# Nodule Navigator Interactive pulmonary nodule education for clinicians, students, and curious minds. Nodule Navigator is a free educational web app about pulmonary nodule imaging. It explains how nodules are described and classified — size in millimetres, density, margin morphology — and how those features relate to malignancy risk. It renders nodules as 3D and augmented reality models at true real-world scale, walks through the underlying concepts in guided lessons, defines the terminology in plain language, and implements the Mayo Clinic malignancy risk model with every variable and coefficient exposed. It is not a medical device. It collects no personal or health data. It is free, requires no account, and has no paywall. ## The three things this site does **Understand** — classification, risk factors, and biomarkers. A library of lessons at [/education](https://nodule.app/education) covering nodule types, lung cancer facts, risk factors and symptoms, and biomarker testing, plus a terminology library and a knowledge check quiz. **Visualize** — real-world scale 3D models with augmented reality. The viewer at [/viewer](https://nodule.app/viewer) renders smooth solid, lobulated, spiculated, ground-glass, and part-solid morphologies at 4 mm, 10 mm, 20 mm, and 30 mm. A comparison mode sets each size beside a familiar object — a grain of rice, a piece of cereal, a US penny, a golf ball — at true relative scale, so a measurement in a radiology report becomes something a person can picture. **Assess** — solitary pulmonary nodule malignancy risk. The calculator at [/calculator](https://nodule.app/calculator) reproduces the Mayo Clinic logistic regression model and shows the arithmetic term by term rather than returning a bare number. ## What a pulmonary nodule is, in one paragraph A pulmonary nodule is a small, rounded opacity in the lung, typically 30 mm or less in diameter. Larger opacities are classified as masses and managed under a different protocol. Most nodules are found incidentally on CT scans ordered for unrelated reasons, and roughly 96% of them are benign — old infections, scar tissue, calcified granulomas, or inflammation. Radiologists assess three features to decide on follow-up interval and urgency: size, density, and margin. ## Where to go next - [Education hub](https://nodule.app/education) — every lesson plus the quiz. - [Nodule Types](https://nodule.app/tutorial) — the four-chapter core lesson. - [3D and AR viewer](https://nodule.app/viewer) — morphology and scale. - [Risk calculator](https://nodule.app/calculator) — the Mayo Clinic model, shown openly. - [Terminology library](https://nodule.app/glossary) — definitions with citations. - [References and disclaimer](https://nodule.app/references) — every source the content rests on. - [llms.txt](https://nodule.app/llms.txt) — scope, limits, and when not to use this site. --- *Educational use only · Not a medical device.* This document mirrors the page at .