Pinnacle3 tps

The body membrane was first established for CT simulation and treatment of each patient. The Philips BrillianceTM16 row CT simulation machine with large aperture was used to simulate the location of all patients with postoperative adjuvant external radiotherapy. CT images were acquired using 5-mm-thick contiguous slices with a radiotherapy CT simulator (Philips Brilliance Big Bore) and transferred to the treatment planning system (Philips Pinnacle³ TPS). The clinical target volume (CTV) covered the common iliac, external iliac, internal iliac, obturator, presacral and parametrial lymph node regions, and was delineated according to the guidelines defining the pelvic node CTV in external beam radiotherapy for uterine cervical cancer of radiation therapy oncology group (RTOG) [15 (link)]. The planned target volume (PTV) was generated by uniformly expanding the CTV boundary by 0.7 cm in three dimensions. Organs at risk (OAR) including bladder, rectum, bowel bag, spinal cord, bone marrow and ovaries were contoured according to the recommendations of the International Commission on Radiation Units Reports (ICRU) 50 and 62 [16 , 17 ]. All radiotherapy plans were created by the physicists with the PTV prescription of 45–50Gy / 25–28F, and the Dmax of the ovaries was ≤6Gy. A total of 59/150 (39.3%) patients received 3D-CRT, and 91/150 (60.7%) patients received IMRT.

Paired image datasets were retrieved for image coregistration, VOI definition, and image processing. Signal changes on the multiple gradient echo images were used to calculate 3D
T2* relaxivity maps. Data processing was performed using in‐house MatLab software (MathWorks, Natick, MA). Signal intensity decay, measured for increasing echo times, was fitted on a voxel‐by‐voxel basis to a monoexponential model using a least‐squares fit method. No data truncation or filtering was used. Calculated
T2* maps were exported in the DICOM format allowing further analysis with a radiotherapy treatment planning system (TPS).
VOIs, including primary and nodal tumor sites, were manually delineated by radiologists (A.M.R. and D.M.K., each having more than 10 years of experience) using the Pinnacle3 TPS (Philips Healthcare, Best, Netherlands). Axial images and
T2* maps from both MRI sessions were coregistered using operator‐assisted rigid body algorithms.
T2* images with significantly varying neck flexion or translation of tumor volume were identified and the coregistration manually corrected. For such cases primary tumor and involved lymph nodes were coregistered independently to compensate for interscan anatomical and positional variation.
T2* values for respective VOIs were exported from the TPS and used for statistical evaluation.