Calibration of 192Ir high-dose-rate afterloading systems.

abstract：:A novel iterative penalized likelihood algorithm with evolutionary components for the optimization of beamlet fluences for intensity modulated radiation therapy (IMRT) is presented. This algorithm is designed to be flexible in terms of the objective function and automatically escalates dose, as long as the objective f...

journal_title：Medical physics

authors： Baydush AH,Marks LB,Das SK

更新日期：2004-08-01 00:00:00

abstract：PURPOSE:This study aims to investigate the feasibility of using the images of the treatment fields acquired by an electronic portal imaging device (EPID) for real-time target localization. METHODS:Forty one patients treated with IMRT and RapidArc were recruited in this study including 37 prostate patients and 4 lung p...

journal_title：Medical physics

authors： Xu Q,Lin M,Chen X,Tong X,Fan J,Dong Z,Chen L,Ma C

更新日期：2012-06-01 00:00:00

abstract：:A computerized scheme is being developed for the detection of masses in digital mammograms. Based on the deviation from the normal architectural symmetry of the right and left breasts, a bilateral subtraction technique is used to enhance the conspicuity of possible masses. The scheme employs two pairs of conventional ...

journal_title：Medical physics

authors： Yin FF,Giger ML,Doi K,Metz CE,Vyborny CJ,Schmidt RA

更新日期：1991-09-01 00:00:00

abstract：PURPOSE:The aims of this work were to evaluate the performance of several deformable image registration (DIR) algorithms implemented in our in-house software (NiftyReg) and the uncertainties inherent to using different algorithms for dose warping. METHODS:The authors describe a DIR based adaptive radiotherapy workflow...

journal_title：Medical physics

authors： Veiga C,Lourenço AM,Mouinuddin S,van Herk M,Modat M,Ourselin S,Royle G,McClelland JR

更新日期：2015-02-01 00:00:00

abstract：PURPOSE:Recent guidance by The Joint Commission and CRCPD recommendations require establishing CT reference dose levels (RDLs) for clinical protocols and recording CT dose metrics in the patient's medical record. This presentation addresses which dose values in the CT report should be recorded for the purposes of monit...

journal_title：Medical physics

authors： Guild J,Arbique G,Blackburn T,Gallet J,Anderson J

更新日期：2012-06-01 00:00:00

abstract：:With the increasing complexity of dose patterns external beam radiotherapy, there is a great need for new types of dosimeters. We studied the first prototype of a new dosimeter array consisting of water-equivalent plastic scintillating fibers for dose measurement in external beam radiotherapy. We found that this array...

journal_title：Medical physics

authors： Archambault L,Beddar AS,Gingras L,Lacroix F,Roy R,Beaulieu L

更新日期：2007-05-01 00:00:00

abstract：:The dosimetry of 192Ir linear sources with a commercial treatment planning computer system has been evaluated. Reference dose rate data were selected from the literature and normalized in a manner consistent with our clinical and dosimetric terminology. The results of the computer calculations are compared to the refe...

journal_title：Medical physics

authors： Kline RW,Gillin MT,Grimm DF,Niroomand-Rad A

更新日期：1985-09-01 00:00:00

abstract：:A new approach to the calculation of the x-ray spectrum emerging from an x-ray tube is proposed. Theoretical results for the bremsstrahlung cross section appearing in the literature are summarized. Four different treatments of electron penetration, based on the work presented in Part I, are then used to generate brems...

journal_title：Medical physics

authors： Poludniowski GG

更新日期：2007-06-01 00:00:00

abstract：PURPOSE:Metal artifact reduction (MAR) is a major problem and a challenging issue in x-ray computed tomography (CT) examinations. Iterative reconstruction from sinograms unaffected by metals shows promising potential in detail recovery. This reconstruction has been the subject of much research in recent years. However,...

journal_title：Medical physics

authors： Zhang H,Wang L,Li L,Cai A,Hu G,Yan B

更新日期：2016-06-01 00:00:00

abstract：:A doorless entry system has been designed for use in high-energy radiation therapy rooms. The doorless entry improves patient access, safety and throughput, increases the physical safety for the radiation therapists, and avoids the significant cost of heavy shielding doors. The design meets concerns relating to radiat...

journal_title：Medical physics

authors： Dawson DJ,Wissing WW,Tonks RE

更新日期：1998-02-01 00:00:00

abstract：PURPOSE:Though failure mode and effects analysis (FMEA) is becoming more widely adopted for risk assessment in radiation therapy, to our knowledge, its output has never been validated against data on errors that actually occur. The objective of this study was to perform FMEA of a stereotactic body radiation therapy (SB...

