Abstract：
:The introduction of negative pions into cancer therapy has required the construction of large new proton accelerators together with special magnetic systems to form and direct the pion beam to a patient. A summary is presented of the fundamental properties of pions and of the methods used to study the therapeutic beams. The dosimetry of these beams requires the use of the older techniques as well as new methods for determining the different LET components. The data for a number of beams is given and the utilization of this data in treatment planning is reviewed. An important problem for therapy is the behavior of inhomogeneities in the pion beam, and experimental methods are described which illuminate this problem. The studies of the effects of inhomogeneities in a beam point the way toward fruitful comparisons with the computerized treatment planning codes known as PION-1 and PIPLAN. A useful step in treatment is the verification of doses in patients during therapy. For this purpose the new methods for measuring the high LET doses in patients are described as well as a timing measurement for checking the stopping effect of the tissues as obtained from the CT scans.
journal_name
Med Physjournal_title
Medical physicsauthors
Richman Cdoi
10.1118/1.594868subject
Has Abstractpub_date
1981-05-01 00:00:00pages
273-91issue
3eissn
0094-2405issn
2473-4209journal_volume
8pub_type
杂志文章,评审相关文献
MEDICAL PHYSICS文献大全abstract：PURPOSE:We propose a new metric called Distance Discordance (DD), which is defined as the distance between two anatomic points from two moving images, which are co-located on some reference image, when deformed onto another reference image. METHODS:To demonstrate the concept of DD, we created a reference software phan...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4736139
更新日期：2012-06-01 00:00:00
abstract：PURPOSE:Concurrent irradiation of the prostate and pelvic lymph nodes is technically challenging due to treating one moving target and one immobile target. The purposes of this article are to propose a new management strategy and to compare this strategy to the conventional isocenter shift method and the previously pro...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3480505
更新日期：2010-09-01 00:00:00
abstract：:Flat-panel imagers consisting of the first large area, self-scanning, pixelated, solid-state arrays made with hydrogenated amorphous silicon (a-Si:H) are under development by the authors for applications in diagnostic x-ray and megavoltage radiotherapy imaging. The arrays, designated by the acronym MASDA for multi-ele...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.596802
更新日期：1992-11-01 00:00:00
abstract：PURPOSE:The use of X-ray imaging in radiation therapy can give a substantial dose to the patient. A Cobalt machine combined with an magnetic resonance imaging (MRI) was recently introduced to clinical work. One positive aspect of using non-ionizing imaging devices is the reduction of the patient exposure. The purpose o...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.12293
更新日期：2017-07-01 00:00:00
abstract：PURPOSE:Current on-board imaging systems commonly used by modern linear accelerators (LINACs) have a limited field of view (FOV) for a cone-beam CT (CBCT) scan, which is typically less than 50 cm. Consequently, truncation artifacts often occur for large patients. The goal of this work is to investigate a novel method t...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3514130
更新日期：2010-12-01 00:00:00
abstract：PURPOSE:The need for an accurate lesion segmentation tool in 18FDG PET is a prerequisite for the estimation of lesion response to therapy, for radionuclide dosimetry, and for the application of 18FDG PET to radiotherapy planning. In this work, the authors have developed an iterative method based on a mathematical fit d...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3222732
更新日期：2009-10-01 00:00:00
abstract：PURPOSE:This study (1) examines a variety of real-world cases where systematic errors were not detected by widely accepted methods for IMRT/VMAT dosimetric accuracy evaluation, and (2) drills-down to identify failure modes and their corresponding means for detection, diagnosis, and mitigation. The primary goal of detai...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4826166
更新日期：2013-11-01 00:00:00
abstract：PURPOSE:The purpose of this study was to develop a practical method for estimating organ doses from kilovoltage cone-beam CT (CBCT) that can be performed with readily available phantoms and dosimeters. The accuracy of organ dose estimates made using the ImPACT patient dose calculator was also evaluated. METHODS:A 100 ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3476459
更新日期：2010-09-01 00:00:00
abstract：:A beam intensity monitor was tested in a 230-MeV proton beam at the Loma Linda Proton Therapy Accelerator during its commissioning at Fermi National Accelerator Laboratory. The intensity monitor was designed to regulate the beam intensity extracted from the proton synchrotron. The proton beam is tunable between 70 and...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.596636
更新日期：1991-07-01 00:00:00
abstract：:The wall of an ionization chamber is commonly assumed to have a negligible effect on chamber response in electron beams. For cylindrical chambers with thin walls this assumption is valid. However, parallel-plate chambers commonly possess large mechanical supports which may affect chamber response in a manner not accou...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.596165
更新日期：1988-01-01 00:00:00
abstract：:An instrument for daily beam checks of medical accelerators is described. Using three silicon diodes, the instrument provides information about calibration, beam symmetry, flatness, and energy variation for both photon and electron beams. Operating characteristics of the instrument and the electronic circuit design pe...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.595756
更新日期：1985-07-01 00:00:00
abstract：PURPOSE:A radiophotoluminescent glass rod dosimeter (RGD) has recently become commercially available. It is being increasingly used for dosimetry in radiotherapy to measure the absorbed dose including scattered low-energy photons on the body surface of a patient and for postal dosimetry audit. In this article, the dosi...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4747261
更新日期：2012-10-01 00:00:00
abstract：:A measurement technique previously proposed for determining dose from primary radiation has been tested using 60Co gamma rays. It is shown that the dose from primary radiation is reliably determined for field sizes of 10 X 10 and 20 X 20 cm2 at depths of 0.5, 5, and 10 cm in water. With further development this techni...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.596534
更新日期：1990-01-01 00:00:00
abstract：:A simple method to measure the line spread function of computed tomographic scanners has been developed. The line spread function of the EMI-Scanner was measured and the MTF of the scanner was calculated. The reproducibility of the method indicated this technique could be utilized to compare the spatial resolution of ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.594283
更新日期：1976-07-01 00:00:00
abstract：PURPOSE:To obtain on-treatment volumetric patient anatomy during respiratory gated volumetric modulated arc therapy (VMAT). METHODS:On-board imaging device integrated with Linacs offers a viable tool for obtaining patient anatomy during radiation treatment delivery. In this study, the authors acquired beam-level kV im...
