Spectra and air-kerma strength for encapsulated 192Ir sources.

Abstract:

:The photon spectra in vacuum around four types of 192Ir HDR brachytherapy sources are calculated using the Monte Carlo code EGS4 and the most recent spectral information on 192Ir decay. The air-kerma strengths per unit activity are calculated based on the photon fluence around a bare 192Ir source and around each of four types of encapsulated sources using recent mass energy-absorption coefficients. For the full spectrum the bare vs encapsulated difference is up to 23% due to the large air-kerma contribution from the unfiltered low-energy photons. For the penetrating part of the photon spectrum (> 11.3 keV), the air-kerma strength per unit source activity on the transverse axis for a bare source is 2-15% higher than for the encapsulated sources due to the attenuation and absorption in the core and the encapsulating material. The contribution to the air-kerma strength from photons scattered in the capsule and from bremsstrahlung are calculated to increase the air-kerma strength by 2-4% and 0.2-0.3%, respectively. Air-kerma strengths for a variety of sources agree well with previously reported results for sources from Nucletron International, Best Industries, Inc., and Alpha-Omega Services, Inc. In addition we present air-kerma strengths for the present model of the HDR source from Nucletron International and the source from Varian Associates, Inc.

journal_name

Med Phys

journal_title

Medical physics

authors

Borg J,Rogers DW

doi

10.1118/1.598763

subject

Has Abstract

pub_date

1999-11-01 00:00:00

pages

2441-4

issue

11

eissn

0094-2405

issn

2473-4209

journal_volume

26

pub_type

杂志文章
  • Characterizing the reflectivity of handheld display devices.

    abstract:PURPOSE:With increased use of handheld and tablet display devices for viewing medical images, methods for consistently measuring reflectivity of the devices are needed. In this note, the authors report on the characterization of diffuse reflections for handheld display devices including mobile phones and tablets using ...

    journal_title:Medical physics

    pub_type: 杂志文章

    doi:10.1118/1.4887813

    authors: Liu P,Badano A

    更新日期:2014-08-01 00:00:00

  • Potential use of P-32 ophthalmic applicator: Monte Carlo simulations for design and dosimetry.

    abstract::Postoperative beta-irradiation after pterygium excision has been considered a valuable therapeutic procedure to reduce the recurrence rate. Recently, it was reported that beta-irradiation also substantially reduced the risk of surgical failure after glaucoma surgery. Pure beta-irradiation using a 90Sr/Y applicator has...

    journal_title:Medical physics

    pub_type: 杂志文章

    doi:10.1118/1.2896076

    authors: Park YK,Ye SJ,Kim IH,Wee WR,Kim MK,Han HS,Son KJ,Park UJ

    更新日期:2008-05-01 00:00:00

  • Hybrid ZTE/Dixon MR-based attenuation correction for quantitative uptake estimation of pelvic lesions in PET/MRI.

    abstract:PURPOSE:This study introduces a new hybrid ZTE/Dixon MR-based attenuation correction (MRAC) method including bone density estimation for PET/MRI and quantifies the effects of bone attenuation on metastatic lesion uptake in the pelvis. METHODS:Six patients with pelvic lesions were scanned using fluorodeoxyglucose (18F-...

    journal_title:Medical physics

    pub_type: 杂志文章

    doi:10.1002/mp.12122

    authors: Leynes AP,Yang J,Shanbhag DD,Kaushik SS,Seo Y,Hope TA,Wiesinger F,Larson PE

    更新日期:2017-03-01 00:00:00

  • The accuracy and reproducibility of a global method to correct for geometric image distortion in the x-ray imaging chain.

    abstract::A method to correct for geometric image distortion in the x-ray imaging chain, so-called dewarping, has been developed. A global two-dimensional polynomial model of which the degree is optimized is used. The performance of the method has been tested in a number of experiments using images of a plate with a 1 cm spaced...

