Unexpected occurrence of right to left shunt during lung perfusion scintigraphy: a problem-based learning exercise

This case report presents a problem-based learning exercise that occurred during lung perfusion scintigraphy with technetium-99m macroaggregated albumin (99mTc-MAA) with the incidental finding of a previously undiagnosed right-to-left shunt. The pathology manifested with a redirection of 99mTc-MAA-loaded blood into systemic circulation and subsequent uptake in gastric, renal, and thyroid tissues. Incorrect radiopharmaceutical administration, radiopharmacy error and independent constituents of 99mTc-MAA offered alternative explanations which required exclusion. Subsequent recommendations included diligent use of safety procedures and appropriate documentation during receiving, dispensing and administration of radiopharmaceuticals. Clinical suspicion of RLS may warrant additional 99mTc-MAA imaging to confirm diagnosis or quantify severity.

1. Griffiths M, King S, Stewart R, Dawson
G. Evaluating the fundamental qualities
of a nuclear medicine radiographer for
the provision of an optimal clinical service.
Radiography, 2010; 16: 238-243.
2. MacDonald A, Burrell S. Infrequently
performed studies in Nuclear Medicine:
Part 1. J Nucl Med Technol, 2008;
36: 132-143.
3. Pieterse T, Lawrence H, Friedrich-
Nel H. Problem-solving abilities of
radiography students at a South African
university. African J Health Prof Education
2014; 6, [1]: 33-36.
4. Terashita T, Tamura N, Kisa K, Kawabata
H, Ogasawara K. Problem-based
learning for radiological technologists:
a comparison of student attitudes
toward plain radiography. BMC Med
Figure 1. Planar lung scintigraphy (VQ). (a) Ventilation phase with normal distribution. (b) Perfusion phase with yellow arrows indicating unusual radionuclide uptake.
Education, 2016; 16: 236.
5. Benchmark document on Nuclear
Medicine Technologists’ Competencies.
European Association of Nuclear Medicine
2017. [Cited 2020April 20]. Available
from https://www.eanm.org/content-eanm/
uploads/2016/11/EANM_2017_TC_Benchmark.
pdf
6. Koyama AK, Maddox C-SS, Li L, Bucknall
T, Westbrook JI. Effectiveness of double
checking to reduce medication administration
errors: a systematic review. BMJ Qual
Saf, 2019; 24, [0]: 1-9.
7. Hakala JL, Hung JC, Mosman EA. Minimizing
human error in radiopharmaceutical
preparation and administration via
a bar code-enhanced nuclear pharmacy
management system. J Nucl Med Technol,
2012; 40: 183-186.
8. Spottswood SE, Pfluger T, Bartold SP, Brandon
D, Burchell N, Delbeke D, Fink-Bennett
DM, Hodges PK, Jolles PR, Lassmann
M, Maurer AH, Seabold JE, Stabin MG,
Treves ST, Vlajkovic M, Society of Nuclear
Medicine and Molecular Imaging, European
Association of Nuclear Medicine.
SNMMI and EANM practice guideline
for Meckel’s diverticulum scintigraphy
2.0. J Nucl Med Technol, 2014; 42, [3]:
163-169.
9. Zolle I. Technetium-99m: preparation
and quality control in nuclear medicine.
Berlin: Springer; 2007: 174.
10. Flug JA, Ponce LM, Osborn HH, Jokerst
CE. Never events in radiology and
strategies to reduce preventable serious
adverse events. RadioGraphics, 2018; 38:
1823-1832.