Nodule Volume & Volume Doubling Time (VDT) — free guideline decision tool
Two CT volumes (or three diameters) plus the interval give percent volume change and volume doubling time, read against NELSON / BTS criteria. Instant, browser-side.
Open guideline tool →Guideline-based
Implements the decision logic from published clinical guidelines.
Runs in your browser
No installation. Enter the patient's values and get a guideline recommendation instantly.
Data stays local
Nothing is uploaded. Results are for licensed clinicians only.
Worked calculation
The values below come from this tool's own example placeholders and are computed server-side with the formula shown on this page, so the arithmetic can be checked quickly. It demonstrates how to substitute values only — it is not clinical advice and not a real case.
| Earlier volume (software; blank to use diameters) | 250 mm³ |
|---|---|
| Current volume (software; blank to use diameters) | 400 mm³ |
| Earlier long axis | 8 mm |
| Current long axis | 10 mm |
| Interval between scans | 90 days |
| Nodule type | Solid |
→Volume doubling time133days
- Earlier / current volume：250 / 400 mm³ (software volumes)
- Volume change：+60.0%
- Reading：Significant growth: VDT <400 days (NELSON positive)
Common questions
What is Nodule Volume & Volume Doubling Time (VDT)?
Two CT volumes (or three diameters) plus the interval give percent volume change and volume doubling time, read against NELSON / BTS criteria. Instant, browser-side.
How is Nodule Volume & Volume Doubling Time (VDT) calculated? What is the core formula?
V = π/6·a·b·c (sphere if only one diameter); VDT = Δt·ln2 / ln(V2/V1); change = (V2−V1)/V1.
When is Nodule Volume & Volume Doubling Time (VDT) used?
Assessing growth of lung nodules on follow-up CT; also usable for other lesions.
What are the key clinical points for Nodule Volume & Volume Doubling Time (VDT)?
Growth = ≥25% volume increase. Solid VDT <400 days is suspicious. 400–600 days indeterminate. Subsolid nodules can have long VDTs.
What are the limits and cautions when using Nodule Volume & Volume Doubling Time (VDT)?
For licensed clinicians and clinical researchers. Interpret results with history, investigations and local protocols; not a diagnosis or prescription, and not a substitute for multidisciplinary decision-making or local guidelines.
Does Nodule Volume & Volume Doubling Time (VDT) upload patient data? Where is it calculated?
Calculation runs locally in the browser; inputs and results are not uploaded. For licensed clinicians only; interpret with history, investigations and local protocols — not a diagnosis or prescription.
How is Nodule Volume & Volume Doubling Time (VDT) calculated in practice? Can you show a worked example?
Inputs: Earlier volume (software; blank to use diameters) 250 mm³, Current volume (software; blank to use diameters) 400 mm³, Earlier long axis 8 mm, Current long axis 10 mm, Interval between scans 90 days, Nodule type Solid → Result: Volume doubling time 133 days（Earlier / current volume: 250 / 400 mm³ (software volumes), Volume change: +60.0%, Reading: Significant growth: VDT <400 days (NELSON positive)）
Run Nodule Volume & Volume Doubling Time (VDT) now
Two CT volumes (or three diameters) plus the interval give percent volume change and volume doubling time, read against NELSON / BTS criteria. Instant, browser-side.
Open guideline tool →For licensed clinicians. Not a substitute for clinical judgement.
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