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Title: SU-E-J-268: Change of CT Number During the Course of Chemoradiation Therapy for Pancreatic Cancer

Abstract

Purpose: It has been observed radiation can induce changes in CT number (CTN) inside tumor during the course of radiation therapy (RT) for several tumor sites including lung and head and neck, suggesting that the CTN change may be potentially used to assess RT response. In this study, we investigate the CTN changes inside tumor during the course of chemoradiation therapy (CRT) for pancreatic cancer. Methods: Daily diagnostic-quality CT data acquired during IGRT for 17 pancreatic head cancer patients using an in-room CT (CTVision, Siemens) were analyzed. All patients were treated with a radiation dose of 50.4 in 1.8 Gy per fraction. On each daily CT set, The contour of the pancreatic head, included in the treatment target, was generated by populating the pancreatic head contour from the planning CT or MRI using an auto-segmentation tool based on deformable registration (ABAS, Elekta) with manual editing if necessary. The CTN at each voxel in the pancreatic head contour was extracted and the 3D distribution of the CTNs was processed using MATLAB. The mean value of CTN distribution was used to quantify the daily CTN change in the pancreatic head. Results: Reduction of CTN in pancreatic head was observed during the CRTmore » delivery in 14 out the 17 (82%) patients studied. Although the average reduction is only 3.5 Houncefield Unit (HU), this change is significant (p<0.01). Among them, there are 7 patients who had a CTN drop larger than 5 HU, ranging from 6.0 to 11.8 HU. In contrast to this trend, CTN was increased in 3 patients. Conclusion: Measurable changes in the CT number in tumor target were observed during the course of chemoradiation therapy for the pancreas cancer patients, indicating this radiation-induced CTN change may be used to assess treatment response.« less

Authors:
; ; ;  [1];  [2]
  1. Medical College of Wisconsin, Milwaukee, WI (United States)
  2. Department of Radiation Oncology, Qianfoshan Hospital Affiliated to Shandon, Jinan, Shandong (China)
Publication Date:
OSTI Identifier:
22499366
Resource Type:
Journal Article
Resource Relation:
Journal Name: Medical Physics; Journal Volume: 42; Journal Issue: 6; Other Information: (c) 2015 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; COMPUTERIZED TOMOGRAPHY; HEAD; LUNGS; NECK; NEOPLASMS; NMR IMAGING; PANCREAS; PATIENTS; RADIATION DOSES; RADIOTHERAPY

