Constructing Kinematic Confidence Regions With Double Quaternions.

A spatial displacement as an element of can be approximated by a 4D rotation, which is an element of . In this way, the problem of constructing confidence regions of uncertain spatial displacements may be studied as that of constructing confidence ellipsoids in . In this light, a double-quaternion formulation of kinematic confidence regions is presented that approximately preserve the geometry of .

SHAPE DEPENDENT MOTION INTERPOLANTS FOR PLANAR OBJECTS.

Kinematics is most commonly about the motion of unbounded spaces. This paper deals with the kinematics of bounded shapes in a plane. This paper studies the problem of motion interpolation of a planar object with its shape taken into consideration.

On the Computation of Mean and Variance of Spatial Displacements.

This paper studies the problem of computing an average (or mean) displacement from a set of given spatial displacements using three types of parametric representations: Euler angles and translation vectors, unit quaternions and translation vectors, and dual quaternions. It is shown that the use of Euclidean norm in the space of unit quaternions reduces the problem to that of computing the mean for each quaternion component separately and independently. While the resulting algorithm is simple, a change in the sign of a unit quaternion could lead to an incorrect result.

On the Construction of Confidence Regions for Uncertain Planar Displacements.

This paper studies the statistical concept of confidence region for a set of uncertain planar displacements with a certain level of confidence or probabilities. Three different representations of planar displacements are compared in this context and it is shown that the most commonly used representation based on the coordinates of the moving frame is the least effective. The other two methods, namely the exponential coordinates and planar quaternions, are equally effective in capturing the group structure of SE(2).

Dose prescription and reporting in stereotactic body radiotherapy: A multi-institutional study.

Background And Purpose: Radiation dose prescriptions are foundational for optimizing treatment efficacy and limiting treatment-related toxicity. We sought to assess the lack of standardization of SBRT dose prescriptions across institutions.

Materials & Methods: Dosimetric data from 1298 patients from 9 academic institutions treated with IMRT and VMAT were collected.

On the Construction of Kinematic Confidence Ellipsoids for Uncertain Spatial Displacements.

This paper deals with the problem of estimating confidence regions of a set of uncertain spatial displacements for a given level of confidence or probabilities. While a direct application of the commonly used statistic methods to the coordinates of the moving frame is straight-forward, it is also the least effective in that it grossly overestimate the confidence region. Based on the dual-quaternion representation, this paper introduces the notion of the kinematic confidence ellipsoids as an alternative to the existing method called rotation and translation confidence limit (RTCL).

On the mean and variance of planar displacements.

This paper studies the problem of computing the mean (or the average displacement) and variance of a set of planar displacements. It presents three parametric representations of a planar displacement and studies how they influence the computations of means and variances. In particular, it advocates the use of the kinematic concept of relative displacements rather than simple difference in kinematic parameters in formulating the variance and for computing the mean of planar displacements.

Effect of Paclitaxel Stereochemistry on X-ray-Triggered Release of Paclitaxel from CaWO/Paclitaxel-Coloaded PEG-PLA Nanoparticles.

For many locally advanced tumors, the chemotherapy-radiotherapy (CT-RT) combination ("chemoradiation") is currently the standard of care. Intratumoral (IT) CT-based chemoradiation has the potential to overcome the limitations of conventional systemic CT-RT (side effects). For maximizing the benefits of IT CT-RT, our laboratory has previously developed a radiation-controlled drug release formulation, in which anticancer drug paclitaxel (PTX) and radioluminescent CaWO (CWO) nanoparticles (NPs) are co-encapsulated with poly(ethylene glycol)-poly(lactic acid) (PEG-PLA) block copolymers ("PEG-PLA/CWO/PTX NPs").

On the Computation of the Average of Planar Displacements.

In this paper, we present four parametric representations of a planar displacements and studied the problem of how to compute the average displacement from a set of given planar displacements using these representations. It has been shown that the optimal average displacement is obtained by using planar quaternions and the concept of relative displacements. Examples are provided to show the comparisons of these methods.

Radioluminescent nanoparticles for radiation-controlled release of drugs.

The present work demonstrates a novel concept for intratumoral chemo-radio combination therapy for locally advanced solid tumors. For some locally advanced tumors, chemoradiation is currently standard of care. This combination treatment can cause acute and long term toxicity that can limit its use in older patients or those with multiple medical comorbidities.

Predictors of Nodal and Metastatic Failure in Early Stage Non-small-cell Lung Cancer After Stereotactic Body Radiation Therapy.

Introduction/background: Many patients with early stage non-small-cell lung cancer (ES-NSCLC) undergoing stereotactic body radiation therapy (SBRT) develop metastases, which is associated with poor outcomes. We sought to identify factors predictive of metastases after lung SBRT and created a risk stratification tool.

Materials And Methods: We included 363 patients with ES-NSCLC who received SBRT; the median follow-up was 5.

Histology, Tumor Volume, and Radiation Dose Predict Outcomes in NSCLC Patients After Stereotactic Ablative Radiotherapy.

Introduction: It remains unclear if histology should be independently considered when choosing stereotactic ablative body radiotherapy dose prescriptions for NSCLC.

Methods: The study population included 508 patients with 561 lesions between 2000 and 2016, of which 442 patients with 482 lesions had complete dosimetric information. Eligible patients had histologically or clinically diagnosed early-stage NSCLC and were treated with 3 to 5 fractions.

State of dose prescription and compliance to international standard (ICRU-83) in intensity modulated radiation therapy among academic institutions.

Purpose: The purpose of this study was to evaluate dose prescription and recording compliance to international standard (International Commission on Radiation Units & Measurements [ICRU]-83) in patients treated with intensity modulated radiation therapy (IMRT) among academic institutions.

Methods And Materials: Ten institutions participated in this study to collect IMRT data to evaluate compliance to ICRU-83. Under institutional review board clearance, data from 5094 patients-including treatment site, technique, planner, physician, prescribed dose, target volume, monitor units, planning system, and dose calculation algorithm-were collected anonymously.

Ability of the National Surgical Quality Improvement Program Risk Calculator to Predict Complications Following Total Laryngectomy.

Importance: The accuracy of the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) risk calculator has been assessed in multiple surgical subspecialties; however, there have been no publications doing the same in the head and neck surgery literature.

Objective: To evaluate the accuracy of the calculator's predictions in a single institution's total laryngectomy (TL) population.

Design, Setting, And Participants: Total laryngectomies performed between 2013 and 2014 at a tertiary referral academic center were evaluated using the risk calculator.

Intensity modulated radiation therapy with field rotation--a time-varying fractionation study.

This paper proposes a novel mathematical approach to the beam selection problem in intensity modulated radiation therapy (IMRT) planning. The approach allows more beams to be used over the course of therapy while limiting the number of beams required in any one session. In the proposed field rotation method, several sets of beams are interchanged throughout the treatment to allow a wider selection of beam angles than would be possible with fixed beam orientations.

The need for rotational margins in intensity-modulated radiotherapy and a new method for planning target volume design.

Purpose: The effect of rotational errors on the coverage of clinical target volumes (CTVs) is examined. A new planning target volume (PTV) construction that considers the individual paths traced by movements of the target boundary points is developed.

Methods And Materials: A standard uniform margin expansion was compared with a PTV constructed from the space swept out by a concave moving target.