Abstract:
PURPOSE:Recent recommendations of the International Commission on Radiological Protection state that the use of effective dose (E) for assessing patient exposure has severe limitations, though it can be kept for dose comparisons. In cardiology procedures, the equivalent dose (H(T)) is one of the most appropriate dose quantity to be evaluated for risk-benefit assessment. In this study, both E and H(T) values for ten critical organs in coronary angiography (CA) and percutaneous coronary interventions (PCI) were derived from in-the-field dose-area-product (DAP) measurements in order to provide a database for doses in those procedures. METHODS:Conversion factors E/DAP calculated by Monte Carlo methods in two different mathematical human phantoms were applied to DAP values measured on 193 patients (118 CA and 75 PCI). Partial DAP values were recorded in-the-field for each projection and for all patients. The partial effective doses of all projections were summed up to calculate the E of the entire procedure. Similarly, equivalent doses for ten critical organs/tissues (bone, colon, heart, liver, lung, esophagus, red bone marrow, skin, stomach, and thyroid) were derived from H(T)/DAP conversion factors for different projections calculated by Monte Carlo method. RESULTS:All parameters related to the patient dose, i.e., fluoroscopy times, number of images, DAP, effective doses, and equivalent doses, show a wide range of values depending on the complexity of the patient case and the experience of the cardiologist. The mean fluoroscopy time, DAP, and E values for coronary angiography patients were approximately threefold lower than those for PCI patients; the number of images for CA was half that for PCI. The correlation between effective dose and DAP was excellent for both CA and PCI. The equivalent doses values were in good correlations with DAP values in CA examinations, with Pearson's coefficients ranging from 0.87 (stomach) to 0.99 (skin) and r(mean) = 0.94. The same analysis was performed for PCI procedures. In this case, the trends were only slightly worse because "r" ranged from 0.70 (stomach) to 0.92 (bone) and r(mean) = 0.85. Simple conversion coefficients to estimate equivalent doses to ten critical organs/tissues from DAP values, for both CA and PCI, were provided for avoiding the need to carry out detailed in-the-field analysis for all projections and for all patients. CONCLUSIONS:Measurements in-the-field of DAP values were carried out for two common cardiology procedures and effective doses were derived for each technique from detailed analysis of dose and projection data, using conversion factors provided by two different theoretical models. Equivalent doses to organs/tissues were also calculated using conversion factors proposed in the literature for different projections and cumulative conversion factors (H)T/DAP for ten organs/tissues were estimated.
journal_name
Med Physjournal_title
Medical physicsauthors
Compagnone G,Ortolani P,Domenichelli S,Ovi V,Califano G,Dall'Ara G,Marzocchi Adoi
10.1118/1.3561508subject
Has Abstractpub_date
2011-04-01 00:00:00pages
2168-75issue
4eissn
0094-2405issn
2473-4209journal_volume
38pub_type
杂志文章相关文献
MEDICAL PHYSICS文献大全abstract:PURPOSE:This work concerns computed tomography (CT)-based cardiac functional analysis (CFA) with a reduced radiation dose. As CT-CFA requires images over the entire heartbeat, the scans are often performed at 10-20% of the tube current settings that are typically used for coronary CT angiography. A large image noise th...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.12425
更新日期:2017-09-01 00:00:00
abstract:PURPOSE:To develop a novel system for patient-specific combined optimization of couch, collimator, and gantry angles for use in volumetric modulated arc therapy (VMAT) treatment planning. The system was designed to produce highly compact dose distributions by extensively sampling the 4π space. Automated fixed couch tra...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.13887
更新日期:2020-02-01 00:00:00
abstract::When a beam-modifying filter such as a wedge or a compensator is placed in an x-ray beam, scattered photons are generated in the filter material. The magnitude of the dose contribution from these photons for a 4-MV x-ray beam was measured. At a distance of 30 cm from the filter, a copper sheet of 1-cm thickness produc...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.595923
更新日期:1986-01-01 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
pub_type: 杂志文章
doi:10.1002/mp.14400
更新日期:2020-10-01 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:PURPOSE:To assess the temporal and spatial accuracy of the GateCT™ system (VisionRT, London, UK), a recently released respiratory tracking system for 4DCT, under both ideal and nonideal respiratory conditions. METHODS:Three experiments were performed by benchmarking and comparing its results with the ground-truth inpu...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.3671941
更新日期:2012-01-01 00:00:00
abstract::A general expression is derived for the NMR signal from a fluid undergoing random directional flow such as encountered within the microcirculation. The dependence of the echo amplitude on flow velocity, sample morphology, and experimental parameters are described in terms of a temporal velocity autocorrelation functio...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.597170
