Wedges Research Articles

Pseudo-static stability analysis of wedges based on the nonlinear Barton-Bandis failure criterion

This paper investigates the stability of a three-dimensional (3D) wedge under the pseudo-static action of an earthquake based on the nonlinear Barton-Bandis (B-B) failure criterion. The influences of the mechanical parameters of the discontinuity surface, the geometric parameters of the wedge and the pseudo-static parameters of the earthquake on the stability of the wedge are analyzed, as well as the sensitivity of these parameters. Moreover, a stereographic projection is used to evaluate the influence of pseudo-static direction on instability mode. The parametric analyses show that the stability coefficient and the instability mode of the wedge depend on the mechanical parameter of the rock mass, the geometric form of the wedge and the pseudo-static state of the earthquake. The friction angle of the rock φb, the roughness coefficient of the structure surface JRC and the two angles related to strikes of the joints θ1 and θ2 are sensitive to stability. Furthermore, the sensitivity of wedge height h, the compressive strength of the rock at the fracture surface JCS and the slope angle α to the stability are insignificant.

Determination of an Effective Wedge Angle by Combination of Two Arbitrary Universal Wedge Fields in Radiation Therapy of Cancer Patients with Megavoltage Photon Beams.

Introduction: Wedge filters are commonly used in radiation oncology for eliminating hot spots and creating a uniform dose distribution in optimizing isodose curves in the target volume for clinical aspects. These are some limited standard physical wedges (15°, 30°, 45°, 60°), or creating an arbitrary wedge angle, like motorized wedge or dynamic wedge, ... The new formulation is presented by the combination of wedge fields for determining an arbitrary effective wedge angle. The isodose curves also are derived for these wedges. Materials and Methods: we performed the dosimetry of Varian Clinac 2100C/D with Scanditronix Wellhofer water blue phantom, CU500E, OmniPro - Accept software and 0.13cc ionization chamber for 6Mv photon beam in depth of 10cm (reference depth) for universal physical wedges (15°, 30°, 45°, and 60°) and reference field 10x10cm2. By combining the isodose curve standard wedge fields with compatible weighting dose for each field, the effective isodose curve is calculated for any wedge angle. Results: The relation between a given effective wedge angle and the weighting of each combining wedge fields was derived. A good agreement was found between the measured and calculated wedge angles and the maximum deviation did not exceed 3°. The difference between the measured and calculated data decreased when the combined wedge angles were closer. The results are in agreement with the motorized single wedge appliance in the literature. Conclusion: This technique showed that the effective wedge angle that is obtained from this method is adequate for clinical applications and the motorized wedge formalism is a special case of this consideration.

Quantification the dosimetric parameters of asymmetric physical wedged-6MV photon beam

Introduction: Physical wedge as a useful tool has been utilized in radiotherapy to modify photon beam shape and intensity such that it distributes dose uniformly in tumor site and reduces hot points. Since during Linac commissioning dosimetric parameters like output factors and lateral dose profiles are measured only for symmetric open and wedged fields, so calculation the parameters for asymmetric wedged fields become necessary. The study aims to achieve output factors and dose profiles for symmetric and asymmetric wedged fields of 6 MV photon beams. Materials and Methods: The Siemens PRIMUS Linac head for 6 MV photon beam was simulated by BEAMnrc and all dose calculations were performed by DOSXYZnrc code. Percentage depth dose (PDD) and profiles for open and wedged (15° and 45°) fields were compared with corresponding measurements. Wedge factors for 10 x 10 cm2 field size as a function of lateral distance from central axis were obtained as well for half beam (negative or positive Y jaws were closed) wedged fields. All mesurments were carried out using 0.125 cm3 Farmer type ionization chamber with DOSE1 electrometer (FC65G, Scanditronix-Wellhofer, Germany) at the depth of 10 cm with source to surface distance (SSD) of 100 cm in 50 cm3 PTW-Blue water phantom and processed by dosimetry software RFAplus (Version 5.2, Scanditronix-Wellhofer, Germany). Results: The calculated doses were in agreement with measured data that confirmed the simulated MC model. The output factors on the central axis of symmetric wedged beams decreased to 0.693 and 0.307 for 15˚ and 45˚ wedges, respectively. The total photon fluence of 15˚ and 45˚ physical wedged fields reduced to 71.6% and 27.7% of fluence for open field, respectively. It was found that the output factor for asymmetric wedged fields is lower than ones from symmetric fields, particularly at field edges. Conclusion: The presences of physical wedge across the beamline decrease the photon fluence and cases beam hardening both for symmetric and asymmetric wedged fields. Lack of scattering photons near the half beam edges in asymmetric wedged field causes a dose fall off in these regions where have potential to overestimate the calculated dose by treatment planning system and consequent cold spots at target volume. Our calculated correction coefficients are recommended to calculate doses by TPS in case of asymmetric wedged fields.

