The line spread function and modulation transfer function of a computed tomographic scanner.

abstract：:Backscatter factors for kVps and half-value layers typical of mammographic beams have been determined as a function of beam diameter and half-value layer. The method utilized thin TLD-100 chips with the scattering medium alternately present and absent. Results indicate that the field-size dependence of the backscatter...

journal_title：Medical physics

authors： Dubuque GL,Cacak RK,Hendee WR

更新日期：1977-09-01 00:00:00

abstract：:Intensity modulated radiation therapy (IMRT) treatment planning typically considers beam optimization and beam delivery as separate tasks. Following optimization, a multi-leaf collimator (MLC) or other beam delivery device is used to generate fluence patterns for patient treatment delivery. Due to limitations and char...

journal_title：Medical physics

authors： Siebers JV,Lauterbach M,Keall PJ,Mohan R

更新日期：2002-06-01 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：OBJECTIVES:To evaluate the performance of RapidArc® (Eclipse 10.0.28) and SmartArc® (Pinnacle 9.0) radiotherapy plans for lung stereotactic body radiation therapy (SBRT) in terms of dosimetric plan quality, delivery efficiency, inhomogeneity corrections and accuracy of dose delivery using a custom-built heterogeneity i...

journal_title：Medical physics

authors： Fakir H,Hoover D,Chen JZ

更新日期：2012-07-01 00:00:00

abstract：PURPOSE:To introduce video surface imaging guidance in synchronization with 4D cone-beam CT (CBCT) scans, and in combination with respiration- gated or target-tracked dose delivery to treat mobile tumors, without collaterally damaging nearby critical structures. METHODS:The approach uses the concept that the integral ...

journal_title：Medical physics

authors： Li S,Haiti B,Serratore D,Neicu T,Chan P,Valakh V,Bizhan M,Miyamoto C,Geng J

更新日期：2012-06-01 00:00:00

abstract：PURPOSE:To evaluate the treatment planning system (TPS) performance of the ZAP-X stereotactic radiosurgery (SRS) system through nondosimetric, dosimetric, and end-to-end (E2E) tests. METHODS:A comprehensive set of TPS commissioning and validation tests were developed using published guidelines. Nondosimetric validatio...

journal_title：Medical physics

authors： Srivastava SP,Jani SS,Pinnaduwage DS,Yan X,Rogers L,Barranco FD,Barani IJ,Sorensen S

更新日期：2021-01-28 00:00:00

abstract：PURPOSE:An improvement in tissue assignment for low-dose rate brachytherapy (LDRB) patients using more accurate Monte Carlo (MC) dose calculation was accomplished with a metallic artifact reduction (MAR) method specific to dual-energy computed tomography (DECT). METHODS:The proposed MAR algorithm followed a four-step ...

journal_title：Medical physics

authors： Côté N,Bedwani S,Carrier JF

更新日期：2016-05-01 00:00:00

abstract：:Computed tomography dose index (CTDI) is a conventional indicator of the patient dose in CT studies. It is measured as the integration of the longitudinal single scan dose profile (SSDP) by using a 100-mm-long pencil ionization chamber and a single axial scan. However, the assumption that most of the SSDP is contained...

journal_title：Medical physics

authors： Nakonechny KD,Fallone BG,Rathee S

更新日期：2005-01-01 00:00:00

abstract：PURPOSE:To develop and test the feasibility of a two-pass iterative reconstruction algorithm with material decomposition designed to obtain quantitative iodine measurements in digital breast tomosynthesis. METHODS:Contrast-enhanced mammography has shown promise as a cost-effective alternative to magnetic resonance ima...

journal_title：Medical physics

authors： Michielsen K,Rodríguez-Ruiz A,Reiser I,Nagy JG,Sechopoulos I

更新日期：2020-10-01 00:00:00

abstract：:Noise characterization through estimation of the noise power spectrum (NPS) is a central component of the evaluation of digital x-ray systems. We begin with a brief review of the fundamentals of NPS theory and measurement, derive explicit expressions for calculation of the one- and two-dimensional (1D and 2D) NPS, and...

journal_title：Medical physics

authors： Williams MB,Mangiafico PA,Simoni PU

更新日期：1999-07-01 00:00:00

abstract：PURPOSE:Ablative hyperthermia (>55 °C) has been used as a definitive treatment for accessible solid tumors not amenable to surgery, whereas mild hyperthermia (40-45 °C) has been shown effective as an adjuvant for both radiotherapy and chemotherapy. An optimal mild hyperthermia treatment is spatially accurate, with prec...