journal_title：Medical physics
pub_type： 信件
doi：10.1118/1.4794925
更新日期：2013-04-01 00:00:00
abstract：PURPOSE:Many biological objects, including neuronal dendrites, blood vasculature, airways, phylogenetic trees, produce tree structured data. Current methods of analysis either ignore the complex structure of trees or use distance-based methods which limit the scope of multivariate modeling. METHODS:We propose a branch...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.12751
更新日期：2018-03-01 00:00:00
abstract：:A new type of radiographic film, EDR (extended dose range) film, has been recently become available for film dosimetry. It is particularly attractive for composite isodose verification of intensity modulated radiation therapy because of its low sensitivity relative to the more common Kodak XV film. For XV film, the re...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.1568979
更新日期：2003-05-01 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
pub_type： 杂志文章
doi：10.1118/1.4822736
更新日期：2013-11-01 00:00:00
abstract：:Skeletal dosimetry based on microCT images of trabecular bone has recently been introduced to calculate the red bone marrow (RBM) and the bone surface cell (BSC) equivalent doses in human phantoms for external exposure to photons. In order to use the microCT images for skeletal dosimetry, spongiosa voxels in the skele...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3242266
更新日期：2009-11-01 00:00:00
abstract：PURPOSE:Liver segmentation is an important prerequisite for the assessment of liver cancer treatment options like tumor resection, image-guided radiation therapy (IGRT), radiofrequency ablation, etc. The purpose of this work was to evaluate a new approach for liver segmentation. METHODS:A graph cuts segmentation metho...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3682171
更新日期：2012-03-01 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
pub_type： 杂志文章
doi：10.1118/1.595327
更新日期：1983-09-01 00:00:00
abstract：:This paper examines statistical errors in the measurement of arterial stenoses by digital videodensitometry. Images of vessel phantoms were acquired using digital subtraction angiographic techniques with low concentrations of an iodine contrast medium and low levels of x-ray exposure. Effects of the spatial and tempor...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.595652
更新日期：1985-11-01 00:00:00
abstract：:The variance in the number of x-ray photons absorbed by a detector is derived from theoretical considerations. The distributions in the number of x-ray photons produced by the x-ray tube, transmitted through the patient, and absorbed by the detector are described. These distributions are compounded to yield a distribu...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.595393
更新日期：1983-07-01 00:00:00
abstract：PURPOSE:As hypoxic cells are more resistant to photon radiation, it is desirable to obtain information about the oxygen distribution in tumors prior to the radiation treatment. Noninvasive techniques are currently not able to provide reliable oxygenation maps with sufficient spatial resolution; therefore mathematical m...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4812431
更新日期：2013-08-01 00:00:00
abstract：:The half-life of two I-125 encapsulated clinical seeds was measured with a Si(Li) semiconductor detector. Two measurements of each seed yielded an average half-life of 59.56 +/- 0.17 days. The results are discussed in terms of the influence of possible I-126 contamination and leakage of I-125 activity through encapsul...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.595423
更新日期：1983-11-01 00:00:00
abstract：:A system for measuring two-dimensional (2D) dose distributions in orthogonal anatomical planes in the cranium was developed and used to evaluate the accuracy of coplanar conformal therapy using ExacTrac image guidance. Dose distributions were measured in the axial, sagittal, and coronal planes using a CIRS (Computeriz...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.2955751
更新日期：2008-08-01 00:00:00
abstract：PURPOSE:The aim of this study was to implement a Dirichlet process mixture (DPM) model for automatic tumor edge identification on (18)F-fluorodeoxyglucose positron emission tomography ((18)F-FDG PET) images by optimizing the parameters on which the algorithm depends, to validate it experimentally, and to test its robus...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4947123
更新日期：2016-05-01 00:00:00
abstract：:A new energy selective detector for dual energy computed radiography has been developed that combines many of the advantages of x-ray tube voltage switching and single exposure double screen detectors. The new active detector utilizes electro-optical modulation of the response of the storage phosphor screens to allow ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.597831
更新日期：1996-10-01 00:00:00
abstract：PURPOSE:Body composition is known to be associated with many diseases including diabetes, cancers, and cardiovascular diseases. In this paper, we developed a fully automatic body tissue decomposition procedure to segment three major compartments that are related to body composition analysis - subcutaneous adipose tissu...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.14465
更新日期：2020-11-01 00:00:00
abstract：OBJECTIVE:To develop an anthropomorphic, deformable and multimodal pelvis phantom with positron emission tomography extension for radiotherapy (ADAM PETer). METHODS:The design of ADAM PETer was based on our previous pelvis phantom (ADAM) and extended for compatibility with PET and use in 3T magnetic resonance imaging ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.14597
更新日期：2020-11-18 00:00:00
