibi, or [99mTc]tetrofosmin and pertechnetate.

Question 17

The glomerular filtration rate (GFR) is measured with which of the following radiopharmaceuticals?
(a)[99mTc]sulfur colloid

(b) [99mTc]pentetate
(c) [99mTc]gluceptate
(d) [99mTc]mertiatide
(e) [99mTc]succimer

Answer 17

(b) Determination of the glomerular filtration rate (GFR) requires an agent that is completely filtered by the glomeruli. [99mTc]pentetate (DTPA) is handled only by glomerular filtration.

Question 18

Radionuclide cystography is performed by the direct method using which of the following radiopharmaceuticals?
(a)[99mTc]pentetate or [99mTc]medronate

(b) [99mTc]pertechnetate or [99mTc]pentetate
(c) [99mTc]pertechnetate or [99mTc]mertiatide
(d) [99mTc]gluceptate or [99mTc]sulfur colloid
(e) [99mTc]pertechnetate or [99mTc]sulfur colloid

Answer 18

(e) Direct radionuclide cystography is performed by instilling [99mTc]pertechnetate, or [99mTc] sulfur colloid, into the urinary bladder. Imaging is performed as the bladder is filling and emptying.

Question 19

Filtered [99mTc]sulfur colloid is required for which of the following examinations?
(a)gastroesophageal reflux

(b) gastric emptying
(c) lymphoscintigraphy
(d) brain imaging
(e) LeVeen shunt patency

Answer 19

(c) Although all procedure listed may be performed with [99mTc]sulfur colloid, only lymphoscintigraphy requires that sulfur colloid be filtered to remove the larger particles. Particle size affects the migration of the tracer through the soft tissue to the lymph system.

Question 20

A patient with a nasogastric tube in place is transferred to the nuclear medicine department for an imaging procedure. The technologist should:
(a)Confirm physician orders for transfer and reestablish suction if required.

(b) Remove the nasogastric tube because it will interfere with the imaging procedure.
(c) Use the nasogastric tube to administer the radiopharmaceutical.
(d) Cancel the study because the presence of a nasogastric tube precludes any imaging procedure being performed.
(e) Clean the nasogastric tube for use during study.

Answer 20

(a) Nasogastric tubes are used for gastric decompression, A physician must order the transfer and interruption of suction. The technologist may be required to reestablish suction upon the patient’s arrival in the department.

Question 21

The appearance of what structure indicates the beginning of the venous phase of a cerebral blood flow study?
(a)anterior cerebral arteries

(b) carotid arteries
(c) nasopharynx
(d) superior sagittal sinus
(e) circle of Willis

Answer 21

(d) In a normal cerebral flow study, the first phase is the arterial phase, indicated by activity in the carotid and anterior cerebral arteries. The capillary phase is followed by the venous phase, indicated by activity in the superior sagittal sinus.

Question 22

In performing cisternography, the purpose of acquiring the first image over the lower thoracic/lumbar spine is to ascertain:
(a)the site of tracer administration

(b) the flow rate of the cerebral spinal fluid
(c) a pressure reading of the cerebrospinal fluid
(d) that spinal cord was not damaged during tracer administration
(e) that the tracer was not infiltrated

Answer 22

(e) The injection site should be imaged first to confirm that the tracer has not infiltrated outside the subarachnoid space. Re-injections may be required if infiltration is confirmed and no activity is visualized in the basal cisterns by 2-3 hr after tracer administration.

Question 23

On Wednesday, a patient had a 123I thyroid study performed; a 125I plasma volume is ordered to be performed on Thursday. Which of the following statements about the situation is correct?
(a)The 123I will not interfere with the plasma volume determination.

(b) The blood volume determination should be postponed until the 123I is decayed.
(c) A baseline plasma sample should be collected before performing the plasma volume.
(d) 131I instead of 125I-human serum albumin should be used for the plasma volume determination.
(e) 123I instead of 125I-human serum albumin should be used for the plasma volume determination.

Answer 23

(c) A blood sample collected before the 125I-albumin is injected can provide the background present in the patient’s plasma. This will permit counts from the plasma sample containing 125I to be corrected for any residual 123I, and the plasma volume can be performed in a timely fashion without ordering a special tracer.

Question 24

[89Sr]chloride is used to treat which of the following conditions?
(a)bone cancer

(b) bone pain
(c) rheumatoid arthritis
(d) malignant effusions
(e) polycythemia vera

Answer 24

(b) 89Sr-chloride is used to relieve bone pain resulting from skeletal metastases.

Question 25

Whole-body imaging with [131I]sodium iodide is optimally performed how long after tracer administration?
(a)12 hr

(b) 48-72 hr
(c) 96 hr
(d) 128 hr
(e) greater than 128 hr

Answer 25

(b) Although 131I whole-body imaging may be performed as early as 24 hr post-administration, optimum images are obtained at 48-72 hr after tracer administration.

Question 26

A patient undergoing an imaging procedure indicates to the technologist that a seizure is impending. The most appropriate action for the technologist is to:
(a)Instruct the patient to breathe deeply to help increase oxygen levels in the brain.

(b) Ignore the patient’s concerns because the timing of seizures cannot be predicted.
(c) Stop the imaging procedure and have the patient lie on the floor with a pillow supporting the head.
(d) Increase the number of physical restraints on the patient to prevent patient movement and injury.
(e) Instruct the patient to hold their breath for as long as they can.

Answer 26

(c) A seizure patient may experience a warning that a seizure is about to occur. The technologist should assist the patient to the floor and away from objects that may injure the patient during the seizure. A pillow will cushion the patient’s head from the floor.

Question 27

After administration of [111In]pentetreotide, which areas of the body should be images?
(a)anterior and posterior whole body

(b) anterior and posterior abdomen
(c) anterior and posterior pelvis
(d) anterior, posterior, and laterals of head and neck
(e) anterior and posterior chest

Answer 27

(a) Because the purpose of 111In-pentetreotide imaging is to visualize the unknown primary site of the cancer or demonstrate the extent of the disease, anterior and posterior whole-body images should be performed.

Question 28

Which of the following is the initial positioning for visualizing gastrointestinal bleeding with labeled red blood cells?
(a)xiphoid in middle of field of view

(b) symphysis pubis in middle of field of view
(c) lower border of liver and spleen at top of field of view
(d) lower esophagus at top of field of view
(e) bladder in the top field of view

Answer 28

(c) Red blood cells labeled with [99mTc]pertechnetate are used for demonstrating intermittent lower gastrointestinal (GI) bleeding. The area between the xiphoid and symphysis pubis must be included in the field of view to visualize bleeding in the lower GI tract.