journal_title：Medical physics

authors： Yang F,Cao N,Young L,Howard J,Logan W,Arbuckle T,Sponseller P,Korssjoen T,Meyer J,Ford E

更新日期：2015-06-01 00:00:00

abstract：:Encapsulated, cylindrical sources containing 2, 5, and 8 Ci of 241Am have been designed and fabricated for intracavitary irradiation of uterine cancers. Exposure rates in air and dose rates in water around these sources have been measured using an ionization chamber and a lithium fluoride thermoluminescent dosimetry s...

journal_title：Medical physics

authors： Nath R,Gray L,Park CH

更新日期：1987-09-01 00:00:00

abstract：:The authors present an alternative approach to inverse planning optimization and apply it to volumetric modulated are therapy (VMAT) in one rotation with a prior knowledge about the type of leaf motions. The optimization is based on the projection theorem in inner product spaces. MLC motion is directly considered in t...

journal_title：Medical physics

authors： Hoegele W,Loeschel R,Zygmanski P

更新日期：2009-08-01 00:00:00

abstract：PURPOSE:Identification of calcifications and hemorrhages is essential for the etiological diagnosis of cerebral lesions. The purpose of this work was to develop a robust method for characterization of para- and diamagnetic intracerebral lesions based on clinical gradient-echo magnetic resonance phase data acquired at 1...

journal_title：Medical physics

authors： Schweser F,Deistung A,Lehr BW,Reichenbach JR

更新日期：2010-10-01 00:00:00

abstract：:Most detectors in current positron emission tomography (PET) scanners and prototypes use lutetium oxyorthosilicate (LSO) or lutetium yttrium oxyorthosilicate (LYSO) scintillators. The aim of this work is to provide a complete set of background energy spectra, due to the scintillator intrinsic radioactivity, for a wide...

journal_title：Medical physics

authors： Domínguez-Jiménez DY,Alva-Sánchez H

更新日期：2021-01-21 00:00:00

abstract：PURPOSE:In the practice code of dosimetry, humidity effect is assumed to be constant as far as the measurements are performed in the relative humidity (RH) range of (20-80)%; thus, the humidity effect can be ignored with a dose uncertainty of 0.15%. This assumption is based on the previous experimental results by Niate...

journal_title：Medical physics

authors： Sato Y,Shimizu M,Morishita Y,Sato M,Hoshina M

更新日期：2019-09-01 00:00:00

abstract：PURPOSE:Dual source CT (DSCT) systems utilize two measurement systems (A) and (B) offset by about 90 degrees. A special challenge in DSCT is cross-scattered radiation, i.e., scattered radiation from x-ray tube (B) detected in detector (A) and vice versa. Cross-scattered radiation can produce artifacts and degrade the c...

journal_title：Medical physics

authors： Petersilka M,Stierstorfer K,Bruder H,Flohr T

更新日期：2010-11-01 00:00:00

abstract：:Three types of iterative algorithms, algebraic inverse treatment planning (AITP), simultaneous iterative inverse treatment planning (SIITP), and iterative least-square inverse treatment planning (ILSITP), differentiated according to their updating sequences, were generalized to three dimension with true beam geometry ...

journal_title：Medical physics

authors： Xing L,Hamilton RJ,Spelbring D,Pelizzari CA,Chen GT,Boyer AL

更新日期：1998-10-01 00:00:00

abstract：PURPOSE:In prostate radiotherapy, dose distribution may be calculated on CT images, while the MRI can be used to enhance soft tissue visualization. Therefore, a registration between MR and CT images could improve the overall treatment planning process, by improving visualization with a demonstrated interobserver deline...

journal_title：Medical physics

authors： Hamdan I,Bert J,Rest CCL,Tasu JP,Boussion N,Valeri A,Dardenne G,Visvikis D

更新日期：2017-12-01 00:00:00

abstract：:Conventional chest radiography is limited by the presence of scattered radiation and the small useful exposure range of radiographic film. A computer-assisted scanning system to minimize these two effects is outlined. The system uses a small beam of radiation swept over the patient's chest in a raster pattern to expos...

