A growing collection of free, guideline-based decision tools for radiologists, referring physicians, and trainees. Each tool produces a structured recommendation in under a minute and links to the source guidelines. The same decision logic powers the Gantry radiology app on iOS and Android.
Contrast dose by blood volume and lean body mass
Iodine dose to injected volume for any agent, with Nadler blood volume and Boer lean body mass. Shows what a fixed volume actually delivers to a woman versus a man of the same height and weight.
Nadler 1962 · Boer 1984 · trial NCT06965790
Iodinated Contrast & Thyroid
Guideline-based decision tool for iodinated CT contrast in patients with thyroid disease. Covers TSH screening, latent/manifest hyperthyroidism, sodium perchlorate premedication, amiodarone, radioiodine washout, and post-thyroidectomy.
Each tool is a decision aid and does not replace clinical judgement, institutional protocols, or specialist consultation. Final responsibility for the diagnostic decision rests with the treating physician.
Not a tool, but next door: MRI from the ground up, twenty-one interactive units from a single hydrogen nucleus to a line of a real scanner protocol. Free, no account, and every curve on the page is computed rather than drawn.
Tools are maintained by Josh Decker, MD, a board-certified radiologist working in Germany. Feedback is welcome via the feedback button inside each tool.
The same logic, on your phone
The decision logic behind these tools also runs in Gantry, a radiology app for iOS and Android. It stores nothing, transmits nothing and contains no analytics, which is set out in the privacy policy. Free, no account.