Evaluation of Three-dimensional Treatment Planning System (TPS) performance in dose calculation of virtual wedged fields using film dosimetry

Introduction: Nowadays radiotherapy plays an important role in cancer treatment. Different radiotherapy techniques improvement emphasizes on using of the precise ، appropriate and useful algorithms. one of these techniques are wedged which is used in radiotherapy to compensate missing tissues and create a uniform dose distribution in tissues. The Siemens Artiste linear accelerator supports a virtual wedge ، that this wedge creates a dose distribution similar to a physical wedge without the use of any extra accessory and wedged profiles are produced moving collimator jaw during irradiation with a constant speed but varying the dose rate. In this study ، TPS performance is evaluated in virtual wedged fields by comparing the calculated and measured results. Materials and Methods: The calculations were performed by the collapsed cone superposition algorithm based TPS for two tangent fields in anthropomorphic slab phantom using 15، 30، 45، 60 virtual wedges for field size of 20 × 20 cm2 for 6 and 15 MV photon beams. Measurements were produced by Gafchromic EBT films and reading exposed films with scanner. Results: Good agreement between the measured dose with film dosimetry and calculated dose with collapsed cone superposition algorithm based TPS with using virtual wedge in heterogeneous environment and different energies were found ، with the maximum difference not exceed 3 -5%. The increase in wedge angle due to increase in the difference between calculated and measured data. Conclusion: : The results from this study showed that the accuracy of collapsed cone superposition algorithm based TPS used with the virtual wedges for two tangent fields is enough for the clinical usage under the studied experimental conditions.

Interpretation of In-air Output Ratio of Wedged Fields in Different Measurement Conditions

Introduction: The head scatter factor (Sc) is one of the important parameters for monitor unit (MU) calculation. There are multiple factors that impact the Sc values, such as, head structures, back scattering in to dose monitoring chambers, wedges and so on. This study aimed to investigate the variations of SC with different build-up cap materials, wall thickness, Source to Skin Distance (SSDs), ionization chambers and variation of the SC with wedge angles in 6MV photon beam. Materials and Methods: In this study, Copper and Perspex build-up caps were designed and fabricated with two different thicknesses for each build-up cap. Measurements were performed on an Elekta Compact medical linear accelerator (6 MV) using RK with sensitive volume of 0.12 cc and Farmer-type ion chamber with sensitive volume of 0.65 cc. In all measurements, build-up caps and ionization chambers were positioned in a stand vertical to the beam central axis. It is also investigated the effect of different SSDs on SC. Results: The presence of wedge influences the SC values significantly. Variation of SC in open and wedged fields had maximum deviation of 0.9% and 6.8% and minimum of 0.4% and 2.7% for 30° and 60° angles of wedge, respectively. different SSD and type of ion chamber had no significant influence on the SC. In small field sizes, the SC values in copper build-up cap is higher than Perspex and in large field sizes, measured SC in perspex build-up cap is higher than copper. Conclusion: It was found that the presence of internal wedge has significant contribution to head scatter factor and it increases with increasing wedge angle. Therefore, it should be takes into account in manually MU calculations.

Dosimetric Comparison of Treatment Plans Using Physical Wedge and Enhanced Dynamic Wedge for the Planning of Breast Radiotherapy.