Question 29

Which of the following tracers is preferred if a first-pass stress and rest cardiac function examination are to be performed on a patient?
(a)[99mTc]pertechnetate

(b) [99mTc]medronate
(c) [99mTc]micro-aggregated albumin
(d) [99mTc]sestamibi
(e) [99mTc]pentetate

Answer 29

(e) Any high-flux radiopharmaceutical that is not trapped in the lungs could be used to perform a first-pass cardiac function study. However, if stress and rest examinations are to be performed, it would be best to perform the two studies in as short a time interval as possible. Therefore, a radiopharmaceutical that clears the blood quickly and does not concentrate in areas that would interfere with the second first-pass study is indicated. Of the tracers listed, only [99mTc]pentetate meets these criteria.

Question 30

Patient preparation for breast imaging with [99mTc]sestamibi includes which of the following?
(a)no caffeine 4 hours before study

(b) fasting for 8 hr before tracer administration
(c) discontinuation of any medications
(d) explanation of the procedure
(e) consumption of a fatty meal

Answer 30

(d) There is no patient preparation for breast imaging with [99mTc]sestamibi except explanation of the procedure to the patient.

Question 31

Historically, a Schilling test may be ordered for a patient with suspected:
(a)hemolytic anemia

(b) multiple myeloma
(c) pernicious anemia
(d) lymphocytic anemia
(e) iron deficiency anemia

Answer 31

(c) The schilling test is used to measure the absorption of vitamin B12 in patients with unexplained anemia. The absorption of vitamin B12 depends on the secretion of intrinsic factor by the stomach. Pernicious anemia is a vitamin B12 deficiency resulting from lack of intrinsic factor.

Question 32

Data derived from a first pass cardiac examination and a region of interest drawn over the lung are used to generate the pulmonary time-activity curve shown here.
(bump on the downward curve)
The arrow indicates:
(a)first pass of activity through the lungs

(b) second pass of activity through the lungs
(c) third pass of activity through the lungs
(d) activity returning prematurely to the lungs
(e) activity returning from the systemic circulation

Answer 32

(d) The arrow indicates tracer returning prematurely to the lungs, an indication of a left-to-right cardiac shunt. Some of the blood on the left side of the heart is being directed back to the right side of the heart, returning to the lungs rather than being ejected out of the left ventricle into the systemic circulation.

Question 33

The proper route of administration for a lymphoscintigraphy exam is an/a:
(a)intravenous injection

(b) orally
(c) intrathecal injection
(d) intramuscular
(e) subcutaneous injection

Answer 33

(e) Subcutaneous injections are needed for a lymphoscintigraphy to determine the sentinel lymph node.

Question 34

A patient’s plasmacrit may be determined by:
(a)multiplying the patient’s hematocrit by 0.9

(b) adding the decimal hematocrit to 1
(c) finding the ratio of plasma volume to red blood cell volume
(d) dividing 1 by the decimal hematocrit
(e) subtracting the decimal hematocrit from 1

Answer 34

(e) The hematocrit represents the portion of the blood made up of cellular components, and the plasmacrit represents the fluid portion. Together, they comprise the total blood volume. Thus, the sum of the hematocrit and the plasmacrit, each expressed in decimal form, is equal to 1.

Question 35

During a red cell sequestration study, counts are obtained from all of the following organs EXCEPT the:
(a)kidneys

(b) spleen
(c) atria of heart
(d) liver
(e) ventricles of heart

Answer 35

(a) Sequestration sites for red blood cells include the liver and spleen. Cardiac counts are used as a standard. Renal areas are not counted.

Question 36

In performing a plasma volume with 125I-albumin, three blood samples are collected at varying times after tracer administration and counts. These counts vs. time are plotted as a semilog graph. The purpose of this graph is to:
(a)give a visual representation of the data

(b) obtain the half-time clearance value used in the calculations
(c) correct for leakage of the radiopharmaceutical
(d) show the decay of the radionuclide
(e) indicate the correct bioroute

Answer 36

(c) There is leakage of the labeled albumin from the vascular system. The multiple blood samples provide the information needed to estimate the leakage rate and determine the plasma counts before any leakage occurred. The plasma counts at zero-time are extrapolated from the graph.

Question 37

Patient preparation for a thyroid uptake test may include discontinuation of anti-thyroid medications. Which of the following is one of these anti-thyroid drugs?
(a)synthroid

(b) potassium perchlorate
(c) propylthiouracil
(d) thyroxine
(e) Lugol’s solution

Answer 37

(c) Propylthiouracil (PTU) interferes with the organification of iodide by the thyroid gland and is one of the antithyroid drugs available to decrease thyroid hormone production.

Question 38

During a radiochromium red cell mass determination, an infusion set may be used to place a needle in the patient’s antecubital vein. To maintain the patency of the infusion set tubing, what substance should be injected into the infusion set tubing?
(a)a chelating agent

(b) normal saline
(c) ACD solution
(d) heparin
(e) bacteriostatic water

Answer 38

(d) Injection of about 0.5 mL of heparin is sufficient to maintain the patency of the infusion set tubing used during a red cell mass determination.

Question 39

A gastric-emptying study uses which of the following radiopharmaceutical?
(a)[99mTc]medronate

(b) [99mTc]disida
(c) [99mTc]pyrophosphate
(d) [99mTc]Macroaggregated Albumin
(e) [99mTc]sulfur colloid

Answer 39

(e) Gastric emptying studies involve combining [99mTc]sulfur colloid with eggs.

Question 40

In the case of insulinoma, which of the following radiopharmaceuticals may cause hypoglycemia?
(a)[111In]white blood cells

(b) [99mTc]sestamibi
(c) [67Ga]citrate
(d) [111In]pentetreotide
(e) [18F]fluorodexyglucose

Answer 40

(d) [111In]pentetreotide binds to somatostatin receptors in certain tumors. In the case of suspected insulinoma, there is a potential for inducing severe hypoglycemia. For this reason, an intravenous infusion of glucose should be readily available.

Question 41

Which of the following structures is normally visualized on an image performed with [18F]fluorodeoxyglucose?
(a)thyroid

(b) brain
(c) pituitary gland
(d) pancreas
(e) bone

Answer 41

(b) Structures normally visualized on an image performed with [18F]FDG include the brain, myocardium, liver, spleen, intestines, kidneys, and urine in the bladder.

