Dosimetric effect due to the motion during deep inspiration breath hold for left‐sided breast cancer radiotherapy

Tang, Xiaoli; Cullip, T; Dooley, John; Zagar, Timothy M.; Jones, Ellen L.; Chang, S; Zhu, Xiaofeng; Lian, Jun; Marks, Lawrence B.

doi:10.1120/jacmp.v16i4.5358

Cited by 21 publications

(19 citation statements)

References 25 publications

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“…Several studies have evaluated patient setup accuracy during DIBH for left‐sided breast cancer for 3D surface matching, but few have investigated any dosimetric effects due to potential positioning deviations. For instance, Tang et al evaluated the dosimetric impact of motion during DIBH for an iterative closest point (ICP)‐based algorithm for surface matching with the AlignRT system, using a ± 3 mm and ±3° tolerance for translational and rotational differences. They reported very small (<1 mm) breath‐hold motion and the dosimetric consequences were found to be small.…”

Section: Introductionmentioning

confidence: 99%

Dosimetric effects of intrafractional isocenter variation during deep inspiration breath‐hold for breast cancer patients using surface‐guided radiotherapy

Kügele

Edvardsson

Berg

et al. 2017

J Applied Clin Med Phys

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The aim of this study was to investigate potential dose reductions to the heart, left anterior descending coronary artery (LAD), and ipsilateral lung for left‐sided breast cancer using visually guided deep inspiration breath‐hold (DIBH) with the optical surface scanning system Catalyst™, and how these potential dosimetric benefits are affected by intrafractional motion in between breath holds. For both DIBH and free breathing (FB), treatment plans were created for 20 tangential and 20 locoregional left‐sided breast cancer patients. During DIBH treatment, beam‐on was triggered by a region of interest on the xiphoid process using a 3 mm gating window. Using a novel nonrigid algorithm, the Catalyst™ system allows for simultaneous real‐time tracking of the isocenter position, which was used to calculate the intrafractional DIBH isocenter reproducibility. The 50% and 90% cumulative probabilities and maximum values of the intrafractional DIBH isocenter reproducibility were calculated and to obtain the dosimetric effect isocenter shifts corresponding to these values were performed in the treatment planning system. For both tangential and locoregional treatment, the dose to the heart, LAD and ipsilateral lung was significantly reduced for DIBH compared to FB. The intrafractional DIBH isocenter reproducibility was very good for the majority of the treatment sessions, with median values of approximately 1 mm in all three translational directions. However, for a few treatment sessions, intrafractional DIBH isocenter reproducibility of up to 5 mm was observed, which resulted in large dosimetric effects on the target volume and organs at risk. Hence, it is of importance to set tolerance levels on the intrafractional isocenter motion and not only perform DIBH based on the xiphoid process.

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Section: Introductionmentioning

confidence: 99%

Dosimetric effects of intrafractional isocenter variation during deep inspiration breath‐hold for breast cancer patients using surface‐guided radiotherapy

Kügele

Edvardsson

Berg

et al. 2017

J Applied Clin Med Phys

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“…A study estimating intra-fractional error using real time monitoring of OSS has presented that the mean motion during DIBH is small with < 1 mm translational and 1° rotational deviation. (17) In another study,(18) set-up error during DIBH was measured using continuous portal imaging in 58 patients. The group mean of fractional and intrafractional set-up error was within 1.7 mm of both systematic and random errors.…”

Section: Discussionmentioning

confidence: 99%

Variation of Heart and Lung Radiation Doses According to Setup Uncertainty in Left Breast Cancer

