Three-dimensional (3D) anatomic location, extension, and timing of severe osteoradionecrosis of the mandible.

Background: The purpose of this study was to describe the topography, extension (volume), and timing of severe osteoradionecrosis (ORN) that required mandible resection in patients previously treated for head and neck cancer at a high-volume Veterans Affairs Medical Center.

Materials And Methods: The records from a reference hyperbaric oxygen clinic were retrospectively analyzed (n = 50, 2018-2021). Inclusion criteria were: I) severe ORN defined as progressive ORN that required resection; II) pathologic confirmation of ORN; and III) availability of pre-operative CT-imaging.

Lack of correlation between external fiducial positions and internal tumor positions during breath-hold CT.

Purpose: For thoracic tumors, if four-dimensional computed tomography (4DCT) is unavailable, the internal margin can be estimated by use of breath-hold (BH) CT scans acquired at end inspiration (EI) and end expiration (EE). By use of external surrogates for tumor position, BH accuracy is estimated by minimizing the difference between respiratory extrema BH and mean equivalent-phase free breathing (FB) positions. We tested the assumption that an external surrogate for BH accuracy correlates with internal tumor positional accuracy during BH CT.

MRI and (1)H MRS of the breast: presence of a choline peak as malignancy marker is related to K21 value of the tumor in patients with invasive ductal carcinoma.

To assess which specific morphologic features, enhancement patterns, or pharmacokinetic parameters on breast Magnetic Resonance Imaging (MRI) could predict a false-negative outcome of Proton MR Spectroscopy ((1)H MRS) exam in patients with invasive breast cancer. Sixteen patients with invasive ductal carcinoma of the breast were prospectively included and underwent both, contrast-enhanced breast MRI and (1)H MRS examination of the breast. The MR images were reviewed and the lesions morphologic features, enhancement patterns and pharmacokinetic parameters (k21-value) were scored according to the ACR BI-RADS-MRI lexicon criteria.

Comparison of breath-hold and free-breathing positions of an external fiducial by analysis of respiratory traces.

An internal target volume (ITV) accounting for respiratory-induced tumor motion is best obtained using 4DCT. However, when 4DCT is not available, inspiratory/expiratory breath-hold (BH insp, BH exp) CT images have been suggested as an alternative. In such cases, an external fiducial on the abdomen can be used as a substitute for tumor motion and CT images are acquired when the marker position matches - as judged by the therapist/physicist - its positions at previously determined free-breathing (FB) respiratory extrema (FB insp, FB exp).

Assessing respiration-induced tumor motion and internal target volume using four-dimensional computed tomography for radiotherapy of lung cancer.

Purpose: To assess three-dimensional tumor motion caused by respiration and internal target volume (ITV) for radiotherapy of lung cancer.

Methods And Materials: Respiration-induced tumor motion was analyzed for 166 tumors from 152 lung cancer patients, 57.2% of whom had Stage III or IV non-small-cell lung cancer.

Quality assurance of magnetic resonance spectroscopic imaging-derived metabolic data.

Purpose: Spatially resolved metabolite maps, as measured by magnetic resonance spectroscopic imaging (MRSI) methods, are being increasingly used to acquire metabolic information to guide therapy, with metabolite ratio maps perhaps providing the most diagnostic information. We present a quality assurance procedure for MRSI-derived metabolic data acquired ultimately for guiding conformal radiotherapy.

Methods And Materials: An MRSI phantom filled with brain-mimicking solutions was custom-built with an insert holding eight vials containing calibration solutions of precisely varying metabolite concentrations that emulated increasing grade/density of brain tumor.

Tumor oximetry: comparison of 19F MR EPI and electrodes.

We recently described a novel approach to measuring regional tumor oxygen tension. This approach is based on 19F pulse burst saturation recovery NMR echo planar imaging relaxometry of hexafluorobenzene or "FREDOM" (Fluorocarbon Relaxometry using Echo planar imaging for Dynamic Oxygen Mapping). We have now compared oxygen tension measurements using FREDOM with a traditional polarographic method (the Eppendorf Histograph) in a group of size matched Dunning prostate rat tumors R3327-AT1.

Inverse planning for functional image-guided intensity-modulated radiation therapy.

Radiation therapy is an image-guided process whose success critically depends on the imaging modality used for treatment planning and the level of integration of the available imaging information. In this work, we establish a dose optimization framework for incorporating metabolic information from functional imaging modalities into the intensity-modulated radiation therapy (IMRT) inverse planning process and to demonstrate the technical feasibility of planning deliberately non-uniform dose distributions in accordance with functional imaging data. For this purpose, a metabolic map from functional images is discretized into a number of abnormality levels (ALs) and then fused with CT images.