Discussion
prostate
PROSTATE
This study demonstrates clinical application and validation of the results from the previous volunteer study. It provides clinical data, using a patient cohort, regarding a time-reduced MRI sequence for sCT generation for prostate MR-only treatment planning. In an MRI-only workflow, additional sequences may be required for volume definition as image contrast and resolution may be enhanced or targeted to the anatomy, or functional sequences may provide additional guidance. The time reduction and associated reduction in image quality for the sCT sequence may be appropriate if anatomical and dose differences in the generated sCT for treatment planning are considered acceptable.The potential trade-offs between reducing MR imaging time and the effects on the MR image quality and subsequent sCT generation accuracy should be considered [The clinical study results compare favourably with our previously reported volunteer study [As discussed previously in Young et al. [The current study considers a comparison of sCT with a gold standard sCT. A more appropriate comparison would be true CT, but the study utilised patient data from an MRI-only sub-study within a clinical trial, so capturing an additional CT was not possible or within the study guidelines. However, as the S-sCT approach was previously benchmarked against CT, it could be considered that this was an indirect comparison of sCT to CT. As sCT use for treatment planning and MRI-only radiotherapy becomes more common, further adjustments or improvements in sCT may need to be considered without the availability of a corresponding CT scan. In these cases similar comparisons may be appropriate in assessing suitability of a new sCT.