The aim of this study is to compare the physical wedge (PW) with enhanced dynamic wedge (EDW) to determine the difference in the dose distribution affecting the treated breast and the contralateral breast, lungs, heart, esophagus, spine, and surrounding skin in the radiotherapy of breast cancer. Computed tomography (CT) data sets of 30 breast cancer patients were selected from the database for the study. The treatment plans which were executed with PW were re-planned with EDW without changing the beam parameters. Keeping the wedge angles same, the analytic anisotropic algorithm (AAA) with heterogeneity correction was used for dose calculation in all plans. The prescription was 50 Gy in 25 fractions. The dose- volume histogram (DVH) of the planning target volume (PTV) and critical structures of both PW and EDW plans were analyzed. The analysis showed that the maximum dose within the target volume is higher in EDW plan compared to PW plan. However the PTV conformity index (CI) remained the same in both plans. For all the critical structures, the EDW technique offered less dose compared to PW technique. The effect of volume of the contralateral breast on the dose to contralateral breast and the effect of volume of PTV breast for patients with carcinoma left breast on the dose to heart were studied and analyzed for the two wedges. No correlation between volumes and dose parameters was found for the two techniques. The number of monitor units to deliver a particular dose with EDW field is less than that of PW field due to change in wedge factor. As EDW produces less scattered dose to structures outside the treatment field, the risk of a second malignancy can be reduced with this technique.

Measuring MTF with wedges: pitfalls and best practices

Measuring MTF with wedges: pitfalls and best practices

ASSOCIATION OF MORB AND SSZ OPHIOLITES ALONG THE SHEAR ZONE BETWEEN COLOURED MÉLANGE AND BAJGAN COMPLEXES (NORTH MAKRAN, IRAN): EVIDENCE FROM THE SORKHBAND AREA

One of the largest worldwide accretionary wedges is exposed in the Makran region (SE Iran). The backstop of this accretionary wedge consists of an imbricate stack of continental and oceanic units, referred as North Makran domain. This domain is characterized by a km-thick shear zone, along which the metamorphic Bajgan Complex is thrust onto the Coloured Melange Complex. Along this shear zone two slices of ophiolites have been identified in the Sorkhband area. The upper tectonic slice consists of gabbros, whereas the lower tectonic one consists of mantle peridotites associated with dunites and chromitite ore deposits. Petrography and geochemistry of gabbros clearly indicate an N-MORB-type affinity, suggesting that they were generated at mid-ocean ridge setting. In contrast, mantle peridotites consist of harzburgites and depleted harzburgites, both showing geochemical features suggesting their genesis in a SSZ setting. The new data presented in this paper indicate that the slices of ophiolites from Sorkhband area derived from two different oceanic domains representing two different geodynamic settings. This occurrence provide new evidence that the boundary between the Coloured Melange and the Bajgan Complexes represents a first-order tectonic structure that played an important role in the geodynamic evolution of the Makran area.

Numerical Simulation of Water Entry of Wedges Based on the CIP Method

The hydrodynamic problems for water entry of wedges are studied by a constrained interpolation profile (CIP) based on Cartesian grid method. The CIP scheme was applied to the Cartesian grid based on flow solver, which was first described. The tangent of hyperbola for interface capturing (THINC) scheme was applied to capture the free surface. The CIP method was extended to capture the dynamics in the water entry approach. The simulations were performed in three aspects. First, pressure distributions for the wedges entering into water with constant speed were predicted, and the results were compared with the similarity solutions by the boundary element method (BEM). Then simulations were conducted for the free-falling wedges entering into water with one degree of freedom. The results were compared with the published experimental data. Finally, the impact of a wedge on the water surface in a free fall motion with an initial heel angle was studied. The motion of the wedge was subjected to three degrees of freedom, and the results were also compared with those of experiments.

Analiza mechanizmu smarowania stawów człowieka w badaniach in vitro oraz in vivo

The aim of the study was to clarify the perfect mechanism of lubrication in the normal joints on the basis of synovial fluid rheology and the identification of structures and shape of the articular surfaces. The lubrication of joints can be determined bioelastohydrodynamic lubrication. Distinguished by generation of normal stresses in the synovial fluid and the effect resulting from the geometryof biobearing, which consists of the acquisition by the load pressure in the anatomical wedges lubricants. (Analysis of lubrication mechanism of human joints in vitro and in vivo).

