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Chest Wall Motion During Active Deep Inspiration Breath Hold: A Study Using a Surface Mapping System in Left-Sided Breast Treatment

W Jiang*, D Cao , V Mehta , D Shepard , Swedish Cancer Institute, Seattle, WA


(Sunday, 7/29/2018) 3:00 PM - 6:00 PM

Room: Exhibit Hall

Purpose: To evaluate the motion of the chest wall for left-sided breast patients during deep inspiration breath hold (DIBH) using a surface guided radiotherapy (SGRT) solution.

Methods: This study involved five patients with left-sided breast cancer who received 3D conformal treatments on an Elekta VersaHD. Each tangential beam was delivered during 1 or 2 breath holds (BH) with the duration controlled by an Active Breathing Coordinator (ABC) device. The chest wall motion was monitored by a C-RAD CatalystHD SGRT solution which consists of 3 high resolution camera/detector pairs. A virtual tracking point on patient’s left chest wall was tracked and recorded using the CatalystHD within each breath hold duration at deep inspiration level. The motion during inter- and intra-breath holds were statistically analyzed.

Results: Total of 136 BHs from 47 treatment sessions were randomly selected and evaluated. The range of patient’s motion varies significantly. The patient with the least motion during DIBH had inter-BH motion of 2.5 ± 0.7 mm and intra-BH motion of 1.3 ± 0.4 mm; the patient observed with the largest motion had inter-BH motion of 13.0 ± 5.4 mm and intra-BH motion of 9.4 ± 3.2 mm. The average duration of 136 BHs was 13.5 ± 7.8 s, and the average of the inter- and intra-BH motion were 7.1 ± 4.9 mm and 4.7 ± 3.9 mm, respectively.

Conclusion: The motion during DIBH exists and should not be overlooked even when ABC is in use. The surface guided system can be a patient-friendly alternative to monitor the respiratory motion at DIBH in left breast cancer patients who cannot tolerate the ABC device. The inter- and intral-BH should be carefully monitored to ensure accurate target dose coverage. An analysis of the dosimetric impact of this motion is underway.

Funding Support, Disclosures, and Conflict of Interest: This study is sponsored by Elekta.


Not Applicable / None Entered.


TH- RT Interfraction motion management : Development (new technology and techniques)

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