更新日期:1994-04-01 00:00:00
abstract::Permanent implants of 125I seeds at Memorial Sloan-Kettering Cancer Center are performed by the method of "dimension averaging" to determine the total activity to be implanted; that is, the activity (in mCi) is taken to be five times the average dimension (in cm) of the target region. A nomograph has recently been dev...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.594269
更新日期:1976-01-01 00:00:00
abstract::Breast density is a strong predictor of the failure of mammography screening to detect breast cancer and is a strong predictor of the risk of developing breast cancer. The many imaging options that are now available for imaging dense breasts show great promise, but there is still the question of determining which wome...
journal_title:Medical physics
pub_type: 杂志文章,评审
doi:10.1118/1.4935141
更新日期:2015-12-01 00:00:00
abstract::A new system of radiation dose mapping based on laser heating of thermoluminescent dosimetric plates (TLDP) has been developed. Application of this technique to intraoperative radiotherapy (IORT) has been investigated. Preliminary results show that TLDP are a possible alternative to radiological films and ionization c...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.597725
更新日期:1996-08-01 00:00:00
abstract:PURPOSE:Color images are visualized on medical monitors that are adjusted by a grayscale standard display function (GSDF) or γ2.2. Although the GSDF is visually displayed as a linear graded grayscale, it does not specify how color medical images should be presented. On the other hand, the usual gamma setting for color ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.13532
更新日期:2019-06-01 00:00:00
abstract:PURPOSE:Most clinically deployed strategies for respiratory motion management in lung radiotherapy (e.g., gating and tracking) use external markers that serve as surrogates for tumor motion. However, typical lung phantoms used to validate these strategies are based on a rigid exterior and a rigid or a deformable-interi...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4918581
更新日期:2015-05-01 00:00:00
abstract::Treatment simulation is usually performed with a conventional simulator using kV X-rays or with a computed tomography (CT) simulator before the treatment course begins. The purpose is to verify patient setup under the same conditions as for treatment planning. Systematic (preparation) setup errors can be introduced by...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.2727299
更新日期:2007-05-01 00:00:00
abstract::A technique was developed to reduce the size and magnitude of the hot and cold spots in the abutting regions of photon and electron fields. The photon and electron fields were set up such that the photon field extended approximately 2 cm into the electron field in the abutting region. The region of the photon beam tha...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.598753
更新日期:1999-11-01 00:00:00
abstract:PURPOSE:Conformal SBRT plans for Lung cancer with static gantry angles are ideal candidates for applying motion tracking because of: (1) better dosimetric conformity with reduced target margin and (2) easier and more faithful target tracking without intensity modulation. This work is to demonstrate that by delivering t...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4734998
更新日期:2012-06-01 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:To demonstrate an objective approach to determining if a negative report from the Radiological Physics Center (RPC) of greater than 10% error is valid or has clinical significance. METHODS:The discrepancy involved the clinical activity (mgRaEq) of Cs-137 sources, some manufactured by 3M and some by Amersham. M...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4735271
更新日期:2012-06-01 00:00:00
abstract:PURPOSE:The quality of a treatment plan for stereotactic body radiotherapy (SBRT) depends on an experience of each treatment planner. Therefore, the treatment plans are subjectively determined by comparison of several treatment plans developed by time consuming iterative manners, while considering the benefit to a tumo...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4735950
更新日期:2012-06-01 00:00:00
abstract:PURPOSE:To compare beam characteristics of superficial X-rays with 6 MeV Electrons for the purpose of replacing superficial treatments with electron fields for skin lesions. METHODS:Electron beam cutouts were made with 12mm thickness cerrobend in diameters 2-5 cm to match superficial X-ray machine cones. Central axis ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4735294
更新日期:2012-06-01 00:00:00
abstract::The BEAMnrc/EGSnrc Monte Carlo code system is employed to develop a model of the National Research Council of Canada primary standard of absorbed dose to tissue in a beta radiation field, comprising an extrapolation chamber and 90Sr/90Y beta source. We benchmark the model against the measured response of the chamber i...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.1997347
更新日期:2005-10-01 00:00:00
abstract::The most favorable treatment for moving body anatomy should aim at utilizing organ motion to minimize the dose to sensitive structures without compromising the dose delivered to the target. The solution of the problem of appropriate intensity redistribution over different phases of body motion is achievable in dynamic...