journal_title：Medical physics

authors： Partanen A,Tillander M,Yarmolenko PS,Wood BJ,Dreher MR,Kohler MO

更新日期：2013-01-01 00:00:00

abstract：:A method is proposed for realistic simulation of the breast ductal network as part of a computer three-dimensional (3-D) breast phantom. The ductal network is simulated using tree models. Synthetic trees are generated based upon a description of ductal branching by ramification matrices (R matrices), whose elements re...

journal_title：Medical physics

authors： Bakic PR,Albert M,Brzakovic D,Maidment AD

更新日期：2003-07-01 00:00:00

abstract：:Accurate and reliable thermometry is essential in the development of microwave-induced hyperthermal cancer therapy. While temperature measurements in strong electromagnetic fields usually require special sensors, this does not hold true for interstitial radiator/sensor systems. Miniature thermistors (with metallic lea...

journal_title：Medical physics

authors： Samaras GM,Rosenbloom S,Cheung AY

更新日期：1983-05-01 00:00:00

abstract：PURPOSE:Electronic portal imagers (EPIDs) with high detective quantum efficiencies (DQEs) are sought to facilitate the use of the megavoltage (MV) radiotherapy treatment beam for image guidance. Potential advantages include high quality (treatment) beam's eye view imaging, and improved cone-beam computed tomography (CB...

journal_title：Medical physics

authors： Star-Lack J,Shedlock D,Swahn D,Humber D,Wang A,Hirsh H,Zentai G,Sawkey D,Kruger I,Sun M,Abel E,Virshup G,Shin M,Fahrig R

更新日期：2015-09-01 00:00:00

abstract：:Gafchromic XRCT, radiochromic film is assessed over a broad energy range, from kilovoltage to megavoltage x rays for variations in reflected optical density to dose response. A large energy dependence was found with reflected optical density output for the same delivered dose varying from 7.8 +/- 0.35 at 25.5 keV (50 ...

journal_title：Medical physics

authors： Butson MJ,Cheung T,Yu PK

更新日期：2006-08-01 00:00:00

abstract：PURPOSE:The authors previously introduced a methodology to generate a realistic three-dimensional (3D), high-resolution, computer-simulated breast phantom based on empirical data. One of the key components of such a phantom is that it provides a means to produce a realistic simulation of clinical breast compression. In...

journal_title：Medical physics

authors： Hsu CM,Palmeri ML,Segars WP,Veress AI,Dobbins JT 3rd

更新日期：2011-10-01 00:00:00

abstract：:While simple, intravascular brachytherapy (IVB) presents a considerable potential for harm to the patient. The medical physicist maintains the responsibility to minimize the likelihood of operational problems or dosimetric errors. The principals for safe operation remain the same as with any radiotherapy treatment: to...

journal_title：Medical physics

authors： Chakri A,Thomadsen B

更新日期：2002-12-01 00:00:00

abstract：PURPOSE:The measurement of malignant pleural mesothelioma is critical to the assessment of tumor response to therapy. Current response assessment standards utilize summed linear measurements acquired on three computed tomography (CT) sections. The purpose of this study was to evaluate manual area measurements as an alt...

journal_title：Medical physics

authors： Labby ZE,Straus C,Caligiuri P,MacMahon H,Li P,Funaki A,Kindler HL,Armato SG 3rd

更新日期：2013-08-01 00:00:00

abstract：:Monte Carlo simulation dosimetry is used to compare 169Yb to 192Ir for breast high dose rate (HDR) brachytherapy applications using multiple catheter implants. Results for bare point sources show that while 169Yb delivers a greater dose rate per unit air kerma strength at the radial distance range of interest to brach...

journal_title：Medical physics

authors： Lymperopoulou G,Papagiannis P,Angelopoulos A,Karaiskos P,Georgiou E,Baltas D

更新日期：2006-12-01 00:00:00

abstract：:A comprehensive performance testing program is an essential ingredient of high-quality single-photon emission computed tomography (SPECT). Many of the procedures previously published are complicated, time consuming, or require a special testing environment. This Task Group developed a protocol for evaluating SPECT ima...

journal_title：Medical physics

authors： Graham LS,Fahey FH,Madsen MT,van Aswegen A,Yester MV

更新日期：1995-04-01 00:00:00

abstract：:Contemporary reconstruction methods employed for clinical helical cone-beam computed tomography (CT) are analytical (noniterative) but mathematically nonexact, i.e., the reconstructed image contains so called cone-beam artifacts, especially for higher cone angles. Besides cone artifacts, these methods also suffer from...

