Quality Assurance and Quality Control for Intracranial Stereotactic Treatment; Process Management & Treatment Technique

In the Netherlands and Belgium a rapidly growing number of radiotherapy centers are being equipped for intracranial as well as extracranial stereotactic radiotherapy. Initially, stereotactic irradiation with a relatively high dose in a single fraction, called stereotactic radiosurgery (SRS), was based on the work of Leksell using a dedicated localization helmet and a dedicated Co-60 radiation source, the GammaKnife. Next there was the development of invasive and non-invasive frames for localization and treatment frames for fractionated stereotactic radiotherapy (fSRT) on (modified) linacs. More recently the development of SRT/SRS tends toward imaged guided frameless radiotherapy with dedicated linacs (Novalis and Cyberknife) mainly for intracranial lesions. The irradiation techniques evolved from arc beams using circular collimators via step and shoot micro MLC beams to stereotactic IMRT and robotic dose painting. Together with the interest of extracranial applications equipment for detection and automatic compensation of intra fractional tumor movements entered the field of SRT. Most treatment planning for fSRT/SRS is performed using a treatment planning system (TPS) that is part of the SRT/SRS hardware of a certain type and brand. Therefore the introduction of stereotactic radiotherapy in the clinic implies the acceptance, commissioning and QA of a stereotactic system as an entity. This includes the acceptance, commissioning and QA of the hardware (linac, mMLC, cone, frames, couch), software (TPS), imaging-system and systems for detection and automatic compensation of tumor movements. For the QC and guidelines of the various subsystems NCS reports are available. The increasing complexity of SRT/SRS and the increasing number of radiotherapy centers that offer this kind of SRT/SRS treatments justify an NCS report on stereotactic radiotherapy that covers the following topics: 

  • QC of mechanical equipment (immobilization, frames, linac, couch, pointers, …….)
  • Recommendations on measurement of beam properties (dosimetry of small beams, recommendation on methods and specific detectors, reference beam data, output factors)
  • Acceptance, commissioning and QC TPS. Referring to NCS QC TPS and supplementary specific QC for SRT.
  • Supplementary QC CT-scanner, MRI, angiography and other imaging techniques, application of 4D-CT
  • Acceptance, commissioning and QC of SRT imaging systems
  • Proposal for End to End tests for SRT/SRS
  • Recommendation on minimal QC (with tolerances)
  • Recommendations on Treatment Verification and Registration and DICOM
  • Recommendations on tests for detection and automated compensation of tumor movements
  • Recommendations on determination of dose outside lesion (risk radiation induced tumors after treatment of benign lesions and functional neurological SRS).
  • Recommendations and/or remarks on special issues related to intra- and extracranial SRT, body SRT, Cone beam, Image Guidance, frameless SRT..

Members of this NCS subcommittee

  • Stan Heukelom (Vrije Universiteit Medisch Centrum, Amsterdam, chairman, s.heukelom-at-vumc.nl)
  • Hans Marijnissen (Erasmus MC, Rotterdam)
  • An Nulens (UZ Gasthuisberg, Leuven)
  • Geert Pittomvils (UZ, Gent)
  • Esther Raaijmakers (Dr. B. Verbeeten Institute,Tilburg)
  • Dirk Verellen (AZ-VUB, Brussel)
  • Thierry Gevaert (AZ-VUB, Brussel)
  • Sandra Vieira (Champalimaud Centre for the Unknown, Lisboa, Portugal, secretary)
  • Nienke Holzer (NKI-AVL, Amsterdam)
  • Joep Hermans (MAASTRO Clinic, Maastricht, representative of the NCS board)