title: Lessons from the Tc-99m shortage: implications of substituting Tl-201 for Tc-99m single-photon emission computed tomography.
abstract: BACKGROUND
  In 2009, the Chalk River nuclear reactor closed for repairs that led to a critical shortage of technetium-99m (Tc-99m). Several centers used thallium-201 (Tl-201) as an alternative radiotracer for myocardial perfusion imaging. Because Tl-201 is considered by many as a suboptimal radiotracer, we sought to understand the impact of using Tl-201 (during the Tc-99m shortage) on downstream resource utilization.
  
  
  RESULTS
  We performed a retrospective study at the Ottawa Heart Institute of 7402 patients (60% men; mean age, 62.6 ± 11.8 years), patients were referred for myocardial perfusion imaging between May 2008 and January 2011 (PRE_Tc-99m [2938 patients]), during (DURING_Tl-201 [2959 patients]), and after (POST_Tc-99m [1505 patients]) the Tc-99m shortage. Patients were followed for 6 months after their index myocardial perfusion imaging to determine subsequent rates of cardiac catheterization or noninvasive imaging. More downstream testing was seen in the Tl-201 cohort (639 [21.4%] patients) than the Tc-99m cohort (537 [12.1%] patients; P<0.001). After adjustment using propensity scores, differences in downstream referral rates were maintained. The downstream investigations resulted in an estimated increase in per-patient costs ($165.22; 95% confidence interval, 153.00-177.42) in the DURING_Tl-201 cohort compared with the Tc-99m cohort ($90.97; 95% confidence interval, 83.42-98.90; P<0.001). As well, the mean effective radiation dose per-patient was higher in DURING_Tl-201 (23.57 mSv; 95% confidence interval, 23.16-23.96) than in Tc-99m (12.92 mSv; 95% confidence interval, 12.55-13.40; P<0.001).
  
  
  CONCLUSIONS
  In this single-center study, the use of Tl-201 during the Tc-99m shortage was associated with an increase in downstream testing, cost, and patient radiation exposure, but these findings may not be generalizable to other centers. Although Tl-201 provided a short-term solution to the unexpected Tc-99m shortage, long-term cost-effective solutions should be areas of future study.
authors.affiliation: Division of Cardiology, Department of Medicine, University of Ottawa Heart Institute, Ottawa, Canada.
authors.forename: Gary R
authors.initials: GR
authors.lastname: Small
authors.forename: Terrence D
authors.initials: TD
authors.lastname: Ruddy
authors.forename: Oana
authors.initials: O
authors.lastname: Simion
authors.forename: Mohammed
authors.initials: M
authors.lastname: Alam
authors.forename: Lyanne
authors.initials: L
authors.lastname: Fuller
authors.forename: Li
authors.initials: L
authors.lastname: Chen
authors.forename: Rob S
authors.initials: RS
authors.lastname: Beanlands
authors.forename: Benjamin J W
authors.initials: BJ
authors.lastname: Chow
mesh_terms: D000368:Aged; D006328:Cardiac Catheterization; D016009:Chi-Square Distribution; D017023:Coronary Angiography; D025401:Echocardiography, Stress; D005260:Female; D017048:Health Care Costs; D006801:Humans; D016013:Likelihood Functions; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D055414:Myocardial Perfusion Imaging / Q000191:economics / Q000379:methods*; D016017:Odds Ratio; D049268:Positron-Emission Tomography; D011237:Predictive Value of Tests; D011829:Radiation Dosage; D011868:Radioisotopes / Q000191:economics / Q000600:supply & distribution*; D019275:Radiopharmaceuticals / Q000191:economics / Q000600:supply & distribution*; D012017:Referral and Consultation; D012042:Registries; D012189:Retrospective Studies; D013667:Technetium / Q000191:economics / Q000600:supply & distribution*; D013794:Thallium Radioisotopes / Q000191:economics / Q000600:supply & distribution*; D013997:Time Factors; D015899:Tomography, Emission-Computed, Single-Photon / Q000191:economics / Q000379:methods*
chemical_list: D011868:Radioisotopes; D019275:Radiopharmaceuticals; D013794:Thallium Radioisotopes; D013667:Technetium
keywords: health resources; technetium; thallium