ST:1 Flashcards Preview


Flashcards in ST:1 Deck (100)
Loading flashcards...

Before tracer administration, all of the following preparations are required for a 27-year-old woman referred for total-body bone imaging EXCEPT:
(a)removing attenuating materials from the patient

(b) answering the patient’s questions
(c) ruling out pregnancy
(d) explaining the procedure to the patient
(e) swab the injection site with alcohol


(a) Explaining the procedure and answering any questions the patient may have are preparations common to any procedure. If the patient is a female of child-bearing age, the possibility of pregnancy must also be ruled out before administering the tracer. Pregnancy is a contraindication for procedures involving radiation unless the procedure is being performed for emergency reasons. It is not necessary to have the patient remove any attenuating materials until just before he or she is imaged.


Which of the following structures normally appear as areas of increased activity on the bone images of children?
(a)diaphyses of the long bones

(b) breast tissue
(c) lumbar spine and cranium
(d) costochrondral junctions and epiphyseal plates
(e) metatarsals


(d) In children, normally increased tracer activity appears in areas of active bone growth. These areas include the epiphyseal plates at the ends of the long bones and the costochondral junctions in the ribs.


If tracer concentration is visualized in the skeleton, stomach, thyroid, and salivary glands on a bone image, the most likely explanation for these findings is that the:
(a)patient was imaged too soon after tracer administration

(b) patient’s renal function is compromised
(c) radiopharmaceutical contained excess free [99mTc] pertechnetate
(d) incorrect radiopharmaceutical was administered
(e) radiopharmaceutical contained excess free [18F]sodium


(c) 99mTc-labeled bone agents are prepared by combining medromite or oxidronate with 99mTc-pertechnetate. Typically about 3%-10% of the pertechnetate does not bind to the medronate or oxidronate, so there is always some unbound of “free” pertechnetate in any bone tracer preparation. However, this percentage is small compared with the amount of 99mTc-medronate or -oxidronate in the preparation and is not visualized on the bone image. If the radiopharmaceutical was not properly compounded or the 99mTc-label detached from the chemical compound, the excess 99mTc-pertechnetate taken up by the thyroid, salivary glands, and stomach is visualized on the bone image.


For interpretation of nuclear medicine lung images, a chest x-ray is required to:
(a)rule out possible causes of the patient’s symptoms

(b) determine cardiac size
(c) rule out previous lung surgery
(d) rule out a pulmonary embolus
(e) rule in a pulmonary embolus


(a) Many of the symptoms of pulmonary emboli are similar to those of rib fracture, myocardial infarction, and pneumonia. A chest radiograph allows the interpreting physician to rule out certain of these conditions, thereby increasing the specificity of the lung image findings.


The image shown here was obtained after the administration of [99mTc]MAA, Which of the following is the most likely explanation for the quality of this lung perfusion image? (ANT/POST SPOTTY LUNG, CHRISTMAS TREE LIGHT)
(a) The image shows lung pathology.

(b) There is radioactive contamination on the patient’s skin or the camera detector.
(c) Blood clotted to MAA particles was injected intravenously.
(d) Too many MAA particles were administered to the patient.
(e) A left to right shunt occurred in the heart.


(c) Blood that is withdrawn into the syringe and allowed to mix with the [99mTc]MAA for a prolonged period may cause the MAA particles to clump together and the blood to clot. If this mixture is then injected into the patient, the clumped particles and “labeled” blood clots are trapped in the lung vasculature and appear as multiple small hot spots on the image.


The purpose of a charcoal filter in a xenon delivery unit is to absorb:

(b) carbon dioxide
(c) xenon gas
(d) moisture
(e) oxygen


(c) The NRC sets limits on the airborne concentration of 133Xe. For this reason, 133Xe that the patient exhales must be trapped for decay. Certain xenon delivery units use activated charcoal for trapping the xenon.


Radionuclide venography may be performed with which of the following radiopharmaceuticals?

(b) [99mTc]pertechnetate
(c) [99mTc]exametazime
(d) [99mTc]mebrofenin
(e) [99mTc]MAA


(e) The deep venous system of the lower extremities may be imaged with [99mTc]MAA or 99mTc-labeled red blood cells. If [99mTc]MAA is used, the lungs may be imaged after the venogram to rule out pulmonary embolism.


If ectopic thyroid tissue is suspected, the technologist can expect to find it most commonly in which of the following areas?
(a)in the brain

(b) in the skull
(c) in the nasopharynx
(d) in the mediastinum
(e) behind the optic nerve


(d) Sublingual thyroid tissue occurs when the tissue does not descend from the base of the tongue to the neck during fetal development. It is often associated with hypothyroidism. Mediastinal thyroid tissue is often discovered after investigation of an anterior mediastinal mass visualized on chest x-ray.


During parathyroid imaging, images of the chest as well as the neck are obtained to:
(a)correct the images series for patient motion

(b) visualize substernal thyroid tissue
(c) visualize ectopic parathyroid tissue
(d) diagnose hyperparathyroidism
(e) to localize the parathyroid


(c) The upper mediastinum between the heart and the thyroid is imaged to visualize ectopic parathyroid tissue.


When performing a gated equilibrium cardiac study, which of the following anatomical views best separates the right and left ventricles?
(a)left lateral

(b) left anterior oblique
(c) left posterior oblique
(d) anterior
(e) posterior


(b) The left anterior oblique view is the projection from which the ejection fraction (EF) is calculated. It is extremely important to separate the two ventricles to obtain an accurate EF value. Typically, 35-45 of rotation accomplishes the separation. However, the camera should be positioned according to the patient’s own anatomy to optimize separation of the two structures.


In preparation for a 201Tl stress test, patients are instructed to fast to:
(a)prevent gastrointestinal upsets during exercise

(b) minimize tracer uptake in the gastrointestinal tract
(c) enhance myocardial tracer uptake
(d) standardize test conditions among patients
(e) prevent redistribution of the tracer


(b) Digestion directs more of the cardiac output toward the gut. Although this probably will not affect myocardial uptake of the tracer significantly, excessive tracer in the upper abdominal viscera interferes with visualization of the myocardial wall, especially when the patient is supine.


Which of the following agents used for pharmacologic stress testing remain in the plasma for the greatest length of time?

(b) adenosine
(c) nitroglycerin
(d) dipyridamole
(e) regadenoson


(d) Nitroglycerin is not used to induce pharmacologic stress. The plasma half-lives for the agents used in pharmacologic stress testing are:

Adenosine <10 seconds
Dobutamine 2 min
Dipyridamole 35-45 min


SPECT liver imaging with [99mTc]sulfur colloid is performed how soon after tracer administration?

(b) 10-15 min
(c) 30-45 min
(d) 1-2 hr
(e) 3-4 hr


(b) A 10-15 min time interval is necessary for the colloidal particles to be completely localized within the liver and spleen.


Significantly increased serum bilirubin levels will most likely cause which of the following to be visualized on hepatobiliary images?

(b) colon
(c) lungs
(d) spleen
(e) pancreas


(a) Increased serum bilirubin levels indicate poorly functioning hepatocytes. Therefore, these cells cannot efficiently remove the tracer from the blood, causing the tracer to be excreted through the urinary system.


