title: A treatment planning comparison between modulated tri-cobalt-60 teletherapy and linear accelerator-based stereotactic body radiotherapy for central early-stage non-small cell lung cancer.
abstract: We evaluated the feasibility of planning stereotactic body radiotherapy (SBRT) for large central early-stage non-small cell lung cancer with a tri-cobalt-60 (tri-(60)Co) system equipped with real-time magnetic resonance imaging (MRI) guidance, as compared to linear accelerator (LINAC)-based SBRT. In all, 20 patients with large central early-stage non-small cell lung cancer who were treated between 2010 and 2015 with LINAC-based SBRT were replanned using a tri-(60)Co system for a prescription dose of 50Gy in 4 fractions. Doses to organs at risk were evaluated based on established MD Anderson constraints for central lung SBRT. R100 values were calculated as the total tissue volume receiving 100% of the dose (V100) divided by the planning target volume and compared to assess dose conformity. Dosimetric comparisons between LINAC-based and tri-(60)Co SBRT plans were performed using Student׳s t-test and Wilcoxon Ranks test. Blinded reviews by radiation oncologists were performed to assess the suitability of both plans for clinical delivery. The mean planning target volume was 48.3cc (range: 12.1 to 139.4cc). Of the tri-(60)Co SBRT plans, a mean 97.4% of dosimetric parameters per patient met MD Anderson dose constraints, whereas a mean 98.8% of dosimetric parameters per patient were met with LINAC-based SBRT planning (p = 0.056). R100 values were similar between both plans (1.20 vs 1.21, p = 0.79). Upon blinded review by 4 radiation oncologists, an average of 90% of the tri-(60)Co SBRT plans were considered acceptable for clinical delivery compared with 100% of the corresponding LINAC-based SBRT plans (p = 0.17). SBRT planning using the tri-(60)Co system with built-in MRI is feasible and achieves clinically acceptable plans for most central lung patients, with similar target dose conformity and organ at risk dosimetry. The added benefit of real-time MRI-guided therapy may further optimize tumor targeting while improving normal tissue sparing, which warrants further investigation in a prospective feasibility clinical trial.
authors.affiliation: Department of Radiation Oncology, David Geffen School of Medicine at UCLA, Los Angeles, CA.
authors.forename: Catherine
authors.initials: C
authors.lastname: Merna
authors.affiliation: Department of Radiation Oncology, David Geffen School of Medicine at UCLA, Los Angeles, CA.
authors.forename: Jean-Claude M
authors.initials: JC
authors.lastname: Rwigema
authors.affiliation: Department of Radiation Oncology, David Geffen School of Medicine at UCLA, Los Angeles, CA.
authors.forename: Minsong
authors.initials: M
authors.lastname: Cao
authors.affiliation: Department of Radiation Oncology, David Geffen School of Medicine at UCLA, Los Angeles, CA.
authors.forename: Pin-Chieh
authors.initials: PC
authors.lastname: Wang
authors.affiliation: Department of Radiation Oncology, David Geffen School of Medicine at UCLA, Los Angeles, CA.
authors.forename: Amar U
authors.initials: AU
authors.lastname: Kishan
authors.affiliation: Department of Radiation Oncology, David Geffen School of Medicine at UCLA, Los Angeles, CA.
authors.forename: Argin
authors.initials: A
authors.lastname: Michailian
authors.affiliation: Department of Radiation Oncology, David Geffen School of Medicine at UCLA, Los Angeles, CA.
authors.forename: James
authors.initials: J
authors.lastname: Lamb
authors.affiliation: Department of Radiation Oncology, David Geffen School of Medicine at UCLA, Los Angeles, CA.
authors.forename: Ke
authors.initials: K
authors.lastname: Sheng
authors.affiliation: Department of Radiation Oncology, David Geffen School of Medicine at UCLA, Los Angeles, CA.
authors.forename: Nzhde
authors.initials: N
authors.lastname: Agazaryan
authors.affiliation: Department of Radiation Oncology, David Geffen School of Medicine at UCLA, Los Angeles, CA.
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Low
authors.affiliation: Department of Radiation Oncology, David Geffen School of Medicine at UCLA, Los Angeles, CA.
authors.forename: Patrick
authors.initials: P
authors.lastname: Kupelian
authors.affiliation: Department of Radiation Oncology, David Geffen School of Medicine at UCLA, Los Angeles, CA.
authors.forename: Michael L
authors.initials: ML
authors.lastname: Steinberg
authors.affiliation: Department of Radiation Oncology, David Geffen School of Medicine at UCLA, Los Angeles, CA. Electronic address: percylee@mednet.ucla.edu.
authors.forename: Percy
authors.initials: P
authors.lastname: Lee
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000532:radiotherapy*; D003037:Cobalt Radioisotopes / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011867:Radioisotope Teletherapy; D016634:Radiosurgery; D011880:Radiotherapy Planning, Computer-Assisted
chemical_list: D003037:Cobalt Radioisotopes
keywords: Early-stage lung cancer; MRI-guided radiotherapy; SBRT; ViewRay; non−small cell lung cancer