Contamination dose from photoneutron processes in bodily tissues during therapeutic radiation delivery.

abstract：PURPOSE:Two ultra-high-resolution (UHR) computed tomography (CT) scanners are clinically available. One is achieved by a CT system with a 0.25 mm × 160 row detector (Detector-UHR), whereas the other is with a 0.6 mm × 32 row detector with in-plane comb filtering in a dual source CT (Comb-UHR). We compared radiation dos...

journal_title：Medical physics

authors： Kawashima H,Ichikawa K,Takata T,Nagata H,Hoshika M,Akagi N

更新日期：2020-02-01 00:00:00

abstract：:Accurately assessing the quality of prostate brachytherapy intraoperatively would be valuable for improved clinical outcome by ensuring the delivery of a prescribed tumoricidal radiation dose to the entire prostate gland. One necessary step towards this goal is the robust and rapid localization of implanted seeds. Sev...

journal_title：Medical physics

authors： Tutar IB,Managuli R,Shamdasani V,Cho PS,Pathak SD,Kim Y

更新日期：2003-12-01 00:00:00

abstract：:Part III (oral exam) is the final part of ABR board exam for Diagnostic Medical Physics. In this exam, each of five oral examiners questions the candidate in each of five question categories. Oral exam has unique challenges to the candidate compared with the written exams. The candidate is expected to have not only ad...

journal_title：Medical physics

authors： Leng S,Chen L,Shu Y,McCollough C

更新日期：2012-06-01 00:00:00

abstract：:Photoelectric-enhanced radiation therapy is a bimodal therapy, consisting of the administration of highly radiation-absorbing substances into the tumor area and localized regional irradiation with orthovoltage x-rays. Irradiation can be performed by a modified computed tomography (CT) unit equipped with an additional ...

journal_title：Medical physics

authors： Jost G,Mensing T,Golfier S,Lawaczeck R,Pietsch H,Hütter J,Cibik L,Gerlach M,Krumrey M,Fratzscher D,Arkadiev V,Wedell R,Haschke M,Langhoff N,Wust P,Lüdemann L

更新日期：2009-06-01 00:00:00

abstract：:Over the past decade, computed tomography (CT) theory, techniques and applications have undergone a rapid development. Since CT is so practical and useful, undoubtedly CT technology will continue advancing biomedical and non-biomedical applications. In this outlook article, we share our opinions on the research and de...

journal_title：Medical physics

authors： Wang G,Yu H,De Man B

更新日期：2008-03-01 00:00:00

abstract：:Volumetric modulated arc therapy (VMAT) has recently been used to improve the dose distribution and efficiency of treatment delivery over the standard intensity-modulated radiotherapy (IMRT) technique. This study compares the dosimetry between RapidArc plan and standard IMRT plan for head and neck cancer. Three head a...

journal_title：Medical physics

authors： Jiang R,Fleck A,Schaly B,Charland P,Zhan L,Alliet K,Rachakonda R,Osei E

更新日期：2012-07-01 00:00:00

abstract：PURPOSE:To measure patient-specific maximum skin dose (MSD) associated with CT fluoroscopy (CTF) lung biopsies and to compare measured MSD with the MSD estimated from phantom measurements, as well as with the CTDIvol of patient examinations. METHODS:Data from 50 patients with lung lesions who underwent a CT fluoroscop...

journal_title：Medical physics

authors： Zanca F,Jacobs A,Crijns W,De Wever W

更新日期：2014-07-01 00:00:00

abstract：:In this work, the authors have evaluated ten different ionization chambers for the relative dosimetry of kilovoltage x-ray beams in the energy range of 50-280 kVp. Percentage depth doses in water and relative detector response (in Solid Water and in air) were measured for each of the x-ray beams studied using a number...

journal_title：Medical physics

authors： Hill R,Mo Z,Haque M,Baldock C

更新日期：2009-09-01 00:00:00

abstract：PURPOSE:The overall goal of this work is to improve the computed tomography (CT) image quality for patients with metal implants or fillings by completing the missing kilovoltage (kV) projection data with selectively acquired megavoltage (MV) data that do not suffer from photon starvation. When both of these imaging sys...