Localization of a Meckel’s diverticulum can be accomplished with which of the following radiopharmaceuticals?

(b) [99mTc]pentetate
(c) [99mTc]MAA
(d) [99mTc]sulfur colloid
(e) [99mTc]pertechnetate


(e) 99mTc-pertechnetate is used to visualize a Meckel’s diverticulum. Often, the Meckel’s diverticulum is lined with gastric mucosa that concentrate this tracer.


In infants, 24 hr images are sometimes performed over what area to demonstrate gastroesophageal reflux?

(b) lung fields
(c) stomach
(d) upper small intestine
(e) lower esophagus


(b) In infants, 24-hour images are useful for demonstrating aspiration of stomach contents.


Effective renal plasma flow (ERPF) is measured with which of the following radiopharmaceuticals?

(b) [99mTc]disofenin
(c) [99mTc]medronate
(d) [99mTc]mertiatide
(e) [99mTc]exametazime


(d) ERPF is primarily a measurement of tubular function. Therefore, a renal agent that is secreted by the tubules must be used. 99mTc-mertiatide is secreted by the renal tubules and is used to determine ERPF.


Evaluating the quality of a bolus injection is best accomplished by which of the following techniques?
(a)generating a time-activity curve for the superior vena cava

(b) calculating the cardiac transit time
(c) determining the heart to lung ratio
(d) imaging the injection site for residual activity
(e) visually inspecting the bolus


(a) Evaluating the quality of a bolus injection is accomplished by generating a time-activity curve over the superior vena cava and measuring the full width at half maximum (FWHM). If the left ventricular ejection fraction is being determined, a FWHM <=1 second indicates a technically satisfactory bolus injection. For a right ventricular ejection fraction, a FWHM of 2-3 sec is adequate.


Which of the following is/are NOT normally visualized on a 67Ga image acquired 72 hr after tracer administration?

(b) lacrimal glands
(c) kidney
(d) liver
(e) sternum


(c) In the first 24 hours after administration, the kidneys excrete almost one-third of the 67Ga injected. Hence, renal activity is normally visualized on images up to 48 hours after tracer administration. After 48 hours, renal activity indicates disease.


Which of the following statements about “transmission-based precautions” is FALSE?
(a)These precautions are applied when a patient is known to be infected with a communicable disease.

(b) These precautions replace “standard precautions.”
(c) These precautions include guidelines for airborne- and droplet-borne diseases.
(d) These precautions include guidelines for contact transmitted diseases.
(e) These precautions must be implemented in the case of diseases such as varicella, tuberculosis, and mumps.


(b) Transmission-based precautions are applied along with standard precautions when a patient is known to be infected with a communicable disease. They are a second level of precautions that include additional safety measures depending on the method in which the disease in question is transmitted.


Which of the following statements about pentetreotide is TRUE?
(a)It exhibits no human antimurine antibody (HAMA) effect.

(b) It is a labeled antibody.
(c) It is a labeled antigen.
(d) It is excreted exclusively through the kidneys.
(e) It is labeled with 99mTc.


(a) Pentetreotide is an analog of the hormone somatostatin that is labeled with 111In. It is a peptide rather than an antibody and, for this reason, does not induce the HAMA effect in patients. The tracer is mostly excreted through the urinary system, but a small amount is also excreted through the gastrointestinal tract.


The purpose of using acetazolamide in conjunction with a brain agent is to:
(a)Tranquilize the patient.

(b) Localize brain tumors.
(c) Localize the area of the brain from which seizures arise.
(d) Evaluate cerebrovascular hematoma.
(e) Evaluate cerebrovascular ischemia.


(e) Acetazolamide (Diamox) is used in conjunction with SPECT brain imaging in patients with transient ischemic attacks, carotid artery disease, and cerebrovascular disease, among others. This technique is used to identify ischemic areas in the brain. Acetazolamide induces cerebral vasodilation. After is is administered, normal blood vessels dilate but diseased ones do not.


The technologist’s responsibilities during tracer administration for a cisternogram include:
(a)ensuring that personnel and the surroundings are not contaminated with radioactivity

(b) obtaining consent to perform the procedure
(c) delivering antihistamines for any adverse reactions to the procedure
(d) testing the pressure of the cerebrospinal fluid
(e) performing the lumbar puncture


(a) Frequently, the radiopharmaceutical for cisternography is administered outside the nuclear medicine department. It is typically the technologist who transports the tracer to the area where the lumbar puncture is being performed and oversees its administration. One of the responsibilities of the technologist is to protect personnel in the work environment by limiting their radiation exposure and confining radioactivity to prevent the spread of contamination. In this instance, the technologist is the onsite expert in handling radioactive materials. Therefore, the technologist should ensure that any contaminated materials used during the lumbar puncture are collected for proper disposal. The administration area should be monitored for contamination and any personnel who handled the radiopharmaceutical should be monitored before they are permitted to leave the area.


Sodium phosphate 32P may be used to treat which of the following conditions?
(a)liver metastases

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


(e) Sodium phosphate 32P is administered intravenously and may be used to treat polycythemia vera.


Supersaturated potassium iodide solution may be administered to the patient for therapy with which of the following radiopharmaceuticals?

(b) [89Sr]chloride
(c) [131I]sodium iodide
(d) [131I]tositumomab
(e) [90Y]chloride


(d) To minimize thyroid uptake of unbound iodine that may be present in the radiopharmaceutical, supersaturated potassium iodide is administered to a patient receiving 131I tositumomab for treatment of non-Hodgkin’s lymphoma. The blocking agent is administered 1 day before and for the next 14 days during therapy.


The first step that a technologist should initiate in a safe environment when an adult patient is determined to be unresponsive is to:
(a)Perform chest compressions.

(b) Establish an airway.
(c) Check for a carotid pulse.
(d) Call for help.
(e) Perform rescue breathing.


(d) American Heart Association standards and guidelines indicate that once verification of cardiac arrest has occurred, the rescuer should call for help first and then initiate CPR.


[111In]Pentetreotide should NOT be administered through an intravenous line containing:

(b) a total parenteral nutrition mixture
(c) dextrose
(d) glucose
(e) 0.9% sodium chloride


(b) 111In-pentetreotide should not be administered through an intravenous line containing total parenteral nutrition (TPN) mixtures, because the tracer may form a complex with components of the TPN mixture. Because the chemical form of the tracer is now altered, its distribution in the body will change.


Dual-isotope gastric emptying studies use which of the following radiopharmaceuticals for each phase of gastric emptying?
Liquid phase - Solid phase
(a)[111ln]Pentetate - [99mTc]Sulfur colloid

(b) [111ln]Pentetreotide - [99mTc]Sulfur colloid
(c) [99mTc]Sulfur colloid - [111ln]Pentetate
(d) [201Tl]Thallous chloride - [99mTc]Sestamibi
(e) [99mTc]Pentetate - [99mTc]Sulfur colloid


(a) When liquid and gastric emptying times are to be determined simultaneously, the solid phase is labeled with 99mTC-sulfur colloid and teh liquid phase is mixed with 111In-pentetate.


