Case Author(s): Michael Roarke, MD and Barry A. Siegel, MD , 4/12/96 . Rating: #D3, #Q5
Diagnosis: Incorrect radiopharmaceutical administered for bone scintigraphy in patient with Paget's disease.
Brief history:
74-year old woman with back
pain and elevated serum alkaline phosphatase level.
Images:
Anterior and posterior images at 4 hours.
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View second image(bs).
Anterior and posterior images at 3 hrs.
View third image(xr).
Plain radiograph of the hand.
Full history/Diagnosis is available below
Diagnosis: Incorrect radiopharmaceutical administered for bone scintigraphy in patient with Paget's disease.
Full history:
74-year old woman with no
history of osteoporosis and on no medications who
presents with an elevated serum alkaline phosphatase level.
Evaluate for malignancy.
Radiopharmaceutical:
Tc-99m DTPA and Tc-99m MDP
Findings:
On the initial examination of 4-8-96,
there is no significant osseous activity seen on the
images. . Virtually all of the administered activity is
within the soft tissues and in the kidneys, collecting systems, and bladder.
Discussion:
The patient was not receiving
therapy with diphosphonate or bisphosphonate
agents. There was no history of osteoporosis or other
bone disorders. The syringe used to inject the patient
with tracer was labeled Tc-99m MDP. Given the
suspicion of a radiopharmaceutical error, we inspected
the multi-dose vial from which the patient's dose had
been drawn. While the outer shielding container was
labeled Tc-99m MDP, the multi-dose vial inside was
labeled Tc-99m DTPA. The patient subsequently returned for
bone scintigraphy two days later with Tc-99m MDP.
These images reveal markedly increased tracer
activity in the left ulna, sacrum, and proximal
phalanx of the fourth digit of the left hand. Plain
radiographs of each of these areas were obtained,
showing the characteristic findings of Paget's disease.
Radiographs of the sacrum did not suggest
sarcomatous degeneration of the sacral Paget's
disease.
Major teaching point(s):
The incorrect administration of Tc-99m DTPA in this patient
does not constitute a radiopharmaceutical misadministration
(as currently defined in U.S. Nuclear Regulatory Commission regulations)
since a byproduct, non-radioiodine radiopharmaceutical was involved and
the effective dose equivalent was less than 5 rem and the
critical organ dose was less than 50 rem. Nonetheless, it is always
essential to verify that the correct radiopharmaceutical is being
given to the correct patient in the correct dose.
Differential Diagnosis List
If incorrect radiopharmaceutical administration has been
excluded, the differential diagnosis for poor skeletal localization
of Tc-99m MDP includes concomitant diphosphonate therapy, poor
radiochemical purity of the Tc-99m MDP preparation,
congestive heart failure, and osteoporosis.
ACR Codes and Keywords:
References and General Discussion of Bone Scintigraphy (Anatomic field:Skeletal System, Category:Other generalized systemic disorder)
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Case number: bs057
Copyright by Wash U MO