Park

Rim

Yoon

2020

Preprint

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PurposeBreast radiotherapy set-up is often uncertain. Actual dose distribution to normal tissues could be different from planned dose distribution. The objective of this study was to investigate such difference in dose distribution according to the extent of set-up error in breast radiotherapy.Materials and methodsA total of 50 Gy with fraction size of 2 Gy was given to 30 left breasts with different set-ups applying a deep inspiration breath holding (DIBH) or a free breathing (FB) technique. Under the assumption that errors might come from translational axes of deep or caudal directions, the isocenter was shifted from the original tangential alignment every 2.5 mm to simulate uncertainty of deep and caudal tangential set-up in DIBH and FB. Changes were evaluated for dosimetric parameters for the heart, the left ventricle (LV), the left anterior descending coronary artery (LAD), and the ipsilateral lung.ResultsOn the original plan, mean doses of heart and ipsilateral lung were 2.0 ± 1.1 Gy and 3.7 ± 1.4 Gy in DIBH and 8.4±1.3 Gy and 7.8±1.5 Gy in FB, respectively. The change of dose distribution for the heart in DIBH was milder than that in FB. The deeper the tangential set-up, the worse the heart, LV, LAD, and ipsilateral lung doses, showing as much as 49.4%, 56.4%, 90.3%, and 26.1% shifts, respectively, in 5 mm DIBH setup. The caudal set-up did not show significant dose difference. In multiple comparison of DIBH, differences of mean dose occurred in all 7.5 mm deep set-ups for the heart (p = 0.025), the LV (p = 0.049), and LAD (p = 0.025) in DIBH.ConclusionsTo correct set-up error over indicated limitation for deep tangential set-up in DIBH at 5 mm action level, mean heart and ipsilateral lung doses are expected to increase approximately 50% and 25%, respectively.

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“…Although comparison of the AlignRT‐indicated offsets when using the CT‐defined reference surface with intentional miscalibrations may not be relevant for SRS treatments (since a new reference image is typically captured after image‐guided shifts have been completed), it is relevant for other utilizations of the AlignRT system that may use the CT‐defined body as a reference surface for the initial setup of the patient. An example would be deep‐inspiration breath hold (DIBH) for the treatment of left‐sided breast or chest wall . In this setting, a miscalibration (without subsequent isocenter calibration) would result in a systematic offset in the reference surface.…”

Section: Discussionmentioning

confidence: 99%

Evaluation of a surface imaging system's isocenter calibration methods

Paxton

Manger

Pawlicki

et al. 2017

J Applied Clin Med Phys

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AlignRT is a surface imaging system that has been utilized for localizing and tracking patient position during radiotherapy. AlignRT has two calibration procedures that can set the system's isocenter called “Monthly Calibration” (MC) and “Isocentre Calibration” (IC). The MC utilizes a calibration plate. In addition to the calibration plate, the IC utilizes a cubic phantom that is imaged with the linac treatment beam to aid in aligning the AlignRT and treatment‐beam isocenters. This work evaluated the effects of misaligning the calibration plate during the calibration process. The plate was intentionally shifted away from isocenter ±3.0 mm in the longitudinal and lateral directions and ±1.0 mm in the longitudinal, lateral, and vertical directions. A mock stereotactic radiosurgery (SRS) treatment was used to evaluate the effects of the miscalibrations. An anthropomorphic head phantom was placed in an SRS treatment position and monitored with the AlignRT system. The AlignRT‐indicated offsets were recorded at 270°, 315°, 0°, 45°, and 90° couch angles for each intentional misalignment of the calibration plate during the MC. The IC was also performed after each miscalibration, and the measurements were repeated and compared to the previous results. With intentional longitudinal and lateral shifts of ±3.0 mm and ±1.0 mm of the calibration plate, the average indicated offsets at couch rotations of ±90° were 4.3 mm and 1.6 mm, respectively. This was in agreement with the theoretical offset of √2*(shift‐of‐the‐calibration plate). Since vertical shifts were along the rotation axis of the couch, these shifts had little effect on the offsets with changing couch angle. When the IC was applied, the indicated offsets were all within 0.5 mm for all couch angles for each of the miscalibrations. These offsets were in agreement with the known magnitude of couch walkout. The IC method effectively removes the potential miscalibration artifacts of the MC method due to misalignments of the calibration plate.

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Dosimetric effect due to the motion during deep inspiration breath hold for left‐sided breast cancer radiotherapy

Cited by 21 publications

References 25 publications

Dosimetric effects of intrafractional isocenter variation during deep inspiration breath‐hold for breast cancer patients using surface‐guided radiotherapy

Dosimetric effects of intrafractional isocenter variation during deep inspiration breath‐hold for breast cancer patients using surface‐guided radiotherapy

Variation of Heart and Lung Radiation Doses According to Setup Uncertainty in Left Breast Cancer

Evaluation of a surface imaging system's isocenter calibration methods

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