title: A planning study investigating dual-gated volumetric arc stereotactic treatment of primary renal cell carcinoma.
abstract: This is a planning study investigating the dosimetric advantages of gated volumetric-modulated arc therapy (VMAT) to the end-exhale and end-inhale breathing phases for patients undergoing stereotactic treatment of primary renal cell carcinoma. VMAT plans were developed from the end-inhale (VMATinh) and the end-exhale (VMATexh) phases of the breathing cycle as well as a VMAT plan and 3-dimensional conformal radiation therapy plan based on an internal target volume (ITV) (VMATitv). An additional VMAT plan was created by giving the respective gated VMAT plan a 50% weighting and summing the inhale and exhale plans together to create a summed gated plan. Dose to organs at risk (OARs) as well as comparison of intermediate and low-dose conformity was evaluated. There was no difference in the volume of healthy tissue receiving the prescribed dose for the planned target volume (PTV) (CI100%) for all the VMAT plans; however, the mean volume of healthy tissue receiving 50% of the prescribed dose for the PTV (CI50%) values were 4.7 (± 0.2), 4.6 (± 0.2), and 4.7 (± 0.6) for the VMATitv, VMATinh, and VMATexh plans, respectively. The VMAT plans based on the exhale and inhale breathing phases showed a 4.8% and 2.4% reduction in dose to 30cm(3) of the small bowel, respectively, compared with that of the ITV-based VMAT plan. The summed gated VMAT plans showed a 6.2% reduction in dose to 30cm(3) of the small bowel compared with that of the VMAT plans based on the ITV. Additionally, when compared with the inhale and the exhale VMAT plans, a 4% and 1.5%, respectively, reduction was observed. Gating VMAT was able to reduce the amount of prescribed, intermediate, and integral dose to healthy tissue when compared with VMAT plans based on an ITV. When summing the inhale and exhale plans together, dose to healthy tissue and OARs was optimized. However, gating VMAT plans would take longer to treat and is a factor that needs to be considered.
authors.affiliation: Radiation Therapy Services, Peter MacCallum Cancer Centre, Melbourne, Australia. Electronic address: thomas.devereux@petermac.org.
authors.forename: Thomas
authors.initials: T
authors.lastname: Devereux
authors.affiliation: Radiation Therapy Services, Peter MacCallum Cancer Centre, Melbourne, Australia.
authors.forename: Daniel
authors.initials: D
authors.lastname: Pham
authors.affiliation: Department of Physical Sciences, Peter MacCallum Cancer Centre, Melbourne, Australia; Sir Peter MacCallum Department of Oncology, Melbourne University, Melbourne, Australia.
authors.forename: Tomas
authors.initials: T
authors.lastname: Kron
authors.affiliation: Sir Peter MacCallum Department of Oncology, Melbourne University, Melbourne, Australia; Radiation Oncology and Cancer Imaging, Peter MacCallum Cancer Centre, Melbourne, Australia.
authors.forename: Farshad
authors.initials: F
authors.lastname: Foroudi
authors.affiliation: School of Applied Sciences, Royal Melbourne Institute of Technology, Melbourne, Australia.
authors.forename: Jeremy
authors.initials: J
authors.lastname: Supple
authors.affiliation: Sir Peter MacCallum Department of Oncology, Melbourne University, Melbourne, Australia; Radiation Oncology and Cancer Imaging, Peter MacCallum Cancer Centre, Melbourne, Australia.
authors.forename: Shankar
authors.initials: S
authors.lastname: Siva
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002292:Carcinoma, Renal Cell / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D005260:Female; D056973:Four-Dimensional Computed Tomography / Q000379:methods; D006801:Humans; D007680:Kidney Neoplasms / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D008297:Male; D016634:Radiosurgery / Q000379:methods*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods; D061089:Radiotherapy, Image-Guided / Q000379:methods*; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D015203:Reproducibility of Results; D055425:Respiratory-Gated Imaging Techniques / Q000379:methods*; D012680:Sensitivity and Specificity; D016896:Treatment Outcome
keywords: Gating; Renal cell carcinoma; Stereotactic body radiation therapy; Volumetric arc therapy