Proper placement of a urine collection bag includes:
(a)placing it across the patient’s lower legs to keep it near the level of the bladder

(b) placing if on the stretcher near the patient’s feet so it is out of the field of view of the camera
(c) discharging the urine collection bag must be done before the exam begins
(d) hanging it from an IV pole and raising it above the level of the bladder
(e) hanging it from the imaging table so it is lower than the level of the bladder


(e) For proper drainage, the urine collection bag must always be lower than the urinary bladder. If it is not lower, the urine may reflux back into the bladder, which may result in a urinary tract infection.


Which of the following radiopharmaceuticals can be used to assess vesicoureteral reflux by the indirect method?

(b) [99mTc]sulfur colloid
(c) [99mTc]pentetate
(d) [99mTc]medronate
(e) [99mTc]albumin


(c) Radionuclide cystography is used to assess vesicoureteral reflux. This study may be performed by the indirect of the direct method. In the indirect method, a renal agent is administered intravenously. When the tracer has cleared from the kidneys into the bladder imaging of the ureters and kidneys is performed after the patient voids.


If 0.02 ug/kg of cholecystokinin is needed for a hepatibiliary study, what volume needs to be drawn for a 175 lb patient with a solution of 10 ug/ml available to draw from
(a)0.115 mL

(b) 0.129 mL
(c) 0.134 mL
(d) 0.149 mL
(e) 0.159 mL


(e) There are 2.2 lbs per kg. Therefore:

How many kg = 175 lbs x 1 kg/2.2 lbs = 79.54 kg

How many micrograms of CCK needed = 79.54 kg x 0.02 ug/1 kg - 1.59 ug total needed for patient

How many mL needed = 1.59 ug needed x 1 mL/10 ug = 0.159 mL volume needed for patient.


Parenteral administration of a drug or radiopharmaceutical would include all of the following routes EXCEPT:

(b) intramuscular
(c) subcutaneous
(d) intravenous
(e) intrathecal


(a) The term parenteral means “other than through the intestine.”


The red cell survival test is most often performed on a patient with suspected:
(a)hemolytic anemia

(b) intestinal malabsorption
(c) iron deficiency anemia
(d) pernicious anemia
(e) GI bleed


(a) The red cell survival test is used to study the lifespan of red blood cells in patients with suspected hemolytic anemia. These patients will have a cell lifespan shorter than normal.


A technologist confirms a referring physician’s request for a nuclear medicine procedure for a hospitalized patient by:
(a)asking the floor nurse

(b) telephoning the patient’s physician for confirmation
(c) locating the order for the test in the patient’s medical record
(d) conferring with the nuclear medicine physician
(e) asking the patient why s/he came to the nuclear medicine department


(c) The referring physician initiates orders for diagnostic testing and enters those orders in the patient’s medical record. It is the technologist’s responsibility to confirm the orders for a nuclear medicine test for each patient.


Which type of collimator should be used for organ counting during a red cell sequestration study?
(a)low-energy, high-sensitivity parallel hole

(b) high-energy, low-resolution parallel hole
(c) pinhole
(d) flat field
(e) converging


(d) A probe system equipped with a flat-field collimator should be used to obtain organ counts, This will allow adequate statistics in reasonable time periods and exclude counts coming from areas outside the region interest.


If a plasma volume has been determined to be 15 L, which of the following events has most likely occurred
(a)completion of a satisfactory study

(b) overhydration of the patient
(c) dehydration of the patient
(d) patient did not fast for the study
(e) infiltration of the tracer


(e) Depending on body weight and gender, a patient’s total blood volume normally ranges from about 3 to 6 L. If a plasma volume has been determined to be 15 L, some technical error probably caused this result. The most plausible explanation is that the tracer was infiltrated. When this occurs, it appears as if the amount of radioactivity thought to be injected has been diluted in a large volume, but what has actually occurred is that not all the tracer was added to the circulation. When a plasma sample is counted, the counts are relatively low compare with a sample in which the tracer has been diluted in a smaller volume. Or, consider the formula used to calculate a plasma volume:

PV (mL) = volume injected x cpm in 1 mL std x dilution / (cpm in 1 mL plasma)

The lower the counts in the plasma sample, the smaller the number in the denominator of the plasma volume formula; hence, the larger the calculated plasma volume.


A biohazard warning label would be found on all of the following EXCEPT a:
(a)contaminated sharps container

(b) refrigerator containing potentially infectious material
(c) receptacle for contaminated laundry
(d) unit of blood released for clinical use
(e) uncontaminated sharps container


(d) Biohazard warning labels are attached to any container of regulated materials. These include refrigerators, freezers, and anything used to store, transfer, or ship blood or infectious materials. Labels are not required on containers of blood that have been released for clinical use, such as blood transfusion.


The total blood volume may be calculated by dividing the plasma volume measured with labeled albumin by the:

(b) plasmacrit
(c) corrected hematocrit
(d) corrected plasmacrit
(e) hemoglobin


(d) The formula for calculating the total blood volume (TBV) based on the plasma volume uses the corrected plasmacrit in the denominator. Correction is needed to account for trapped plasma and to adjust the venous hematocrit to an average whole body hematocrit. The formula is:

TBV= plasma volume/ (1 - (HCT x 0.97 x 0.91))


If radioactivity in the circulation from a previous nuclear medicine test is unaccounted for, results of a plasma volume determination will be:
(a)falsely decreased

(b) falsely elevated
(c) positive
(d) impossible to predict
(e) unaffected


(a) When residual radioactivity is present in the circulation, it appears as if the amount of radioactivity injected has been diluted in a smaller volume than it actually has. When a plasma sample is counted, the counts are relatively high compared with a sample in which the tracer has been diluted in large volume. Or, consider the formula used to calculate a plasma volume:

PV (mL) = volume x cpm in 1 mL std x dilution / (cpm in 1 mL plasma)


The recommended amount of captopril to be given orally an hour before renal imaging in a hypertension study is:
(a)10-15 mg

(b) 15-20 mg
(c) 25-50 mg
(d) 55-100 mg
(e) 105-110 mg


(c) 25-50 mg tablet, usually given orally 1 hr before hypertension renal study.


Imaging with [111In]pentetreotide routinely includes what area(s) of the body?
(a)head and chest

(b) chest
(c) abdomen
(d) head to upper femurs
(e) lower extremities


(d) Imaging with 111In-pentetreotide routinely includes the head to upper femurs, because detection of both the primary tumor and any metastases is the goal of the examination. If indicated, the extremities may also be included


A patient scheduled for scintimammography has symptoms involving her left breast. Which of the following sites is the best choice for injection of the radiopharmaceutical?
(a)subcutaneous in the left breast

(b) right carotid artery
(c) right antecubital area
(d) left hand
(e) left carotid artery


(c) If the suspected disease is in the left breast, it would be best to use the contralateral side of the body for injection at a site distant from the breast or lymph nodes that may also be involved.

Based on the net counts data shown here:
Right lung: 175,362
Left lung: 325,672
What is the percentage perfusion to the right lung?