journal_title：Medical physics

authors： Sunnegårdh J,Danielsson PE

更新日期：2008-09-01 00:00:00

abstract：PURPOSE:This paper describes the clinical implementation and medical commissioning of the MedAustron Particle Therapy Accelerator (MAPTA) for non-isocentric scanned proton beam treatments. METHODS:Medical physics involvement during technical commissioning work is presented. Acceptance testing procedures, including adv...

journal_title：Medical physics

authors： Grevillot L,Osorio Moreno J,Letellier V,Dreindl R,Elia A,Fuchs H,Carlino A,Kragl G,Palmans H,Vatnitsky S,Stock M

更新日期：2020-02-01 00:00:00

abstract：:A calculation is described that enables the rapid assessment of dose rate at various points of interest within the eye (lens, optic nerve, etc.) for the treatment of choroidal melanoma by plaque therapy. 125I seeds are used as the radiation source. The location of the plaque and its associated seeds relative to the ey...

journal_title：Medical physics

authors： Kepka AG,Johnson PM,Kline RW

更新日期：1988-05-01 00:00:00

abstract：:Intensity Modulated Arc Therapy (IMAT) is a rotational variant of Intensity Modulated Radiation Therapy (IMRT) that can be implemented with or without angular dose rate optimization. The purpose of this study is to determine the inter-relationship among arc range, Multi-Leaf Collimator (MLC) leaf positions and angular...

journal_title：Medical physics

authors： Oliver M,Chen J,Wong E

更新日期：2008-07-01 00:00:00

abstract：PURPOSE:High dose rate (HDR) brachytherapy is a radiation treatment technique capable of delivering large dose rates to the tumor. Radiation is delivered using remote afterloaders to drive highly active sources (commonly (192)Ir with an air KERMA strength range between 20,000 and 40,000 U, where 1 U = 1 μGy m(2)/h in a...

journal_title：Medical physics

authors： Espinoza A,Beeksma B,Petasecca M,Fuduli I,Porumb C,Cutajar D,Corde S,Jackson M,Lerch ML,Rosenfeld AB

更新日期：2013-11-01 00:00:00

abstract：PURPOSE:Compton camera imaging (CCI) systems are currently under investigation for radiotherapy dose reconstruction and verification. The ability of such a system to provide real-time images during dose delivery will be limited by the computational speed of the image reconstruction algorithm. In this work, the authors ...

journal_title：Medical physics

authors： Mundy DW,Herman MG

更新日期：2011-01-01 00:00:00

abstract：:Intrafraction organ motion can limit the advantage of highly conformal dose techniques such as intensity modulated radiation therapy (IMRT) due to target position uncertainty. To ensure high accuracy in beam targeting, real-time knowledge of the target location is highly desired throughout the beam delivery process. T...

journal_title：Medical physics

authors： Mao W,Wiersma RD,Xing L

更新日期：2008-05-01 00:00:00

abstract：:Stereotactic X-ray mammography (SM) and ultrasound (US) guidance are both commonly used for breast biopsy. While SM provides three-dimensional (3D) targeting information and US provides real-time guidance, both have limitations. SM is a long and uncomfortable procedure and the US guided procedure is inherently two dim...

journal_title：Medical physics

authors： Surry KJ,Mills GR,Bevan K,Downey DB,Fenster A

更新日期：2007-11-01 00:00:00

abstract：PURPOSE:Tomosynthesis is a promising modality for breast imaging. The appearance of the tomosynthesis reconstructed image is greatly affected by the choice of acquisition and reconstruction parameters. The purpose of this study was to investigate the limitations of tomosynthesis breast imaging due to scan parameters an...

journal_title：Medical physics

authors： Reiser I,Nishikawa RM

更新日期：2010-04-01 00:00:00

abstract：PURPOSE:In recent years, laser-based acceleration of charged particles has rapidly progressed and medical applications, e.g., in radiotherapy, might become feasible in the coming decade. Requirements are monoenergetic particle beams with long-term stable and reproducible properties as well as sufficient particle intens...

journal_title：Medical physics

authors： Beyreuther E,Enghardt W,Kaluza M,Karsch L,Laschinsky L,Lessmann E,Nicolai M,Pawelke J,Richter C,Sauerbrey R,Schlenvoigt HP,Baumann M

更新日期：2010-04-01 00:00:00