journal_title：Medical physics

authors： Plewes DB

更新日期：1983-09-01 00:00:00

abstract：PURPOSE:To evaluate the replacement of Cerrobend by copper for electron beam cutouts. METHODS:The dosimetric comparisons for circular copper-and Cerrobend-cutouts with diameters (1.0, 2.0, 3.0, 5.0, 7.5, 10.0, and 12.5 cm) were made using electron beams with energies (6, 9, 12, 16, and 20 MeV) from 3 Varian accelerato...

journal_title：Medical physics

authors： Chu A,Feng W,Ahmad M,Chen Z,Nath R

更新日期：2012-06-01 00:00:00

abstract：:Total body photon irradiation (TBI) may be delivered with a number of standard techniques, typically using extended SSD geometries to obtain large field sizes. Since 1982 we have treated over 620 patients (adult and pediatric) mostly in the floor-located prone/supine treatment position with AP/PA beams using a column ...

journal_title：Medical physics

authors： Evans M,Ruo R,Seuntjens J,Freeman CR,Parker W

更新日期：2012-07-01 00:00:00

abstract：PURPOSE:To study and compare the dose response curves of the new GafChromic EBT3 film for megavoltage and kilovoltage x-ray beams, with different spatial resolution. METHODS:Two sets of EBT3 films (lot#A101711-02) were exposed to each x-ray beam (6MV, 15MV and 50kV) at 8 dose values (50-3200cGy). The megavoltage beams...

journal_title：Medical physics

authors： Chiu-Tsao S,Massillon-Jl G,Domingo-Muñoz I,Chan M

更新日期：2012-06-01 00:00:00

abstract：:A new scheme, called direct aperture deformation (DAD), for online correction of interfraction geometric uncertainties under volumetric imaging guidance is presented. Using deformable image registration, the three-dimensional geometric transformation matrix can be derived that associates the planning image set and the...

journal_title：Medical physics

authors： Feng Y,Castro-Pareja C,Shekhar R,Yu C

更新日期：2006-12-01 00:00:00

abstract：PURPOSE:A dosimetry evaluation model for treatment planning of esophageal radiation therapy is developed using a deep learning model. The model predicts dose volume histogram (DVH) from distance to target histogram (DTH) based on stacked de-noise auto-encoder (SDAE) and one-dimensional convolutional network (1D-CN). M...

journal_title：Medical physics

authors： Jiang D,Yan H,Chang N,Li T,Mao R,Du C,Guo B,Liu J

更新日期：2020-10-01 00:00:00

abstract：PURPOSE:To develop a hypothesis-generating framework for automatic extraction of dose-outcome relationships from an in-house, analytic oncology database. METHODS:Dose-volume histograms (DVH) and clinical outcomes have been routinely stored to the authors' database for 684 head and neck cancer patients treated from 200...

journal_title：Medical physics

authors： Robertson SP,Quon H,Kiess AP,Moore JA,Yang W,Cheng Z,Afonso S,Allen M,Richardson M,Choflet A,Sharabi A,McNutt TR

更新日期：2015-07-01 00:00:00

abstract：:In this study, BrachyDose, a recently developed EGSnrc Monte Carlo code for rapid brachytherapy dose calculations, has been benchmarked by reproducing previously published dosimetry parameters for three brachytherapy seeds with varied internal structure and encapsulation. Calculations are performed for two 125I seeds ...

journal_title：Medical physics

authors： Taylor RE,Yegin G,Rogers DW

更新日期：2007-02-01 00:00:00

abstract：PURPOSE:Deformable image registration (DIR) is often validated based on a distance-to-agreement (DTA) criterion of automatically propagated anatomical landmarks that were manually identified. Due to human observer variability, however, the performance of the registration method is diluted. The purpose of this study was...

journal_title：Medical physics

authors： Mencarelli A,van Beek S,van Kranen S,Rasch C,van Herk M,Sonke JJ

更新日期：2012-11-01 00:00:00

abstract：PURPOSE:Modulated electron radiation therapy (MERT) can offer significant advantages for breast treatments over conventional radiotherapy in terms of sparing distal critical structures. While intensity modulated radiation therapy (IMRT) has the advantage of achieving better dose homogeneity inside the target combining ...

journal_title：Medical physics

authors： Eldib A,Li J,Jin L,Ma C

更新日期：2012-06-01 00:00:00

abstract：:An easy-to-use phantom has been constructed for checking the accuracy of a stereotactic computed tomography localization system. This phantom has been used on a commercially available stereotactic radiosurgery system. With this system, the phantom reference point, whose location is established by means of a precision ...

journal_title：Medical physics

authors： Ekstrand KE,Olds WW,Branch CL

更新日期：1993-03-01 00:00:00