    journal_title:Medical physics

    pub_type: 杂志文章

    doi:10.1118/1.598101

    authors: Gronenschild E

    更新日期:1997-12-01 00:00:00

  • The effect of rectal heterogeneity on wall dose in high dose rate brachytherapy.

    abstract::When treating prostate cancer using high dose rate (HDR) brachytherapy, overdosing the rectal wall may lead to post-treatment rectal complications. An area of concern is related to how the rectal wall dose is calculated by treatment planning systems (TPSs). TPSs are used to calculate the dose delivered to the rectal w...

    journal_title:Medical physics

    pub_type: 杂志文章

    doi:10.1118/1.3031111

    authors: Kwan IS,Wilkinson D,Cutajar D,Lerch M,Rosenfeld A,Howie A,Bucci J,Chin Y,Perevertaylo VL

    更新日期:2009-01-01 00:00:00

  • Simultaneous respiratory motion correction and image reconstruction in 4D-multi pinhole small animal SPECT.

    abstract:PURPOSE:Respiratory motion in the chest region during single photon emission computed tomography (SPECT) is a major degrading factor that reduces the accuracy of image quantification. This effect is more notable when the tumor is very small, or the spatial resolution of the imaging system is less than the respiratory m...

    journal_title:Medical physics

    pub_type: 杂志文章

    doi:10.1002/mp.13807

    authors: Naseri M,Rajabi H,Wang J,Abbasi M,Kalantari F

    更新日期:2019-11-01 00:00:00

  • Characteristics of metal-plate/film detectors at therapy energies. II. Detective quantum efficiency.

    abstract::Noise power spectrum (NPS) and detective quantum efficiency (DQE) for metal-plate/film portal detectors are reported for the Co-60 and Linac 10 MV spectra. The detectors consist of a double-emulsion portal film secured between plates of aluminum, copper, brass, or lead. The NPS was found to be independent of the detec...

    journal_title:Medical physics

    pub_type: 杂志文章

    doi:10.1118/1.598437

    authors: Falco T,Fallone BG

    更新日期:1998-12-01 00:00:00

  • SU-E-I-108: Simple Approach to Determine Patient's Entrance Skin Exposure for Radiographic.

    abstract:PURPOSE:To evaluate a model which can predict patient's Entrance Skin Exposure (ESE) from height and weight and a single kVp mR/mAs measurement for radiographic. METHODS:Patient height, weight and post exposure mAs are obtained to assess ESE based on IAEA model. Patient's thickness is obtained by assuming a cylindrica...

    journal_title:Medical physics

    pub_type: 杂志文章

    doi:10.1118/1.4734825

    authors: Maricle S,Jeutang L,Prasad G

    更新日期:2012-06-01 00:00:00

  • The use of modified single pencil beam dose kernels to improve IMRT dose calculation accuracy.

    abstract::Intensity modulated radiation therapy (IMRT) is used to deliver highly conformal radiation doses to tumors while sparing nearby sensitive tissues. Discrepancies between calculated and measured dose distributions have been reported for regions of high dose gradients corresponding to complex radiation fluence patterns. ...

    journal_title:Medical physics

    pub_type: 杂志文章

    doi:10.1118/1.1812851

    authors: Bergman AM,Otto K,Duzenli C

    更新日期:2004-12-01 00:00:00

  • MR acoustic radiation force imaging: in vivo comparison to ultrasound motion tracking.

    abstract::MR acoustic radiation force (ARF) imaging was developed for measuring tiSsue elastic properties using focused ultrasound to deliver a localized tissue motion. In this study, an imaging ultrasound transducer was mounted on the focused ultrasound transducer and ultrasound motion tracking was performed simultaneously to ...

    journal_title:Medical physics

    pub_type: 杂志文章

    doi:10.1118/1.3120289

    authors: Huang Y,Curiel L,Kukic A,Plewes DB,Chopra R,Hynynen K

    更新日期:2009-06-01 00:00:00

  • Film dosimetry analyses on the effect of gold shielding for iodine-125 eye plaque therapy for choroidal melanoma.