Citation Formats

Chen, X, Dalah, E, Liu, F, Li, X, and Zhang, J. SU-E-J-268: Change of CT Number During the Course of Chemoradiation Therapy for Pancreatic Cancer. United States: N. p., 2015. Web. doi:10.1118/1.4924354.
Chen, X, Dalah, E, Liu, F, Li, X, & Zhang, J. SU-E-J-268: Change of CT Number During the Course of Chemoradiation Therapy for Pancreatic Cancer. United States. doi:10.1118/1.4924354.
Chen, X, Dalah, E, Liu, F, Li, X, and Zhang, J. Mon . "SU-E-J-268: Change of CT Number During the Course of Chemoradiation Therapy for Pancreatic Cancer". United States. doi:10.1118/1.4924354.
@article{osti_22499366,
title = {SU-E-J-268: Change of CT Number During the Course of Chemoradiation Therapy for Pancreatic Cancer},
author = {Chen, X and Dalah, E and Liu, F and Li, X and Zhang, J},
abstractNote = {Purpose: It has been observed radiation can induce changes in CT number (CTN) inside tumor during the course of radiation therapy (RT) for several tumor sites including lung and head and neck, suggesting that the CTN change may be potentially used to assess RT response. In this study, we investigate the CTN changes inside tumor during the course of chemoradiation therapy (CRT) for pancreatic cancer. Methods: Daily diagnostic-quality CT data acquired during IGRT for 17 pancreatic head cancer patients using an in-room CT (CTVision, Siemens) were analyzed. All patients were treated with a radiation dose of 50.4 in 1.8 Gy per fraction. On each daily CT set, The contour of the pancreatic head, included in the treatment target, was generated by populating the pancreatic head contour from the planning CT or MRI using an auto-segmentation tool based on deformable registration (ABAS, Elekta) with manual editing if necessary. The CTN at each voxel in the pancreatic head contour was extracted and the 3D distribution of the CTNs was processed using MATLAB. The mean value of CTN distribution was used to quantify the daily CTN change in the pancreatic head. Results: Reduction of CTN in pancreatic head was observed during the CRT delivery in 14 out the 17 (82%) patients studied. Although the average reduction is only 3.5 Houncefield Unit (HU), this change is significant (p<0.01). Among them, there are 7 patients who had a CTN drop larger than 5 HU, ranging from 6.0 to 11.8 HU. In contrast to this trend, CTN was increased in 3 patients. Conclusion: Measurable changes in the CT number in tumor target were observed during the course of chemoradiation therapy for the pancreas cancer patients, indicating this radiation-induced CTN change may be used to assess treatment response.},
doi = {10.1118/1.4924354},
journal = {Medical Physics},
number = 6,
volume = 42,
place = {United States},
year = {Mon Jun 15 00:00:00 EDT 2015},
month = {Mon Jun 15 00:00:00 EDT 2015}
}
  • Purpose: In an effort of early assessment of treatment response, we investigate radiation induced changes in CT number histogram of GTV during the delivery of chemoradiation therapy (CRT) for pancreatic cancer. Methods: Diagnostic-quality CT data acquired daily during routine CT-guided CRT using a CT-on-rails for 20 pancreatic head cancer patients were analyzed. All patients were treated with a radiation dose of 50.4 in 28 fractions. On each daily CT set, the contours of the pancreatic head and the spinal cord were delineated. The Hounsfiled Units (HU) histogram in these contourswere extracted and processed using MATLAB. Eight parameters of the histogrammore » including the mean HU over all the voxels, peak position, volume, standard deviation (SD), skewness, kurtosis, energy, and entropy were calculated for each fraction. The significances were inspected using paired two-tailed t-test and the correlations were analyzed using Spearman rank correlation tests. Results: In general, HU histogram in pancreatic head (but not in spinal cord) changed during the CRT delivery. Changes from the first to the last fraction in mean HU in pancreatic head ranged from −13.4 to 3.7 HU with an average of −4.4 HU, which was significant (P<0.001). Among other quantities, the volume decreased, the skewness increased (less skewed), and the kurtosis decreased (less sharp) during the CRT delivery. The changes of mean HU, volume, skewness, and kurtosis became significant after two weeks of treatment. Patient pathological response status is associated with the changes of SD (ΔSD), i.e., ΔSD= 1.85 (average of 7 patients) for good reponse, −0.08 (average of 6 patients) for moderate and poor response. Conclusion: Significant changes in HU histogram and the histogram-based metrics (e.g., meam HU, skewness, and kurtosis) in tumor were observed during the course of chemoradiation therapy for pancreas cancer. These changes may be potentially used for early assessment of treatment response.« less
  • Purpose: It has been reported recently that radiation can induce CT number (CTN) change during radiation therapy (RT) delivery. In the effort to explore whether CTN can be used to assess RT response, we analyze the relationship between the pathological treatment response (PTR) and the changes of CTN, MRI, and PET before and after the neoadjuvant chemoradiation (nCR) for pancreatic adenocarcinoma. Methods: The preand post-nCR CT, MRI, and PET data for a total of 8 patients with resectable, or borderline resectable pancreatic head adenocarcinoma treated with nCR were retrospectively analyzed. Radiographic characteristics were correlated to PTR data. The histograms, meansmore » and standard derivations (SD) of the CTNs in pancreatic head (CTNPH), the GTV defined by ADC (CTNGTV), and the rest of pancreatic head (CTNPH-CTNGTV) were compared. Changes before and after nCR were correlated with the corresponding changes of ADC, lean body mass normalized SUV (SUVlb), and PTR using Pearson’ s correlation coefficient test. Results: The average mean and SD in CTPH for all the patients analyzed were higher in post-nCR (53.17 ± 31.05 HU) compared to those at pre-nCR (28.09 ± 4.253 HU). The CTNGTV were generally higher than CTNPH and CTNPH-CTNGTV, though the differences were not significant. The post-nCR changes of mean CTN, ADC, and SUVlb values in pancreatic head were correlated with PTR (R=0.3273/P=0.5357, R=−0.5455/P<0.0001, and R=0.7638/P=0.0357, respectively). The mean difference in the maximum tumor dimension measured from CTN, ADC, and SUVlb as compared with pathological measurements was −2.1, −0.5, and 0.22 cm, respectively. Conclusion: The radiation-induced change of CTN in pancreas head after chemoradiation therapy of pancreatic cancer was observed, which may be related to treatment responses as assessed by biological imaging and pathology. More data are needed to determine whether the CTN can be used as a quantitative biomarker for response to neoadjuvant therapy.« less
