T Lin*¹, J Piskorski¹, M Blau¹, A Ritter², J Shah², C Ma¹, (1)Fox Chase Cancer Center, Temple University, Philadelphia, PA (2) Siemens Healthineers

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  T Lin

PO-GePV-M-354 (Sunday, 7/10/2022)   [Eastern Time (GMT-4)]

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Purpose: Functional imaging has been proposed that uses 4DCT images to calculate lung ventilation(4DCT-ventilation) to aid treatment planning. The purpose is to avoid highly ventilated areas of lungs to reduce toxicity at the treatment planning stage. This retrospective study aims to validate the correlation between the Siemens 4DCT-ventilation prototype (Siemens Healthineers, Germany) and patient pulmonary function for stereotactic body radiotherapy (SBRT) lung treatments.

Methods: 138 NSCLC (non-small cell lung cancer) patients, received SBRT treatment, at a single institution between 2011-2019, were retrospectively identified from our patient database. 111 out of 138 patients received 10x5 Gy with an average target volume 31.52 c.c. Pulmonary function tests(PFTs) information (%Ref. FEV1, FVC, FEV1/FVC, FEV1) within 3 years of starting radiation therapy(RT) were gathered. The ventilation maps calculated based on Hounsfield Units changes with deformable registration are used in the E-Xamine. The coefficient of ventilation was correlated with pre and post PFTs results.

Results: 66 out of 111 SBRT patients with PFTs within 3 years prior to starting radiation RT and also with meaningful ventilation maps derived from the prototype were correlated. The correlation between %Ref. FEV1 and mean ventilation is measured by R^2 = 0.6233. Compared to FEV1 (R^2 = 0.4481) and FEV1/FVC (R^2 = 0.1337), FEV1 had the strongest association with mean ventilation. The correlation between FEV1 and mean ventilation is significantly reduced by the outliers in the data, which likely represent patients with compromised ventilation maps.

Conclusion: Ventilation maps calculated using the E-Xamine based prototype have a medium acceptable level respective to the PFT value changes.

Keywords

Ventilation/perfusion, Lung

Taxonomy

TH- Response Assessment: Imaging-based: CT

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