Use of modular metal block augments and medullary stem augments in primary total knee arthroplasty ( 2-year follow-up)

Background The success of total knee arthroplasty depends on obtaining and restoring mechanical alignment, maintaining the joint line, balancing ligaments and soft tissue, restoring the function of quadriceps, achieving a stable implant, and reconstructing substantial amounts of bone lost using metal wedges or by stem augmentation. The benefits of modular augments lie in the simplicity of rectifying the bone defect without the additional risks associated with bone grafts. The aim of this study was to present the results obtained from the use of augments in a group of patients with primary osteoarthritis, who had a significant degree of varus deformity, and to show its applicability. Patients and methods Twenty-five patients (average age 69 years) who had a varus alignment of the knee of more than 20π were included in this study. The mean follow-up period was 24 months. All procedures were performed using a standard technique, and a P.F.C. Sigma Knee Replacement was implanted in all cases. Rehabilitation and mobilization began on the first postoperative day assisted by a physical therapist with full weight bearing. Outcomes were evaluated using the American Knee Society Score. Results The mean improvement in the postoperative arc of flexion was 33π. The average Knee Society knee score was 44 points preoperatively and 82 points at the final follow-up. One patient developed peroneal nerve palsy; this patient recovered after 2 months. Conclusion The study concludes that the use of modular metal block augmentation devices for peripheral tibial defects could serve as a simple, rapid, and dependable technique that yields predictable results, and the inclusion of a medullary modular stem in the implant component confers greater stability for the prosthesis. There are no standards for the augmentation in primary total knee arthroplasty, and each case should be dealt with according to the degree of deformity and bony defect intraoperatively.

CAPILARITY AND SOLUTE TRANSPORT IN SWELLING AND SHRINKING SOILS

The Aranca Low Plain (SW of Romania), with accumulative relief, a slow dip and an obvious subsidence, is covered with fluvio-lacustrine deposits with various grain sizes, from gravels to smectite clays. The phreatic waters are mineralized and sodium ions reach into the colloidal complex, destroying soil structure. The rise of water in the soil from a free water surface has been termed capillarity rise. The maximum height to which water may rise through capillarity varies between 1.5 and 4 m in Fluvisols and Vertisols. Capillarity rise of soil water takes place above the ground water level and is due to matric suction. The complex geometry of soil pare space creates numerous combinations of interfaces, capillaries and wedges in which water is retained. In addition, water is absorbed on to solid surfaces, with considerable force at close distances. Solutes can interact strongly with soil surfaces and their transport can be slowed in a process known as retardation. In Fluvisols, like in Chernozems and Phaeozems, soluble salts are concentrated in the first 50 cm of the soil profile, while in Vertisols most soluble salts are concentrated at the bottom of the profile. The water potential in a Vertisol is the sum of gravitational potential, capillarity potential and overburden potential. The overburden potential is related to civil engineers effective stress. The phenomenon of capillarity is thus dependent on solid and liquid interfacial properties such as surface tension, contact, angle and solid surface roughness and geometry. These phenomena, partial attributed to capillarity, determine retention and movement of water and solutes through soils.

FACIES PARTITIONING AND SEQUENCE STRATIGRAPHY OF A MIXED SILICICLASTIC-CARBONATE RAMP STACK IN THE GELASIAN OF SICILY (S ITALY): A POTENTIAL MODEL FOR ICEHOUSE, DISTALLY-STEEPENED HETEROZOAN RAMPS

The Gelasian succession of the Capodarso area (Enna-Caltanissetta basin, Sicily, Italy) consists of an offlapping stack of cycles composed of siliciclastic units passing to carbonate heterozoan, clino-stratified wedges, developed from a growing positive tectonic structure. Identification of a number of facies tracts, based on sedimentary facies, biofacies and taphofacies, provided important information about the differentiation and characterisation of systems tracts and key stratal surfaces of sequence stratigraphy. The bulk of carbonate wedges are interpreted as representing the rapid falling-stage progradation of distally steepened ramps. The inferred highest rate of carbonate production during forced regressions was concomitant with active downramp resedimentation by storm-driven downwelling flows, leading to storing of most carbonate sediment on the ramp slope as clino-beds of the prograding bodies. Comparison of the Capodarso ramps with other icehouse carbonate ramps, with particular regard to the Mediterranean Plio-Pleistocene, provides clues for defining some common features. These are inferred to include: (1) brief, rapid episodes of progradation concomitant with orbitally-forced sea-level changes, resulting in limited ramp width; (2) preferential fostering of growth and downramp resedimentation of heterozoan carbonates during glacial hemicycles marked by enhanced atmospheric and marine circulation; (3) building out from positive features of entirely submerged distally-steepened ramps with storm-wave-graded profile and distinctive clinoforms; (4) ramp stacks generally consisting of mixed clastic-carbonate sequences showing an ordered spectrum of distinct frequencies; (5) rapid, continuous changes in environmental parameters, leading to the short-lived persistence of faunal communities, climax communities generally having insufficient time to form.