journal_title：Medical physics

authors： Wu M,Keil A,Constantin D,Star-Lack J,Zhu L,Fahrig R

更新日期：2014-12-01 00:00:00

abstract：PURPOSE:The number of pencil beam scanned proton therapy (PBS-PT) facilities equipped with cone-beam computed tomography (CBCT) imaging treating thoracic indications is constantly rising. To enable daily internal motion monitoring during PBS-PT treatments of thoracic tumors, we assess the performance of Motion-Aware Re...

journal_title：Medical physics

authors： den Otter LA,Chen K,Janssens G,Meijers A,Both S,Langendijk JA,Rosen LR,Wu HT,Knopf AC

更新日期：2020-12-01 00:00:00

abstract：:The accurate calculation of the skeleton of an object is a problem not satisfactorily solved by existing approaches. Most algorithms require a significant amount of user interaction and use a voxel grid to compute discrete and often coarse approximations of this representation of the data. We present a novel, automati...

journal_title：Medical physics

authors： Van Uitert R,Bitter I

更新日期：2007-02-01 00:00:00

abstract：PURPOSE:Radiosurgery uses small fields and high-radiation doses to treat intra- and extracranial lesions in a single session. The lack of a lateral electronic equilibrium and the presence of high-dose gradients in these fields are challenges for adequate measurements. The availability of radiation detectors with the hi...

journal_title：Medical physics

authors： Larraga-Gutierrez JM,Garcia-Hernandez D,Garcia-Garduno OA,Galvan de la Cruz OO,Ballesteros-Zebadua P,Esparza-Moreno KP

更新日期：2012-10-01 00:00:00

abstract：PURPOSE:The feasibility of magnetic resonance image (MRI)-based proton therapy is based, among several other factors, on the implementation of appropriate extensions on current dose calculation methods. This work aims to develop a pencil beam algorithm (PBA) for dose calculation of proton beams within magnetic field re...

journal_title：Medical physics

authors： Padilla-Cabal F,Georg D,Fuchs H

更新日期：2018-05-01 00:00:00

abstract：:Current dosimetry protocols for clinical protons do not take into account any secondary electron fluence perturbation in ion chambers. In this work, we performed a systematic study of secondary electron fluence perturbation factors for spherical and cylindrical ion chambers in proton beams (70-250 MeV). The electron f...

journal_title：Medical physics

authors： Verhaegen F,Palmans H

更新日期：2001-10-01 00:00:00

abstract：PURPOSE:An improved method of image guidance for lung tumor biopsies could help reduce the high rate of false negatives. The aim of this work is to optimize the geometry of the scanning-beam digital tomography system (SBDX) for providing real-time 3D tomographic reconstructions for target verification. The unique geome...

journal_title：Medical physics

authors： Nelson G,Yoon S,Krishna G,Wilfley B,Fahrig R

更新日期：2013-11-01 00:00:00

abstract：:The purpose of this paper is to examine the thermal dose distribution, to configure the optimal absorbed power deposition, and to design an appropriate heating strategy for ultrasound thermal therapy. This work employs simulation programs, which are based on the transient bio-heat transfer equation and an ideal absorb...

journal_title：Medical physics

authors： Lin WL,Liang TC,Yen JY,Liu HL,Chen YY

更新日期：2001-10-01 00:00:00

abstract：PURPOSE:Intensity-Modulated Radiation Therapy (IMRT), including its variations (including IMRT, Volumetric Arc Therapy (VMAT), and Tomotherapy), is a widely used and critically important technology for cancer treatment. It is a knowledge-intensive technology due not only to its own technical complexity, but also to the...

journal_title：Medical physics

authors： Ge Y,Wu QJ

更新日期：2019-06-01 00:00:00

abstract：PURPOSE:The purpose of this work was to investigate the use of an experimental complementary metal-oxide-semiconductor (CMOS) active pixel sensor (APS) for tracking of moving fiducial markers during radiotherapy. METHODS:The APS has an active area of 5.4 × 5.4 cm and maximum full frame read-out rate of 20 frame s(-1),...

journal_title：Medical physics

authors： Osmond JP,Zin HM,Harris EJ,Lupica G,Allinson NM,Evans PM

更新日期：2011-11-01 00:00:00

abstract：PURPOSE:To measure the calibration curves of EBT3 dosimetry films in photon and proton beams and to quantify the related uncertainties from one beam type to another. METHODS:EBT3 Gafchromic films have similar properties than EBT2 with a symmetric construction and a matte polyester substrate to prevent Newton's ring ar...

