Clinical experience with 3-dimensional surface matching-based deep inspiration breath hold for left-sided breast cancer radiation therapy.
OBJECTIVE
Three-dimensional (3D) surface matching is a novel method to administer deep inspiration breath-hold (DIBH) radiation therapy for left-sided breast cancer to reduce cardiac exposure. We analyzed port (x-ray) films to assess patient setup accuracy and treatment times to assess the practical workflow of this system.


METHODS
The data from 50 left-sided breast cancer patients treated with DIBH were studied. AlignRT (London, UK) was used. The distance between the field edge and the anterior pericardial shadow as seen on the routine port films (dPORT), and the corresponding distance seen on the digitally reconstructed radiographs (DRR) from the planning (dDRR) were compared as a quantitative measure of setup accuracy. Variations of dPORT - dDRR over the treatment course were assessed. In a subset of 21 patients treated with tangential beams alone, the daily treatment durations were analyzed to assess the practical workflow of this system.


RESULTS
Considering all 50 patients, the mean absolute systematic uncertainty between dPORT and dDRR was 0.20 cm (range, 0 to 1.22 cm), the mean systematic uncertainty was -0.07 cm (range, -1.22 to 0.67 cm), and their mean random uncertainty was 0.19 cm (range, 0 to 0.84 cm). There was no significant change in dPORT - dDRR during the course of treatment. The mean patient treatment duration for the 21 patients studied was 11 minutes 48 seconds. On intrapatient assessments, 15/21 had nonsignificant trends toward reduced treatment durations during their course of therapy. On interpatient comparisons, the mean treatment times declined as we gained more experience with this technique.


CONCLUSIONS
The DIBH patient setup appears to provide a fairly reproducible degree of cardiac sparing with random uncertainties of ≈ 0.2 cm. The treatment durations are clinically acceptable and appear not to change significantly over time on an intrapatient basis, and to improve over time on an interpatient basis.
Department of Radiation Oncology, University of North Carolina Chapel Hill, Chapel Hill, North Carolina. Electronic address: xiaoli_tang@med.unc.edu.
Xiaoli
X
Tang
Department of Radiation Oncology, University of North Carolina Chapel Hill, Chapel Hill, North Carolina.
Timothy M
TM
Zagar
Department of Biostatistics, University of North Carolina Chapel Hill, Chapel Hill, North Carolina.
Eric
E
Bair
Department of Radiation Oncology, University of North Carolina Chapel Hill, Chapel Hill, North Carolina.
Ellen L
EL
Jones
Department of Imaging Physics, University of Texas MD Anderson Cancer Center, Houston, Texas.
David
D
Fried
Department of Radiation Oncology, XuZhou Medical College, XuZhou, JiangSu, China.
Longzhen
L
Zhang
Department of Radiation Oncology, University of North Carolina Chapel Hill, Chapel Hill, North Carolina.
Gregg
G
Tracton
Department of Radiation Oncology, Duke University, Durham, North Carolina.
Zijie
Z
Xu
Department of Radiation Oncology, University of North Carolina Chapel Hill, Chapel Hill, North Carolina.
Traci
T
Leach
Department of Radiation Oncology, University of North Carolina Chapel Hill, Chapel Hill, North Carolina.
Sha
S
Chang
Department of Radiation Oncology, University of North Carolina Chapel Hill, Chapel Hill, North Carolina.
Lawrence B
LB
Marks
D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy*; D062485:Breath Holding; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D001239:Inhalation; D008168:Lung / Q000000981:diagnostic imaging*; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed / Q000379:methods