journal_title:Medical physics
pub_type: 信件
doi:10.1118/1.2804722
更新日期:2007-12-01 00:00:00
abstract:PURPOSE:To evaluate the image quality of virtual monochromatic images synthesized from dual-source dual-energy computed tomography (CT) in comparison with conventional polychromatic single-energy CT for the same radiation dose. METHODS:In dual-energy CT, besides the material-specific information, one may also synthesi...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.3658568
更新日期:2011-12-01 00:00:00
abstract:PURPOSE:There are several options to consider in the design of a vault that will house a cyclotron for radioisotopes production with regards to the door entrance. Alternatives are a direct-shielded door, a simple maze, or a double-legged maze. In this work, the impact of the neutron and photon doses at the vault entran...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.3515458
更新日期:2010-12-01 00:00:00
abstract::Both the design considerations and the dosimetric properties of the Siemens Model 5800 linear accelerator are discussed. This unit is of such an energy (3.3 MV) as to imitate Cobalt-60 teletherapy depth doses. A linear relation of dmax to depth dose at low energies was found for various wave guides and targets. The en...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.596487
更新日期:1990-05-01 00:00:00
abstract:PURPOSE:The hematopoietically active tissues of skeletal bone marrow are a prime target for computational dosimetry given potential risks of leukemia and, at higher dose levels, acute marrow toxicity. The complex three-dimensional geometry of trabecular spongiosa, however, complicates schema for dose assessment in such...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.12002
更新日期:2017-01-01 00:00:00
abstract::Motion and deformation of the cardiac wall may be measured by following the positions of implanted radiopaque markers in three dimensions, using two x-ray cameras simultaneously. Regularly, calibration of the position measurement system is obtained by registration of the images of a calibration object, containing 10-2...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.598518
更新日期:1999-02-01 00:00:00
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
更新日期:2009-01-01 00:00:00
abstract:PURPOSE:This study aims to investigate the prompt secondary gamma spectrum and thedepth-dose distributions of incident 40 MeV protons onto various phantom materials.The goal is to find a relationship between the secondary prompt gamma emissions andthe range of the incident particles. METHODS:An application was constru...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4735388
更新日期:2012-06-01 00:00:00
abstract:PURPOSE:Discuss optimised Accelerated Partial Breast Irradiation (APBI) using a Strut-Adjused Volume Implant (SAVI) applicator for patients with implanted pacemeker, without overdosing or relocating the pacemaker. METHODS:A right breast cancer patient with an in situ pacemaker (Medtronic model ADDR01) on the right sid...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4735299
更新日期:2012-06-01 00:00:00
abstract::Spread of invasive carcinoma throughout breast tissue is believed to occur at supramolecular levels, beyond the range of standard histopathology identification. Small angle x-ray scattering (SAXS) is capable of characterizing the structural properties of collagen and tissue found in the breast at the scale of tens to ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.3147144
更新日期:2009-07-01 00:00:00