Extending deterministic transport capabilities for very-high and ultra-high energy electron beams.

Focused Very-High Energy Electron (VHEE, 50-300 MeV) and Ultra-High Energy Electron (UHEE, > 300 MeV) beams can accurately target both large and deeply seated human tumors with high sparing properties, while avoiding the spatial requirements and cost of proton and heavy ion facilities. Advanced testing phases are underway at the CLEAR facilities at CERN (Switzerland), NLCTA at Stanford (USA), and SPARC at INFN (Italy), aiming to accelerate the transition to clinical application. Currently, Monte Carlo (MC) transport is the sole paradigm supporting preclinical trials and imminent clinical deployment. In this paper, we propose an alternative: the first extension of the nuclear-reactor deterministic chain NJOY-DRAGON for VHEE and UHEE applications. We have extended the Boltzmann-Fokker-Planck (BFP) multigroup formalism and validated it using standard radio-oncology benchmarks, complex assemblies with a wide range of atomic numbers, and comprehensive irradiation of the entire periodic table. We report that [Formula: see text] of water voxels exhibit a BFP-MC deviation below [Formula: see text] for electron energies under [Formula: see text]. Additionally, we demonstrate that at least [Formula: see text] of voxels of bone, lung, adipose tissue, muscle, soft tissue, tumor, steel, and aluminum meet the same criterion between [Formula: see text] and [Formula: see text]. For water, the thorax, and the breast intra-operative benchmark, typical average BFP-MC deviations of [Formula: see text] and [Formula: see text] were observed at [Formula: see text] and [Formula: see text], respectively. By irradiating the entire periodic table, we observed similar performance between lithium ([Formula: see text]) and cerium ([Formula: see text]). Deficiencies observed between praseodymium ([Formula: see text]) and einsteinium ([Formula: see text]) have been reported, analyzed, and quantified, offering critical insights for the ongoing development of the Evaluated Nuclear Data File mode in NJOY.

Feasibility of a multigroup Boltzmann-Fokker-Planck solution for electron beam dose calculations.

Legacy nuclear-reactor Boltzmann solvers start clinical deployment as an alternative to Monte Carlo (MC) codes and Fermi-Eyges semiemprical models in radiation oncology treatment planning. Today's certified clinical solvers are limited to photon beams. In this paper, ELECTR, a state-of-the-art multigroup electron cross sections generation module in NJOY is presented and validated against Lockwood's calorimetric measurements, EGS-nrc and GEANT-4 for 1-20 MeV unidirectional electron beams. The nuclear-reactor DRAGON-5 solver is upgraded to access the library and solve the Boltzmann-Fokker-Planck (BFP) equation. A variety of heterogeneous radiotherapy and radiosurgery phantom configurations were used for validation purpose. Case studies include a thorax benchmark, that of a typical breast Intra-Operative Radiotherapy and a high-heterogeneity patient-like benchmark. For all beams, [Formula: see text] of the water voxels satisfied the American Association of Physicists in Medicine accuracy criterion for a BFP-MC dose error below [Formula: see text]. At least, [Formula: see text] of adipose, muscle, bone, lung, tumor and breast voxels satisfied the [Formula: see text] criterion. The average BFP-MC relative error was about [Formula: see text] for all voxels, beams and materials combined. By irradiating homogeneous slabs from [Formula: see text] (hydrogen) to [Formula: see text] (einsteinium), we reported performance and defects of the CEPXS mode [US. Sandia National Lab., SAND-89-1685] in ELECTR for the entire periodic table. For all Lockwood's benchmarks, NJOY-DRAGON dose predictions are within the experimental data precision for [Formula: see text] of voxels.

Stage III Intraoperative Adjustmentof Eye Muscle Surgery (Under General Anesthesia) for Neuroparalytic and Mechanical (Restrictive) Incomitant Strabismus: Report of Results in a Series: Outcomes in 20 Eye Muscle Surgeries in Twelve Patients.

Techniques for the adjustment of surgery intraoperatively (especially those termed Stage I and II techniques) have proven maximally successful in improving surgical results for comitant strabismus. Stage III adjustments (end-operative) have been described but not studied. In a retrospective study of 20 eye muscle procedures in 12 patients with neuroparalytic and mechanical strabismus, the usefulness of various intraoperative adjustment techniques Stage I, II, and III was investigated for the first time. Stage I adjustments (adjusting the surgical plan based on the binocular misalignment following induction) were not helpful. Stage II adjustments (R. Bedrossian technique: adjusting the amount of surgery performed to create an actual change in binocular alignment under anesthesia matching the change in alignment desired clinically) were appropriate for horizontal mechanical and (all) vertical cases but not appropriate for horizontal neuroparalytic cases. Stage III adjustments, at the end of surgery, were appropriate in virtually all cases (20 muscles, 12 patients). Significant overcorrection, well beyond the theoretically ideal final intraoperative binocular alignment of 30 PD (prism diopters) was appropriate in all cases, but varied with type of case. Verticals (all) required a 5-10 PD overcorrection. Horizontal mechanical cases required a 22-30 PD overcorrection. Horizontal neuroparalytic cases required a 15-38 PD overcorrection, in the last group, in each case, graded according to the presence of contractures and the size of the preoperative deviation. The use of Stage III (and Stage II as noted above) adjustments brought postoperative binocular alignment to orthotropia +/- 10 PD in all cases, the conventional standard for satisfactory results in strabismus surgery.