(b) 35%
(c) 54%
(d) 65%
(e) 77%


% activity in ROI = (counts in ROI / (total counts in all ROIs)) x 100

% activity right lung = (175,362 cts / (175,362 cts + 325,672 cts)) x 100

= (175,362 cts / 501,034 cts) x 100 = 35%


If 375 mCi 99mTc are present on the column of a 99Mo/99mTc generator, and after elution, 342 mCi 99mTc are assayed in the elution vial, the approximate elution efficiency of the generator is:

(b) 91%
(c) 33%
(d) 11%
(e) 5%


(b) Elution does not remove all 99mTc present on the generator column. Elution efficiency is expressed as the percentage of 99mTc activity on the column that is eluted:

elution efficiency = (99mTc activity eluted / 99mTc activity on column) x 100

In this case:

elution efficiency = (342 mCi / 375 mCi) x 100 = 91%


250 kilobecquerels are equivalent to how many microcuries?
(a)0.25 uCi

(b) 0.55 uCi
(c) 6.76 uCi
(d) 9.25 uCi
(e) 10.35 uCi


(c) Conversions between the CGS and SI systems can be accomplished easily if you remember the three following relationships:

1 Ci = 37 GBq
1 mCi = 37 MBq
1 uCi = 37 kBq

Then to convert kilobecquerels to microcuries:

350 kBq x 1 uCi / 37 kBq = 6.75 uCi


If a 99Mo/99mTc generator is eluted on Monday at 0600, the maximum 99mTc activity could next be eluted at what time?
(a)0600 on Tuesday

(b) 1200 on Monday
(c) 1800 on Monday
(d) 0600 on Wednesday
(e) 1200 on Tuesday


(a) Maximum 99mTc activity is obtained about 24 hours after the last elution of 99mTc


According to the NRC, 99Mo contamination in 99mTc eluate must be measured how often?

(b) daily
(c) only after the first elution
(d) yearly
(e) after each elution


(c) According to the NRC, 99Mo breakthrough must be measured in the first elution from a 99Mo/99mTc generator


If these results shown were obtained when 99mTc eluate was assayed for 99Mo breakthrough at 0600, immediately after elution:
99Mo: 10 uCi
99mTc: 416 mCi
which of the following statements about this elution at 1700 is true?
(a)The eluate should not be used to label compounds with 99mTC.

(b) The eluate does not contain sufficient 99mTc activity.
(c) The eluate does not contain sufficient 99Mo activity.
(d) The eluate must not be administered to patients.
(e) The eluate may be administered to patients.


(e) At 0600, the 99Mo contamination in the eluate is below the maximum allowable limit of 0.15 uCi 99Mo per mCi 99mTc:
10 uCi 99Mo / 416 mCi 99mTc = 0.024 uCi 99Mo/mCi 99mTc
To determine the 99Mo concentration in the eluate at 1700, decay correct both the 99Mo and 99mTc activities obtained at 0600 for 11 hours (0600 to 1700 = 11 hr):
99Mo: 10 uCi x 0.891 = 8.9 uCi
(0.891 is the 99Mo decay factor for 11 hours)
99mTc: 416 mCi x 0.282 = 117 mCi
(0.282 is the 99mTc decay factor for 11 hours)
At 1700, then, the 99Mo concentration is equal to:
8.9 uCi 99Mo / 117 mCi 99mTc = 0.08 uCi 99Mo/mCi 99mTc
This level is below the maximum allowable limite of 99Mo contamination set by the NRC. Therefore, the eluate may be administered to patients at 1700.


A technologist performs an aluminum ion breakthrough test on 99mTc eluate and obtains the following results: When the indicator paper is spotted with aluminum ion solution, a faint red color is observed, but when the paper is spotted with eluate, no color change is observer. These results indicate:
(a)absence of radionuclidic impurities in the eluate

(b) absence of free [99mTc]pertechnetate
(c) the aluminum ion concentration in the eluate is below the U.S. Pharmacopeia (USP) limit
(d) the aluminum ion solution contains less aluminum than the eluate
(e) the eluate should be discarded


(c) Aluminum is a chemical impurity that is measured using a colorimetric test consisting of a special indicator paper and a reference solution of known aluminum ion concentration. No color change represents an aluminum ion concentration below 10 ug/mL of eluate, the USP limit. Therefore, this eluate may be administered to patients and used to prepare other 99mTc-labeled radiopharmaceuticals. 99mTc does contain radionuclidic impurities such as 99Mo, but these impurities are assayed in a different manner.


All of the following procedures may be performed with [99mTc]sulfur colloid EXCEPT:
(a)gastric-emptying study

(b) gastroesophageal reflux study
(c) gastrointestinal-bleeding localization
(d) Meckel’s diverticulum localization
(e) bone marrow imaging


(d) Gastric emptying and gastroesophageal reflux studies and gastrointestinal bleeding localization all may be performed with 99mTc-sulfur colloid. 99mTc-pertechnetate is used to localized a Meckel’s diverticulum.


Based on the day’s clinic schedule shown here:
Patient A - Thyroid uptake and image
Patient B - Therapy for hyperthyroidism
Patient C - Cisternogram
the technologist should prepare or order which of the following radiopharmaceuticals?
(a)[123I]sodium iodide, [131I]sodium iodide, [111In]pentetate

(b) [111ln]oxine and [123I]sodium iodide
(c) [123I]sodium iodide, [99mTc]sulfur colloid, [99mTc] Macroaggregated Albumin
(d) [131I]sodium iodide and [111In]chloride
(e) [131I]human serum albumin, [131I]sodium iodide, [99mTc]pertechnetate


(a) 131I-sodium iodide is the agent used for treatment of hyperthyroidism. 123I-sodium iodide is the agent of choice for thyroid uptake and may be used for thyroid imaging as well. 111In-pentetate is administered for cisternography.


If an MAA kit must be reconstituted with 3.5 mL of [99mTc]pertechnetate, what are the consequences if only 2.0 mL are added to the kit?
(a)Patients will receive more MAA particles per milliliter of [99mTc]MAA.

(b) Patients will receive more pertechnetate per milliliter of recommended patient dose.
(c) Patients will receive the recommended number of particles if the correct activity is administered
(d) The resulting perfusion lung images will have the appearance of decreased tracer uptake
(e) Patients will receive fewer MAA particles per milliliter of [99mTc]MAA


(a) The volume added to an MAA kit governs the numbers of particles in each milliliter of radiopharmaceutical and, therefore, the number of particles a patient will receive. For example, if a vial of MAA contains 2 million particles and 2 mL 99mTc-pertechnetate are added to the vial, there will be approximately 1 million MAA particles in each milliliter. If only 1 mL is added, there will be twice as many particles in each milliliter. Therefore, a patient would receive twice as many particles in a unit dose from the second preparation.


Reconstituted “cold” pyrophosphate is administered to the patient in which red blood cell labeling method(s)
(a)in vitro method

(b) both the in vivo method and the modified in vivo method
(c) modified in vivo method
(d) both the in vitro method and the in vivo method
(e) in vivo method


(b) In both the in vivo and modified in vivo techniques, reconstituted “cold” pyrophosphate, containing stannous ion that permits 99mTc-pertechnetate to permeate red cell membranes, is administered intravenously to the patient. In the in vitro method, the entire labeling process takes place outside the patient. A blood sample is collected to which stannous ions are added. After an incubation period, 99mTc-pertechnetate is added to the red cells after they have been isolated from the plasma. After another incubation period, the red cells are washed to remove unbound tracer, reconstituted, and injected back into the patient.


