Fracture morphology and ossification process of the keel bone in modern laying hens based on radiographic imaging.

Keel bone fractures (KBF) are one of the most important welfare problems in commercial laying hens. Despite extensive research on the matter, its etiology remains unclear. Studying fracture characteristics in radiographic images can aid in the understanding of the disorder.

Automatic gross tumor segmentation of canine head and neck cancer using deep learning and cross-species transfer learning.

Background: Radiotherapy (RT) is increasingly being used on dogs with spontaneous head and neck cancer (HNC), which account for a large percentage of veterinary patients treated with RT. Accurate definition of the gross tumor volume (GTV) is a vital part of RT planning, ensuring adequate dose coverage of the tumor while limiting the radiation dose to surrounding tissues. Currently the GTV is contoured manually in medical images, which is a time-consuming and challenging task.

Lack of radioprotection knowledge and compliance in Norwegian equine ambulatory practice.

There is an increasing use of mobile radiographic units in equine ambulatory practices in Norway. Horse owners or handlers often participate in the radiographic examination in a non-controlled area. The aim of this descriptive, cross-sectional, survey study was to evaluate the radiation safety and protection in use of mobile radiography, and to identify areas where special attention from the regulatory authorities as well as veterinary educators would be required.

Dose or 'LET' painting--What is optimal in particle therapy of hypoxic tumors?

Background: Dose painting is a concept that may increase the tumor control probability (TCP). In particle therapy of hypoxic tumors, it may also be beneficial to redistribute the linear energy transfer (LET) so that the oxygen effect is minimized; so-called LET painting. The purpose of the present study was to use TCP estimates for comparing dose and LET painting of hypoxic tumors.

Functional imaging to monitor vascular and metabolic response in canine head and neck tumors during fractionated radiotherapy.

Radiotherapy causes alterations in tumor biology, and non-invasive early assessment of such alterations may become useful for identifying treatment resistant disease. The purpose of the current work is to assess changes in vascular and metabolic features derived from functional imaging of canine head and neck tumors during fractionated radiotherapy. Material and methods.

Dosimetric verification of biologically adapted IMRT.

Purpose: To investigate the delivery of biologically adapted high resolution intensity modulated radiotherapy (IMRT) to an anthropomorphic phantom, using dosimetric and radiobiologic measures.

Methods: A compartment based 3D hypoxia map of a highly heterogeneous tumor was imported into the CT planning basis of an anthropomorphic phantom. Biologically adapted IMRT was planned according to the corresponding 3D dose prescription map with elevated dose to the hypoxic regions.

Spatiotemporal analysis of tumor uptake patterns in dynamic (18)FDG-PET and dynamic contrast enhanced CT.

Background: Molecular and functional imaging techniques such as dynamic positron emission tomography (DPET) and dynamic contrast enhanced computed tomography (DCECT) may provide improved characterization of tumors compared to conventional anatomic imaging. The purpose of the current work was to compare spatiotemporal uptake patterns in DPET and DCECT images.

Materials And Methods: A PET/CT protocol comprising DCECT with an iodine based contrast agent and DPET with (18)F-fluorodeoxyglucose was set up.

Influence of MLC leaf width on biologically adapted IMRT plans.

Introduction: High resolution beam delivery may be required for optimal biology-guided adaptive therapy. In this work, we have studied the influence of multi leaf collimator (MLC) leaf widths on the treatment outcome following adapted IMRT of a hypoxic tumour.

Material And Methods: Dynamic contrast enhanced MR images of a dog with a spontaneous tumour in the nasal region were used to create a tentative hypoxia map following a previously published procedure.

Adaptive radiotherapy based on contrast enhanced cone beam CT imaging.

Cone beam CT (CBCT) imaging has become an integral part of radiation therapy, with images typically used for offline or online patient setup corrections based on bony anatomy co-registration. Ideally, the co-registration should be based on tumor localization. However, soft tissue contrast in CBCT images may be limited.

Adapting biological feedback in radiotherapy.

Recently, there has been much interest in how to use information on patient-specific tumor biology and normal tissue function to individualize cancer treatment. In radiation therapy, dose may be escalated to radioresistant regions within a tumor, or regions of particular functional importance in normal organs may be preferentially spared. However, tumor and normal tissue biology may change during treatment, and adaptation of therapy may be necessary to ensure that optimal therapy is delivered.

Strategies for biologic image-guided dose escalation: a review.

There is increasing interest in how to incorporate functional and molecular information obtained by noninvasive, three-dimensional tumor imaging into radiotherapy. The key issues are to identify radioresistant regions that can be targeted for dose escalation, and to develop radiation dose prescription and delivery strategies providing optimal treatment for the individual patient. In the present work, we review the proposed strategies for biologic image-guided dose escalation with intensity-modulated radiation therapy.

DCEMRI monitoring of canine tumors during fractionated radiotherapy.

Purpose: To monitor the contrast enhancement in spontaneous canine tumors during fractionated radiotherapy by Dynamic Contrast Enhanced Magnetic Resonance Imaging (DCEMRI).

Methods And Material: Six dogs with tumors in the oral or nasal cavity received fractionated conformal radiotherapy with 54 Gy given in 18 fractions. T1 weighted DCE imaging was performed prior to each treatment fraction.

On the parameter describing the generalised equivalent uniform dose (gEUD) for tumours.

The purpose of the present work was to estimate the parameter 'a' describing the generalised equivalent uniform dose (gEUD) for tumours and its dependence on radiobiological parameters. The consequences of uncertainties in a on the gEUD were also studied. An estimate of a was found by requiring that, for a given target dose distribution, the mechanistic EUD (based on radiobiological linear quadratic modelling) equals gEUD.

Radiotherapy adapted to spatial and temporal variability in tumor hypoxia.

Purpose: To explore the feasibility and clinical potential of adapting radiotherapy to temporal and spatial variations in tumor oxygenation.

Methods And Materials: Repeated dynamic contrast enhanced magnetic resonance (DCEMR) images were taken of a canine sarcoma during the course of fractionated radiation therapy. The tumor contrast enhancement was assumed to represent the oxygen distribution.

Optimization of tumour control probability in hypoxic tumours by radiation dose redistribution: a modelling study.

Tumour hypoxia is a known cause of clinical resistance to radiation therapy. The purpose of this work was to model the effects on tumour control probability (TCP) of selectively boosting the dose to hypoxic regions in a tumour, while keeping the mean tumour dose constant. A tumour model with a continuous oxygen distribution, incorporating pO(2) histograms published for head and neck patients, was developed.

Adapting radiotherapy to hypoxic tumours.

In the current work, the concepts of biologically adapted radiotherapy of hypoxic tumours in a framework encompassing functional tumour imaging, tumour control predictions, inverse treatment planning and intensity modulated radiotherapy (IMRT) were presented. Dynamic contrast enhanced magnetic resonance imaging (DCEMRI) of a spontaneous sarcoma in the nasal region of a dog was employed. The tracer concentration in the tumour was assumed related to the oxygen tension and compared to Eppendorf histograph measurements.