Question 42

The [14C] urea breath test is used to:
(a)detect the presence of peptic ulcers

(b) detect delayed gastric emptying
(c) detect the presence of Helicobacter pylori bacteria
(d) rule out Zollinger-Ellison syndrome
(e) identify gastric cancers

Answer 42

(c) The [14C]urea breath test is used to detect the presence of Helicobacter pylori bacteria. All patients with duodenal ulcers and 80% of patients with non-drug-induced gastric ulcers are infected with H. pylori. the test may be used to initially diagnose the presence of infection, as well as for follow-up after treatment.

Question 43

On the basis of these data:

Time - Counts/min
Capsule 0900 - 216789
Background 0900 - 92
Thyroid 1500 - 94954
Thigh 1500 - 521

What is the patient’s thyroid uptake at 1500 if a [123I]sodium iodide capsule administered to the patient used as the standard?
(a)32%

(b) 44%
(c) 51%
(d) 60%
(e) 87%

Answer 43

(d) In this instance, the capsule that is administered to the patient is first counted as the standard. The counts in the patient’s thyroid are compared with the counts in the standard to determine the percent of radioiodine uptake. Because the patient’s thyroid is not counted until 6 hr after the measurement of the capsule, the capsule counts collected at 0900 must be decay-corrected for 6 hr. It will be assumed that room background remains about the same over the 6-hr period. To decay-correct the capsule counts’ multiply the capsule counts by the 6-hr decay factor for 123I:
216,789 cpm x 0.73 = 158,256 cpm
Then, calculate the thyroid uptake using the following formula:
% thyroid uptake = (thyroid cpm - thigh cpm) x 100 /(Standard cpm - bkg cpm)
= (94,954 cpm - 521 cpm) x 100 / (158,256 cpm - 92 cpm)
=94,433 cpm x 100 / 158,164 cpm
=60%

Question 44

If the elution efficiency of a 99Mo/99mTc generator is 96% and 11.7 MBq 99mTc is present on the column, approximately how much activity will be removed during elution?
(a)0.46 MBq

(b) 11.2 MBq
(c) 11.7 MBq
(d) 12.2 MBq
(e) 14.5 MBq

Answer 44

(b) Elution efficiency is expressed as the percentage of 99mTc on the column that is eluted.
elution efficiency = 99mTc activity eluted x 100 / 99mTc activity on column
Thus.
99mTc activity eluted = elution efficiency x 99mTc activity on column
= 0.96 x 11.7 MBq
= 11.2 MBq

Question 45

A dry column generator is eluted with 5 mL of saline, and the eluate containing 863 mCi is collected into a 10 mL evacuated vial. What is the concentration of the eluate?
(a)172.6 mCi/ml

(b) 86.3 mCi/ml
(c) 57.5 mCi/ml
(d) 5.79 mCi/ml
(e) 3.58 mCi/ml

Answer 45

(a) For a dry-column generator, the eluate volume is equal to the saline volume used to elute the generator. In this example:
concentration = 863 mCi / 5 mL = 172.6 mCi/mL
Using an evacuated vial with a volume larger than the saline volume causes air to be pulled over the column, completely removing any saline, hence the name dry-column generator.

Question 46

If no eluate is obtained during generator elution, the technologist should next:
(a)disassemble the generator to determine the cause

(b) attempt elution with another evacuated elution vial
(c) check the generator tubing for kinks or leaks
(d) add more saline to the generator column
(e) contact the generator manufacturer

Answer 46

(b) Loss of vacuum from the elution vial is most likely the cause of this problem and the easiest to rule out. checking the tubing may cause increased radiation exposure to the technologist because the column shielding meets only U.S. DOT requirements for shipping radioactive materials - additional shielding is usually required around the generator to decrease radiation exposure to individuals in its vicinity. Also, changing tubing is not practical, because it will compromise the sterility of the generator components. Adding more saline probably will not force the first saline volume from the column. A vacuum is needed to draw the liquid from the column. Contacting the manufacturer first may delay resolution of an easily solvable problem.

Question 47

According to the NRC, records of 99Mo concentration in 99mTc eluate must be maintained for how long?
(a)1 year

(b) 2 years
(c) 3 years
(d) 5 years
(e) 10 years

Answer 47

(c) The NRC requires that records of 99Mo concentration in 99mTc eluates be retained for 3 years.

Question 48

According to the NRC, the concentration of what radionuclidic impurity must be determined after the first elution of a 99Mo/99mTc generator?
(a)Al3+

(b) 99Mo
(c) free pertechnetate
(d) 99mTc-NaCl
(e) 99Tc

Answer 48

(b) Aluminum is a chemical impurity and not subject to regulation by the NRC. Free pertechnetate is [99mTc]pertechnetate that is not bound to another compound. 99mTc is eluted from a generator as [99mTc]pertechnetate. 99Mo is a radionuclidic impurity, a radionuclide other than the desired one, in 99mTc eluate. According to NRC regulations, its concentration must be determined in the first elution of a 99Mo/99mTc generator.

Question 49

Based on this day's clinic schedule:
Patient - Procedure
Patient A - Renal function study
Patient B - Total body bone image
Patient C - Meckel's diverticulum localization
Patient D - Hepatobiliary study
the technologist should prepare or order all of the following radiopharmaceuticals EXCEPT:
(a)[99mTc]macroaggregated albumin

(b) [99mTc]mebrofenin
(c) [99mTc]medronate
(d) [99mTc]mertiatide
(e) [99mTc]pertechnetate

Answer 49

(a) The technologist does not have to order or prepare [99mTc]macroaggregated albumin, the agent used to perform perfusion lung imaging. A renal function study may be performed with [99mTc]mertiatide, bone imaging with [99mTc]medronate, Meckel’s diverticulum localization with [99mTc]pertechnetate, and a hepatobiliary study with [99mTc]mebrofenin.

Question 50

According to NRC regulations, records of written directives must be maintained for how long?
(a)1 years

(b) 3 years
(c) 5 years
(d) 10 years
(e) indefinitely

Answer 50

(b) The NRC requires that records of written directives be maintained for three years.

Question 51

Which of the following radiopharmaceuticals should be prepared if a renal function study is being performed to determine the glomerular filtration rate?
(a)[99mTc]gluceptate

(b) [99mTc]mertiatide
(c) [99mTc]pentetate
(d) [99mTc]succimer
(e) [99mTc]sulfur colloid

Answer 51

(c) [99mTc]pentetate is the renal agent used to determine glomerular filtration rate because it is handled by the kidneys solely by glomerular filtration. It is neither bound to protein nor secreted by the renal tubules as are other renal agents.

