Beam modeling and verification of a photon beam multisource model.

abstract：PURPOSE:In order to build up a reliable dose monitoring system for boron neutron capture therapy (BNCT) applications at the TRIGA reactor in Mainz, a computer model for the entire reactor was established, simulating the radiation field by means of the Monte Carlo method. The impact of different source definition techni...

journal_title：Medical physics

authors： Ziegner M,Schmitz T,Khan R,Blaickner M,Palmans H,Sharpe P,Hampel G,Böck H

更新日期：2014-11-01 00:00:00

abstract：PURPOSE:Prostate biopsy, performed using two-dimensional (2D) transrectal ultrasound (TRUS) guidance, is the clinical standard for a definitive diagnosis of prostate cancer. Histological analysis of the biopsies can reveal cancerous, noncancerous, or suspicious, possibly precancerous, tissue. During subsequent biopsy s...

journal_title：Medical physics

authors： Karnik VV,Fenster A,Bax J,Cool DW,Gardi L,Gyacskov I,Romagnoli C,Ward AD

更新日期：2010-02-01 00:00:00

abstract：PURPOSE:The authors use reduced-order constrained optimization (ROCO) to create clinically acceptable IMRT plans quickly and automatically for advanced lung cancer patients. Their new ROCO implementation works with the treatment planning system and full dose calculation used at Memorial Sloan-Kettering Cancer Center (M...

journal_title：Medical physics

authors： Stabenau H,Rivera L,Yorke E,Yang J,Lu R,Radke RJ,Jackson A

更新日期：2011-05-01 00:00:00

abstract：:Studies suggest that clinical outcomes are improved in repeat trigeminal neuralgia (TN) Gamma Knife radiosurgery if a different part of the nerve from the previous radiosurgery is treated. The MR images taken in the first and repeat radiosurgery need to be coregistered to map the first radiosurgery volume onto the sec...

journal_title：Medical physics

authors： Li X,Zhang P,Brisman R,Kutcher G

更新日期：2005-07-01 00:00:00

abstract：PURPOSE:Hybrid Photon Counting (HPC) detectors profoundly improved x-ray diffraction experiments at third generation synchrotron facilities. Enabling the simultaneous measurement of x-ray intensities in multiple energy bins, they also have many potential applications in the field of medical imaging. A prerequisite for ...

journal_title：Medical physics

authors： Trueb P,Zambon P,Broennimann C

更新日期：2017-09-01 00:00:00

abstract：PURPOSE:There is significant current interest in the use of biological image guidance in radiotherapy planning. In lung-cancer treatment, tumor motion due to respiration is known to be a limitation. This is particularly true in PET, where image data are collected over a number of minutes. An in-house-developed 4D PET a...

journal_title：Medical physics

authors： Perrin R,Evans PM,Webb S,Partridge M

更新日期：2010-02-01 00:00:00

abstract：PURPOSE:To evaluate the image quality of virtual monochromatic images synthesized from dual-source dual-energy computed tomography (CT) in comparison with conventional polychromatic single-energy CT for the same radiation dose. METHODS:In dual-energy CT, besides the material-specific information, one may also synthesi...

journal_title：Medical physics

authors： Yu L,Christner JA,Leng S,Wang J,Fletcher JG,McCollough CH

更新日期：2011-12-01 00:00:00

abstract：PURPOSE:Because the small-radius photon beams shaped by cones in stereotactic radiosurgery (SRS) lack lateral electronic equilibrium and a detector's finite cross section, direct experimental measurement of dosimetric data for these beams can be subject to large uncertainties. As the dose calculation accuracy of a trea...

journal_title：Medical physics

authors： Yang JN,Ding X,Du W,Pino R

更新日期：2010-10-01 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：:The BEAMnrc/EGSnrc Monte Carlo code system is employed to develop a model of the National Research Council of Canada primary standard of absorbed dose to tissue in a beta radiation field, comprising an extrapolation chamber and 90Sr/90Y beta source. We benchmark the model against the measured response of the chamber i...

journal_title：Medical physics

authors： Selvam TP,Saull PR,Rogers DW,National Research Council of Canada.

