With the increased use of cone beam CT (CBCT) for daily patient setup, accumulated dose from CBCT may be significantly higher than that simulation or portal imaging. The objective this work is to measure pelvic scans with fixed technical settings and collimations. were acquired in half-fan mode using a half bowtie x-rays delivered pulsed-fluoro mode. skin doses seven prostate patients measured on an IRB-approved protocol. TLD capsules placed patient's at central axis three beams: AP, left...

China's Mars probe, named Tianwen-1, including an orbiter and a landing rover, will be launched during the July-August 2020 launch windows. Selected to among rover payloads is Subsurface Penetrating Radar module (RoSPR). The main scientific objective of RoSPR characterize thickness sub-layer distribution Martian soil. consists two channels. low frequency channel penetrate soil depths 10 100 m with resolution few meters. higher depth 3 centimeters. This paper describes design instrument some...

The purpose of this study was to evaluate the accuracy a two-dimensional (2D) three-dimensional (3D) image-fusion-guided target localization system and mask based stereotactic for fractionated radiotherapy (FSRT) cranial lesions. A commercial x-ray image guidance originally developed extracranial radiosurgery used FSRT quantitatively evaluated with an anthropomorphic head phantom implanted eight small radiopaque markers (BBs) in different locations. its clinical reliability were also...

This study is to demonstrate the technical and clinical experience of applying image guided spinal radiosurgery for treatment localized metastasis. A dedicated shaped beam unit with intensity modulated radiotherapy (IMRT) x-ray based image-guided (IGRT) were used procedure. total 196 patients 270 lesions metastases treated this procedure from May 2001 October 2005. All received single dose involved spine only. The was escalated 10 18 Gy in 2 increments. using IMRT planning IGRT...

We describe an approach for external beam radiotherapy of breast cancer that utilizes the three‐dimensional (3D) surface information breast. The data are obtained from a 3D optical camera is rigidly mounted on ceiling treatment vault. This light in visible range therefore it introduces no ionization radiation to patient. In addition topographical treated area, also captures gray‐scale overlaid image. allows us visualize skin markers and automatically determine isocenter position angles...

Dose distribution throughout a hollow organ is represented by either dose‐surface histogram (DSH) or dose‐wall (DWH). A spherical shell model for the bladder and cylindrical rectum were introduced quantifying difference between DWH DSH. The was given subtraction of percent volume wall from area surface any specific dose level. Taking dose‐grid size contour‐delineation uncertainties into account, DSH calculation errors estimated simplified formulas. DSHs DWHs in patients undergoing...

Retrospective analysis of patients with recurrences at or closely adjacent to the site prior lung stereotactic body radiation therapy (SBRT) who received repeat SBRT.Nine non-small cell cancer (n = 8) oligometastatic colonic adenocarcinoma 1) were treated image-guided SBRT a median 60 Gy (range, 30-60) in 3 fractions (3-5). Patients developed in-field relapse 3) recurrence (≤ 3.5 cm away) previous tumor location 6) and 2 nd Gy.Median follow-up after was 22 months (4-40). All completed...

Background and purposeDosimetric leaf gap (DLG) is a parameter to model the round-leaf-end effect of multi-leaf collimators (MLC) that important for treatment planning dose calculations in radiotherapy. In this study we investigated on relationship between DLG values calculation errors high-definition MLC.Materials methodsThree sets experiments were conducted: (1) physical measurements using sweeping-gap technique, (2) adjustment based spine radiosurgery plan measurements, (3) verification...

Dose measurement for narrow stereotactic beams and intensity modulation radiotherapy beamlets is difficult error‐prone due to the lack of lateral electron equilibrium. A small detector position error finite sensitive volume as well nonfocus collimation could result in considerable (>10%) errors. new method introduced here measure dose components so that accuracy precision can be improved. Based on superposition principle, we create exactly field interest by subtraction a reference open...

