PathView

PathView is my second take on browser-based digital pathology, building on what I learned making TPN's WSI Viewer. This time it's a full telepathology workspace, not just a viewer.

What I built

• Deep-zoom viewer. OpenSeadragon with a navigator minimap, scale bar, rotation, 0.5× to 40× zoom, go-to-region and screenshot capture.
• Annotation and measurement. Rectangle, ellipse, polygon, freehand and arrow tools plus a ruler, with pathology labels (tumour, margin, inflammation, necrosis, artefact) and threaded comments.
• Case workflow. A case queue, slides, consultations for second opinions, and reports with sign and amend permissions.
• Roles. Separate permissions for administrators, pathologists, physicians and technicians.
• Ready for a global audience. Four languages (English, French, Spanish and Chinese) and dark mode.

Under the hood

A Python tiler reads Aperio SVS slides with OpenSlide and writes Deep Zoom pyramids of 256-pixel JPEG tiles in parallel, with per-slide metadata. A 98,304 × 75,264-pixel test slide becomes 18 zoom levels and about 46,000 tiles, and the viewer only ever fetches the handful on screen. The front end is SvelteKit with Svelte 5 and TypeScript, Annotorious for drawing, and Playwright and Vitest for tests.

Where it stands

PathView is a working prototype running on public research slides and demo data, ready to be wired to a production backend.