Details

Autor(en) / Beteiligte

• Paul, Jijo, PhD
• Yang, Cungeng, PhD
• Wu, Hui, MD
• Tai, An, PhD
• Dalah, Entesar, PhD
• Zheng, Cheng, PhD
• Johnstone, Candice, MD
• Kong, Feng-Ming, MD
• Gore, Elizabeth, MD
• Li, X. Allen, PhD

Titel

Early Assessment of Treatment Responses during Radiation Therapy of Lung Cancer Based on Quantitative Analysis of Daily CT

Ist Teil von

• International journal of radiation oncology, biology, physics, 2017

Erscheinungsjahr

2017

Link zum Volltext

Quelle

Elsevier ScienceDirect Journals Complete

Beschreibungen/Notizen

• Abstract Purpose To investigate early tumor and normal tissue responses during the course of radiation therapy (RT) of lung cancer based on quantitative analysis of daily CTs. Methods and materials Daily diagnostic-quality CTs acquired using CT-on-Rails during CT-guided RT for 20 lung cancer patients were quantitatively analyzed. On each daily CT set, contours of gross tumor volume (GTV) and lungs were generated and the x-ray dose delivered was reconstructed. The changes in CT image intensity (Hounsfield unit, HU) features in the GTV and in the multiple normal lung tissue shells around GTV were extracted from daily CTs. Associations between the changes in mean HU, GTV volume, accumulated dose during RT delivery and patient survival rate were analyzed. Results During the course of RT, radiation can induce substantial changes in HU histogram features in the daily CTs with reductions of GTV mean HU (dH) observed in the range of 11- 48HU (median 30HU). The dH is statistically related to the accumulated GTV dose (R2 >0.99), while it is weakly correlated with the change of GTV (R2 = 0.3481). Statistically significant increases in patient survival rates (p= 0.038) were observed for patients with higher dH in GTV. In normal lung, the four regions proximal to the GTV showed statistically significant (<0.001) HU reductions from the first to last fractions. Conclusion Quantitative analysis of daily CT indicates that the mean HUs in lung tumor and the surrounding normal tissue were reduced during RT delivery. This reduction was observed in the early phase of the treatment and is patient specific and correlated to the delivered dose. Larger HU reduction in GTV is significantly correlated with higher patient survival. The change of daily CT feature, such as mean HU, may be used for early assessment of radiation responses during RT delivery for lung cancer.