Single-institution report of setup margins of voluntary deep-inspiration breath-hold (DIBH) whole breast radiotherapy implemented with real-time surface imaging.
J Appl Clin Med Phys
; 19(4): 205-213, 2018 Jul.
Article
in En
| MEDLINE
| ID: mdl-29935001
ABSTRACT
PURPOSE:
We calculated setup margins for whole breast radiotherapy during voluntary deep-inspiration breath-hold (vDIBH) using real-time surface imaging (SI). METHODS AND MATERIALS Patients (n = 58) with a 27-to-31 split between right- and left-sided cancers were analyzed. Treatment beams were gated using AlignRT by registering the whole breast region-of-interest to the surface generated from the simulation CT scan. AlignRT recorded (three-dimensional) 3D displacements and the beam-on-state every 0.3 s. Means and standard deviations of the displacements during vDIBH for each fraction were used to calculate setup margins. Intra-DIBH stability and the intrafraction reproducibility were estimated from the medians of the 5th to 95th percentile range of the translations in each breath-hold and fraction, respectively.RESULTS:
A total of 7269 breath-holds were detected over 1305 fractions in which a median dose of 200 cGy was delivered. Each fraction was monitored for 5.95 ± 2.44 min. Calculated setup margins were 4.8 mm (A/P), 4.9 mm (S/I), and 6.4 mm (L/R). The intra-DIBH stability and the intrafraction reproducibility were ≤0.7 mm and ≤2.2 mm, respectively. The isotropic margin according to SI (9.2 mm) was comparable to other institutions' calculations that relied on x-ray imaging and/or spirometry for patients with left-sided cancer (9.8-11.0 mm). Likewise, intra-DIBH variability and intrafraction reproducibility of breast surface measured with SI agreed with spirometry-based positioning to within 1.2 and 0.36 mm, respectively.CONCLUSIONS:
We demonstrated that intra-DIBH variability, intrafraction reproducibility, and setup margins are similar to those reported by peer studies who utilized spirometry-based positioning.Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Breath Holding
Type of study:
Observational_studies
Limits:
Humans
Language:
En
Journal:
J Appl Clin Med Phys
Journal subject:
BIOFISICA
Year:
2018
Document type:
Article
Affiliation country:
United States