Syngo pt planning version 13

Treatment planning was performed using native and contrast enhanced CT/MRI. Patients were immobilized with individualized thermoplastic head masks. Technical details of CIRT are described elsewhere (24 (link), 25 (link)). Treatment planning for CIRT was performed using Syngo PT Planning, Version 13 (Siemens, Erlangen, Germany) and TomoTherapy^®-Planning Station (Accuray, Sunnyvale, CA, USA) for photon radiotherapy planning. Patients were treated with a fixed horizontal beam/gantry for CIRT utilizing 1-2 coplanar/non-coplanar beams.
All patients received combined IMRT and CIRT. The base plan was performed using a helical intensity-modulated radiotherapy (IMRT) with daily image guidance (TomoTherapy^®, Accuray, Sunnyvale, CA, USA), with 5 daily fractions per week (Figure 1).

For treatment planning Syngo PT PlanningVersion 13 (Siemens, Erlangen, Germany) was applied for CIRT and TomoTherapy^®-Planning Station (Accuray, Sunnyvale, CA, USA) for photon RT (24 (link)). Carbon ion boost to the PTV1 was performed with 18–24 Gy in 3.0 Gy (RBE, relative biological effectiveness) fractions (five to six fractions per week) and photon RT to the PTV2 was performed with 46 Gy to 56 Gy in 2.0 Gy fractions (five fractions per week) for both postoperative and definitive RT due to the local aggressiveness and radioresistance of ACC. Median total equivalent dose to 2.0 Gy fractions (EQD2) prescribed to the median PTV and covering the 95% prescription isodose was 80 Gy (range 71–82 Gy).
Delivered doses to critical structures were limited according to current guidelines as low as possible in order to reduce RT-related toxicity (Supplementary Table 1) (25 (link), 26 (link)). In Table 1, treatment characteristics are shown in detail. In Figure 1, the combined treatment plan for a patient with a pT3pN0 (0/34) ACC of the left parotid gland is shown. CTV2 involved the left parotid space and the left cervical lymphatic drainage (Figures 1A–C) and CTV1 involved the left parotid space only (Figures 1D–F).

Patients were immobilized with a thermoplastic head–mask system. Contrast-enhanced computed tomography (CT) scans (3-mm slice thickness) were used for treatment planning, and contrast-enhanced T1-weighted magnetic resonance imaging (MRI) was used for image registration. Treatment planning was conducted using Syngo PT Planning version 13 (Siemens®, Erlangen, Germany). The clinical target volume (CTV) included the visible tumor on contrast-enhanced CT or MRI (gross tumor volume or GTV) with a margin of 2–5 mm for subclinical disease spread. The resection cavity was included in the CTV for patients with prior surgical resection. Depending on patient positioning and beam arrangement, an additional margin of 2–3 mm was added for the planning target volume (PTV).
Treatment was exclusively performed with carbon ions using the active raster-scanning method with daily image guidance by orthogonal X-rays. Imaging follow-up included a contrast-enhanced MRI or a CT scan of the head and neck 6–8 weeks after treatment completion and every 3 months within the first 2 years after CIR. Treatment-related toxicities were recorded with the same frequency during follow-up visits and examinations by a radiation oncologist at our institution. Furthermore, patients saw an ear, nose, and throat (ENT) specialist at each follow-up visit.