An introduction to molecular imaging in radiation oncology: a report by the AAPM Working Group on Molecular Imaging in Radiation Oncology (WGMIR).

abstract：PURPOSE:We report on the development of the open-source cross-platform radiation treatment planning toolkit matRad and its comparison against validated treatment planning systems. The toolkit enables three-dimensional intensity-modulated radiation therapy treatment planning for photons, scanned protons and scanned carb...

journal_title：Medical physics

authors： Wieser HP,Cisternas E,Wahl N,Ulrich S,Stadler A,Mescher H,Müller LR,Klinge T,Gabrys H,Burigo L,Mairani A,Ecker S,Ackermann B,Ellerbrock M,Parodi K,Jäkel O,Bangert M

更新日期：2017-06-01 00:00:00

abstract：:Results of an 18-alternative forced-choice experiment have shown that observers were capable of detecting a signal with a contrast of 1 in terms of 10-bit data which were displayed on a CRT monitor with an 8-bit video generator and a window width setting of 1024. We investigated the conditions under which 10-bit signa...

journal_title：Medical physics

authors： Giger ML,Ohara K,Doi K

更新日期：1986-05-01 00:00:00

abstract：:Variations in the atomic composition, and mass and electron densities of polystyrene and polymethylmethacrylate (PMM) plastics were assessed from experimentally determined mass attenuation coefficients for 125I and 137Cs gamma rays. The means and standard deviations in the mass densities of 16 samples of PMM and 10 sa...

journal_title：Medical physics

authors： Schulz RJ,Nath R

更新日期：1979-03-01 00:00:00

abstract：:An in vitro radiographic technique which uses saline/iodine displacement has been developed to study the thickness of bone-equivalent and soft-tissue-equivalent materials within atherosclerotic plaques in arterial specimens which have been cut open longitudinally and laid flat. Results concerning the optimization of t...

journal_title：Medical physics

authors： Moreau M,Holdsworth DW,Fenster A

更新日期：1997-01-01 00:00:00

abstract：:For the case of eye tumor therapy with protons, improvements are introduced compared to the standard dose calculation which implies straight-line optics and the constant-density assumption for the eye and its surrounding. The progress consists of (i) taking account of the lateral scattering of the protons in tissue by...

journal_title：Medical physics

authors： Rethfeldt C,Fuchs H,Gardey KU

更新日期：2006-03-01 00:00:00

abstract：PURPOSE:The collimator monitoring fill factor (CM-FF) introduced by Stelljes et al. (2017) and the FWHM fill factor (FWHM-FF) introduced by Gago-Arias et al. (2012) were determined using the measured photon fluence response functions of various 2D-arrays. The error detection capabilities of 2D-arrays were studied by co...

journal_title：Medical physics

authors： Stelljes TS,Poppinga D,Kretschmer J,Brodbek L,Looe HK,Poppe B

更新日期：2019-04-01 00:00:00

abstract：PURPOSE:The Alvarez-Macovski method extracts the x-ray energy-dependent information by expanding the attenuation coefficient as a linear combination of functions of energy multiplied by basis set coefficients. Since the basis functions are known a priori, the coefficients represent all the energy-dependent information....

journal_title：Medical physics

authors： Alvarez RE

更新日期：2019-01-01 00:00:00

abstract：:One limitation to the widespread implementation of Monte Carlo (MC) patient dose-calculation algorithms for radiotherapy is the lack of a general and accurate source model of the accelerator radiation source. Our aim in this work is to investigate the sensitivity of the photon-beam subsource distributions in a MC sour...

journal_title：Medical physics

authors： Fix MK,Keall PJ,Siebers JV

更新日期：2005-04-01 00:00:00

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 fo...

journal_title：Medical physics

authors： Borg J,Rogers DW

更新日期：1999-11-01 00:00:00

abstract：PURPOSE:The biologically effective dose (BED) of temporary brachytherapy treatments is a function of both chosen radionuclide (R) and implant duration (T). This study endeavored to evaluate BED delivered to the tumor volume and surrounding ocular structures as a function of plaque position (P), prescription dose, R, an...

