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Society of Nuclear Medicine Procedure Guideline for
C-14 Urea Breath Test
version 3.0, approved June 23, 2001
Authors: Helena R. Balon, MD (William Beaumont Hospital, Royal Oak, MI); Eileen Roff, RN, MSA, (William BeaumontHospital, Royal Oak, MI); John E. Freitas, MD (St. Joseph Mercy Hospital, Ann Arbor, MI); Vanessa Gates, MS (WilliamBeaumont Hospital, Royal Oak, MI); and Howard J. Dworkin, MD (William Beaumont Hospital, Royal Oak, MI).
istration of C-14 urea, followed by sampling of the ex-haled breath at timed intervals. The breath samples The purpose of this guideline is to assist nuclear are then analyzed in a liquid scintillation counter.
medicine practitioners in recommending, perform-ing, interpreting and reporting the results of the C-14 urea breath test. III. Common Indications
Detection of the presence of H. pylori in the stomach.
II. Background Information and Definitions
A. Given the very high probability of patients w i t h duodenal ulcers being infected with H. pylori, t h e The discovery of the Gram-negative spiral rod, Heli- C-14 urea breath test has not been routinely cobacter pylori, in the 1980s radically changed the ap- recommended for initial diagnosis, but has proach to treatment of peptic ulcer disease (PUD).
been recommended to document H. pylori e r a d- The causal relationship between H. pylori infection ication following anti-H. pylori therapy. Eradi- and chronic gastritis is well established. Althoughonly a small fraction of H. pylori-positive patients de- cation should be confirmed no sooner than 1 velop PUD, essentially all patients with duodenal ul- month, and preferably longer, after completion cers and about 80% of patients with other than non- steroidal anti-inflammatory drug (NSAID)-induced B. Since the prevalence of H. pylori in gastric ulcer gastric ulcers are infected with H. pylori. Eradication patients (non-NSAID-induced gastric ulcers) is of H. pylori markedly reduces ulcer recurrence to about 80%, the C-14 urea breath test may be used <10% in 1 yr vs. 60-100% recurrence rate in 1 yr with for initial diagnosis as well as follow-up in this There is also evidence that H. pylori infection is as- s o c i a t e d with adenocarcinoma and lymphoma of the IV. Procedure
stomach, although in the United States fewer than 1%of H. pylori-infected people will develop gastric cancer.
Further research is needed to determine the role of 1. Patients should be off the following medica- H. pylori eradication in gastric cancer prevention.
The presence of active H. pylori infection can be di- a. Antibiotics and bismuth compounds for 30 agnosed non-invasively with the C-14 urea breath test. This test is based on the detection of the enzyme urease produced by H. pylori. Since urease is not pre- (e.g., omeprazole, esomeprazole, lansopra- sent in normal human tissues, and since other ure- zole, rabeprazole, pantoprazole) for 2 wk ase-producing bacteria do not colonize the stomach, the presence of urease in the stomach can be equated 2. Patients should be NPO for at least 6 hr before In the presence of urease, orally administered C- B. Information Pertinent to Performing the Procedure 14 urea will be hydrolyzed into ammonia and A relevant history should be obtained; particu- 1 4C O2. 1 4C O2 is absorbed into the circulation and ex- larly, a list of relevant medications and the time haled by the lungs. The presence of a significant of their most recent administration should be amount of 1 4C O2 in the exhaled breath indicates ac- tive H. pylori i n f e c t i o n .
The C-14 urea breath test consists of the oral admin- Radiation Dosimetry for C-14 Urea*
Administered Activity
Organ Receiving the
Effective Dose
L a r g e s t Radiation Dose
Equivalent+
( r a d / m C i )
(rem/mCi)
*from Stubbs JB, Marshall BJ. Radiation dose estimates for the C-14 labeled urea breath test.
tion fluid (e.g., BCST M, Econo-SafeT M) is C-14 urea in a capsule form containing 1 mg urea labeled with 37 kBq (1 mCi) C-14. This prepara- breath collection and mixed thoroughly.
tion is currently available as PYTestT M f r o m Kimberly-Clark/Ballard Medical Products.