    abstract::One of the methods currently being used to treat choroidal melanoma employs an episcleral plaque containing I-125 radioactive seeds. However, comprehensive dosimetry studies on the plaque are scarce and controversial. For this work, we use film to study the dosimetry outside the lip of the gold shield of the eye plaqu...

    journal_title:Medical physics

    pub_type: 杂志文章

    doi:10.1118/1.596556

    authors: Wu A,Krasin F

    更新日期:1990-09-01 00:00:00

  • Monte Carlo simulation of diagnostic x-ray scatter.

    abstract::A Monte Carlo method was developed and implemented to simulate x-ray photon transport. Simulations consisted of a pencil beam of monoenergetic photons with energies from 50 to 110 keV incident on water and aluminum slabs. The dependence of scatter fraction and multiple scattering on x-ray energy, scatterer thickness, ...

    journal_title:Medical physics

    pub_type: 杂志文章

    doi:10.1118/1.596268

    authors: Papin PJ,Rielly PS

    更新日期:1988-11-01 00:00:00

  • Optical spectroscopy of the breast in premenopausal women reveals tissue variation with changes in age and parity.

    abstract:PURPOSE:Variations during breast tissue development can influence later breast cancer risk. In particular, prolonged nulliparity increases risk. The authors used optical spectroscopy to compare breast tissue in 115 nulliparous women aged 31-40 (group 2) to 140 nulliparous women aged 18-21 (group 1), and also to 36 paro...

    journal_title:Medical physics

    pub_type: 杂志文章

    doi:10.1118/1.3276737

    authors: Knight JA,Blackmore KM,Wong J,Tharmalingam S,Lilge L

    更新日期:2010-02-01 00:00:00

  • Minimax optimization for handling range and setup uncertainties in proton therapy.

    abstract:PURPOSE:Intensity modulated proton therapy (IMPT) is sensitive to errors, mainly due to high stopping power dependency and steep beam dose gradients. Conventional margins are often insufficient to ensure robustness of treatment plans. In this article, a method is developed that takes the uncertainties into account duri...

    journal_title:Medical physics

    pub_type: 杂志文章

    doi:10.1118/1.3556559

    authors: Fredriksson A,Forsgren A,Hårdemark B

    更新日期:2011-03-01 00:00:00

  • Stereotactic mammography imaging combined with 3D US imaging for image guided breast biopsy.

    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

    pub_type: 杂志文章

    doi:10.1118/1.2794175

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

    更新日期:2007-11-01 00:00:00

  • Characterization of a two-dimensional liquid-filled ion chamber detector array used for verification of the treatments in radiotherapy.

    abstract:PURPOSE:The purpose of the study is to investigate the characteristics of a two-dimensional (2D) liquid-filled ion chamber detector array, which is used for the verification of radiotherapy treatment plans that use small field sizes of up to 10 × 10 cm. METHODS:The device used in this study was Octavius 1000 SRS model...

    journal_title:Medical physics

    pub_type: 杂志文章

    doi:10.1118/1.4870439

    authors: Markovic M,Stathakis S,Mavroidis P,Jurkovic IA,Papanikolaou N

    更新日期:2014-05-01 00:00:00

  • An algorithm for fast beam angle selection in intensity modulated radiotherapy.

    abstract:PURPOSE:This article aims to introduce a novel algorithm for fast beam angle selection in intensity modulated radiotherapy (IMRT). METHODS:The algorithm models the optimization problem as a beam angle ranking problem and chooses suitable beam angles according to their rank. A new parameter called "beam intensity profi...

    journal_title:Medical physics

    pub_type: 杂志文章

    doi:10.1118/1.3517866

    authors: Vaitheeswaran R,Narayanan VK,Bhangle JR,Nirhali A,Kumar N,Basu S,Maiya V

