The study aims at quantifying the registration error obtained in routine patients in different parts of the prostate and for operators with different experience in order to assess the average precision of the elastic MR-ultrasound fusion obtained by Koelis™ system. Patients referred for placement of intraprostatic fiducials before radiotherapy for prostate cancer will be prospectively offered to enter the study. The fiducials will be placed under transrectal ultrasound guidance, in the prostate apex, midgland and base, according to our routine procedure. A 3D Ultrasound acquisition of the prostate will be obtained at the end of the placement. As per our routine procedure, patients will undergo unenhanced prostate MRI to control the position of the fiducials. An elastic fusion of the MR images and the 3D ultrasound acquisitions will be retrospectively performed by operators of varying experience using the Koelis system. The fiducials (visible on MR and ultrasound images) will be used to quantify the registration error.
Study Type
OBSERVATIONAL
Enrollment
30
Hospital of Edouard Herriot
Lyon, France
RECRUITINGAccuracy of the overall registration obtained by the Koelis™ system
The fusion will be performed retrospectively without interfering with patient management. This fusion is an off-line analysis that will be performed within one month of the images acquisition. Each of the four operators will perform a US/MR fusion for all patients and will be blinded to the fusions performed by the others. The results will be presented when all operators have finished the fusions in all patients. The overall registration error (TRE3D, defined as the Euclidean distance between the US marker and the MR marker after fusion) will be calculated based on the 3D coordinates of the fiducials on MR and ultrasound images.
Time frame: 1 month
Influence on TRE3D of the position of the fiducials (apex, midgland and base)
The fusion will be performed retrospectively without interfering with patient management. This fusion is an off-line analysis that will be performed within one month of the images acquisition. Each of the four operators will perform a US/MR fusion for all patients and will be blinded to the fusions performed by the others. The results will be presented when all operators have finished the fusions in all patients. The distribution of TRE3D for the markers at the apex, midgalnd and base will be compared
Time frame: 1 month
Influence on TRE3D of the experience of the fusion operators
The fusion will be performed retrospectively without interfering with patient management. This fusion is an off-line analysis that will be performed within one month of the images acquisition. Each of the four operators will perform a US/MR fusion for all patients and will be blinded to the fusions performed by the others. The results will be presented when all operators have finished the fusions in all patients. The distribution of TRE3D for the four operators will be compared
Time frame: 1 month
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