(Tuesday, 7/16/2019) 3:45 PM - 4:15 PM
Room: Exhibit Hall | Forum 5
Purpose: to investigate the reduction of dose to ipsilateral lung and heart with voluntary Deep Inspiration Breath Hold (vDIBH) during locoregional right breast 3D conformal radiotherapy.
Methods: five patients receiving 50.4 Gy in 28 fractions of locoregional 3DCRT to the right breast /right chest wall including the intra mammary nodes (IMNs). Simulations were performed with free breathing FB and vDIBH technique. Two of patients’ breathing signals were monitored and tracked using calypso system, while three patients’ breathing signals were monitored and tracked using respiratory motion management system RPM. Contours of targets and organs at risks were delineated on both FB and vDIBH simulation CTs. 3D tangential field-in-field treatment plans using Varian Eclipse 13.7 treatment planning system were generated on both FB-CT and vDIBH-CT achieving comparable and acceptable target coverage (D95% covering 100% of the CTV contoured by the clinicians). V20, V10, and V5 for total lungs and Mean dose, Max dose, V25 of the heart and were obtained from Dose Volume Histograms for each patients’ FB-plan and vDIBH-plan.
Results: The volume of ipsilateral lung receiving 20Gy was reduced by 38.3% on average with vDIBH-plans compared to FB-plans for all 5 patients, V10 and V5 were reduced by 32.6% and 22.6% on average respectively. Mean dose to the heart was reduced by 31.6% on average for all 5 patients, while maximum dose was reduced by 59.2% on average. V25 was reduced 40% on average for all 5 patients.
Conclusion: Sacrificing dose to the lung and heart to insure adequate coverage to the IMNs was noticeable in the sub-optimal FB-plans. Whereas vDIBH-plans offered significant decrease of dose to heart and lung without compromising the target coverage. When vDIBH is achievable it should be implemented in locoregional Rt-Breast radiotherapy to reduce the ipsilateral lung and heart doses to acceptable dose tolerance.
Keywords
Lung, Heart, Treatment Techniques
Taxonomy
TH- External beam- photons: Motion management (intrafraction)
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