    更新日期:2010-12-01 00:00:00

  • Calculating output factors for photon beam radiotherapy using a convolution/superposition method based on a dual source photon beam model.

    abstract::A realistic photon beam model based on Monte Carlo simulation of clinical linear accelerators was implemented in a convolution/superposition dose calculation algorithm. A primary and an extra-focal sources were used in this beam model to represent the direct photons from the target and the scattered photons from other...

    journal_title:Medical physics

    pub_type: 杂志文章

    doi:10.1118/1.598111

    authors: Liu HH,Mackie TR,McCullough EC

    更新日期:1997-12-01 00:00:00

  • Toward consensus on quantitative assessment of medical imaging systems.

    abstract::Consensus has been developing over the past few decades on a number of measurements required for the laboratory assessment of medical imaging modalities. Nevertheless, understanding of the connection between these measurements and human observer performance in a broad range of tasks remains far from complete. Focusing...

    journal_title:Medical physics

    pub_type: 杂志文章,评审

    doi:10.1118/1.597511

    authors: Metz CE,Wagner RF,Doi K,Brown DG,Nishikawa RM,Myers KJ

    更新日期:1995-07-01 00:00:00

  • Validation of reconstructed bremsstrahlung spectra between 6 MV and 25 MV from measured transmission data.

    abstract::We have previously investigated a method of high-energy x-ray spectral reconstruction from transmission data by direct resolution of a matrix system. This technique uses the spectral vectorial algebra formalism. The resolution has previously been tested on a 12 MV photon beam. To extend and to test the validity of the...

    journal_title:Medical physics

    pub_type: 杂志文章

    doi:10.1118/1.597998

    authors: Francois P,Coste F,Bonnet J,Caselles O

    更新日期:1997-05-01 00:00:00

  • Technical Note: Influence of Compton currents on profile measurements in small-volume ion chambers.

    abstract:PURPOSE:This work is to evaluate the effects of Compton current generation in three small-volume ionization chambers on measured beam characteristics for electron fields. METHODS:Beam scans were performed using Exradin A16, A26, and PTW 31014 microchambers. Scans with varying chamber components shielded were performed...

    journal_title:Medical physics

    pub_type: 杂志文章

    doi:10.1118/1.4929555

    authors: Tanny S,Holmes S,Sperling N,Parsai EI

    更新日期:2015-10-01 00:00:00

  • X-ray quantum limited portal imaging using amorphous silicon flat-panel arrays.

    abstract::We have measured the linearity, spatial resolution (MTF), noise (NPS), and signal-to-noise characteristics (DQE) of an electronic portal imaging device (EPID) based on an amorphous silicon flat-panel array. The array has a 128 x 128-pixel matrix and each pixel is 0.75 x 0.75 mm2 in dimension so the array covers an are...

    journal_title:Medical physics

    pub_type: 杂志文章

    doi:10.1118/1.598252

    authors: Munro P,Bouius DC

    更新日期:1998-05-01 00:00:00

  • DMLC tracking and gating can improve dose coverage for prostate VMAT.

    abstract:PURPOSE:To assess and compare the dosimetric impact of dynamic multileaf collimator (DMLC) tracking and gating as motion correction strategies to account for intrafraction motion during conventionally fractionated prostate radiotherapy. METHODS:A dose reconstruction method was used to retrospectively assess the dose d...

    journal_title:Medical physics

    pub_type: 杂志文章

    doi:10.1118/1.4892605

    authors: Colvill E,Poulsen PR,Booth JT,O'Brien RT,Ng JA,Keall PJ

    更新日期:2014-09-01 00:00:00

  • Four-dimensional computed tomography: image formation and clinical protocol.

    abstract::Respiratory motion can introduce significant errors in radiotherapy. Conventional CT scans as commonly used for treatment planning can include severe motion artifacts that result from interplay effects between the advancing scan plane and object motion. To explicitly include organ/target motion in treatment planning a...

