Evaluating the impact of a rigid and a deformable registration method of pre-treatment images for hypoxia-based dose painting.

Purpose: To assess the impact of rigid and deformable image registration methods (RIR, DIR) on the outcome of a hypoxia-based dose painting strategy.

Materials And Methods: Thirty head and neck cancer patients were imaged with [F]FMISO-PET/CT before radiotherapy. [F]FMISO-PET/CT images were registered to the planning-CT by RIR or DIR.

Photon and Proton Dose Painting Based on Oxygen Distribution - Feasibility Study and Tumour Control Probability Assessment.

Solid tumours may present hypoxic sub-regions of increased radioresistance. Hypoxia quantification requires of clinically implementable, non-invasive and reproducible techniques as positron emission tomography (PET). PET-based dose painting strategies aiming at targeting those sub-regions may be limited by the resolution gap between the PET imaging resolution and the smaller scale at which hypoxia occurs.

Implications of the Harmonization of [F]FDG-PET/CT Imaging for Response Assessment of Treatment in Radiotherapy Planning.

The purpose of this work is to present useful recommendations for the use of [F]FDG-PET/CT imaging in radiotherapy planning and monitoring under different versions of EARL accreditation for harmonization of PET devices. A proof-of-concept experiment designed on an anthropomorphic phantom was carried out to establish the most suitable interpolation methods of the PET images in the different steps of the planning procedure. Based on PET/CT images obtained by using these optimal interpolations for the old EARL accreditation (EARL1) and for the new one (EARL2), the treatment plannings of representative actual clinical cases were calculated, and the clinical implications of the resulting differences were analyzed.

Assessment of the Probability of Tumour Control for Prescribed Doses Based on Imaging of Oxygen Partial Pressure.

In radiotherapy, hypoxia is a known negative factor, occurring especially in solid malignant tumours. Nitroimidazole-based positron emission tomography (PET) tracers, due to their selective binding to hypoxic cells, could be used as surrogates to image and quantify the underlying oxygen distributions in tissues. The spatial resolution of a clinical PET image, however, is much larger than the cellular spatial scale where hypoxia occurs.