New PET radiotracers for neuroendocrine tumors (NETs) first widened and then narrowed an imaging access gap for rural patients, according to a study by the Harvey L. Neiman Health Policy Institute. 

Researchers found that when gallium-68 (Ga-68) DOTATATE/DOTATOC PET tracers replaced Octreoscan as the standard imaging technique in 2017, rural patients were forced to travel 134.9 additional miles for the scans compared with only 26.7 additional miles for urban patients, but that the gap largely disappeared after a longer-lived copper-based tracer entered the market in 2021. 

“PET/CT-based imaging with gallium-68 can only be performed when the radiotracer is produced locally due to its extremely short half-life [68 minutes]. For this reason, patients living in small-rural areas had to travel long distances,” noted lead author Cindy Yuan, MD, of Indiana University, and colleagues. The study was published April 30 in the Journal of the American College of Radiology. 

Patients in metropolitan areas and higher-income communities are more likely to access PET-based radiotracers, whereas those in rural or socioeconomically disadvantaged areas often rely on older modalities (gamma or SPECT-based radiotracers) such as Octreoscan, or may lack access to functional imaging altogether, the researchers explained. 

To assess the issue, the group analyzed 3,365 claims for NET radiotracers from a 5% Medicare fee-for-service sample covering 2014 to 2023. They tracked travel distances and market share for Octreoscan, Ga-68 DOTATATE/DOTATOC, and copper-64 (Cu-64) DOTATATE stratified by urbanicity. 

According to the results, Ga-68 DOTATATE/DOTATOC captured 33.8% market share in their 2017 debut and reached 90.9% by 2020. When Cu-64 DOTATATE launched in 2021, it brought a 12.7-hour half-life that permitted centralized production in St. Louis, with nationwide shipping, the researchers noted. 

Subsequently, Cu-64 DOTATATE  grew to capture 40.6% market share by 2023, with notably stronger rural penetration: 54.9% of rural claims versus 39.4% in metropolitan areas. In addition, the mean travel distance for these scans for rural patients fell to 89.7 miles, according to the results. 

"The introduction of copper-64 DOTATATE in 2021 largely eliminated the metropolitan–micropolitan versus small–rural differences in access to PET-based radiotracers," the authors wrote. 

The findings carry particular weight in NETs because the diagnostic PET scans are the gateway to therapy for patients, added co-author Elizabeth Rula, PhD, executive director of the Neiman Institute, in a news release. 

"These access disparities to the diagnostic phase likely reflect similar access disparities to the therapeutic phase given that the diagnostic step precedes the therapeutic step," she said. 

The authors noted limitations, namely the restriction to Medicare fee-for-service beneficiaries, ZIP code-level distance calculations, and an observational design that cannot explain individual tracer or site selection. 

Ultimately, the study suggests that it may be beneficial to continue using Ga-68 DOTATATE/DOTATOC in larger markets where its local production costs may be more broadly diffused, while the use of Cu-64 DOTATATE in smaller markets may facilitate substantially broader access for small–rural patients, the authors concluded. 

The full study is available here.