Helical tomotherapy

• Applicant: Professor Dr. Volker Budach
• Co-Applicants: Professor Dr. Roland Felix; Professor Dr. Wolfgang Hinkelbein (†)
• Subject Area: Nuclear Medicine, Radiotherapy, Radiobiology
• Term: from 2005 to 2008
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 20578821

Systems for helical tomotherapy are now commercially available. The tomotherapy method is a standardised way to plan and apply a dose distribution based on a three-dimensional CT dataset in an arbitrary anatomical region. Utilising every (two-dimensional) beam direction and the freedom to modulate the intensity in every field we achieve a fairly good dose distribution, at least the physically at best achievable distribution using 6 MV photons. By selecting a series of target volumes (requiring different total doses depending on risk) and addressing very detailed dose-volume-histograms (DVH) to every normal tissue (maximum, mean and minimum dose), we have theoretically a very powerful tool to generate individualised dose distributions with moderate effort. The first key question is the cost-benefit-ratio of this new radiation method, i.e. how much effort do we need to prepare and apply these doses and how fine are the dose distributions in terms of the DVH in comparison to the “conventional” treatment technique (which might be conformal 3D radiotherapy, intensity-modulated radiotherapy, radiosurgery, TBI).As a second key question we want to quantify the advantage from the MV-CT (at 3 MV), which we achieve on a routine basis for every patient in the beginning of every fraction.The tomotherapy method implies the obvious possibility to integrate directly additional information from other imaging modalities. Therefore as a third issue, we want to employ a new PET-CT scanner (on basis of a HBFG procedure, nearby to the designated room for the tomotherapy system) to further specify the target volumes and to individualise the radiotherapy.We expect clinical improvements by employing these three capabilities characteristic for tomotherapy (individualised dose forming, MV-CT, inclusion of functional imaging). On one hand dose escalation in tumors, which need high doses (e.g. lung cancer, prostate cancer, liver metastases) might become possible. Moreover, better tolerance might be acchieved by sparing organs of risk, if they are close to the target, yielding the same dose in the tumor (head and neck tumors, total body). Both clinical objectives are worthwhile to evaluate in clinical studies.

• DFG Programme: Major Instrumentation Initiatives
• Major Instrumentation: HI-ART System - Highly Integrated Adaptive Radiotherapy System mit Zubehör
• Instrumentation Group: 3250 Beschleuniger (Medizin)