Question 52

What is the final concentration of the [99mTc]sulfur colloid if the maximum activity is prepared with the following reagents?
Reaction vial - Lyophilized thiosulfate mixture
Sulfur colloid kit
Syringe I - 1.6 mL acid
Syring II - 1.6 mL buffer
Maximum activity to be added - 400 mCi
99mTc volume to be added 1.0-3.0 mL
[99mTc]pertechnetate
Concentration - 75.5 mCi/mL
Total volume - 15 mL
(a)75.5 mCi/mL

(b) 47.0 mCi/mL
(c) 42.7 mCi/mL
(d) 36.5 mCi/mL
(e) 23.6 mCi/mL

Answer 52

(d) The maximum activity that can be prepared from this kit is equal to:
maximum reconstituting volume x 99mTc concentration
maximum activity = 2 mL x 75.5 mCi/mL
= 226.5 mCi
To calculate the concentration of the kit, note that the reaction vial contains lyophilized reagents with no appreciable volume. Hence, the total volume in the kit is the sum of the [99mTc]pertechnetate volume and the volumes in the two syringes:
concentration = total activity in preparation / total vol in preparation
= maximum activity to be prepared / (99mTc vol + vol to be prepared in syringes I + II)
=226.5 mCi / (3 mL + 1.6 mL +1.6 mL) = 36.5 mCi/mL

Question 53

Heating is required during the preparation of all of the following 99mTc-labeled radiopharmaceuticals EXCEPT:
(a)filtered sulfur colloid

(b) bicisate
(c) sestamibi
(d) sulfur colloid
(e) mertiatide

Answer 53

(b) Heating is required for the preparation of [99mTc]mertiatide, [99mTc]sestamibi, and [99mTc]sulfur colloid. The preparation of [99mTc]bicisate requires 30-min incubation at room temperature.

Question 54

To calculate the yield of a 99Mo/99mTc generator, in what sequence should the following steps be performed?
I. Measure the amount of 99mTc activity eluted from the generator.
II. Determine the amount of 99Mo activity present on the generator at a given time t.
III. Calculate the fraction of 99mTc activity eluted compared with the 99mTc activity present on the generator column.
IV. Determine how much 99mTc activity has formed by 99Mo decay at a given time t.
V. Determine the elapsed time from calibration to time t.
(a)I, II, III ,IV, V

(b) V, II ,IV, I, III
(c) IV, II, V, III, I
(d) I, V, II, IV, III
(e) II, V, I, IV, III

Answer 54

(b) Generator yield - amount of 99mTc that may be eluted from a 99Mo/99mTc generator - is calculated by using decay equations that determine the amount of 99mTc formed from the decay of 99Mo at any given time. The sequence for calculating the generator yield is as follows:
1. Determine the time elapsed between calibration of the 99Mo activity and generator elution.
2. Calculate the amount of 99Mo activity in the generator at the time of elution by decay correcting the initial 99Mo activity.
3. Determine how much 99Tc activity is in the generator by calculating how much has formed from the decay of 99Mo.
4. After elution, measure the amount of 99mTc activity (with a dose calibrator) collected from the generator.
5. Calculate the generator yield, or elution efficiency, by comparing the measured activity of 99mTc eluted from the generator to the 99mTc activity calculated to be in the generator in step 3.

Question 55

When performing radiochromatography on a radiopharmaceutical sample, the locations of the radiochemical components on the chromatography strip are as shown here. What is the Rf value of hydrolyzed-reduced 99mTc if the solvent front is 12.6 cm from the origin?
Radiochemical component - Distance form origin
Hydrolyzed-reduced 99mTc - 2.5 cm
[99mTc]pertechnetate - 12.6 cm
99mTc-labeled radiopharmaceutical - 0 cm
(a)0.003

(b) 0.012
(c) 0.20
(d) 2.0
(e) 4.8

Answer 55

(c) The Rf value is the distance traveled by a given radiochemical component compared with the solvent front:
Rf = distance from origin to radiochemical component / distance from origin to solvent front
In this instance, the Rf value for the hydrolyzed-reduced 99mTc is:
Rf = 2.5 cm / 12.6 cm = 0.20

Question 56

All of the following units are expressions of radiopharmaceutical specific activity EXCEPT:
(a)uCi/mg

(b) kBq/mL
(c) Ci/g
(d) MBq/mol
(e) mCi/ug

Answer 56

(b) Specific activity is defined as the amount of radioactivity per unit mass of a radionuclide or labeled compound and is expressed in units of radioactivity per mass. Megabecquerels per mole (MBq/mole), Ci/g, and uCi/mg are units of specific activity. Kilobecquerels per milliliter (kBq/mL) is an expression of concentration, the amount of radioactivity per unit volume.

Question 57

A technologist needs 1 mCi [111In]chloride at 0900 on May 18. The label on the radiopharmaceutical vial contains the following information:
Total activity:3.0 mCi
Total volume: 3.0 mL
Assay: 1200, May 21
What volume is required to obtain the necessary activity on May 18?
(a)0.48 mL

(b) 0.69 mL
(c) 1.41 mL
(d) 1.78 mL
(e) 2.1 mL

Answer 57

(a) The elapsed time between calibration and dose calculation is three days (May 18-21). In this instance, the radiopharmaceutical is being used before the calibration time. Tehrefore, the initial concentration on May 18 is the unknown, and the known concentration is divided by the decay factor. The concentration on May 21 is 1.0 mCi/mL (3.0 mCi/3.0 mL):
C(0) x 0.480 = 1.0 mCi/mL
C(0) = 1.0 mCi/mL / 0.480 = 2.1 mCi/mL
Then, determine the required volume:
volume = activity required / C(t) = 1.0 mCi / 2.1 mCi/mL = 0.48 mL

Question 58

If 25 uCi of a radiopharmaceutical are to be administered for each kilogram of body weight, approximately how much activity should be administered to a child weighting 15.5 kg?
(a)65 mCi

(b) 28 mCi
(c) 11 mCi
(d) 1.6 mCi
(e) 0.39 mCi

Answer 58

(e) Calculate the total activity to be administered to the patient based on body weight:
15.5 kg x 25 uCi/kg = 387.5 uCi
None of the options match this answer unless it is expressed in millicuries. Thus,
387.5 uCi x mCi / 1000 uCi = 0.39 mCi

Question 59

For labeling red blood cells, the prescribed adult dosage of [99mTc] pertechnetate is 925 MBq +-10%. Which of the following dose calibrator readings obtained from the syringed containing the patient dosage would verify that the prescribed activity was dispensed?
(a)21 mCi

(b) 28 mCi
(c) 20 mCi
(d) 29 mCi
(e) 25.5 mCi

Answer 59

(e) 925 MBq = 25mCi
925 MBq x mCi / 37 MBq = 25 mCi
The prescribed dosage is expressed as a range, +-10% of 925 MBq or 25 mCi:
0.10 x 25 mCi = 2.5 mCi
Therefore, the prescribed range is 22.5 mCi (25 mCi - 2.5 mCi) to 27.5 mCi (25 mCi + 2.5 mCi). Any dose calibrator reading between 22.5 mCi and 27.5 mCi verifies that the prescribed activity was withdrawn into the syringe.