更新日期：2005-10-01 00:00:00

abstract：PURPOSE:The most appropriate method of evaluating the effective atomic number necessitates consideration of energy-dependent behavior. Previously, this required quite laborious calculation, which is why many scientists revert to over-simplistic power-law methods. The purpose of this work is to develop user-friendly sof...

journal_title：Medical physics

authors： Taylor ML,Smith RL,Dossing F,Franich RD

更新日期：2012-04-01 00:00:00

abstract：PURPOSE:Respiration-induced intrafraction target motion is a concern in liver cancer radiotherapy, especially in stereotactic body radiotherapy (SBRT), and therefore, verification of its motion is necessary. An effective means to localize the liver cancer is to insert metal fiducial markers to or near the tumor with si...

journal_title：Medical physics

authors： Park JC,Park SH,Kim JH,Yoon SM,Kim SS,Kim JS,Liu Z,Watkins T,Song WY

更新日期：2011-02-01 00:00:00

abstract：:An automated technique has been developed for the verification of treatment field size and shape in external beam radiation therapy. Portal images from film or digital on-line imaging system are analyzed, and basic parameters are derived to describe the field size and shape from the contour points on the field boundar...

journal_title：Medical physics

authors： Leszczynski KW,Shalev S,Gluhchev G

更新日期：1993-05-01 00:00:00

abstract：PURPOSE:Imaging the knee under realistic load-bearing conditions can be carried out in a horizontal plane using a C-arm CT scanner. Human subjects can be scanned in a standing position and acquired data successfully reconstructed. However, reconstructing this data is a challenge due to significant artifacts that are in...

journal_title：Medical physics

authors： Choi JH,Keil A,Maier A,Pal S,McWalter EJ,Fahrig R

更新日期：2012-06-01 00:00:00

abstract：PURPOSE:Anomalous pixels may be defined as those pixels whose exposure response relationship is deviant from the typical, expected or calibrated response. A group of anomalous pixels may Result in visible correlated artifacts. Here we demonstrate an approach to identify anomalous pixels and correlated artifacts using f...

journal_title：Medical physics

authors： Dave J,Gingold E,Yorkston J,Bercha I,Goldman L,Walz-Flannigan A,Willis C

更新日期：2012-06-01 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：PURPOSE:We investigated the feasibility of using simpler methods than manual whole-organ volume-of-interest (VOI) definition to estimate the organ activity concentration in single photon emission computed tomography (SPECT) in cases where the activity in the organ can be assumed to be uniformly distributed on the scale...

journal_title：Medical physics

authors： Vicente EM,Lodge MA,Rowe SP,Wahl RL,Frey EC

更新日期：2017-05-01 00:00:00

abstract：:Recently, the clinical application of electronic portal imaging devices has enabled more frequent verification of patient setup for radiation treatment. However, the image quality has sometimes proven to be inadequate, motivating the investigation of alternative sensors with better image quality. Amorphous selenium (a...

journal_title：Medical physics

authors： Mah D,Rowlands JA,Rawlinson JA

更新日期：1998-04-01 00:00:00

abstract：:In addition to the familiar problems of reduced contrast and signal-to-noise ratio (SNR) in the single energy case, dual-energy subtractions in the presence of scattered radiation suffer further degradations from: (1) artifacts due to nonuniform subtraction of scatter, and (2) a serious deterioration of the signal of ...

journal_title：Medical physics

authors： Wagner FC,Macovski A,Nishimura DG

更新日期：1988-09-01 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：:Treatment of cervical cancer often involves intracavitary high dose rate (HDR) brachytherapy. Dose delivered to the bladder and rectum are typically estimated using the ICRU reference points. Dose to the sigmoid and small bowel are not estimated, yet these organs typically exhibit significant complication rates. The o...

