# GTV, CTV and PTV (target volumes)

Source: https://onco.cc/terms/planning-target-volume/  
OnCo record `planning-target-volume` (Term). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

The nested outlines a radiation plan is built on: the visible tumour (GTV), the tumour plus the tissue likely to hold microscopic spread (CTV), and a further margin for daily movement and setup error (PTV).

## Summary

The gross tumour volume is what imaging and examination show; the clinical target volume adds the margin of suspected microscopic disease and, in many cancers, the lymph node regions at risk; the planning target volume adds a geometric margin so that the CTV receives the dose despite setup and organ motion. Image guidance, motion management and adaptive radiotherapy all work by allowing the PTV margin to shrink.

## Fields

- Kind: Term
- Last checked: 2026-09-16
- Tags: radiation-wave1

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Radiation_treatment_planning
- Wikipedia: https://en.wikipedia.org/wiki/Radiation_treatment_planning

## Connected records

- technologies: [Adaptive radiotherapy (online replanning)](https://onco.cc/technologies/adaptive-radiotherapy/), [IMRT / IGRT (modern external beam)](https://onco.cc/technologies/imrt-igrt/), [Volumetric modulated arc therapy (VMAT)](https://onco.cc/technologies/vmat/)
- trials: [EORTC 22922/10925](https://onco.cc/trials/eortc-22922/)

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JSON: https://onco.cc/api/v1/entities/planning-target-volume.json