Which of the following radiopharmaceutical kit formulations is light-sensitive?

(b) oxidronate
(c) mertiatide
(d) exametazime
(e) pertechnetate


(c) The contents in the mertiatide reaction vial are light-sensitive and must be protected from light.


When performing radiochromatography on a radiopharmaceutical sample, the solvent front is located 8.5 cm from the origin and the radiochemical impurity is at the origin. What is the Rf value of the radiochemical impurity?

(b) 0
(c) 1.0
(d) 8.5
(e) 0.85


(b) 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 example, the radiochemical component in question is the radiochemical impurirty. Because the impurity remained at the origin, the distance from the origin to the impurity is zero. This, the value for the radiochemical impurity is:
Rf = 0 cm / 8.5 cm = 0


According to the USP, most 99mTc-labeled radiopharmaceuticals should have a radiochemical purity of at least what percentage to be administered to patients?

(b) 95%
(c) 90%
(d) 88%
(e) 85%


(c) According to the USP, most 99mTc-labeled radiopharmaceuticals should have a radiochemical purity of at least 90%

A technologist must administer 8 mCi [99mTc]mebrofenin to a patient at 1100. On the basis of this vial label information:
Calibration: 0700, August 4
Total activity: 100 mCi
Total volume: 8.5 mL
Concentration: 11.8 mCi/mL
Expiration: 1500, August 4
what volume of [99mTc]mebrofenin should be administered to the patient?
(a)1.1 mL

(b) 0.92 mL
(c) 0.68 mL
(d) 0.52 mL
(e) 0.13 mL


(a) The elapsed time between calibration and unit dosage administration is 4 hours (0700-1100). From a decay fact-table from 99mTc, the decay factor for 4 hours is 0.631. The initial concentration is decay-corrected to determine the concentration at 1100:
C(t) = C(0) x DF =11.8 mCi/mL x 0.631 = 7.4 mCi/mL at 1100
Then the volume to be administered is calculated based on the prescribed patient dosage and the concentration at the time of administration:
volume = patient dosage / C(t) = 8 mCi / 7.4 mCi/mL = 1.1 mL

A technologist must administer 37 MBq [201Tl]thallous chloride at 1000 on February 16. On the basis of this vial label information:
Calibration: 1200, February 14
Total activity: 222 MBq
Total volume: 4.0 mL
Concentration: 55.5MBq/mL
Expiration: 1200, February 17
what volume should be administered to the patient?
(a)1.0 mL

(b) 0.96 mL
(c) 0.84 mL
(d) 0.44 mL
(e) 0.23 mL


(a) The elapesed time between calibration an unit dosage administration is 46 hours (1200 on February 14 - 1000 on February 16). From a decay factor table for 201Tl, the decay factor for 46 hours is approximately 0.646. The initial concentration is decay-corrected for 46 hours to determine the concentration at 1000 on February 16:
C(t) = C(0) x DF = 55.5 MBq/ml x 0.646 = 35.8 MBq/mL at 1000 on 2/16
Then the volume to be administered is calculated based on the prescribed patient dosage and the concentration at the time of administration:
volume = patient dosage / C(t) = 37 MBq / 35.8 MBq/mL = 1.0mL


A technologist needs 4 mCi [201Tl]thallous chloride at 0800 on June 29. The label on the radiopharmaceutical vial contains this information:
Total activity: 10.0 mCi
Total volume: 5.5 mL
Assay: 1200, July 1
what volume is required to obtain the necessary activity on June 29?
(a)3.6 mL

(b) 1.35 mL
(c) 0.74 mL
(d) 0.28 mL
(e) 0.13 mL


(b) The elapsed time between calibration and dosage calculation is 52 hours (0800 on June 29 - 1200 on July 1). In this example, the radiopharmaceutical is being used before the calibration time. Therefore, the initial concentration on June 29 is the unknown, and the known concentration is divided by the decay factor. The concentration on July 1 is 1.8 mCi/mL (10.0 mCi / 5.5 mL):
C(0) x 0.609 = 1.8 mCi/mL
C(0) = 1.8 mCi/mL / 0.609 = 2.96 mCi/mL
Then, determine the required volume:
volume = activity required / C(t) = 4.0 mCi / 2.96 mCi/ml = 1.35 mL


Which radiopharmaceutical is used to label red blood cells with 99mTc

(b) [99mTc]pertechnetate
(c) [99mTc]sulfur colloid
(d) [99mTc]pyrophosphate
(e) [99mTc]exametazime


(b) The three methods of labeling red blood cells with 99mTc all use 99mTc-pertechnetate. 99mTc-pertechnetate enters the red blood cell and binds to hemoglobin. Part of the red blood cell labeling process involves administration of a reconstituted “cold” pyrophosphate kit to provide the stannous compound necessary for labeling to occur. 99mTc-albumin is a blood-pool agent; that is, it remains in the circulation for a period of time after intravenous injection. It does not bind to the red blood cells. 99mTc-exametazime is used to label white blood cells.


Which of the following radiopharmaceuticals is used to label white blood cells with 99mTc?

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


(e) 99mTc-exametazime is used to label white blood cells. 99mTc-pertechnetate is used to label red blood cells. 99mTc-bicisate is used to demonstrate regional brain perfusion. 99mTc sestamibi is used to myocardial imaging as well as other applications.


When [99mTc]exametazime is used to label white blood cells, which of the following reagents is omitted from its preparation?

(b) 0.9% sodium chloride
(c) heparin
(d) methylene blue stabilizer
(e) ACD solution


(d) When 99mTc-exametazime is used to label white blood cells, methylene blue stabilized is omitted from its preparation.

If 4 millicuries of [201Tl]thallous chloride is the prescribed unit dosage which of the following dose calibrator measurements, according to the NRC, verifies that a dosage within acceptable limits has been dispensed into the syringe?
I. 3.5 mCi
II. 4.0 mCi
III. 4.3 mCi
IV. 4.5 mCi
(a)I only

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


(e) The NRC states that the administered dosage must fall within the prescribed dosage range or may not differ from the prescribed dosage by more than 20%. If the prescribed dosage is 4 mCi, the measured dosage must be between 3.2 and 4.8 mCi (+-20% of 4 mCi).


In labeling red blood cells with radiochromium, the order of components to be added to the vial containing ACD solution is:
(a)radiochromium, ACD, patient blood, ascorbic acid

(b) radiochromium, patient blood, ascorbic acid
(c) radiochromium, ascorbic acid, patient blood
(d) patient blood, radiochromium, ascorbic acid
(e) ascorbic acid, radiochromium, patient blood


(d) Radiochromium should not be added to the ACD solution before the patient’s blood, because ACD may change the valence of the radiochromium before labeling can take place. Ascorbic acid is added at the end of the labeling procedure to stop the tagging before the blood is returned to the patient.


If a unit dosage of [99mTc]MAA contains 148 MBq and 325,000 particles in 0.75 mL at 1000, approximately how many particles will be contained in 148 MBq at 1600?