C-14 is a pure beta-emitter with a physical half life of 5730 yr and maximum energy of 160 keV.
known activity is stated on the vial) to a To measure beta emissions, C-14 is counted in a blank breath sample (a breath sample con- taining no C-14). The same volume of scin- tillation fluid that is used for patient sam- At time zero, the patient swallows the capsule containing 37 kBq (1 mCi) C-14 urea with 20 ml lukewarm water. At 3 min post-dose, the breath sample from a person not receiving patient drinks another 20 ml lukewarm water.
At 10 min post-dose, the patient is asked to d. All timed breath samples, the blank sample take a deep breath, hold it for approximately and the C-14 standard are counted for 5–20 5–10 sec and then exhale through a straw into min in a liquid scintillation counter (LSC), sample (into another balloon) can be obtained a. For each balloon, 2.5 ml trapping solution is pipetted into a scintillation vial. The trap- ping solution (collection fluid) is availablefrom the manufacturer and contains 1 thalein. The air from the balloons is trans- ferred into the scintillation vials using an change of the collection fluid (from blue to colorless) indicates the end point of trans- counter for the specific procedure and the specific scintillation cocktail can then be trapped. Ten milliliters of suitable scintilla- SOCIETY OF NUCLEAR MEDICINE PROCEDURE GUIDELINES MANUAL JUNE 2002 Efficiency = (standard cpm – blank cpm) 2. Causes of potential false-positive results: a. Resective gastric surgery with potential re- sultant bacterial overgrowth (non- H. pylori shipped to another institution/laboratory, if a liquid scintillation counter is not available If a value of 50–300 dpm is obtained immedi- ately after the addition of the scintillation fluid, the sample should be recounted in 1–2 hr or the next day, to exclude falsely elevated Reference values recommended by the manufac- V. Issues Requiring Further Clarification
VI. Concise Bibliography
≥ 200 dpm at 10 min Positive for H. pylori Friedman LS. Helicobacter pylori and nonulcer dyspep- sia (editorial). New Engl J Med. 1998;339: 1928–1930.
Aside from patient demographics, the report NIH Consensus Statement. Helicobacter pylori in peptic should include the following information: ulcer disease. JAMA. 1994;272:65–69.
1. Indication for the study (e.g., suspected H. py- P Y T e s tTM package insert. Ballard Medical Products, l o r i infection, follow-up after anti-H. pylori Soll AH. Consensus Statement. Medical treatment of 2. Procedure (i.e., radiopharmaceutical and peptic ulcer disease - practice guidelines. J A M A.
dosage, number and timing of breath samples Stubbs JB, Marshall BJ. Radiation dose estimates for the 3. Result (i.e., net dpm in the 10 min sample) C-14 labeled urea breath test. J Nucl Med. 5. Study limitations, confounding factors6. Interpretation (i.e., positive, negative, indeter- Disclaimer
minate for the presence of active H. pylori in-fection) The Society of Nuclear Medicine has written and approved guidelines to promote the cost-effective use of high quality nuclear medicine procedures.
Proper calibration and QC of the LSC should These generic recommendations cannot be applied be performed as per facility procedure.
to all patients in all practice settings. The guidelines should not be deemed inclusive of all proper proce- 1. Causes of potential false-negative results: dures or exclusive of other procedures reasonably a. Antibiotics (if administered within 30 days directed to obtaining the same results. The spec- trum of patients seen in a specialized practice set- b. Bismuth (if administered within 30 days of ting may be quite different than the spectrum of pa- tients seen in a more general practice setting. The c. Sucralfate (if administered within 14 days appropriateness of a procedure will depend in part on the prevalence of disease in the patient d. Proton pump inhibitors (see examples in population. In addition, the resources available to section IV.A.b.) if administered within 14 care for patients may vary greatly from one med- ical facility to another. For these reasons, guide- Advances in medicine occur at a rapid rate. The g. Difficulty with swallowing test capsule date of a guideline should always be considered in (additional breath samples collected at 15 determining its current applicability.

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