One assignee leads the ranked field with 775 of the 7,420 records in scope, well ahead of the fifth-place holder at 152 and tenth place at 113. The top 5 assignees together hold 27.0% of all records, and the top 10 hold 34.7%, which means concentration is real at the very top but drops off quickly after that. Most of the remaining ranked assignees hold only a handful of records each, forming a long tail typical of hospital systems, university labs and smaller device makers.

Filing activity peaked in 2018 at 432 records and has eased since; the last fully comparable window, 2021 to 2024, shows a 14% decline from 251 to 216 filings. Figures for 2025 and 2026 look lower still, but that is expected because publication typically lags actual filing by around 18 months, so those years are not yet complete. The honest read is a field that has cooled from its 2018 peak rather than one in active decline.

Nuclear and X-radiation measurement claims (IPC class G01T) appear on 35.3% of the 7,420 records, and diagnosis and surgery claims (A61B) appear on 29.7%, making detector hardware and acquisition method claims the densest ground in the corpus. Radiopharmaceutical-adjacent classes A61K and A61P also carry meaningful shares at 31.1% and 12.1%, reflecting how tightly tracer chemistry and imaging hardware claims overlap in this field. Image data processing (G06T) is comparatively lighter at 10.2%, which is worth noting for anyone assessing where claim space is less crowded.

Relative to the 35.3% claim density in core detector measurement classes, image processing and reconstruction claims sit at just 10.2% of records, suggesting more room to file there than in raw detector hardware. Specific branches worth checking include real-time attenuation correction algorithms, collimator sensitivity-resolution trade-off geometries, and compact CZT-based camera designs, all of which show up as narrower slices within the broader classes rather than as heavily claimed categories on their own. Any white-space claim should still be checked against the leading assignees' existing portfolios before drafting, since large filers can hold blocking claims even in lighter-density branches.

US8115171B2 claims a gamma camera built around a cadmium zinc telluride (CZT) detector housed with a retractable wall for positioning breast tissue in the field of view, plus a chamfered housing edge that lets two such cameras be paired in an L-mode configuration for nuclear mammography. It is a fairly specific mechanical and configuration claim rather than a broad claim over CZT gamma detection itself, so it primarily constrains dual-camera breast-imaging form factors with that particular retractable-wall and chamfered-edge combination. Designs using CZT detection in other anatomical applications, or breast-imaging systems that avoid the specific housing geometry, would need a separate claim-by-claim check rather than being blocked outright by this patent alone.