Question 60

When red blood cells are labeled with 99mTc using the in vivo method, in what order are the reagents injected into the patient?
(a)Stannous pyrophosphate and [99mTc]pertechnetate are administered at the same time.

(b) Stannous pyrophosphate is administered 15-30 min before [99mTc]pertechnetate
(c) Stannous pyrophosphate is administered 2-3 hr before [99mTc]pertechnetate
(d) [99mTc]pertechnetate is administered 15-30 min before stannous pyrophosphate
(e) [99mTc]pertechnetate is administered 2-3 hr before stannous pyrophosphate

Answer 60

(b) Reconstructed stannouse pyrophosphate must be administered first. This step, sometimes referred to as “pretining,” permits [99mTc]pertechnetate to enter the red blood cells

Question 61

If the following reagents are available, what volume of each reagent must be added together to prepare 20 mCi of [99mTc]succimer?
Succimer kit
2.2 mL succimer reagent: Use 1 part by volume to 2 parts of [99mTc]pertechnetate
[99mTc]Pertechnetate
Concentration: 20 mCi/mL
Total volume: 10 mL

Succimer volume: - 99mTc volume:
(a)2.0 mL - 4.5 mL

(b) 1.0 mL - 2.5 mL
(c) 0.75 mL - 0.5 mL
(d) 1.0 mL - 0.5 mL
(e) 0.5 mL - 1.0 mL

Answer 61

(e) Because the total activity to be prepared is known, it is easiest to calculate the volume of [99mTc]pertechnetate. The volume of [99mTc]pertechnetate is equal to
Activity desired / concentration of 99mTc = 20mCi / 20mCi/mL = 1.0 mCi
Then, determine the volume of succimer reagent needed. If 1.0 mL = 2 parts, then 1 part must equal half of that, or 0.5 mL.

Question 62

Venipuncture materials labeled with which of the following expiration dates may be used safely on August 10, 2017?
I. July 31, 2017
II. August 31, 2017
III. September 30, 2017
IV. October 1, 2018
(a)IV only

(b) III or IV only
(c) II or III only
(d) II, III, or IV only
(e) I, II, III, or IV

Answer 62

(d) Material that has passed its expiration date should not be used with patients. In the case of venipuncture materials, the sterility of the materials may be compromised.

Question 63

According to NRC regulations, all of the following information must appear in the record of 99Mo concentration measurements EXCEPT:
(a)dose calibrator make and model

(b) date of measurement
(c) name of the individual making the measurement
(d) ratio of 99Mo to 99mTc activities
(e) time of measurement

Answer 63

(a) Records of 99Mo concentration measurements must contain the ration of 99Mo to 99mTc, time and date of the measurement, and name of the individual making the measurement.

Question 64

According to the NRC, a written directive must be prepared for administration of which of the following radiopharmaceuticals?
(a)1 mCi [111In]oxine

(b) 5 mCi [201Tl]chloride
(c) 10 mCi [67Ga]citrate
(d) 5 mCi [131I]sodium iodide
(e) 30 mCi [99mTc]sestamibi

Answer 64

(d) According to the NRC, a written directive is required for any dosage of [131I]sodium iodide greater than 30 uCi or for any therapy dosage of an unsealed byproduct material.

Question 65

If 99mTc eluate has to be diluted to prepare other 99mTc-labeled products, the correct diluent is which of the following?
(a)sterile saline containing 0.2% thiosulfate

(b) preservative-free isotonic saline
(c) bacteriostatic saline
(d) distilled water
(e) sterile water

Answer 65

(b) If 99mTc eluate needs to be diluted to prepare other 99mTc-labeled products, the correct diluent is preservative-free isotonic saline. Preservatives may act as oxidizing agents that reverse the effect of reducing agents in kits. The reducing agents are necessary to make 99mTc more chemically active so it will bind to the compound being labeled.

Question 66

A unit dosage of [67Ga]citrate calibrated for 0800 on Jul 9 contains 5 mCi in 2.6 mL. If 3 mCi are needed on July 10 at 0800, what volume should be retained in the syringe?
(a)2.7 mL

(b) 1.9 mL
(c) 1.5 mL
(d) 1.3 mL
(e) 1.1 mL

Answer 66

(b) Decay-correct the total activity for 24 hr (July 9, 0800, to July 10, 0800 = 24 hr(:
5 mCi x 0.808 = 4 mCi
Determine the concentration:
concentration = total activity / total volume = 4.0 mCi / 2.6 mL = 1.54 mCi/mL
Determine the volume that will contain the required activity and will have to be retained in the syringe:
volume = activity required / concentration = 3.0 mCi / 1.54 mCi/mL = 1.9 mCi/mL

Question 67

If a 2.5-Ci 99Mo/99mTc generator is estimated to contain 268 mCi of [99mTc]pertechnetate, but 198 mCi are eluted, what is the approximate elution efficiency of the generator?
(a)94%

(b) 85%
(c) 74%
(d) 58%
(e) 11%

Answer 67

(c) The elution efficiency of a generator is expressed as a percentage of the estimated amount of [99mTc]pertechnetate on the generator column compared to what is actually collected in the elution vial.
(198 mCi / 268 mCi) x 100% = 74%

Question 68

What is the volume contained in the syringe shown here?
[]>
( ] 2.0 mL EDGE )( > 1.4 mL ARROW)
(a)1.4 mL

(b) 2.0 mL
(c) 3.8 mL
(d) 4.0 mL
(e) 4.6 mL

Answer 68

(b) The volume of a solution in a syringe is measured at the edge of the plunger’s stopper, where the calibration mark aligns with the edge of the stopper.