journal_title：Medical physics

authors： Gagne N,Rivard M

更新日期：2012-06-01 00:00:00

abstract：:Recently, new imaging modalities based on the detection of weak phase perturbations effects, among which are phase contrast and diffraction imaging, have been developed by several researchers. Due to their high sensitivity to weakly absorbing details, these techniques seem to be very promising for applications in the ...

journal_title：Medical physics

authors： Olivo A,Arfelli F,Cantatore G,Longo R,Menk RH,Pani S,Prest M,Poropat P,Rigon L,Tromba G,Vallazza E,Castelli E

更新日期：2001-08-01 00:00:00

abstract：PURPOSE:A prototype in-house program was developed to assist deriving image guidance shifts clinically using our 4DCT method for lung SBRT. METHODS:Our in-house prototype program was implemented in MATLAB. The 4D DICOM CT dataset of interest is imported by the program from AW and subsequently accepts input from the us...

journal_title：Medical physics

authors： Wang B,Sarkar V,Busselberg C,Rassiah-Szegedi P,Zhao H,Huang Y,Szegedi M,Salter B

更新日期：2012-06-01 00:00:00

abstract：:Some limitations of conventional two-dimensional computer programs used to plan radiation therapy are presented. These include: a lack of involvement in defining the clinical problem; deficiencies in the algorithms for computing dose; failure to compute dose throughout the volume of interest; an inability to handle tr...

journal_title：Medical physics

authors： Goitein M

更新日期：1982-07-01 00:00:00

abstract：PURPOSE:Water equivalent diameter (WED) is the preferred surrogate for patient size in CT. It is better than geometric size surrogates and patient weight/height/BMI/age because it correlates the best with x-ray attenuation. The administration of oral/IV contrast agents increases a patient's attenuation and should there...

journal_title：Medical physics

authors： Viggiano B,Rose S,Szczykutowicz TP

更新日期：2021-01-13 00:00:00

abstract：PURPOSE:Scatter is a major factor degrading the image quality of cone beam computed tomography (CBCT). Conventional scatter correction strategies require handcrafted analytical models with ad hoc assumptions, which often leads to less accurate scatter removal. This study aims to develop an effective scatter correction ...

journal_title：Medical physics

authors： Nomura Y,Xu Q,Shirato H,Shimizu S,Xing L

更新日期：2019-07-01 00:00:00

abstract：PURPOSE:The aim of in vivo skin dosimetry was to measure the absorbed dose to the skin during radiotherapy, when treatment planning calculations cannot be relied on. It is of particularly importance in hypo-fractionated stereotactic modalities, where excessive dose can lead to severe skin toxicity. Currently, commercia...

journal_title：Medical physics

authors： Vicoroski N,Espinoza A,Duncan M,Oborn BM,Carolan M,Metcalfe P,Menichelli D,Perevertaylo VL,Lerch MLF,Rosenfeld AB,Petasecca M

更新日期：2017-10-01 00:00:00

abstract：PURPOSE:To investigate the dosimetric robustness of dynamically collimated proton therapy (DCPT) treatment plans delivered using a dynamic collimation system (DCS) with respect to random uncertainties in beam spot and collimator position as well as systematic offsets in the DCS mounting alignment. This work also demons...

journal_title：Medical physics

authors： Smith BR,Hyer DE,Culberson WS

更新日期：2020-08-01 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

authors： Vinci JP,Hogstrom KR,Neck DW

更新日期：2008-08-01 00:00:00

abstract：:We are developing a computer program for automated detection of clustered microcalcifications on mammograms. In this study, we investigated the effectiveness of a signal classifier based on a convolution neural network (CNN) approach for improvement of the accuracy of the detection program. Fifty-two mammograms with c...

journal_title：Medical physics

authors： Chan HP,Lo SC,Sahiner B,Lam KL,Helvie MA

更新日期：1995-10-01 00:00:00

abstract：:Tissue absorbed dose (D) is a computed result for internal emitters. For fixed geometries, D is calculated by a matrix (S) multiplication of the integrated activity vector (Ã). The last quantity is usually measured by nuclear imaging of activity in various source organs and performing a temporal integration. Ã is the ...

journal_title：Medical physics

authors： Williams L

更新日期：2012-06-01 00:00:00

abstract：:Assessment of clinic and site specific margins are essential for the effective use of three-dimensional and intensity modulated radiation therapy. An electronic portal imaging device (EPID) based methodology is introduced which allows individual and population based CTV-to-PTV margins to be determined and compared wit...

