Search

Purpose: Locally advanced pancreatic cancer (LAPC) patients are prone to experience daily anatomical variations, which can lead to additional doses in organs-at-risk (OAR) during SBRT. A patient selection tool was developed to identify who may be at risk of exceeding dose tolerances, by quantifying the dosimetric impact of daily variations using an OAR motion model., Materials and Methods: The study included 133 CT scans from 35 LAPC patients. By following a leave-one-out approach, an OAR motion model trained with the remaining 34 subjects variations was used to simulate organ deformations on the left-out patient planning CT anatomy. Dose-volume histograms obtained from planned doses sampled on simulated organs resulted in the probability of exceeding OAR dose-constraints due to anatomical variations. Simulated probabilities were clustered with a threshold per organ according to clinical observations. If the prediction of at least one OAR was above the established thresholds, the patient was classified as being at risk., Results: Clinically, in 20/35 patients at least one OAR exceeded dose-constraints in the daily CTs. The model-based prediction had an accuracy of 89%, 71%, 91% in estimating the risk of exceeding dose tolerances for the duodenum, stomach and bowel, respectively. By combining the three predictions, our approach resulted in a correct patient classification for 29/35 patients (83%) when compared with clinical observations., Conclusions: Our model-based patient selection tool is able to predict who might be at risk of exceeding dose-constraints during SBRT. It is a promising tool to tailor LAPC treatments, e.g. by employing online adaptive SBRT; and hence, to minimize toxicity of patients being at risk., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Background: Nintedanib has anti-fibrotic and anti-inflammatory activity and is approved for the treatment of idiopathic pulmonary fibrosis. The aim of this study was to noninvasively assess the efficacy of nintedanib in a mouse model of partial lung irradiation to prevent radiation-induced lung damage (RILD)., Methods: 266 C57BL/6 adult male mice were irradiated with a single radiation dose (0, 4, 8, 12, 16 or 20Gy) using parallel-opposed fields targeting the upper right lung using a precision image-guided small animal irradiator sparing heart and spine based on micro-CT images. One week post irradiation, mice were randomized across nintedanib daily oral gavage treatment (0, 30 or 60mg/kg). CT density analysis of the lungs was performed on monthly acquired micro-CT images. After 39weeks, lungs were processed to evaluate the fibrotic phenotype., Results: Although the CT density increase correlated with the radiation dose, nintedanib did not influence this relationship. Immunohistochemical analysis confirmed the ability of nintedanib to reduce the microscopic fibrotic phenotype, in particular interstitial edema, interstitial and perivascular fibrosis and inflammation, and vasculitis., Conclusions: Nintedanib reduces radiation-induced lung fibrosis after partial lung irradiation without adverse effects, however, noninvasive CT imaging measuring electron density cannot be applied for monitoring its effects., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Small animal models are crucial to link molecular discoveries and implementation of clinically relevant therapeutics in oncology. Using these models requires noninvasive imaging techniques to monitor disease progression and therapy response. Micro-computed tomography (CT) is less studied for the in vivo monitoring of murine intracranial tumors and traditionally suffers from poor soft tissue contrast, whereas bioluminescence imaging (BLI) is known for its sensitivity but is not frequently employed for quantifying tumor volume. A widely used orthotopic glioblastoma multiforme (GBM) tumor model was applied in nude mice, and tumor growth was evaluated by BLI and contrast-enhanced microCT imaging. A strong correlation was observed between CT volume and BLI-integrated intensity (Pearson coefficient (r)  =  .85, p  =  .0002). Repeated contouring of contrast-enhanced microCT-delineated tumor volumes achieved an intraobserver average pairwise overlap ratio of 0.84 and an average tumor volume coefficient of variance of 0.11. MicroCT-delineated tumor size was found to correlate with tumor size obtained via histologic analysis (Pearson coefficient (r)  =  .88, p  =  .005). We conclude that BLI intensity can be used to derive tumor volume but that the use of both contrast-enhanced microCT and BLI provides complementary tumor growth information, which is particularly useful for modern small animal irradiation devices that make use of microCT and BLI for treatment planning, targeting, and monitoring.

Dual-energy computed tomography (CT) enables 3-dimensional,noninvasive, and nondestructive imaging with material separation. Dual-energy CT is generally used to segment hydrated tissues within the clinical context. We apply dual-energy CT to an ancient Egyptian mummy and present several techniques designed to separate bone from desiccated tissue and resin. Automated and semiautomated dual-energy CT techniques are compared to manual segmentation and thresholding-based techniques. Semiautomated techniques enable substantial reductions in operator time compared to manual segmentation.