Question 69

Which of the following federal (U.S.) agencies regulates the packaging and transport of radioactive materials?
(a)United States Pharmacopeia

(b) Environmental Protection Agency
(c) Department of Transportation
(d) Nuclear Regulatory Commission
(e) Food and Drug Administration

Answer 69

(c) The U.S. Department of Transportation (DOT) regulates the packaging and transport of radioactive materials. NRC regulations follow DOT requirements.

Question 70

Which of following exposure rates indicate that a package containing radioactive material must be labeled with a Category II DOT label?
At package surface - At 1 m
(a)75 mR/hr - 6.5 mR/hr

(b) 65 mR/hr - 5.5 mR/hr
(c) 52 mR/hr - 2.2 mR/hr
(d) 35 mR/hr 1.0 mR/hr
(e) 0.6 mR/hr No Detectable Radiation (NDR)

Answer 70

(d) The label types and exposure rate limits for packages containing radioactive materials are:
Label category - At surface - At 1 meter
Category I (white) - <=0.5 - No detectable radiation
Category II (yellow) - <=50 - <= 1.0
Category III (yellow) - <=200 - <= 10

Question 71

If the radiation intensity of a point source at 0.5 m measures 36 mR/hr, at what distance will the intensity be halved?
(a)7.1 m

(b) 5.3 m
(c) 2.2 m
(d) 1.1 m
(e) 0.7 m

Answer 71

(e) Use the inverse square law:
(I1)(D1)^2 = (I2)(D2)^2
where I1 = intensity at original distance (D1) and I2 = intensity at new distance (D2). In this example:
(36 mR/hr)(0.5 m)^2 - (18 mR/hr)(D2)^2
Isolate the unknown and solve:
(D2)^2 = (36 mR/hr)(0.5 m)^2 /18 mR/hr
= 0.5 m^2
Take the square root of each side: 
D2 = 0.7 m

Question 72

If the HVL of 60Co in lead is 1.25 cm, what percentage of 60Co photons is absorbed from a 60Co source shielded with 2.5 cm of lead?
(a)75%

(b) 50%
(c) 35%
(d) 27.5%
(e) 25%

Answer 72

(a) If 1.25 cm of lead is one HVL, then twice that thickness (2 x 1.25 cm) is two HVL. Each HVL absorbs 50% of the photons and allows 50% to be transmitted through the shield.
Number of HVLs - 0 - 1 - 2 - 3
Photon intensity (%) 100 - 50 - 25 - 12.5
% absorbed 0 - 50 -75 - 87.5
% transmitted 100 - 50 - 25 - 12.5

Question 73

According to the NRC, a written directive is required for the administration of all of the following radiopharmaceuticals EXCEPT:
(a)35 mCi [131I]sodium iodide

(b) 15 mCi [32P]sodium chromate
(c) 15 mCi [32P]sodium phosphate
(d) 10 mCi [89Sr]chloride
(e) 20 mCi [18F]FDG

Answer 73

(e) The NRC requires a written directive before administration of 131I in quantities greater than 30 mCi and any other unsealed byproduct material that is used for therapy. [32P]sodium phosphate and [89Sr]chloride are used for therapy, whereas [18f]FDG is used for diagnostic purposes.

Question 74

According to NRC regulations, the annual occupational dose limit for any organ or tissue other than the eye is:
(a)50 mSv

(b) 5 mSv
(c) 15 Rem
(d) 35 Rem
(e) 50 Rem

Answer 74

(e) According to the NRC, the annual occupational dose limit to any organ or tissue, other than the eye, is 50 Rem or 500 mSv.

Question 75

According to NRC regulations, which of the following cannot be disposed of in the sewage system?
(a)unused [123I]sodium iodide capsules

(b) feces from a patient who received [131I]therapy
(c) spit from an aerosol [99mTc]pentetate
(d) urine from a renal test
(e) disposable diaper of a child who has received [67Ga]

Answer 75

(a) According to NRC regulations, only patient excreta are exempt from any limits when discarded into the sewage system. Disposal limits for other radioactive waste are based on the solubility and rate of waste water discharge from a facility.

Question 76

In performing a room survey with a G-M counter, the technologist should first:
(a)perform a battery check on the counter

(b) calibrate the unit
(c) measure each area designated on the survey diagram
(d) perform a wipe test on each designated area
(e) measure the room background

Answer 76

(a) To ensure that the batteries are functional, a battery check should be performed immediately before taking any measurements with a survey meter.

Question 77

What is the maximum exposure rate that can be measure with the G-M meter shown here?
(scale 0-5 mR/hr) (knob x10, x1, x0.1)
(a)50,000 mR/hr

(b) 5,000 mR/hr
(c) 500 mR/hr
(d) 50 mR/hr
(e) 5 mR/hr

Answer 77

(d) The needle will register 5 for a full-scale deflection on this meter. The maximum scale is 10. The maximum exposure rate that could be measured is the product of the number at full deflection and the maximum scale. Thus,
5 mR/hr x 10 = 50 mR/hr

Question 78

A technologist monitors the empty carton from a shipment of [131I]sodium iodide. The container measures 0.08 mR/hr, and room background measures 0.07 mR/hr. The technologist should next:
(a)Notify the RSO.

(b) Dispose of the container as radioactive waste.
(c) Wipe test the container for removable contamination.
(d) Obliterate any radiation symbols and dispose of teh container in regular trash.
(e) Notify the NRC.

Answer 78

(d) the exposure rate of the packing material is approximately the same as room background, so the carton may be disposed of in the regular trash after any radiation symbols are removed or obliterated.

Question 79

According to NRC regulations, in what areas can radioxenon be administered?
(a)in any room that can be closed off with doors

(b) only in rooms that have xenon alarm systems
(c) only in imaging rooms that can be negatively pressurized
(d) in any room where a G-M detector is available to use
(e) only in imaging rooms that can be positively pressurized

Answer 79

(c) NRC regulations require facilities to use facility design and procedures that will minimize the potential for contamination to the extent practicable. Rooms in which radioxenon is used should be tested to determine the amount of time required for evacuation of gas from the room after a gas spill. A negative air pressure exhaust system would be necessary to draw the xenon out of the room without spreading it to adjacent areas.

Question 80

When can a decay factor be used to calibrate a unit dosage in place of measuring the dosage in a dose calibrator?
(a)A dose calibrator must be used to measure every dosage.