    journal_title:Medical physics

    pub_type: 杂志文章

    doi:10.1118/1.1869852

    authors: Rietzel E,Pan T,Chen GT

    更新日期:2005-04-01 00:00:00

  • A numerical study of the acoustic radiation due to eddy current-cryostat interactions.

    abstract:PURPOSE:To investigate the acoustic radiation due to eddy current-cryostat interactions and perform a qualitative analysis on noise reduction methods. METHODS:In order to evaluate the sound pressure level (SPL) of the eddy current induced warm bore wall vibration, a Finite Element (FE) model was created to simulate th...

    journal_title:Medical physics

    pub_type: 杂志文章

    doi:10.1002/mp.12261

    authors: Wang Y,Liu F,Zhou X,Li Y,Crozier S

    更新日期:2017-06-01 00:00:00

  • Comparison of CBCT-based dose calculation methods in head and neck cancer radiotherapy: from Hounsfield unit to density calibration curve to deep learning.

    abstract:PURPOSE:Anatomical variations occur during head and neck (H&N) radiotherapy treatment. kV cone-beam computed tomography (CBCT) images can be used for daily dose monitoring to assess dose variations owing to anatomic changes. Deep learning methods (DLMs) have recently been proposed to generate pseudo-CT (pCT) from CBCT ...

    journal_title:Medical physics

    pub_type: 杂志文章

    doi:10.1002/mp.14387

    authors: Barateau A,De Crevoisier R,Largent A,Mylona E,Perichon N,Castelli J,Chajon E,Acosta O,Simon A,Nunes JC,Lafond C

    更新日期:2020-10-01 00:00:00

  • On calculating kerma, collision kerma and radiative yields.

    abstract:PURPOSE:To study the relationships between dose (D), kerma (K), and collision kerma ( K col ) in photon beams and to investigate total radiative yields for electrons and positrons as a functio...

    journal_title:Medical physics

    pub_type: 杂志文章

    doi:10.1002/mp.13744

    authors: Rogers DWO,Townson RW

    更新日期:2019-11-01 00:00:00

  • Noise, resolution, and sensitivity considerations in the design of a single-slice emission-transmission computed tomographic system.

    abstract::A prototype Emission-Transmission Computed Tomography (ETCT) system is being developed that will acquire single-slice x-ray transmission CT images simultaneously with single photon emission computed tomography (SPECT) images. This system will permit the correlation of anatomical information from x-ray CT with function...

    journal_title:Medical physics

    pub_type: 杂志文章

    doi:10.1118/1.596643

    authors: Liew SC,Hasegawa BH

    更新日期:1991-09-01 00:00:00

  • A filtering method for signal equalization in region-of-interest fluoroscopy.

    abstract::A method to significantly reduce the exposure area product in fluoroscopy using a pre-patient region-of-interest (ROI) attenuator is presented. The attenuator has a thin central region and a gradually increasing thickness away from the center. It is shown that the unwanted brightening artifact caused by the attenuator...

    journal_title:Medical physics

    pub_type: 杂志文章

    doi:10.1118/1.1470205

    authors: Robert N,Komljenovic PT,Rowlands JA

    更新日期:2002-05-01 00:00:00

  • Feasibility study on inverse four-dimensional dose reconstruction using the continuous dose-image of EPID.

    abstract:PURPOSE:When an intensity-modulated radiation beam is delivered to a moving target, the interplay effect between dynamic beam delivery and the target motion due to miss-synchronization can cause unpredictable dose delivery. The portal dose image in electronic portal imaging device (EPID) represents radiation attenuated...

    journal_title:Medical physics

    pub_type: 杂志文章

    doi:10.1118/1.4799941

    authors: Yeo IJ,Jung JW,Yi BY,Kim JO

    更新日期:2013-05-01 00:00:00