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 mounted 4 MV linac, and more recently with a fixed field, extended SSD, Cobalt teletherapy unit. This treatment position has many advantages for TBI including ease of delivery (especially for pediatric or compromised patients), improved dose uniformity, simplicity for partial or complete organ shielding, and imaging capabilities to name a few. In an effort to transfer this technique to a conventional isocentric linac, we have undertaken a feasibility study for RapidArc based extended SSD total body irradiation. Proof of principle was first explored using the DBD (Dynamic Beam Delivery) toolbox to configure a 6 MV beam with an 80 degree arc, centered on the 12 o'clock gantry angle with a sliding-window beam. This was followed by the development of an ECLIPSE generated 80 degree RapidArc plan. Initial measurements were conducted with a Varian 21EX using the 6 MV DBD beam to explore characteristics such as PDD, surface dose, off-axis ratios, output, dose per MU, and linearity. Subsequently ECLIPSE generated RapidArc TBI plans using similar partial arcs were also evaluated. Encouraged by our results, we believe this technique shows potential for making floor-located AP/PA total body photon irradiation possible for any standard RapidArc enabled isocentric linac.
journal_name
Med Physjournal_title
Medical physicsauthors
Evans M,Ruo R,Seuntjens J,Freeman CR,Parker Wdoi
10.1118/1.4740139subject
Has Abstractpub_date
2012-07-01 00:00:00pages
4630issue
7Part3eissn
0094-2405issn
2473-4209journal_volume
39pub_type
杂志文章相关文献
MEDICAL PHYSICS文献大全abstract：PURPOSE:Automated detection of solitary pulmonary nodules using positron emission tomography (PET) and computed tomography (CT) images shows good sensitivity; however, it is difficult to detect nodules in contact with normal organs, and additional efforts are needed so that the number of false positives (FPs) can be fu...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4948498
更新日期：2016-06-01 00:00:00
abstract：:Model-based deformable organ registration techniques using the finite element method (FEM) have recently been investigated intensively and applied to image-guided adaptive radiotherapy (IGART). These techniques assume that human organs are linearly elastic material, and their mechanical properties are predetermined. U...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.2163838
更新日期：2006-02-01 00:00:00
abstract：PURPOSE:Different approaches have been used in dynamic elastography to assess mechanical properties of biological tissues. Most techniques are based on a simple inversion based on the measurement of the shear wave speed to assess elasticity, whereas some recent strategies use more elaborated analytical or finite elemen...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4942813
更新日期：2016-04-01 00:00:00
abstract：:The purpose of this work is to compare the efficacy of mathematical models in predicting the occurrence of radiotherapy-induced left ventricular perfusion defects assessed using single-photon emission computed tomography (SPECT). The basis of this study is data from 73 left-sided breast/ chestwall patients treated wit...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.1823571
更新日期：2005-01-01 00:00:00
abstract：PURPOSE:Although x-ray projection mammography has been very effective in early detection of breast cancer, its utility is reduced in the detection of small lesions that are occult or in dense breasts. One drawback is that the inherent superposition of parenchymal structures makes visualization of small lesions difficul...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3312435
更新日期：2010-03-01 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
pub_type： 杂志文章
doi：10.1118/1.2400843
更新日期：2007-02-01 00:00:00
abstract：:Conventional IMRT dose verification using film and ion chamber measurements is useful but limited with respect to the actual dose distribution received by the patient. The Monte Carlo simulation has been introduced as an independent dose verification tool for IMRT using the patient CT data and MLC leaf sequence files,...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.2208916
更新日期：2006-07-01 00:00:00
abstract：PURPOSE:Distortions in magnetic resonance imaging (MRI) compromise spatial fidelity, potentially impacting delineation and dose calculation. We characterized 2D and 3D large field of view (FOV), sequence-independent distortion at various positions in a 1.0 T high-field open MR simulator (MR-SIM) to implement correction...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4930245
更新日期：2015-10-01 00:00:00
abstract：PURPOSE:To investigate the effect of the number of projection views on image noise in cone-beam CT (CBCT) with a flat-panel detector. METHODS:This fairly fundamental consideration in CBCT system design and operation was addressed experimentally (using a phantom presenting a uniform medium as well as statistically moti...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4875688
更新日期：2014-06-01 00:00:00
abstract：PURPOSE:Accurate calculation of proton stopping power ratio (SPR) relative to water is crucial to proton therapy treatment planning, since SPR affects prediction of beam range. Current standard practice derives SPR using a single CT scan. Recent studies showed that dual-energy CT (DECT) offers advantages to accurately ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.12796
更新日期：2018-04-01 00:00:00
abstract：:Performance characteristics sufficient to provide physical data base specific to the Siemen's Stabilipan 2 orthovoltage x-ray therapy machine are presented. Operating conditions covering the working range of the unit from 100 to 300 kVp are selected. Beam quality, output, the central axis depth dose, relative output f...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.596016
更新日期：1987-09-01 00:00:00
abstract：:To develop volumetric micro-CT fluoroscopy for small animal imaging, we have proposed a cone-beam system with multiple x-ray sources. In this paper, we extend Parker's single-source half-scan weighting scheme to the case of an odd number of x-ray sources that are equiangularly distributed, and apply it for half-scan F...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.1381549
更新日期：2001-07-01 00:00:00
abstract：:This article is the first in a series on the calculation of electron dose using multiple-scattering theory. In it we develop a unified theory, which we term Gaussian multiple-scattering theory, starting from a number of contributions already in the literature: the Fermi-Eyges multiple-scattering theory, the Yang path ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.596166
更新日期：1988-03-01 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
