With these adaptations, mobile CT may increase the efficiency of intraoperative scanning by making it available to multiple operating rooms without committing it to any room for an entire operation and may increase the efficiency and safety of CT of critically ill patients who currently need to leave the intensive care unit to travel to a fixed CT installation and back.

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The nearly tissue equivalent MRI properties and the unique ability of registering 3D dose distributions of polymer gels were exploited to assess the total geometrical accuracy in clinical Gamma Knife applications, taking into account the combined effect of the unit's mechanical accuracy, dose delivery precision and the geometrical distortions inherent in MR images used for irradiation planning. Comparison between planned and experimental data suggests that the MR-related distortions due to susceptibility effects dominate the total clinical geometrical accuracy which was found within 1 mm. The dosimetric effect of the observed sub-millimetre uncertainties on single shot GK irradiation plans was assessed using the target percentage coverage criterion, and a considerable target dose underestimation was found.

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Purpose: Beam matched accelerators can provide the flexibility within the radiotherapy department. Furthermore, the accelerators could be represented by single beam data set in the treatment planning system (TPS). The aim of this study was to evaluate the match between dosimetrical characteristics of Elekta accelerators. Method and Materials: The data from three accelerators was used in analysis. Three photon and six electron beams were matched according to the vendor specification. The first accelerator data served as reference. Subset of commissioning measurements for second and third accelerators was performed. The comparison was done in absolute terms, i.e. that PDDs and profiles were used with corresponding accelerator output factors. Results: The average difference between the sets of open field PDDs was −0.7%, −0.1% and −0.1% for 6, 10 and 15MV, respectively. Difference up to −2.2% was observed for 60° motorized wedge PDDs. Aligned profiles showed good agreement, with differences generally less than 1% at dmax and 10 cm for field sizes up to 30×30 cm2. For 40×40 cm2 diagonal profiles at dmax the maximum differences of 2.4% was observed. The difference of up to 4.5% between output factors for small fields have been observed which may result in larger discrepancies in IMRT fields. Conclusion: Beam match for photon beams showed a satisfactory agreement for open fields and support the use of a single data set for TPS. However, vendor's beam matching criteria is not strict enough and better beam matching could be achieved if instead of single value the subset of dosimetrical data is used together with corresponding output factors for both open and wedged fields. Although, scanned data for electron beams showed good agreement larger differences (up to 5%) in electron cone output factors does not support the use of a single dataset in TPS.