journal_title：Medical physics

authors： Lekx-Toniolo KS,Hunter R,Patel M,Voruganti S,Johanson C,Dhamanaskar K,Farrell T

更新日期：2008-07-01 00:00:00

abstract：:Small photon fields are increasingly used in modern radiotherapy and especially in IMRT and SRS/SRT treatments. The uncertainties related to small field profile measurements can introduce significant systematic errors to the overall treatment process. These measurements are challenging mainly due to the absence of cha...

journal_title：Medical physics

authors： Pappas E,Maris TG,Zacharopoulou F,Papadakis A,Manolopoulos S,Green S,Wojnecki C

更新日期：2008-10-01 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：PURPOSE:Intraoperative electron radiation therapy (IOERT) involves the delivery of a high radiation dose during tumor resection in a shorter time than other radiation techniques, thus improving local control of tumors. However, a linear accelerator device is needed to produce the beam safely. Mobile linear accelerators...

journal_title：Medical physics

authors： Marinetto E,Victores JG,García-Sevilla M,Muñoz M,Calvo FÁ,Balaguer C,Desco M,Pascau J

更新日期：2017-10-01 00:00:00

abstract：PURPOSE:Elastography using computer tomography (CT) is a promising methodology that can provide patient-specific regional distributions of lung biomechanical properties. The purpose of this paper is to investigate the feasibility of performing elastography using simulated lower dose CT scans. METHODS:A cohort of eight...

journal_title：Medical physics

authors： Hasse K,Hsieh SS,O'Connell D,Stiehl B,Min Y,Neylon J,Low DA,Santhanam AP

更新日期：2020-08-01 00:00:00

abstract：PURPOSE:This work describes the performance characterization of a cone-beam CT-guided radiosurgery device, the Gamma Knife® Icon™. METHODS:The performance tests have been categorized into: (a) image quality and mechanical integrity; (b) image coregistration fidelity; (c) adaptive treatment delivery quality; (d) high d...

journal_title：Medical physics

authors： Sarfehnia A,Ruschin M,Chugh B,Yeboah C,Becker N,Cho YB,Lee Y

更新日期：2018-06-29 00:00:00

abstract：PURPOSE:The small number of samples available for training and testing is often the limiting factor in finding the most effective features and designing an optimal computer-aided diagnosis (CAD) system. Training on a limited set of samples introduces bias and variance in the performance of a CAD system relative to that...

journal_title：Medical physics

authors： Way TW,Sahiner B,Hadjiiski LM,Chan HP

更新日期：2010-02-01 00:00:00

abstract：PURPOSE:Image guidance is crucial for percutaneous tumor ablations, enabling accurate needle-like applicator placement into target tumors while avoiding tissues that are sensitive to injury and/or correcting needle deflection. Although ultrasound (US) is widely used for image guidance, magnetic resonance (MR) is prefer...

journal_title：Medical physics

authors： Yamada A,Tokuda J,Naka S,Murakami K,Tani T,Morikawa S

更新日期：2020-03-01 00:00:00

abstract：:Estimated photon energy spectra are derived from transmission measurements using aluminium, copper, and sodium iodide absorbers. Two spectral models are proposed. One is based on a previously published model that analyzes the electron's penetration into the anode, and the production and attenuation of bremsstrahlung p...

journal_title：Medical physics

authors： Ruth C,Joseph PM

更新日期：1997-05-01 00:00:00

abstract：PURPOSE:Cherenkov light during MV radiotherapy has recently found imaging and therapeutic applications but is challenged by relatively low fluence. Our purpose is to investigate the feasibility of increasing Cherenkov light production during MV radiotherapy by increasing photon energy and applying specialized beam-hard...

journal_title：Medical physics

authors： Shrock Z,Yoon SW,Gunasingha R,Oldham M,Adamson J

更新日期：2018-07-01 00:00:00