Bodyfix

Patients were immobilized using the BodyFix (Elekta AB, Stockholm, Sweden). SBRT plans were calculated using Monaco with the Monte Carlo algorithm. Dose prescription depended on tumor site and volume and was delivered with VMAT by VERSA HD (Elekta AB, Stockholm, Sweden) in 1–3 fractions each of 10–12 Gy to the 70% isodose-line. Among the patients treated with the single-fraction regimen, if after the first restaging at 1 month it was still possible to define BTV, an additional adaptive single 10Gy-fraction was delivered. With regard to the dose constraints for OAR, those reported in TG101 were used [13 (link)]. Before each treatment, cone-beam CT (XVI system, VERSA HD) was obtained to verify the isocenter.

SBRT was delivered using a variety of radiotherapy platforms: helical tomotherapy, CyberKnife® robotic radiotherapy (Accuray Inc., Sunnyvale, CA, USA) or isocentric linear accelerators with volumetric modulated arc therapy (VMAT). Dose schedules were 60 Gy in three to five fractions for peripheral lesions, and 50 Gy in five fractions or 60 Gy in eight fractions for central lesions.
Patients were treated either with near-real-time tumor tracking with CyberKnife® or using an internal target volume (ITV) with VMAT or helical tomotherapy. CyberKnife® tumor tracking was achieved using fiducials or, when tumor was sufficiently large and dense, using a soft tissue tracking technique (Xsight Lung, Accuray Inc., Sunnyvale, CA, USA) [11 (link)].
All patients had a noncontrast 4D planning CT scan in supine position. The gross tumor volume (GTV) was delineated on the expiratory phase of 4D CT and corresponded to the macroscopic tumor on pulmonary CT windows. For patients treated with VMAT or helical tomotherapy, a BodyFIX (Elekta, Stockholm, Sweden) whole body vaccum immobilization device was also used. ITV was based on tumor motion in extreme phases of the respiratory cycle. An additional planning tumor volume (PTV) margin of 5 mm was added to the GTV in fiducials or Xsight Lung cases, or to the ITV, alternatively.

Data from 10 consecutive LAPC patients treated with chemoradiotherapy at our institution between January 2009 and August 2009 were used in this study. All patients had undergone three additional CT scans, performed at an interval of 1–2 weeks during a chemoradiotherapy course and under the same conditions as in the simulation CT scan. The characteristics of the patients are shown in Table 1.
CT was performed under EBH condition using the LightSpeed RT scanner (GE Healthcare, Little Chalfont, UK) and Real‐time Position Management system (RPM; Varian Medical Systems, Palo Alto, CA). The CT slice thickness was 2.5 mm. Patients fasted for at least 3 h and were immobilized in the supine position with both arms raised in a BodyFIX vacuum cushion (Elekta, Stockholm, Sweden).

This study included 7 patients with PC and 20 patients (19 males and 1 female) with HNC who were given VMAT. The median ages of the PC and HNC patients were 75 (range: 69–82) and 65 (49–74) years, respectively. All PC patients were treated with a full bladder. The patients were in a supine position, five of them were immobilized using BodyFix (Elekta AB, Stockholm, Sweden), and two of them were immobilized in a prone position using a thermoplastic shell (CIVCO Radiotherapy, Orange city, IA, USA). All HNC patients were immobilized using a thermoplastic shell (Klarity Medical Products, Newark, OH, USA). Of the 20 HNC patients, 18 were treated with concurrent chemoradiotherapy. This study was approved by the Institutional Review Board of our university hospital.