journal_title：Medical physics

authors： Prisciandaro JI,Frechette CM,Herman MG,Brown PD,Garces YI,Foote RL

更新日期：2004-11-01 00:00:00

abstract：:The use of the stable isotope 48Ca as a tracer in biological systems has been studied. Determination of 48Ca concentrations in samples was accomplished by proton activation via the (p,n) reaction with subsequent measurement of gamma-ray spectra from 44-h 48Sc and 4-h 44Sc. With protons of about 5.5 MeV and a Ge(Li) ga...

journal_title：Medical physics

authors： Edwards FM,Kraushaar JJ,Ristinen RA,Rudolph H

更新日期：1977-01-01 00:00:00

abstract：PURPOSE:To investigate the sensitivity of the plan-class specific correction factor to dose distributions in composite nonstandard field dosimetry. METHODS:A cylindrical water-filled PMMA phantom was constructed at the center of which reference absorbed dose could be measured. Ten different TomoTherapy(®)-based IMRT f...

journal_title：Medical physics

authors： Chung E,Soisson E,Seuntjens J

更新日期：2012-01-01 00:00:00

abstract：:We believe that, for the purpose of evaluation and optimization of treatment plans, quasirandom sampling is superior to grid sampling and should be the method of choice. We believe it to be on average more efficient than grid sampling (i.e., more accurate for any given number of dose estimates) and, even more importan...

journal_title：Medical physics

authors： Niemierko A,Goitein M

更新日期：1993-09-01 00:00:00

abstract：:Respiratory motion can produce misregistration errors between CT and PET images in cardiac PET/CT imaging. The objective of this study was to determine if manual registration of a single-phase end-expiration CT scan to the PET image would eliminate respiratory-induced artifacts. Listmode data from 71 cardiac PET patie...

journal_title：Medical physics

authors： Wells RG

更新日期：2008-07-01 00:00:00

abstract：:Deionized water is commonly used to couple microwave applicators to the patient surface in the administration of local hyperthermia. Profiles of the specific absorption rate (SAR) at 1-cm depth show that deionized water coupling significantly distorts the SAR distributions of the Clini-Therm 915-MHz 10 X 10 and 15 X 1...

journal_title：Medical physics

authors： Waterman FM,Nerlinger RE

更新日期：1986-05-01 00:00:00

abstract：:The concept of equivalent uniform dose (EUD) has been suggested as a means to quantitatively consider heterogeneous dose distributions within targets. Tumor cell density/function is typically assumed to be uniform. We herein propose to use 18F-labeled 2-deoxyglucose (FDG) positron emission tomography (PET) tumor imagi...

journal_title：Medical physics

authors： Zhou SM,Wong TZ,Marks LB

更新日期：2004-09-01 00:00:00

abstract：PURPOSE:The purpose of this study is to evaluate the performance of a recently developed benchtop dual cone-beam computed tomography (CBCT) system with two orthogonally placed tube∕detector sets. METHODS:The benchtop dual CBCT system consists of two orthogonally placed 40 × 30 cm flat-panel detectors and two conventio...

journal_title：Medical physics

authors： Li H,Giles W,Bowsher J,Yin FF

更新日期：2013-02-01 00:00:00

abstract：PURPOSE:This study developed and validated a Motion Artifact Quantification algorithm to automatically quantify the severity of motion artifacts on coronary computed tomography angiography (CCTA) images. The algorithm was then used to develop a Motion IQ Decision method to automatically identify whether a CCTA dataset ...

journal_title：Medical physics

authors： Ma H,Gros E,Baginski SG,Laste ZR,Kulkarni NM,Okerlund D,Schmidt TG

更新日期：2018-12-01 00:00:00

abstract：:An experiment to determine the peak of the energy spectrum of the photon beam from a Toshiba LMR-15 medical linear accelerator is described. It is found that the flattening filters removed much of the bremsstrahlung spectrum below approximately 1 MeV, resulting in a photon spectrum which peaks around 1.2 MeV. ...

journal_title：Medical physics

authors： Brownridge J,Samnick S,Stiles P,Tipton P,Veselka J,Yeh N

更新日期：1984-11-01 00:00:00