  • Purpose: Pilot study developing a CT-texture based model for early assessment of treatment response during the delivery of chemoradiation therapy (CRT) for pancreatic cancer. Methods: Daily CT data acquired for 24 pancreatic head cancer patients using CT-on-rails, during the routine CT-guided CRT delivery with a radiation dose of 50.4 Gy in 28 fractions, were analyzed. The pancreas head was contoured on each daily CT. Texture analysis was performed within the pancreas head contour using a research tool (IBEX). Over 1300 texture metrics including: grey level co-occurrence, run-length, histogram, neighborhood intensity difference, and geometrical shape features were calculated for each dailymore » CT. Metric-trend information was established by finding the best fit of either a linear, quadratic, or exponential function for each metric value verses accumulated dose. Thus all the daily CT texture information was consolidated into a best-fit trend type for a given patient and texture metric. Linear correlation was performed between the patient histological response vector (good, medium, poor) and all combinations of 23 patient subgroups (statistical jackknife) determining which metrics were most correlated to response and repeatedly reliable across most patients. Control correlations against CT scanner, reconstruction kernel, and gated/nongated CT images were also calculated. Euclidean distance measure was used to group/sort patient vectors based on the data of these trend-response metrics. Results: We found four specific trend-metrics (Gray Level Coocurence Matrix311-1InverseDiffMomentNorm, Gray Level Coocurence Matrix311-1InverseDiffNorm, Gray Level Coocurence Matrix311-1 Homogeneity2, and Intensity Direct Local StdMean) that were highly correlated with patient response and repeatedly reliable. Our four trend-metric model successfully ordered our pilot response dataset (p=0.00070). We found no significant correlation to our control parameters: gating (p=0.7717), scanner (p=0.9741), and kernel (p=0.8586). Conclusion: We have successfully created a CT-texture based early treatment response prediction model using the CTs acquired during the delivery of chemoradiation therapy for pancreatic cancer. Future testing is required to validate the model with more patient data.« less
  • Purpose: To measure CT number (CTN) changes in tumor and normal lung as a function of radiation therapy (RT) dose during the course of RT delivery for lung cancer using daily IGRT CT images and single respiration phase CT images. Methods: 4D CT acquired during planning simulation and daily 3D CT acquired during daily IGRT for 10 lung cancer cases randomly selected in terms of age, caner type and stage, were analyzed using an in-house developed software tool. All patients were treated in 2 Gy fractions to primary tumors and involved nodal regions. Regions enclosed by a series of isodosemore » surfaces in normal lung were delineated. The obtained contours along with target contours (GTVs) were populated to each singlephase planning CT and daily CT. CTN in term of Hounsfield Unit (HU) of each voxel in these delineated regions were collectively analyzed using histogram, mean, mode and linear correlation. Results: Respiration induced normal lung CTN change, as analyzed from single-phase planning CTs, ranged from 9 to 23 (±2) HU for the patients studied. Normal lung CTN change was as large as 50 (±12) HU over the entire treatment course, was dose and patient dependent and was measurable with dose changes as low as 1.5 Gy. For patients with obvious tumor volume regression, CTN within the GTV drops monotonically as much as 10 (±1) HU during the early fractions with a total dose of 20 Gy delivered. The GTV and CTN reductions are significantly correlated with correlation coefficient >0.95. Conclusion: Significant RT dose induced CTN changes in lung tissue and tumor region can be observed during even the early phase of RT delivery, and may potentially be used for early prediction of radiation response. Single respiration phase CT images have dramatically reduced statistical noise in ROIs, making daily dose response evaluation possible.« less
  • Purpose: We retrospectively investigated the impact of weight change (WC) during concurrent chemoradiation therapy (C-CRT) on clinical outcomes of stage 3B non-small cell lung cancer (NSCLC) patients. Methods and Materials: A total of 425 patients treated with C-CRT were included. All patients received 60 to 66 Gy of thoracic radiation therapy concurrently with 1 to 3 cycles of platinum-based chemotherapy. Pre- and posttreatment weight measurements on first and last days of C-CRT were used for WC. Patients were divided into 2 groups: group 1 = weight loss (WL); group 2 = weight preservation/gain (WP) for comparative analyses. Results: Following C-CRT,more » 252 patients (59.3%) experienced WL, while 89 patients (20.9%) and 84 patients (19.8%) showed WP or WG. At median 24.2 months of follow-up, 142 patients (33.4%) were alive (84 WP [48.6%] and 58 WL [23.0%]), and 58 (13.6%) of them were free of disease progression (41 [23.7%] for WP and 17 [6.7%] for WL). Median overall survival (OS), locoregional progression-free survival (LRPFS), progression-free survival (PFS), and distant metastases-free survival (DMFS) for the entire population were 22.8, 14.4, 10.6, and 11.7 months, respectively. Intergroup comparisons between WP and WL cohorts revealed significantly superior OS, LRPFS, PFS, and DMFS in WP patients (P<.05 for each). On multivariate analyses, only WL and advanced T stage were associated with poor prognosis (P<.05). Conclusions: Present results in 425 stage 3B NSCLC patients demonstrated that WL during C-CRT is strongly associated with inferior survival outcomes compared to WP. This emerging finding might be useful by forming an encouraging basis for future investigations in facilitating a way to improve the outcomes of these patients experiencing WL during C-CRT.« less