Towards real-time topical detection and characterization of FDG dose infiltration prior to PET imaging

Abstract

Purpose To dynamically detect and characterize 18F-fluorodeoxyglucose (FDG) dose infiltrations and evaluate their effects on positron emission tomography (PET) standardized uptake values (SUV) at the injection site and in control tissue. Methods Investigational gamma scintillation sensors were topically applied to patients with locally advanced breast cancer scheduled to undergo limited whole-body FDG-PET as part of an ongoing clinical study. Relative to the affected breast, sensors were placed on the contralateral injection arm and ipsilateral control arm during the resting uptake phase prior to each patient’s PET scan. Time activity curves (TACs) from the sensors were integrated at varying intervals (0–10, 0–20, 0–30, 0–40, and 30–40 min) post-FDG and the resulting areas-under-the-curve (AUCs) were compared to SUVs obtained from PET. Results In cases of infiltration, observed in three sensor recordings (30%), the injection arm TAC shape varied depending on the extent and severity of infiltration. In two of these cases TAC characteristics suggested the infiltration was partially resolving prior to image acquisition, although it was still apparent on subsequent PET. Areas under the TAC 0–10 and 0–20 min post-FDG were significantly different in infiltrated versus non-infiltrated cases (Mann-Whitney, p < 0.05). When normalized to control, all TAC integration intervals from the injection arm were significantly correlated with SUVpeak and SUVmax measured over the infiltration site (Spearman ρ ≥ 0.77, p < 0.05). Receiver operating characteristic (ROC) analyses, testing the ability of the first 10 minutes of post-FDG sensor data to predict infiltration visibility on the ensuing PET, yielded an area under the ROC curve of 0.92. Conclusion Topical sensors applied near the injection site provide dynamic information from the time of FDG administration through the uptake period and may be useful in detecting infiltrations regardless of PET image field of view. This dynamic information may also complement the static PET image to better characterize the true extent of infiltrations.

Topical Sensor for the Assessment of Injection Quality for 18F-FDG, 68Ga-PSMA and 68Ga-DOTATATE Positron Emission Tomography

“…Clinically, PET and SUV, traditionally for 18F-FDG and now also for 68Ga-PSMA and 68Ga-DOTATATE, require pharmacokinetic assumptions including predictable dose delivery. Extravasation or infiltration occurs when the dose, or part thereof, is administered outside the venous system [2][3][4]. Partial extravasation of the intravenous (IV) dose administration undermines predictability of dose delivery and potentially the accuracy of SUV calculations [2].…”

“…Extravasation or infiltration occurs when the dose, or part thereof, is administered outside the venous system [2][3][4]. Partial extravasation of the intravenous (IV) dose administration undermines predictability of dose delivery and potentially the accuracy of SUV calculations [2]. The dose administration should be a bolus over approximately 1 minute [3].…”

“…A simple method for detecting extravasation is the use of the LARA (Lucerno Dynamics, LLC, Cary, NC) device that uses topically applied scintillation sensors to monitor activity migration in from the injection site during the uptake phase. Williams et al [2], used a topical device (LARA) in FDG PET patients and demonstrated that it helped to detect partial dose extravasation independent of the imaging protocol and provided dynamic data that assisted in characterising the extravasation. Visual detection of extravasated doses identified 38% incidence but the addition of the LARA device demonstrated the true extravasation rate was in fact 55% [7].…”

Technical Note: Characterization of technology to detect residual injection site radioactivity

“…The remaining pulses are then counted to produce a sensor output in counts per second (cps). For this proposed clinical use, the sensor, along with a second sensor placed on the contralateral arm to collect reference data, could identify the presence of excessive residual radiotracer near the injection site . Both sensors would then be removed prior to imaging.…”

“…For this proposed clinical use, the sensor, along with a second sensor placed on the contralateral arm to collect reference data, could identify the presence of excessive residual radiotracer near the injection site. 50,51 Both sensors would then be removed prior to imaging. Based on the sensor design, it may not be possible to provide absolute quantification of the radiotracer near the injection site, but a semi-quantitative assessment would still be valuable.…”