Clinical volumes

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As Clinical volumes is referred to in the radiotherapy defined volumes as part of a treatment planning are defined. The terms were introduced by the ICRU Report 50 and adopted in the German standards DIN 6814-8 and DIN 6827-1.

In the treatment of malignant diseases, a distinction is made between the following areas:

  • The macroscopic tumor volume (Gross Tumor Volume - GTV) describes the volume that is visible through diagnostics
  • The clinical target volume (CTV) is a coherent area that, in addition to the macroscopic tumor volume, includes areas in which proliferating tumor cells are suspected (tumor spreading area ).
  • The planning target volume (PTV), sometimes just called the target volume , usually takes into account spatial shifts in the clinical target volume by adding a safety margin, e.g. B. by breathing or peristalsis , but also the limited accuracy in reproducing the patient's position in the case of fractional radiation therapy.
  • The treated volume (TV) describes the volume that is bounded by a specified isodose area over which the absorbed dose is considered sufficient to achieve the treatment goal .
  • The irradiated volume (IV) describes the volume that is unintentionally exposed to radiation as a by-product of radiation therapy.

The differences between the clinical target volume and the planning target volume therefore not only depend on the irradiated organ, but also on the quality of a reproducible positioning of the patient, as well as the proliferation speed of the tumor.

Since in brachytherapy the radiation source is brought directly to or into the clinical target volume, the clinical target volume and the planning target volume are usually identical.

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  • Rolf Sauer . Radiotherapy. In: Günter W Kauffmann, Ernst Moser, Rolf Sauer. Radiology. Urban and Fischer 2006. ISBN 978-3-437-44415-9 .
  • DIN 6814-8: 2000-12 Terms in radiological technology - Part 8: Radiation therapy
  • DIN 6827-3: 2002-12 Logging in the medical application of ionizing radiation - Part 3: Brachytherapy with enclosed radiation sources