(b) 325,000
(c) 433,333
(d) 522,000
(e) 650,000


(e) The concentration at 1000 is:
148 MBq / 0.75 mL = 197 MBq/mL
At 1600, after correcting for decay, the concentration is:
197 MBq/mL x 0.5 = 98.5 MBq/mL
Therefore, the volume of a unit dosage at 1600 is:
148 MBq / 98.5 MBq/mL = 1.5 mL
The number of particles in 1 mL remains constant over time and is:
325,000 particles / 0.75 mL = 433,333 particles/mL
Therefore, the 1600 dosage contains twice as many particles as the 1000 dosage, because the 1600 dosage contains twice the volume to obtain the same unit dosage of 148 MBq:
433,333 particles/mL x 1.5 mL = 650,000 particles


If a unit dosage of radioactivity contains 4.5 mCi in 1.2 mL, how many milliliters must be removed so 3.5 mCi remain in the syringe?
(a)0.93 mL

(b) 0.78 mL
(c) 0.27 mL
(d) 0.13 mL
(e) 0.02 mL


(c) Determine the concentration:
concentration = total activity / total volume = 4.5 mCi / 1.2 mL = 3.75 mCi/mL
Determine the volume that will contain the required activity:
volume = activity required / concentration = 3.5 mCi / 3.75 mCi/mL = 0.93 mL
Determine the volume that will have to be removed from the syringe:
Total volume - volume required = volume to be removed
1.2 mL - 0.93 mL = 0.27 mL


If a radiopharmaceutical kit must be reconstituted with 30 mCi contained in 5 mL and the eluate has an activity of 350 mCi in 7 mL, how many milliliters of preservative-free saline must be added?
(a)0.6 mL

(b) 4.4 mL
(c) 4.9 mL
(d) 5.2 mL
(e) 6.0 mL


(b) Determine the concentration of the eluate:
concentration = total activity / total volume = 350 mCi / 7 mL = 50 mCi/mL
Determine the volume of 99mTc-pertechnetate needed to obtain the required activity:
volume = activity required / concentration = 30 mCi / 50 mCi/mL = 0.6 mL
Because the activity must be contained in a specific volume (5 mL), sterile, preservative-free saline must be added to make up the required volume:
Reconstituting volume = 99mTc-pertechnetate volume + saline volume
Saline volume = reconstituting volume - 99mTc-pertechnetate volume
Saline volume = 5 mL - 0.6 mL = 4.4 mL


What is the minimal centrifugation time needed if a protocol specifies 5000 g for 5 min, but the maximum relative centrifugal force that can be obtained is 2500 g?
(a)2 min

(b) 2.5 min
(c) 7.5 min
(d) 10 min
(e) 12.5 min


(d) In this case, the centrifuge cannot provide the necessary relative centrifugal force (RCF) identified in the protocol. However, by adjusting the time, the same degree of centrifugation may be obtained. The relationship is:
T1G1 = T2G2
where T1 and G1 are the minimum time of centrifugation and RCF, respectively, and T2 and G2 are the alternative time and RCF, respectively. Solving for the alternative time:
T2 = T1G1 / G2 = (5 min)(5000 g) / 2500 g = 10 min


According to the NRC, imaging rooms should be posted with which of the following signs?
(a)No posting is required.

(b) “Caution: No Food or Drink”
(c) “Caution: Radiation Area”
(d) “Caution: Radioactive Materials”
(e) “Caution: High Radiation Area”


(d) The NRC requires that restricted areas, such as imaging rooms, be posted with specific signs depending on the radiation level present. A “Caution: Radioactive Materials” sign should be posted in areas where certain quantities of radioactive materials are used or stored. There quantities are those exceeding 10 times the quantities specified in Appendix C to 10 CFR Part 20. The quantities for commonly used radionuclides that will result in required posting include: as excess of 10 mCi of 99mTc, 67Ga, 133Xe, or 201 Tl; an excess of 1 mCi of 123I or 111In; more than 10 uCi of 131I.


Which of the following exposure rates indicate that a package containing radioactive material must have a category III DOT label? Select all that apply.
At package surface - At 1 m
(a)76 mR/hr - 5.5 mR/hr

(b) 56 mR/hr - 3.5 mR/hr
(c) 22 mR/hr - 0.9 mR/hr
(d) 1.5 mR/hr - 1.0 mR/hr
(e) 0.5 mR/hr - No detectable radiation
(f) Both A and B


(f) The label types and exposure rate limits for packages containing radio active materials are:

Label category - At surface (mR/h) - At 1 m
Category I (white) - <= 0.5 - No detectable radiation
Category II (yellow) - <= 50 - <= 1.0
Category III (yellow) - <= 200 - <= 10

If a point source produces an exposure rate of 30 mR/hr at a distance of 15 cm, what is the exposure rate at 40 cm from the source?
(a)4.2 mR/hr

(b) 8.5 mR/hr
(c) 11.2 mR/hr
(d) 22 mR/hr
(e) 25 mR/hr

(a) Use the inverse square law:
(I1)(D2)^2 = (I2)(D2)^2
where I1 = intensity at original distance (D1) and I2 = intensity at new distance (D2).
In this example:
(30 mR/hr)(15 cm)^2 = (I2)(40 cm)^2
Isolate the unknown and solve:
I2 = (30 mR/hr)(15cm)^2 / (40cm)^2
I2 = 4.2 mR/hr

If the half-value layer (HVL) for 131I in lead is 0.3 cm, what is the minimum thickness of lead that is required to reduce the exposure rate of an 131I source form 12 mR/hr to less than 2 mR/hr
(a)0.3 cm

(b) 0.6 cm
(c) 0.75 cm
(d) 0.9 cm
(e) 1.2 cm


(d) Each half-value layer (HVL) will decrease the activity to one-half of the previous activity.
No. of HVLs - Exposure rate (mR/h)
0 - 12
1 - 6
2 - 3
3 - 1.5
Thus three HVLs are required to decrease the exposure rate to less than 2 mR/h. Hence, the thickness of lead required is three times the HVL, or 3 x 0.3 cm = 0.9 cm.


A patient receives a unit dosage of [89Sr]chloride intended for another patient. Which of the following statements about this situation is TRUE?
(a)Because the patient received only a unit dosage of 89Sr, no report to the NRC is required.

(b) According to the NRC, this does not constitute a medical event, but a departmental record should be maintained.
(c) The situation describes a medical event that has to be reported only to the nuclear medicine supervisor and the authorized user.
(d) No report is necessary since it does not reach the dose threshold for reporting.
(e) The situation describes a medical event requiring notification of the NRC.


(e) A licensee must notify the NRC of medical events, which are defined as an administration of a licensed material that results in an effective equivalent dose (EDE) greater than 5 Rem, a dose to an organ or tissue that is greater than 50 Rem, or shallow dose exposure (SDE) to the skin greater than 50 Rem because of any of the following:

The total dosage delivered differs from the prescribed dosage by 20% or more.
The total dosage falls outside the prescribed range.
The wrong radioactive drug was administered.
The radioactive drug was administered by the wrong route.
The radioactive dosage was administered to the wrong person.