Analýza distorzních účinků vlivu zdanění na finanční a investiční rozhodování na základě metody výpočtu efektivní daňové sazby

Cilem tohoto přispěvku bylo zkoumani využiti efektivnich daňových sazeb ve vztahu k různým druhům aktiv a zdrojům financovani pro výpocet daňových klinů ke stanoveni vlivu zdaněni na investicni rozhodovani. Metodologie použivana k výpoctu efektivnich daňových sazeb je založena na přistupu vytvořenem autory Kingem a Fullertonem (1984), ktera je nejvice rozsiřenou metodou pro výpocet tzv. daňových klinů. Výse daňových klinů se lisi podle typu aktiv: strojů, budov, zasob a typu financnich zdrojů: akcie, dluh, nerozdělený zisk. Efektivni daňove sazby jsou sazby, ktere berou v uvahu nejen zakonem stanovenou sazbu daně ze zisku, ale take ostatni aspekty daňoveho systemu, ktere ovlivňuji celkovou výsi zaplacene daně a výnosnost investic, zohledňuji take osobni zdaněni. Daňový system, který zajisťuje sve přijmy způsobem, který nevyvolava distorzni efekty, se považuje za neutralni daňový system. Cilem tohoto přispěvku bylo na bazi výpoctu daňových klinů posoudit, do jake miry zdaněni v Ceske republice může ovlivňovat investicni rozhodovani (porovnani let 2000 a 2010).

Regressive and transgressive cycles in a rift-basin: Depositional model and sedimentary partitioning of the Middle Jurassic Hugin Formation, Southern Viking Graben, North Sea

The Jurassic Hugin Formation consists of shallow-marine sandstones that belong to a significant hydrocarbon reservoir in the Sleipner area in the Norwegian North Sea. The formation encompasses coarsening-upward units of mouth bar and shoreface facies, interpreted to record delta outbuilding during regression; and fining-upward units with tidal channel, dune, and tidal flat facies interpreted as part of an estuary environment during transgression. The correlations reveal that the studied part of the Hugin Formation consists of 8 sequences, each with a transgressive and a regressive unit, representing the transgressive systems tract and the highstand systems tract respectively. The sequences are stacked retrogradationally landward as a result of rapid tectonic subsidence and rifting of the Viking Graben. Rifting led to the development of an elongate graben where tidal currents were amplified, wave-action damped and longshore drift (as sediments supply) reduced or absent. Lowstand and forced regressive systems tracts are not identified, and their absence is interpreted to reflect suppression of relative sea level falls in a rapidly subsiding basin where the basin subsidence rate outpaced any potential fall in eustatic sea level. Through facies interpretation and sequence-stratigraphic correlations between wells, these regressive and transgressive units are shown to exhibit characteristic thickness trends in the form of sigmoidal-shaped wedges, stacked in an offset manner in a landward to basinward orientation. These thickness trends illustrate sediment partitioning within the sequences and are explained by the relationship between accommodation versus sediment supply in terms of mass-balance. During regression, the focus of sedimentation was pushed basinward, and during transgression it was pushed landward as sediments were trapped there. The mapping of these sequence-stratigraphic units serves as input to reservoir models and to help increase recovery and identify new exploration targets.

Plane wave analysis of panel wedges

In the present work, a wedge structure made of absorbing panels has been analyzed by making use of the matrizant analysis with the help of the Boundary-Condition-Transfer (BCT) algorithm. The rectangular panel wedge, as it is called in this manuscript, is simple in geometry. The theoretical model, based on the plane wave acoustical coupling between multiple interacting ducts of variable cross sectional area, is applied to predict the pressure reflection coefficient of the present wedge configuration. Bulk reaction and hence wave propagation in the wedge material has been assumed in the proposed model. An asymptotic solution using the Peano-Baker series of matrix calculus is derived for different variable area ducts and then solved with the aid of the boundary condition transfer algorithm. A brief parametric study is also included as an aid to designers.

