OBJECTIVE Stereotactic radiosurgery (SRS) with or without whole-brain radiotherapy can be used to achieve local control (> 90%) for small brain metastases after resection. However, many are unsuitable SRS because of their size previous treatment, and is associated significant neurocognitive morbidity. The purpose this study was investigate the efficacy toxicity surgery iodine-125 ( 125 I) brachytherapy metastases. METHODS A total 95 consecutive patients treated 105 at a single institution...

Because numerical simulation parameters may significantly influence the accuracy of results, evaluating sensitivity results to variations in is essential. Although field analysis well developed, systematic application such methods complex biological models limited due associated high computational costs and substantial technical challenges for implementation. In specific case forward problem electrocardiography, lack robust, feasible, comprehensive has left many aspects unresolved subject...

Abstract Purpose Treatment planning system (TPS) dose calculation is sensitive to multileaf collimator (MLC) modeling, especially when treating with intensity‐modulated radiation therapy (IMRT) or VMAT. This study investigates the dosimetric impact of MLC leaf‐tip model in a commercial TPS (RayStation v.6.1). The detectability modeling errors was assessed through both measurements an anthropomorphic head‐and‐neck phantom and patient‐specific IMRT QA using 3D diode array. Methods Materials An...

Purpose: Radiation therapy with high dose rate and flattening filter‐free (FFF) beams has the potential advantage of greatly reduced treatment time out‐of‐field dose. Current inverse planning algorithms are, however, not customized for nonuniform incident profiles resultant IMRT plans are often inefficient in delivery. The authors propose a total‐variation regularization (TVR)‐based formalism by taking inherent shapes beam into account. Methods: A novel TVR‐based is established profiles....

Gated Volumetric Modulated Arc Therapy (VMAT) is an emerging radiation therapy modality for treatment of tumors affected by respiratory motion. However, gating significantly prolongs the time, as delivery only activated during a single phase. To enhance efficiency gated VMAT delivery, novel dual-gated (DG-VMAT) technique, in which executed at both exhale and inhale phases given arc rotation, developed experimentally evaluated. two realized sequentially interleaving control points consisting...

To safely perform single-iso multi-target (SIMT) stereotactic radiosurgery (SRS), clinics must demonstrate SRS delivery accuracy for off-axis targets. The traditional Winston-Lutz (W-L) was widely adopted because it provides a simple and accurate solution testing radiation-isocenter coincidence that uses static target, enables arbitrary treatment angles, does not require expensive commercial phantoms. current noncommercial tests are cumbersome insufficiently accurate. For an (OAWL) test, one...

Surface-guided radiation therapy (SGRT) is a nonionizing imaging approach for patient setup guidance, intra-fraction monitoring, and automated breath-hold gating of treatments. SGRT employs the premise that external surface correlates to internal anatomy, infer treatment isocenter position at time delivery. Deformations posture variations are known impact correlation between anatomy. However, degree, magnitude, algorithm dependence this not intuitive currently no methods exist assess...

Mathematical models of biophysical phenomena have proven useful in the reconstruction experimental data and prediction biological behavior. By quantifying sensitivity a model to certain parameters, one can place an appropriate amount emphasis accuracy with which those parameters are determined. In addition, investigation stochastic lead greater understanding behavior captured by model. This possible reductions, or point out shortcomings be addressed. We present polynomial chaos as...

Clinical medical physics duties include routine tasks, special procedures, and development projects. It can be challenging to distribute the effort equitably across all team members, especially in large clinics or systems where physicists cover multiple sites. The purpose of this work is study an equitable workload distribution system radiotherapy that addresses complex dynamic nature assignment.We formed a working group defined relevant clinical tasks estimated total time spent per task....

Quantification of the sensitivity electro-cardiographic forward problem to various parameters can effectively direct generalization patient specific models without significant loss in accuracy. To this purpose we applied polynomial chaos based stochastic finite elements assess effect variations distributions tissue conductivity a two-dimensional torso geometry generated from MRI scans and epicardial boundary conditions specified by intra-operatively recorded heart potentials. The methodology...

Purpose: Respiration-gated radiation therapy restricts delivery to a window around specific phase or amplitude of the external breathing trace. In planning, computed doses assume no motion within gating and ignores residual window. We deliver IMRT torso phantom while (1) stationary (2) undergoing 2 cm superior-inferior motion, measure resulting dose distributions using gafchromic film, compare delivered planned doses. Methods: A respiration-gated treatment in Eclipse was Quasar on 1D stage...

Purpose: Respiration‐gated intensity modulated radiation therapy (IMRT) and volumetric (VMAT) deliver the treatment beam at a single phase to reduce dose uncertainties resulting from respiratory‐induced organ motion. In some cases, gating can significantly prolong times, leading increased patient discomfort, duration, uncertainty due postural shifts. To decrease duration without increasing uncertainty, we propose dual‐gating in conjunction with alternating coached five ten second breath...

Purpose: Dual‐gated intensity modulated radiation therapy (DG‐IMRT) is a novel delivery method for speeding respiratory‐gated IMRT in which dose delivered during both inhale and exhale windows. To determine the feasibility of designing DG‐IMRT plans using current clinical treatment planning systems, we design evaluate lung patient plan Eclipse. Methods: Tumor target volumes were contoured on CTs cancer with ∼1mm motion. Separate 5‐field optimized Eclipse PTV CT CT. The was mapped to geometry...

Purpose: Respiration-gated radiation therapy delivers the beam at either inhale or exhale phases. To increase duty cycle of gating and improve treatment efficiency, we propose delivering both windows. This work presents a planning method that enables dual-gated delivery while maintaining plan quality.Methods: The accumulated dose is weighted sum distributions two We minimize least squares difference between prescribed computed doses under set dose-volume (DVH) constraints. Optimization...

Purpose: We quantified the impact of various phase shifts between an external surrogate motion and internal target on 4D modeling using a dynamic phantom. Method Materials: The CIRS Dynamic Thorax phantom Model 008 (CIRS, Norfolk, VA) is capable separating motions via two independent motors. Phase shift images was studied for types breathing signals: standard sinusoidal signal real patient signal. imaged LightSpeed RT CT 16 slice scanner (GE Health Care, Waukesha, WI) at 0.5s per revolution,...

Deformable image registration (DIR) is developing rapidly and poised to substantially improve dose fusion accuracy for adaptive retreatment planning motion management PET enhance contour delineation treatment planning. However, DIR warping difficult quantify, in general, particularly do so on a patient-specific basis. As clinical options become more widely available, there an increased need understand the implications of incorporating into workflow. Several groups have assessed clinically...