Dummy run and conformity indices in the ongoing EORTC low-grade glioma trial 22033-26033: First evaluation of quality of radiotherapy planning

Radiother Oncol. 2010 May;95(2):218-24. doi: 10.1016/j.radonc.2010.03.005. Epub 2010 Apr 6.


Purpose: Early assessment of radiotherapy (RT) quality in the ongoing EORTC trial comparing primary temozolomide versus RT in low-grade gliomas.

Materials and methods: RT plans provided for dummy cases were evaluated and compared against expert plans. We analysed: (1) tumour and organs-at-risk delineation, (2) geometric and dosimetric characteristics, (3) planning parameters, compliance with dose prescription and Dmax for OAR (4) indices: RTOG conformity index (CI), coverage factor (CF), tissue protection factor (PF); conformity number (CN = PF x CF); dose homogeneity in PTV (U).

Results: Forty-one RT plans were evaluated. Only two (5%) centres were requested to repeat CTV-PTV delineations. Three (7%) plans had a significant under-dosage and dose homogeneity in one deviated > 10%. Dose distribution was good with mean values of 1.5, 1, 0.68, and 0.68 (ideal values = 1) for CI, CF, PF, and CN, respectively. CI and CN strongly correlated with PF and they correlated with PTV. Planning with more beams seems to increase PTV(Dmin), improving CF. U correlated with PTV(Dmax).

Conclusion: Preliminary results of the dummy run procedure indicate that most centres conformed to protocol requirements. To quantify plan quality we recommend systematic calculation of U and either CI or CN, both of which measure the amount of irradiated normal brain tissue.

Publication types

  • Case Reports
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Antineoplastic Agents, Alkylating / therapeutic use*
  • Central Nervous System Neoplasms / radiotherapy*
  • Dacarbazine / analogs & derivatives*
  • Dacarbazine / therapeutic use
  • Female
  • Glioma / radiotherapy*
  • Humans
  • Male
  • Middle Aged
  • Neoplasm Staging
  • Radiotherapy Planning, Computer-Assisted / methods*
  • Radiotherapy, Conformal
  • Temozolomide
  • Treatment Outcome


  • Antineoplastic Agents, Alkylating
  • Dacarbazine
  • Temozolomide