The Scientific and Clinical Case for Reviewing Diagnostic Radiopharmaceutical Extravasation Long-Standing Assumptions

Abstract

Background: The patient benefit from a diagnostic nuclear medicine procedure far outweighs the associated radiation risk. This benefit/risk ratio assumes a properly administered radiopharmaceutical. However, a significant diagnostic radiopharmaceutical extravasation can confound the procedure in many ways. We identified three current extravasation hypotheses espoused by medical societies, advisory committees, and hundreds of individual members of the nuclear medicine community: diagnostic extravasations do not cause harm, do not result in high absorbed dose to tissue, and require complex dosimetry methods that are not readily available in nuclear medicine centers. We tested these hypotheses against a framework of current knowledge, recent developments, and original research. We conducted a literature review, searched regulatory databases, examined five clinical cases of extravasated patients, and performed dosimetry on those extravasations to test these globally accepted hypotheses.Results: A literature review found 58 peer-reviewed documents suggesting patient harm. Adverse event/vigilance report database reviews for extravasations were conducted and revealed 38 adverse events which listed diagnostic radiopharmaceutical extravasation as a factor, despite a regulatory exemption for required reporting. In our own case material, assessment of care was evaluated for five extravasated patients who underwent repeat imaging. Findings reflected results of literature review and included mis- or non-identification of lesions, underestimation of Standardized Uptake Values (SUVs) by 19–73%, classification of scans as non-diagnostic, and the need to repeat imaging with the associated additional radiation exposure, inconvenience, or delays in care. Dosimetry was performed for the same five cases of diagnostic radiopharmaceutical extravasation. Absorbed doses to 5 cm3 of tissue were between 1.1 and 8.7 Gy, and shallow dose equivalent for 10 cm2 of skin was as high as 4.2 Sv.Conclusions: Our findings suggest that significant extravasations can or have caused patient harm and can irradiate patients' tissue with doses that exceed medical event reporting limits and deterministic effect thresholds. Therefore, diagnostic radiopharmaceutical injections should be monitored, and dosimetry of extravasated tissue should be performed in certain cases where thresholds are thought to have been exceeded. Process improvement efforts should be implemented to reduce the frequency of extravasation in nuclear medicine.

Safety injections of Nuclear Medicine radiotracers: towards a new modality for a real-time detection of extravasation events and 18F-FDG SUV data correction.

“…normal, abnormal, extravasation) similar to those already mentioned in the literature [12,14,17,19].…”

“…Extravasation should be avoided as the undue absorbed doses in the injection site can alter the result of the study and diagnostic procedures that could be repeated [8], as well as can cause local damage to the patient such as rash or epithelial necrosis, especially in therapeutic treatments. Even if the consequences of extravasation events are considered more dangerous with therapeutic radiopharmaceuticals (beta or alpha emitters) [8], also with diagnostic activity, extravasation can potentially undermine the accuracy of some quantitative parameters affecting clinical diagnosis [9][10][11][12][13][14]. Radiopharmaceutical extravasation can confound the diagnostic procedure in many ways that include mis-or non-identi cation of lesions, classi cations of scans as non-diagnostic, underestimation of Standardized Uptake Values (SUV) by 19-73%, and the need to repeat imaging with the associated additional radiation exposure [22].…”

“…The SUV accuracy estimation assumes the entire injected dose is administered intravenously, distributing itself completely within the body before the examination is performed; an extravasation event can affect its evaluation. Improper injections can cause extravasations which in turn lower the SUV values, by approximately 10% [14], which in the most serious cases can reach up to 21-50% [10,12]. From an analysis of 1367 patient, in 18% of studies, there was extravasation with an erroneous accumulation of the injected dose between 1 and 22% [15], while a single-centre analysis highlighted up to 38% of patients with extravasated doses [16].…”

Detection of Excess Presence of 99mTc-MDP Near Injection Site—A Case Report

“…In another publication, we highlighted the effects of significant extravasations on the quality and quantification of additional FDG PET studies and the quality of an MDP study by reimaging these patients several days after their extravasated studies. These cases also had patient care implications (16).…”

“…Significant extravasations can also potentially lead to high absorbed radiation doses to underlying tissue and skin (18). While bone scans and other routine diagnostic studies are often viewed as very low risk to patients, recent research indicates that significant extravasations of routinely used diagnostic radiopharmaceuticals like 99m Tc-MDP can result in high doses to the tissue and adverse tissue reactions (16,18).…”