When a medical event (misadministration) occurs, the NRC requires the licensee to notify the NRC, the referring physician, and the involved individual, unless the referring physician determines, on the basis of medical judgment, that such notification would be harmful to the patient.


According to NRC regulations, the annual occupational dose limit to the eye is:
(a)150 mSv

(b) 100 mSv
(c) 75 mSv
(d) 50 mSv
(e) 5 mSv


(a) According to the NRC, the annual occupational dose limit to the eye is 15 Rem or 150 mSv.


A vial of 133 Xe has been decayed in storage for 2 months. When the vial is monitored with a survey meter, the reading is twice the background radiation level. What should the technologist do next?
(a)Remove any radiation symbols from the vial, then dispose of it.

(b) Perform a wipe check.
(c) Return the vial to storage.
(d) Vent the radioactivity left in the vial into a fume hood.
(e) Dispose of the vial as biohazardous waste.


(c) According to NRC regulations, decay in storage of radioactive materials requires that the materials remain in storage until the radioactivity is indistinguishable form background radiation, using a survey meter on the most-sensitive scale and without any shielding in place.


According to the NRC, wipe tests of areas where radiopharmaceuticals are prepared or administered must be performed:
(a)on a reasonable schedule

(b) every day on which radiopharmaceuticals are used
(c) weekly
(d) only if contamination occurs
(e) monthly


(a) NRC regulations required a survey of areas where radiopharmaceuticals that require a written directive are prepared or administered. This would include therapeutic radiopharmaceuticals and dosages of 131I greater than 30 uCi.
As of October 2002, the NRC no longer requires daily surveys and weekly wipe tests. Instead, it allows facilities to establish a survey and wipe test schedule. The schedule must be reasonable, based on the need to determine radiation levels, concentrations or quantities of radioactive materials, and potential radiological hazards.


What is the measured exposure rate shown on the diagram of the G-M meter depicted here?
(line at 1.7 mR/hr & knob at x 0.1)
(a)0.017 mR/hr

(b) 0.17 mR/hr
(c) 1.7 mR/hr
(d) 17 mR/hr
(e) 170 mR/hr


(b) The measured exposure rate is the product of the number indicated by the needle on the meter and the scale. In this example, the reading on the meter is 1.7 on a scale of 0.1. Thus, 1.7 mR/h x 0.1 = 0.17 mR/h


When opening packages containing radioactive material, which of the following steps should be performed first?
(a)Perform a survey using Geiger counter.

(b) Wipe-test the package receiving area.
(c) Put on disposable gloves.
(d) Wipe-test the package for contamination.
(e) Verify the package contents against the packing slip.


(c) Because it has not been determined that the package is free of contamination, gloves should be put on before the package or its contents are handled.


During cleanup of a radioactive spill, decontamination of the area must continue until wipe checks reveal that:
(a)The exposure rate of the area is less than 3 mRem/hr.

(b) The exposure rate of the area cannot be distinguished from background activity.
(c) The contamination is reduced to a small area.
(d) No one would receive the maximum allowable total effective dose equivalent (TEDE) if he/she remained in the area.
(e) No more contamination can be removed from the area.


(e) Decontamination of a radioactive spill should continue until the residual radioactivity is below the action level set by the licensee or until no further contamination can be removed by cleaning the area. If residual radioactivity is present after thorough decontamination, the area should be covered as a reminder for personnel to limit their time in that area.


Personnel must wear a radiation monitoring device during work hours if they are:
(a)exposed to radiation at any time during work hours

(b) exposed to radiation above background levels
(c) likely to exceed 10% of the annual maximum allowable occupational exposure
(d) likely to exceed the annual maximum allowable occupational exposure
(e) a radiologic technologist


(c) The NRC requires monitoring of occupationally exposed individuals if they are likely to exceed 10% of the annual allowable limit for external exposure of internal uptake.


A patient can be released after receiving a therapeutic radiopharmaceutical if no other individual is likely to receive an exposure dose, from being exposed to the patient, exceeding how many Rems?
(a)0.5 Rem

(b) 0.7 Rem
(c) 2.5 Rem
(d) 5.0 Rem
(e) 7.0 Rem


(a) According to the NRC, an individual who has received a therapeutic dosage of radiopharmaceutical can be released if no other individual is likely to receive a total effective dose equivalent (TEDE) exceeding 0.5 Rem (5mSv) as a result of contact with the person who received the radiopharmaceutical.


If a source of radioactive contamination produced an exposure rate of 3 mR/hr, how long will it take for the exposure rate to drop to a background exposure rate of 0.05 mR/hr
(a)5 half-lives

(b) 6 half-lives
(c) 7 half-lives
(d) 8 half-lives
(e) 9 half-lives

(b) For each half-life that passes, the activity decreases to half of the previous activity.
No. of half-lives - Exposure rate (mR/h)
0 - 3
1 - 1.5
2 - 0.75
3 - 0.37
4 - 0.19
5 - 0.09
6 - 0.05
After 6 half-lives, the original activity has decreased to background activity.

According to the NRC, records of surveys must be retained for how many years?
(a)as long as the facility’s license is in effect

(b) 7 years
(c) 5 years
(d) 4 years
(e) 3 years


(e)According to the NRC, the results of all surveys must be retained for three years.


Which of the following materials is recommended for shielding syringes containing positron-emitting radionuclides?

(b) tungsten
(c) gold
(d) steel
(e) plastic-lined lead


(b) Tungsten is recommended, because it will absorb more radiation than the same thickness of lead.


If a nuclear medicine technologist needs a diagnostic x-ray, how should this exposure be included in his/her occupational exposure record?
(a)The technologist should wear his/her radiation dosimeter during the x-ray examination.

(b) The exposure from the x-ray examination must not be included in the occupational exposure record.
(c) The RSO will supply a separate dosimeter for the technologist to wear during the x-ray examination.
(d) A pocket dosimeter should be used.
(e) The RSO will estimate the probable exposure and add it to the technologist’s permanent record.


(b) Only radiation exposure directly related to the practice of nuclear medicine as an occupation is recorded in the individual’s dosimetry record. Personal diagnostic and therapeutic exposures are not included.


According to the standard of practice, if the results of a dose calibrator geometric variation test demonstrate that the measured values exceed the values by 12-15%, the technologist should:
(a)Replace the instrument.

(b) Use a correction factor to determine true activities.
(c) Perform a chi-square analysis.
(d) Use the actual dose calibrator activity readings.
(e) Have the instrument repaired.


(b) The NRC requires that dose calibrators be tested for proper function according to nationally recognized standards. The standard of practice dictates that the measured activity should be within +- 10% of the expected activity when the instrument is tested for linearity. If the instrument exceeds this level of error, a correction factor should be calculated and applied to all measurements in the affected activity range.


A technologist measures a 57Co standard in a dose calibrator on the following settings - 57Co, 99mTc, 123I, 131I, 133Xe, and 201 Tl - and then calculates the percentage difference between the calculated and measured activities. the technologist is assessing:

(b) chi-square analysis
(c) linearity
(d) geometric variation
(e) accuracy


(a) Using a long-lived source, a reading is obtained for each of the commonly used preset buttons on the dose calibrator. Although this dose not provide an accurate (true) reading, it shows whether the instrument is performing with precision (reproducibility). The reading should be within +- 10% of the expected decay-corrected reading.

