Dextrose solutions yield radiochemical impurities: the "sweet" scans.
OBJECTIVE
If additional chemicals are inadvertently introduced in the preparation of radiopharmaceutical kits, radiochemical impurities may be formed. We report our experience with erroneously diluting (99m)Tc-pertechnetate eluate with 5% dextrose solution rather than normal saline during the preparation of (99m)Tc-tetrofosmin, (99m)Tc-methylene diphosphonate (MDP), (99m)Tc-stannous colloid, and (99m)Tc-mebrofenin.


METHODS
Scintigrams for 3 of the 4 radiochemicals unintentionally prepared with 5% dextrose were found to have an altered biodistribution. Therefore, radiopharmacy procedures for the day were reviewed, and instant thin-layer chromatography (ITLC) was performed.


RESULTS
Scintigrams showed an altered biodistribution consistent with an impurity. Review of procedures that day uncovered the error of using 5% dextrose to dilute the (99m)Tc eluate. The altered biodistribution on (99m)Tc-stannous colloid, (99m)Tc-MDP, and (99m)Tc-mebrofenin scintigrams consisted of cardiac blood-pool activity (possibly as a result of slow clearance of (99m)Tc-dextrose), soft-tissue background activity (possibly as a result of interstitial distribution of (99m)Tc-dextrose), renal and bladder activity (possibly as a result of renal elimination of (99m)Tc-dextrose), and gallbladder activity (possibly as a result of hepatobiliary excretion of (99m)Tc-dextrose). Both scintigrams and ITLC showed no evidence of impurities for the (99m)Tc-tetrofosmin prepared using 5% dextrose.


CONCLUSIONS
Unintended preparation of radiochemicals with 5% dextrose rather than normal saline often results in the production of impurities, possibly (99m)Tc-dextrose. Because some but not all commercial radiochemical kits prepared with 5% dextrose will suffer this fate, nuclear medicine physicians reviewing the day's images will be confronted with a confusing combination of expected and grossly abnormal findings.
Al-Enizi
Eman
E
Department of Nuclear Medicine, Faculty of Medicine, Kuwait University, Kuwait.
Kazem
Nafisah
N
Owunwanne
Azu
A
Collier
B David
BD
Mathew
Mercy
M
D005947:Glucose; D006801:Humans; D011854:Radiochemistry; D019275:Radiopharmaceuticals; D011933:Reagent Kits, Diagnostic; D012965:Sodium Chloride; D013670:Sodium Pertechnetate Tc 99m; D014018:Tissue Distribution
D019275:Radiopharmaceuticals; D011933:Reagent Kits, Diagnostic; D012965:Sodium Chloride; D013670:Sodium Pertechnetate Tc 99m; D005947:Glucose