Patients who undergo PET/CT imaging as part of cancer care depend on the accuracy of their results, yet those results can be compromised by radiotracer infiltration. This problem occurs when a portion of the imaging agent injected into a patient’s vein fails to enter the circulatory system and instead pools near the injection site. Cancer staging can be too high or too low as a result, and patient care decisions may be based on faulty conclusions. SmartBrief spoke with Dr. Jackson Kiser about this issue and a recent set of studies that explored the frequency of infiltration at seven centers as well as a protocol for quality improvement.
A recent quality improvement project presented at SNMMI 2018 evaluated infiltration rates in PET/CT radiotracer injections and whether they could be improved. What was the protocol?
The Lara Quality Improvement project (Lara-QI) was a prospective, multi-center project designed to assess rates of radiotracer infiltrations. The project also evaluated whether centers could reduce their infiltration rates. An IRB for each of the seven participating centers confirmed the project was not research as defined by the federal government in 45CFR46.102(d). The protocol had two primary phases. Phase 1 was blinded and assessed infiltration rates in consecutive PET/CT patients. Phase 2 assessed whether centers could reduce their infiltration rates using analytics that revealed factors associated with infiltrations. Centers used the same technologists on the same number of patients and remeasured their rates. Each phase could be completed in about three months.
How did this protocol affect technologists, patients and physicians day-to-day? For example, does it take more time or change interactions between patients and clinicians?
Lara® is used while the patient is resting quietly during the uptake process and is easily incorporated into the technologist’s routine. Technologists use atraumatic adhesive pads to place the sensor on the patient’s arms after gaining venous access but before injection. Lara® adds about 30 seconds to the patient experience and about two minutes to the technologist workload (including placing/removing the pads and completing data entry). Before the patient is imaged, the technologist downloads the results. During phase 1, the PI was made aware of moderate and significant infiltrations. After phase 1, I asked to have the time-activity curves provided with their PET/CT images to help me assess the quality of the scan.
What happened to rates of infiltration once the protocol was implemented?
All seven centers learned their infiltration rates. In four centers that could immediately move to phase 2, rates were reduced (p<0.0001). These reductions have been sustained.
CT and chemotherapy injections are already monitored to ensure patient care is not compromised. Could radiotracer injections and rates of infiltration be next?
I hope so. Delivering the dose as a bolus is important to the quality of the image. And the delivery and accuracy of the dose is critical to quantification. There are QC efforts today (e.g., synchronizing clocks, recording residual doses) to ensure the accuracy of the administered dose. But there is no QC to ensure the administered dose is entering the patient’s circulation. Radiotracer injections are currently not monitored or reported. While infiltrations may not cause immediate pain and discomfort to the patient, the literature is clear that nuclear medicine infiltrations can and have negatively impacted patients. Once monitored, injection quality should improve just as it did when chemotherapy and contrast CT monitoring and reporting was initiated.
What first steps would you recommend to technologists and physicians who are concerned about infiltration?
Improvement starts with monitoring your process. Lara® can monitor what you can’t see now. And she can provide factors to help you improve your injection quality.
Jackson W. Kiser, MD is the Medical Director of Molecular Imaging at the Carilion Clinic in Roanoke, VA. He has been in practice in this area for 21 years and is a graduate of the VCU School of Medicine (formerly known as Medical College of Virginia). He received certification from the American Board of Internal Medicine in 1993 and is currently board eligible. He also obtained certification from the American Board of Radiology in 1997 and Special Competency in Nuclear Medicine from the ABR in 1998.