A 137Cs reference standard is counted daily with a scintillation spectrometer, using the same gain, window, and high voltage setting. On the basis of these data:
Date - Net counts per minute
July 15 - 12,555
July 16 - 12,534
July 17 - 12,613
July 20 - 10,678
on July 20, the technologist should:
(a)Use the spectrometer for clinical studies.

(b) Arrange for repair of the instrument.
(c) Change the gain setting.
(d) Change the fine gain setting.
(e) Recalibrate the operating voltage.


(e) Voltage may drift slightly from one day to the next, causing the gamma ray spectrum to shift to the right or left, out of the preset window. From the data, it appears that this is what may have happened. Before using the instrument for clinical studies or sending it for repair, the technologist should recalibrate the operating voltage by observing the counting rate at the most recent voltage setting and voltages settings just above and below that setting. If the counting rate increases when counts are obtained off the original operating voltage, the voltage should be adjusted until a maximum counting rate is reached. The voltage at which a maximum counting rate is obtained is the new operating voltage. If there is significant voltage fluctuation from day to day, the instrument should be serviced.


According to the standard of practice, how often should dose calibrator linearity testing be performed?

(b) quarterly
(c) monthly
(d) daily
(e) hourly


(b) Dose calibrator linearity should be performed quarterly.


To repair the non uniformity demonstrated on the intrinsic uniformity image shown here: (round cold spot on edge of the circle)
the service engineer will need to
(a)Replace the crystal.

(b) Redo reference map calibration.
(c) Repair the collimator.
(d) Replace a photomultiplier tube.
(e) replace the x,y localization board.


(d) The round photopenic area corresponds to failure of a single photomultiplier tube. Damage to the crystal would appear more irregular. Because this is an intrinsic flood, the collimator is not in place. However, collimator or damage would also have an irregular appearance. Failure of the x,y localization hardware or software would result in a misshapen flood image.


Which of the following sources is the most appropriate for assessing dose calibrator constancy?

(b) 57Co
(c) 125I
(d) 131I
(e) 99mTc


(a) The reference source used for monitoring dose calibrator constancy must be long-lived to permit comparison of measured and predicted activities over an extended period. 57Co (half-life = 270days) and 137Cs (half-life - 30 years) are sufficiently long-lived to meet this criterion.


Which of the following statements about the effect of the filter-cutoff frequency is TRUE?
(a)The lower the cutoff frequency, the smoother the image.

(b) The higher the cutoff frequency, the noisier the image.
(c) Adjusting the cutoff frequency will not affect image appearance.
(d) The cutoff frequency cannot be adjusted after the image has been acquired.
(e) The lower the cutoff frequency, the noisier the image.


(e) The cutoff frequency of a filter determines which frequencies are passed unchanged and which are altered or suppressed. Lowering the cutoff frequency eliminates more of the high-frequency signal that gives the image its sharp details. As more of the high frequencies are removed, the images becomes smoother or less detailed, eventually decreasing resolution. (a and b?)


Temporal resolution is related to which of the following acquisition parameters?
(a)percentage energy window

(b) matrix size
(c) framing rate
(d) collimator
(e) crystal size


(c) Temporal resolution is the ability to demonstrate changes in radiopharmaceutical distribution over time. Therefore, this is a factor in dynamic and multiple-gated acquisitions, both of which acquire data in sequential frames. The framing rate is the acquisition time per frame (for example, 20 sec/frame). If the framing rate is too long, changes in radiopharmaceutical distribution can be missed. If the framing rate is too short, too few counts will be acquired in each frame and the resolution of the images may be affected.


It would be appropriate to apply temporal smoothing in which of the following studies?
(a)gated-equilibrium cardiac function study

(b) SPECT study of the brain
(c) SPECT study of the liver
(d) thyroid image
(e) whole-body bone image


(a)Temporal smoothing is used in dynamic studies to produce a gradual variation in counts and smoother motion from one frame to the next. Therefore, it is useful in gated studies, but it is not useful in static imaging, such as thyroid or whole-body images or nongated SPECT.


If an image is acquired into a 128 x 128 matrix on a scintillation camera with a 350 mm diameter field of view, what are the dimensions of each pixel?
(a)2.73 x 2.73 mm

(b) 3.14 x 3.14 mm
(c) 5.92 x 5.92 mm
(d) 6.51 x 6.51 mm
(e) 7.83 x 7.83 mm


(a) Pixel size is determined by the matrix dimensions and the size of the field of view.
pixel size (mm) = diameter of field of view (mm) / number of pixels
In this example:
350 mm / 128 pixels = 2.73 mm
Because pixels are square, the dimensions of each pixel in this 128 x 128 matrix are 2.73 x 2.73 mm.


Which of the following instruments should be used to determine whether all removable contamination has been eliminated?
(a)Geiger-Mueller counter

(b) well counter
(c) dose calibrator
(d) uptake probe
(e) cutie pie (ionization chamber)


(b)When Geiger counter readings no longer decrease as the cleanup progresses, a wipe test, which is measured in a well counter, is performed. If the wipe test shows activity does not exceed background levels, then all removable contamination has been eliminated. If nonremovable activity remains, shielding of the spill area may be necessary.


Which of the following matrix sizes and acquisition modes would be most appropriate for a blood flow study of the feet?
(a)64 x 64 word

(b) 64 x 64 byte
(c) 256 x 256 byte
(d) 256 x 256 word
(e) 512 x 512 byte


(b) A blood-flow study of the feet would be acquired at a framing rate of 2-4 sec/frame, so few counts would be obtained in each frame. Therefore, a small matrix must be used: 64 x 64. Because there will be few counts per frame, byte mode will be adequate, since it can store up to 255 counts per pixel. In word mode, about 65,000 counts can be acquired for each pixel; however, twice as much computer storage space is needed. Because this level of activity will not be present, it is wasteful - but not harmful - to use word mode.


A daily uniformity flood for a scintillation camera should contain a minimum of how many counts?

(b) 1-2 million
(c) 3-5 million
(d) 6-10 million
(e) 20-30 million


(c) For a small-field-of-view camera, 3 million counts should be acquired; for a large field of view, 5 million counts should be obtained. More counts are required as the crystal becomes larger to ensure a minimum of 10,000 counts per pixel. This minimizes the effect of noise and assures an adequate count density so uniformity can be accurately evaluated.


As a pinhole collimator is moved farther away from the thyroid, how will it affect the image?
(a)The gland will appear larger.

(b) The image will be flipped.
(c) The gland will appear smaller.
(d) There is no change in size or orientation.
(e) Right and left are reversed.


(c) As pinhole collimator is moved form a source, the image of the source becomes smaller. As it is moved closer, the image becomes larger.


During geometric variation testing of a dose calibrator, activity in a 1 mL syringe measures 253 uCi when the expected reading is 212 uCi. Which of the following correction factors should be applied to the measured reading?

(b) 4.1
(c) 1.19
(d) 0.84
(e) 0.51


(d) 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 determine the correction factor, the following equation is used:
correction factor = expected activity / actual activity
For this example:
212 uCi / 253 uCi = 0.84