pub_type： 杂志文章
doi：10.1118/1.1944287
更新日期：2005-07-01 00:00:00
abstract：:To account for clinical divergent and polychromatic photon beams, we have developed kernel tilting and kernel hardening correction methods for convolution dose calculation algorithms. The new correction methods were validated by Monte Carlo simulation. The accuracy and computation time of the our kernel tilting and ke...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.597960
更新日期：1997-11-01 00:00:00
abstract：:Quantification of transit time of a remote after-loading high dose rate (HDR) brachytherapy source is important both for accurate treatment planning and for quality assurance checks. In this investigation, an HDR-1000 well ionization chamber and a precision electrometer are used to measure the transit time of the Ir-1...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.1386779
更新日期：2001-08-01 00:00:00
abstract：PURPOSE:To evaluate a simple, semi-automated lung mass estimation method on CT scans from a variety of acquisition techniques for mass correction of MIRD dose estimates. METHODS:CT scans from ten patients undergoing stereotactic body radiation therapy treatment planning on a GE DST PET/CT scanner were analyzed retrosp...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4734654
更新日期：2012-06-01 00:00:00
abstract：:Highly focused dose distributions for radiosurgery applications are successfully achieved using either multiple static high-energy particle beams or multiple-arc circular x-ray beams from a linac. It has been suggested that conformal x-ray techniques using dynamically shaped beams with a moving radiation source would ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.597654
更新日期：1995-12-01 00:00:00
abstract：PURPOSE:Cone-beam CT (CBCT) images contain severe shading artifacts mostly due to scatter. Many algorithms have been proposed to alleviate this problem by data correction on projections. Sophisticated methods have also been designed to further improve the image quality when prior patient information is available. In th...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4736218
更新日期：2012-06-01 00:00:00
abstract：PURPOSE:Breast magnetic resonance imaging is highly sensitive but not very specific for the detection of breast cancer. Opportunities exist to supplement the image acquisition with a more specific modality provided the technical challenges of meeting space limitations inside the bore, restricted breast access, and elec...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4820361
更新日期：2013-10-01 00:00:00
abstract：PURPOSE:This work introduces a rigid registration framework for patient positioning in radiotherapy, based on real-time surface acquisition by a time-of-flight (ToF) camera. Dynamic properties of the system are also investigated for future gating/tracking strategies. METHODS:A novel preregistration algorithm, based on...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3664006
更新日期：2012-01-01 00:00:00
abstract：PURPOSE:Radiation scattered from the breast in digital breast tomosynthesis (DBT) causes image degradation, including loss of contrast between cancerous and background tissue. Unlike in 2-dimensional (2D) mammography, an antiscatter grid cannot readily be used in DBT because changing alignment between the tube and dete...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4943632
更新日期：2016-04-01 00:00:00
abstract：:Various techniques have been developed to localize radioactive sources in brachytherapy implants. The most common methods include the orthogonal film method, the stereo-shift film method, and recently, direct localization from a series of contiguous CT transverse images. The major advantage of the CT method is that it...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.598548
更新日期：1999-04-01 00:00:00
abstract：:We employed an elastic reservoir filled with tissue-equivalent fluid as an x-ray beam filter for exposure equalization. The filter is designed to be placed between the upper compression plate and the breast. During compression, it will conform to the shape of the peripheral region of the breast and fill the space betw...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.596502
更新日期：1990-03-01 00:00:00
abstract：:As a quality control procedure, a post-implant seed migration survey has been accomplished on 340 prostate cancer patients since November 2001. Pulmonary seed embolization and intracardiac seed embolization have been detected. A case of thyroid uptake due to leaking iodine-125 (I-125) sources was also seized. In order...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.2207319
更新日期：2006-07-01 00:00:00
abstract：PURPOSE:Patient-specific QA of highly conformal radiotherapy treatments are usually conducted using 2D or 3D dosimetry of the incident dose distribution in a water-equivalent phantom. However, dosimeters typically used for this task usually lack in either spatial resolution or dose accuracy. The purpose of this work is...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4736526
更新日期：2012-08-01 00:00:00
abstract：:In this study we address the problem of predicting the position of a moving lung tumor during respiration on the basis of external breathing signals--a technique used for beam gating, tracking, and other dynamic motion management techniques in radiation therapy. We demonstrate the use of neural network filters to corr...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.2134958
更新日期：2005-12-01 00:00:00
abstract：PURPOSE:This paper provides a comparison between a fast, commercial, in-patient Monte Carlo dose calculation algorithm (GPUMCD) and geant4. It also evaluates the dosimetric impact of the application of an external 1.5 T magnetic field. METHODS:A stand-alone version of the Elekta™ GPUMCD algorithm, to be used within th...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4939808
更新日期：2016-02-01 00:00:00
abstract：:An addendum to the AAPM's TG-51 protocol for the determination of absorbed dose to water in megavoltage photon beams is presented. This addendum continues the procedure laid out in TG-51 but new kQ data for photon beams, based on Monte Carlo simulations, are presented and recommendations are given to improve the accur...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4866223
更新日期：2014-04-01 00:00:00
abstract：:The trend toward conformal techniques in stereotactic radiosurgery necessitates an accurate and practical method for verification of irregular three-dimensional dose distributions. This work presents the design and evaluation of a phantom system facilitating the measurement of conformal dose distributions using one or...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.598962
更新日期：2000-05-01 00:00:00