(b) only if the same size and type syringe is used
(c) only if a unit dosage was not manipulated after preparation and calibration
(d) Only if the dosage contains less than 1 mCi activity
(e) only if the dosage contains 99mTc

Answer 80

(c) According to NRC regulations, a unit dosage can be calibrated before administration by one of the following methods: direct calibration using a dose calibrator, or application of a decay factor to the original activity if the dosage has not been manipulated (adjusted) after it was originally prepared and calibrated.

Question 81

A patient received 5 mCi of [131I]sodium iodide for treatment of hyperthyroidism. The patient should adhere to all of the following instruction EXCEPT:
(a)Minimize close contact with others.

(b) Remain at home at least 30 days.
(c) Use separate personal utensils for first week after therapy.
(d) Drink plenty of liquids.
(e) Wash hands after using the toilet.

Answer 81

(b) Patients should be given instructions to follow for 3-7 days that will minimize spread of contamination and radiation exposure to others.

Question 82

After a 99mTc spill, decontamination procedures have not been able to remove all of the spilled material. If the current exposure rate is 32 mR/hr, how long will it take for the exposure rate to drop to 2 mR/hr?
(a)24 hr

(b) 18 hr
(c) 12 hr
(d) 8 hr
(e) 4 hr

Answer 82

(a) For each half-life that passes, the activity decreases to half of the previous activity. In this case, four half-lives are required for the activity to drop to the specified level. If each half-life is 6 hr, the total time required is 24 hr.

Question 83

If a patient must be hospitalized in isolation after receiving a high activity of 131I, which of the following signs must be placed on the door of the isolation room?
(a)”Authorized Personnel Only”

(b) “Caution: Airborne Radioactivity”
(c) “Reverse Isolation Procedures Required”
(d) Length of time a visitor may stay in the room
(e) Sign-in sheet to record name and age of each visitor

Answer 83

(d) If a person is hospitalized after administration of a therapeutic dosage of 131I, the door of the room must have signage that indicates the length of time a visitor may stay.

Question 84

How soon after a medical event has occurred must the NRC be notified?
(a)written report within 24 hr

(b) telephone notification within 72 hr
(c) telephone notification no later than the following calendar day
(d) written report within 30 calendar days
(e) written report within 5 regular work days

Answer 84

(c) NRC regulations state that the NRC Operations Center must be notified of a medical event (error, misadministration) no later than the next calendar day.

Question 85

According to the NRC, written instructions must be provided to a patient who has received radionuclide therapy when:
(a)the patient is a female of childbearing age

(b) the patient resides with children younger than 18 years of age
(c) the patient is under the age of 18 years old
(d) every patient must receive instructions, regardless of dosage
(e) another individual may receive an exposure greater than 0.1 Rem (1mSv) from the patient

Answer 85

(e) NRC regulations state that written instructions for precautions must be provided to the patient or the patient’s parent or guardian if any individual is likely to exceed 0.1 Rem (1 mSv) exposure from the therapy patient.

Question 86

Which of the following statements about the shielding method of performing a dose calibrator linearity test is TRUE?
(a)The linearity check must be done over a 24 hr period.

(b) Only a few microcuries of radioactivity are needed to perform the test.
(c) Linearity must be tested more frequently if this method is used.
(d) A different source activity is required for each shield combination.
(e) When the shields are first used, the decay method must be used to confirm their accuracy.

Answer 86

(e) To ensure that the shields will give accurate results, the decay method must be performed at the same time the shields are first used.

Question 87

The following dose calibrator constancy test results were obtained with a 57Co reference source:
Radionuclide setting - measured value - calculated value
57Co - 56.6 uCi - 57.8 uCi
99mTc - 59.2 uCi - 58.7 uCi
123I - 46.9 uCi - 51.7 uCi
201Tl - 47.9 uCi - 53.5 uCi
Which of the following measurd values fall within the limits according to the standard of practice
(a)57Co, 99mTc, 123I

(b) 57Co, 201 Tl
(c) 99mTc, 123I, 201 Tl
(d) 57Co, 99mTc
(e) 57Co, 99mTc, 123I, 201 Tl

Answer 87

(a) The NRC requires that dose calibrators be tested for proper functioning according to nationally recognized standards. The standard of practice requires the measured value to be within +-10% of the calculated value. In this example, the measured values for 57Co, 99mTc, and 123I are within that limit. The measured value for 201Tl, however, varies by more than 10% of the calculated value.
0.10 (53.5 uCi) = 5.35 uCi
The measured value at the 201Tl setting could vary from 48.15 uCi to 58.85 uCi and be within the prescribed limit. However, the measured value is outside this range.

Question 88

Based on the graph shown here:
(Peak 680 keV, 15K cpm)(Midway 655 keV, 705 keV 7.5K cpm)
The full width at half maximum (FWHM) is:
(a)2500 cpm

(b) 680 keV
(c) 7500 cpm
(d) 50 keV
(e) 500 cpm

Answer 88

(d) The full width at half maximum (FWHM) is defined as the width of the photopeak, expressed in keV, at one-half of the maximum or peak counts. This value is used to determine the energy resolution of a scintillation counter. The FVVI-IM is determined by calculating 50% of the highest count obtained. In this example, 50% of 15,000 cpm is 7,500 cpm. Then, a horizontal line is drawn from one side of the photopeak to the other at the 50% point. At the two places on each side of the graph where the horizontal intersects with the graph, a vertical line is dropped to the x-axis. the FWHM is calculated by subtracting the larger value from the smaller. In this example, the width of the photopeak is 50 keV (705-655 keV).

Question 89

To perform a constancy test on a dose calibrator that is being used in a general nuclear medicine imaging department, the best choice of radionuclide settings on which to count the reference standard would include which of the following?
(a)123I, 125I, 131I

(b) 125I, 57Co, 137Cs
(c) 99mTc, 201Tl, 137Cs
(d) 57Co, 137Cs, 131I
(e) 99mTc, 201Tl, 123I

Answer 89

(e) After the long-lived reference is read on its setting, the same source should be used to obtain a reading on each commonly used radionuclide setting. 99mTc, 201Tl, 123I, and 131I are commonly used radionuclides, whereas 125I is used infrequently. 57Co and 137Cs are reference standards that are counted only on a daily basis.

Question 90

The scintillation camera quality control image shown here:
(circle with lots of identical dots)
was obtained with which of the following transmission phantoms?
(a)4-quadrant bar

(b) orthogonal hole
(c) Moire phantom
(d) parallel-line equal-space (PLES)
(e) Hine-Duley

Answer 90

(b) The linearity/resolution image was obtained with an orthogonal-hole phantom.

