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 patientâ€™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 patientâ€™s motion varies significantly. The patient with the least motion during DIBH had inter-BH motion of 2.5 Â± 0.7 mm and intra-BH motion of 1.3 Â± 0.4 mm; the patient observed with the largest motion had inter-BH motion of 13.0 Â± 5.4 mm and intra-BH motion of 9.4 Â± 3.2 mm. The average duration of 136 BHs was 13.5 Â± 7.8 s, and the average of the inter- and intra-BH motion were 7.1 Â± 4.9 mm and 4.7 Â± 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.