International Journal of
Radiation Oncology biology
physics
www.redjournal.org
Physics Contribution
Computed Tomography Number Changes Observed During Computed TomographyeGuided Radiation Therapy for Head and Neck Cancer Mei Feng, MD,*,y Cungeng Yang, PhD,* Xiaojian Chen, PhD,* Shouping Xu, MSc,* Ion Moraru, PhD,* Jinyi Lang, MD,y Christopher Schultz, MD,* and X. Allen Li, PhD* *Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, Wisconsin; and y Department of Radiation Oncology, Sichuan Cancer Hospital, Chengdu, China Received Jun 10, 2014, and in revised form Dec 15, 2014. Accepted for publication Dec 20, 2014.
Summary Radiation-induced CT number changes in gross tumor volume (GTV) and organs at risk in head and neck cancer (HNC) were determined from diagnostic-quality CTs acquired during daily CTguided radiation therapy for HNC. The CT numbers in GTV and parotid glands were reduced for a subset of patients and were correlated with the doses received.
Purpose: To investigate CT number (CTN) changes in gross tumor volume (GTV) and organ at risk (OAR) according to daily diagnostic-quality CT acquired during CTguided intensity modulated radiation therapy for head and neck cancer (HNC) patients. Methods and Materials: Computed tomography scans acquired using a CT-on-rails during daily CT-guided intensity modulated radiation therapy for 15 patients with stage II to IVa squamous cell carcinoma of the head and neck were analyzed. The GTV, parotid glands, spinal cord, and nonspecified tissue were generated on each selected daily CT. The changes in CTN distributions and the mean and mode values were collected. Pearson analysis was used to assess the correlation between the CTN change, organ volume reduction, and delivered radiation dose. Results: Volume and CTN changes for GTV and parotid glands can be observed during radiation therapy delivery for HNC. The mean (SD) CTNs in GTV and ipsi- and contralateral parotid glands were reduced by 6 10, 8 7, and 11 10 Hounsfield units, respectively, for all patients studied. The mean CTN changes in both spinal cord and nonspecified tissue were almost invisible (
Radiation Oncology biology
physics
www.redjournal.org
Physics Contribution
Computed Tomography Number Changes Observed During Computed TomographyeGuided Radiation Therapy for Head and Neck Cancer Mei Feng, MD,*,y Cungeng Yang, PhD,* Xiaojian Chen, PhD,* Shouping Xu, MSc,* Ion Moraru, PhD,* Jinyi Lang, MD,y Christopher Schultz, MD,* and X. Allen Li, PhD* *Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, Wisconsin; and y Department of Radiation Oncology, Sichuan Cancer Hospital, Chengdu, China Received Jun 10, 2014, and in revised form Dec 15, 2014. Accepted for publication Dec 20, 2014.
Summary Radiation-induced CT number changes in gross tumor volume (GTV) and organs at risk in head and neck cancer (HNC) were determined from diagnostic-quality CTs acquired during daily CTguided radiation therapy for HNC. The CT numbers in GTV and parotid glands were reduced for a subset of patients and were correlated with the doses received.
Purpose: To investigate CT number (CTN) changes in gross tumor volume (GTV) and organ at risk (OAR) according to daily diagnostic-quality CT acquired during CTguided intensity modulated radiation therapy for head and neck cancer (HNC) patients. Methods and Materials: Computed tomography scans acquired using a CT-on-rails during daily CT-guided intensity modulated radiation therapy for 15 patients with stage II to IVa squamous cell carcinoma of the head and neck were analyzed. The GTV, parotid glands, spinal cord, and nonspecified tissue were generated on each selected daily CT. The changes in CTN distributions and the mean and mode values were collected. Pearson analysis was used to assess the correlation between the CTN change, organ volume reduction, and delivered radiation dose. Results: Volume and CTN changes for GTV and parotid glands can be observed during radiation therapy delivery for HNC. The mean (SD) CTNs in GTV and ipsi- and contralateral parotid glands were reduced by 6 10, 8 7, and 11 10 Hounsfield units, respectively, for all patients studied. The mean CTN changes in both spinal cord and nonspecified tissue were almost invisible (