NEW THERMOBARIC CONSTRAINTS ON THE EXHUMATION HISTORY OF THE LIGURIDE ACCRETIONARY WEDGE, SOUTHERN ITALY

New constraints on the thermobaric evolution of the Liguride complex of the Southern Apennines are provided by inorganic and organic thermal indicators. In detail, quantitative data on the thermobaric signature of the medium-to low-metamorphic Frido Unit and non-metamorphic North-Calabrian Unit have been derived using different methodologies such as clay mineralogy, fluid inclusion microthermometry, fission tracks analyses, and organic matter maturity. A good convergence among data from different, indipendent methods was obtained. The Frido Unit underwent temperatures in the range of anchizone (250- 300°C) according to data derived from both clay mineralogy and fluid inclusion microthermometry. Pressure estimates by white mica b0 parameter are typical of accretionary wedges and in the range of 6-8 kbar. In the non metamorphosed North Calabrian Unit, clay mineralogy, organic matter maturity and fluid inclusion microthermometry record thermal conditions from diagenesis (~ 130°C) to the late diagenesis - anchizone boundary (~ 200°C) for the Crete Nere Fm., and diagenetic conditions (temperatures around 100-110°C) for the Saraceno Fm. In a regional framework, these data help to better constraint the thermal evolution of the units belonging to the Liguride complex with respect to the timing of final exhumation at 5-6 My, as suggested by apatite fission tracks data.

THE LOWER EOCENE RODA SANDSTONE (SOUTH-CENTRAL PYRENEES):AN EXAMPLE OF A FLOOD-DOMINATED RIVER-DELTA SYSTEMIN A TECTONICALLY CONTROLLED BASIN

The lower Eocene Roda Sandstone (Figols Group, south-central Pyrenees) mainly consists of mouth bars and delta-front sandstone lobes deposited in a flood-dominated river-delta system. The deposition of these bodies was strongly controlled by an interaction between flood-dominated gravity flows entering seawater, topographic confinement and tidal currents. The Roda Sandstone is made up of six depositional sequences of different hierarchical order each of which is characterized by a basal deltaic sandstone wedge (R1 to R6) that passes upward into a siltstone and mudstone interval. Each basal deltaic sandstone wedge is composed of three types of facies association and respective facies tract ( sensu Mutti 1992) that, from proximal to distal zones, are indicated as T1, T2 and T3. These three facies tracts are created by the downcurrent evolution of different types of sediment-laden stream flows entering seawater and related hyperpycnal flows. Their deposits are constituted by three different types of coarse-grained mouth bars and corresponding fine-grained delta-front sandstone lobes. The tidal influence is present in facies tract T3 in the R5 and R6 sandstone units, where the passage between flood-dominated mouth bars and the delta-front sandstone lobes occurs through intermediate facies characterized by different types of sigmoidal-cross stratification whose meaning will be discussed. The basal deltaic sandstone wedges of Roda sandstone are characterized by a progressive forestepping culminating in the R6 unit that erodes the underlying R5 unit and by an overlying backstepping unit indicated as R7. The erosive surface at the base of R6 unit is interpreted as a sequence boundary that divides the Roda Sandstone into two parts: 1) an underlying highstand system tract (HST) and falling stage system tract (FSST) (units R1 to R5) and 2) an overlying low-stand delta (the R6 unit) that passes upward into highstand mudstone through a transgressive system tract represented by the R7 unit. Pdf

Technical Notes and Tips: Fibreglass Cast Wedging

The wedging of casts to correct angulatory deformities of longbone fractures is a well-established technique. Traditionally, cork and wooden wedges have been utilised; however, these materials frequently fragment or compress. We have found that fibreglass wedges are a more robust and cost-effective solution that is readily available in the plaster room. Fibreglass casting tape (e.g. Scotchcast(tm) Casting Tape, 3M, St Paul, MN, USA) is twisted around itself to form a solid bar. Custom wedges can then be cut from the bar using a plaster or hand saw and inserted as required (Fig. 1). Figure 1 Fibreglass bar and wedged cast.

Present and Future Developments in Radiotherapy Treatment Units.

Technical advances in the design of medical accelerators are making possible the exploration of new treatment techniques. Technology currently available to the radiation oncologist allows the use of internal and dynamic wedges. Multileaf collimators can be used for static treatment ports, and dynamic field shaping and beam modulation using multileaf collimators has been shown to be feasible. Computer interfaces are necessary to transfer the complex treatment sequences that are possible with these devices. Such network interfaces also provide for more efficient conventional treatments. New machines such as X-band linear accelerators and advanced proton accelerators are being developed for applications such as boron neutron capture therapy and proton conformal therapy.