Implementation of a lung radiosurgery program: technical considerations and quality assurance in an Australian institution.
BACKGROUND
The Peter MacCallum Cancer Centre has established a stereotactic lung radiosurgery program for the treatment of isolated lung metastases. The aim of this study was to critically assess the technical feasibility of performing stereotactic lung radiosurgery in an Australian institution.


METHODS
A single 26-Gy fraction of radiotherapy was delivered to patients with positron emission tomography (PET) staged solitary lung metastases. Motion management was addressed using four-dimensional computed tomographic simulation, and cone beam CT (CBCT) online soft-tissue matching. Treatments were with multiple coplanar and non-coplanar asymmetric beams. Patients were immobilised in a dedicated stereotactic body cradle. Quality assurance (QA) of treatment plans with both ion chamber and film measurements was performed accounting for patient-specific respiratory motion.


RESULTS
Between February 2010 and February 2011, nine patients received stereotactic lung radiosurgery. One grade 1 toxicity and one grade 2 toxicity were recorded after treatment. The mean planning target volume was 22.6 cc. A median of eight beams were delivered per treatment plan (range 7-10) with a median of two non-coplanar beams (range 0-6). At treatment plan QA, the difference between planned and delivered dose was ≤1.76% in all static and dynamic ion chamber recordings. A mid-treatment CBCT was performed at a median time of 21 min, with the mean displacement discrepancy from initial set-up being 0.4 mm (range 0-2 mm).


CONCLUSIONS
Stereotactic radiosurgery to the lung was both feasible and tolerable at our institution. Intrafractional immobilisation within 2 mm was reproducible. Excellent concordance between planned and delivered treatments was achieved in the phantom QA.
Department of Radiation Oncology, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia. shankar.siva@petermac.org
Shankar
S
Siva
Brent
B
Chesson
Yolanda
Y
Aarons
Natalie
N
Clements
Tomas
T
Kron
Michael
M
MacManus
David
D
Ball
D000328:Adult; D000368:Aged; D005260:Female; D019983:Guideline Adherence; D006801:Humans; D008175:Lung Neoplasms / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D017410:Practice Guidelines as Topic; D011785:Quality Assurance, Health Care / Q000379:methods* / Q000458:organization & administration*; D016634:Radiosurgery / Q000592:standards*; D016896:Treatment Outcome; D014739:Victoria