journal_title：Medical physics

authors： Sorriaux J,Rossomme S,Kacperek A,Bertrand D,Vynckier S,Sterpin E

更新日期：2012-06-01 00:00:00

abstract：:This paper outlines a method for determining proper removal-diffusion parameters to be used in removal-diffusion theory calculations for the purpose of BNCT treatment planning. Additionally, this paper demonstrates that, given the proper choice of removal-diffusion parameters, removal-diffusion theory may provide an a...

journal_title：Medical physics

authors： Albertson BJ,Blue TE,Niemkiewicz J

更新日期：2001-09-01 00:00:00

abstract：PURPOSE:To analyze the noise performance of the edge illumination phase-based x-ray imaging technique when applying "single-shot" phase retrieval. The latter consists in applying a sample-specific low-pass filter to the raw data, leading to "hybrid" images in which phase and attenuation contrast are merged with each ot...

journal_title：Medical physics

authors： Hagen CK,Roche I Morgó O,Olivo A

更新日期：2020-09-01 00:00:00

abstract：PURPOSE:In this work, the authors introduce a novel framework, the anatomically constrained registration (AnCoR) scheme and apply it to create a fused anatomic-disease atlas of the prostate which the authors refer to as the prostatome. The prostatome combines a MRI based anatomic and a histology based disease atlas. St...

journal_title：Medical physics

authors： Rusu M,Bloch BN,Jaffe CC,Genega EM,Lenkinski RE,Rofsky NM,Feleppa E,Madabhushi A

更新日期：2014-07-01 00:00:00

abstract：:The synchronization of dynamic multileaf collimator (DMLC) response with respiratory motion is critical to ensure the accuracy of DMLC-based four dimensional (4D) radiation delivery. In practice, however, a finite time delay (response time) between the acquisition of tumor position and multileaf collimator response ne...

journal_title：Medical physics

authors： Vedam S,Docef A,Fix M,Murphy M,Keall P

更新日期：2005-06-01 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：:In a recent paper of Miller et al. (Med. Phys. 43(5), 2141-2152 (2016), the voltage dependence polarity effect of microionization chambers was studied. It was identified that polarity effect arises from the difference in electric potential between the collecting electrode and the guard electrode, which in turn deforms...

journal_title：Medical physics

authors： Brivio D,Sajo E,Zygmanski P

更新日期：2017-03-01 00:00:00

abstract：:Monte Carlo (MC) techniques can be used to build a simulation model of an electron accelerator to calculate output factors for electron fields. This can be useful during commissioning of electron beams from a linac and in clinical practice where irregular fields are also encountered. The Monte Carlo code BEAM/EGS4 was...

journal_title：Medical physics

authors： Verhaegen F,Mubata C,Pettingell J,Bidmead AM,Rosenberg I,Mockridge D,Nahum AE

更新日期：2001-06-01 00:00:00

abstract：:Ultrasound has been the greatest imaging modality worldwide for many years by equipment purchase value and by number of machines and examinations. It is becoming increasingly the front end imaging modality; serving often as an extension of the physician's fingers. We believe that at the other extreme, high-end systems...

journal_title：Medical physics

authors： Carson PL,Fenster A

更新日期：2009-02-01 00:00:00

abstract：:The gamma index is a tool that compares a dose distribution with a reference distribution by combining dose-difference and distance-to-agreement criteria. It has been widely used for ten years despite its high computational cost. This cost is due to both a search process for each reference point and the necessity to r...

journal_title：Medical physics

authors： Blanpain B,Mercier D

更新日期：2009-03-01 00:00:00

abstract：PURPOSE:Credentialing can have an impact on whether or not a clinical trial produces useful quality data that is comparable between various institutions and scanners. With the recent increase of dynamic contrast enhanced-computed tomography (DCE-CT) usage as a companion biomarker in clinical trials, effective quality a...

journal_title：Medical physics

authors： Driscoll B,Keller H,Jaffray D,Coolens C

更新日期：2013-08-01 00:00:00

abstract：:The aim of this study is to perform a statistical analysis to verify the calculated percentage depth dose (PDD) based on the tissue maximum ratio (TMR) with the PDD measurements taken in water. 6 and 15 MV photon beams produced by a Varian linear 2100 C/D accelerator were used. PDDs and TMRs were measured at various d...

journal_title：Medical physics

authors： Isa M,Iqbal K,Afzal M,Buzdar S,Chow J

更新日期：2012-07-01 00:00:00