Question 91

The following data were obtained during a dose calibrator accuracy test:
Radionuclide - Calculated value - Measure value
57Co - 80.6 uCi -71.0 uCi
137Cs - 62.3 uCi - 55.9 uCi
On the basis of these results, which of the following statement is TRUE?
(a)The wrong radionuclides were used to perform his test.

(b) The instrument should be repaired or replaced.
(c) Too much radioactivity was used to perform his test.
(d) The instrument accurately measures radionuclides of different energies.
(e) Insufficient radioactivity was used to perform this test.

Answer 91

(b) The standard of practice for performing a dose calibrator accuracy test calls for the use of at least two long-lived reference sources. The measured value should be within +-10% of the calculated value. If the instrument fails to meet this standard, it should be repaired or replaced.

Question 92

Which of the following is a high-pass filter?
(a)Ramp

(b) Hanning
(c) Parzen
(d) Newcomer
(e) Butterworth

Answer 92

(a) The ramp filter is a high-pass filter; that is, it permits high frequencies to pass through while altering the lower frequencies. This suppresses the star artifact created during filtered backprojection and increase resolution. However, it has little effect on statistical noise, so a low-pass filter, such as Butterworth, Hanning, or Parzen, must be used to eliminate some of this noise, thereby smoothing the image.

Question 93

In quantitating scintillation camera detector uniformity, the central field of view (CFOV) is defined as the diameter of the useful field of view (UFOV) times:
(a)0.95

(b) 0.75
(c) 0.33
(d) 0.25
(e) 0.15

Answer 93

(b) The UFOV is first determined by measuring the diameter of the largest area that can be inscribed within the collimated field of view. Then, the CFOV is defined as a circle with a diameter that is 75% of the UFOV diameter.

Question 94

When the heart rate is 95 beats/min, what is the length of an average R-R interval?
(a)0.63 sec

(b) 1 sec
(c) 1.6 sec
(d) 1.9 sec
(e) 2.5 sec

Answer 94

(a) If the patient’s heart rate is 95 beats per minute, then each heart beat or R-R interval is:
60 sec / 95 beats = 0.63 sec/beat

Question 95

To perform pixel calibration, two capillary sources are placed on the camera surface 15 cm apart. From an image acquired using a 128 x 128 matrix, an activity profile is generated on the computer. If the profile shows that there are 45 pixels between the two activity peaks, the pixel size is:
(a)0.02 cm

(b) 0.12 cm
(c) 0.20 cm
(d) 0.33 cm
(e) 0.42 cm

Answer 95

(d) the following calculation is used when using the point source or line source method for pixel calibration:
pixel size = distance between sources / number of pixels between activity profile peaks

In this example: 15 cm / 45 pixels = 0.33 cm

Question 96

Coincidence loss is likely to occur when using a well counter if the:
(a)energy of the radionuclide is below 50 keV

(b) energy of the radionuclide is above 300 keV
(c) activity of the source is below 1 uCi
(d) activity of the source is above 2 mCi
(e) activity of the source is between 1 uCi and 1 mCi

Answer 96

(d) With activities in the millicurie range and sometimes much lower, photons are striking the well counter crystal at very short intervals. The instrument is in deadtime while many photons are interacting with the crystal. These photons will not be counted and are therefore “lost.”

Question 97

To assure a maximum error of 2% at the 95% confidence level, all samples that are measured in a well counter should be counted for a time interval that produces at least:
(a)7,500 counts

(b) 5,000 counts
(c) 1,000 cpm
(d) 500 cpm
(e) 10,000 counts

Answer 97

(e) The 95% confidence level is most commonly used in nuclear medicine. To determine the minimum counts (N) needed to assure a maximum given percent error, the following equation is used:
% error = (2)(100%) / ((N)^(1/2))
In this example:
2% = (2)(100%) / ((N)^(1/2))

Question 98

If a 137Cs source used to determine constancy of a dose calibrator was originally calibrated to contain 200 uCi on June 1, 1998, what would be the expected activity of the source on June 1, 2002 (1 year decay factor of 0.977; 2 year decay of 0.955)?
(a)182.4 uCi

(b) 185.0 uCi
(c) 186.6 uCi
(d) 191.0 uCi
(e) 195.4 uCi

Answer 98

(a) When the decay factor for a desired time is not available, a combination of decay factors can be used to obtain the correct one. In this case, the 2-year decay factor is multiplied by itself to obtain the 4-year decay factor. The original activity is then multiplied by the decay factor to obtain the expected activity of the source.
0. 955 x 0.955 x 200 uCi = 182.4 uCi

Question 99

A 57Co source used to determine dose calibrator constancy was originally calibrated to contain 325.8 uCi 35 days ago. If the source is measured today, the dose calibrator reading must fall within what range of activities to meet the accepted standard?
Days - 57Co decay factor
1 - 0.997
2 - 0.995
3 - 0.992
4 - 0.990
5 - 0.987
10 - 0.975
20 - 0.95
30 - 0.926
40 - 0.902
(a)238.2-357 uCi

(b) 258.0-337.6 uCi
(c) 268.0-327.6 uCi
(d) 280.3-342.7 uCi
(e) 271.5-331.9 uCi

Answer 99

(c) First, the source activity must be decay-corrected for 35 days. When the specific decay factor is not available, a combination of decay factors can be used. To obtain the 35-day decay factor, multiply the 30-days factors by the 5-days factor:
0.926 x 0.987 = 0.914
Determine the decay-corrected source activity by multiplaying the original activity by the calculated decay factor:
325.8 uCi x 0.914 = 297.8 uCi
According to the accepted limits for dose calibrator constancy, the measured activity of the source should be within +-10% of the calculated or expected activity. Determine the +-10% range:
297.8 uCi x 0.1 = 29.8 uCi
297.8 uCi +- 29.8 = 268.0 x 327.6 uCi
If the dose calibrator reading falls within this range, it meets the standard of practice for dose calibrator constancy.

Question 100

It has been determined that a correction factor of 1.15 must be used when a 5 mL syringe containing about 25 mCi is measured in a particular dose calibrator. If a unit dosage activity reads 26.2 mCi, what is the true activity?
(a)22.7 mCi

(b) 25.1 mCi
(c) 30.1 mCi
(d) 40.1 mCi
(e) 47.4 mCi

Answer 100

(c) When the geometric variation varies from the expected by more than 10%, a correction factor must be calculated and applied whenever that configuration and activity range are measured. To apply a correction factor:
true activity = actual activity reading x correction factor
In this example:
26.2 mCi x 1.15 = 30.1 mCi