Accurate and precise head refixation in fractionated stereotactic radiotherapy has been achieved through alignment of real-time 3D-surface images with a reference surface image. The image is either 3D optical taken at simulation the desired treatment position, or CT/MRI-surface rendering plan corrections for patient motion during CT/MRI scans partial volume effects. are rapidly captured by using video camera mounted on ceiling vault. Any facial expression such as mouth opening that affects...

A set of experiments were conducted to evaluate six similarity measures for intensity-based rigid-body 3D/2D image registration. Similarity measure is an index that the between a digitally reconstructed radiograph (DRR) and x-ray planar image. The registration accomplished by maximizing sum biplane images corresponding DRRs in iterative fashion. We have evaluated accuracy attraction ranges registrations using different on phantom head, thorax, pelvis. acquired Varian Medial System On-Board...

The purpose of this study was to develop a technique that could quantitatively monitor the nonrespiratory motion patient during stereotactic body radiotherapy (SBRT). Multiple infrared external markers were placed on patient's chest and abdominal surface obtain signals. These signals contained both respiratory information. usually has much larger amplitude than surface. Assuming is rigid translation, we have developed computer algorithm derive instantly from two sets In first-order...

On 1 December 2020, China’s Chang’E-5 (CE-5) probe successfully landed in the northeastern Oceanus Procellarum. This work mainly presents results of Lunar Regolith Penetrating Radar (LRPR) equipped on CE-5 Lander. The lunar regolith structure landing site from surface to 3-m depth is unveiled by LRPR, which found that abundant rock fragments are distributed uniform regolith. imaging result proved drilling and sampling process was prevented big rocks at about 100 cm depth. basis response soil...

Purpose Application of linear‐quadratic (LQ) model to large fractional dose treatments is inconsistent with observed cell survival curves having a straight portion at high doses. We have proposed unified multi‐activation (UMA) fit over the entire range that allows us calculate EQD2 for hypofractionated SBRT, SRT, SRS, and HDRB. Methods A formula using only extrapolation number n slope D o was derived. Coefficient determination, R 2 , relative residuals, r, experimental errors, e, normalized...

Real-time stereovision-guidance has been introduced for efficient and convenient fractionated stereotactic radiotherapy (FSR) image-guided intensity-modulated radiation therapy (IMRT). This first pilot study is to clinically evaluate its accuracy precision as well impact on treatment doses. Sixty-one FSR patients wearing masks (SMs) nine IMRT flexible (FMs), were accrued. Daily target reposition was initially based-on biplane-radiographs then adjusted in six degrees of freedom under...

Image-guided radiotherapy using a three-dimensional (3D) camera as the on-board surface imaging system requires precise and accurate registration of 3D images in treatment machine coordinate system. Two simple calibration methods, an analytical solution three-point matching least-squares estimation method multipoint registration, were introduced to correlate stereo-vision frame with Both types calibrations utilized template placed on top couch. Image transformational parameters derived from...

Rapid optical three-dimensional (O3D) imaging systems provide accurate digitized 3D surface data in real-time, with no patient contact nor radiation. The images offer crucial information image-guided radiation therapy (IGRT) treatments for repositioning and respiration management. However, applications of O3D techniques to radiotherapy have been clinically challenged by body deformation, pathological anatomical variations among individual patients, extremely high dimensionality the data,...

The congestion issue of spectrum resources can be effectively addressed by orbital angular momentum (OAM). A novel broadband OAM array antenna is designed, where a conformal structure generates vortex electromagnetic beams applying equal amplitude but different phase excitations to the units. According simulation results, radiate with 6 modes, and relative bandwidth reaches 14.31%, making it practically valuable in certain scenarios.

Purpose: To demonstrate a simple but efficient optimization technique improving the conformity, uniformity, and tumor coverage for SRS plans with equally weighted dynamic conformal arcs. Material method: Dynamical arc radiosurgery in Brainscan planning shapes arcs every 10 degrees based on limited 2D projection. Although desired of segments can be automatically achieved through user-defined margin around target, plan doesn't fully consider 3D dose distribution information. The conformity is...