The use of a diode matrix in commissioning activities for electron energies > or = 9 MeV: a feasibility study.

abstract：PURPOSE:Dose verification in highly conformal radiation therapy such as IMRT or proton therapy can benefit from the high spatial resolution offered by radio-chromic films such as Gafchromic EBT or EBT2. Recently, a new generation of these films, EBT3, has become available. The composition and thickness of the sensitive...

journal_title：Medical physics

authors： Reinhardt S,Hillbrand M,Wilkens JJ,Assmann W

更新日期：2012-08-01 00:00:00

abstract：PURPOSE:Developed herein is a three-dimensional (3D) flow contrast imaging system leveraging advancements in the extension of laser speckle contrast imaging theories to deep tissues along with our recently developed finite-element diffuse correlation tomography (DCT) reconstruction scheme. This technique, termed speckl...

journal_title：Medical physics

authors： Huang C,Irwin D,Lin Y,Shang Y,He L,Kong W,Luo J,Yu G

更新日期：2015-07-01 00:00:00

abstract：PURPOSE:Lower radiation tolerance of the whole liver hinders dose escalations of stereotactic body radiation therapy (SBRT) in hepatocellular carcinoma (HCC) treatment. This study was conducted to define the exact doses that result in radiation-induced liver disease (RILD) as well as to determine dose constraints for t...

journal_title：Medical physics

authors： Wu ZF,Zhang JY,Shen XY,Zhou LY,Gao YB,Hu Y,Zeng ZC

更新日期：2016-07-01 00:00:00

abstract：:In patients with lymphoma, identification and quantification of the tumor extent on serial CT examinations is critical for assessing tumor response to therapy. In this paper, we present a computer method to automatically match and segment lymphomas in follow-up CT images. The method requires that target lymph nodes in...

journal_title：Medical physics

authors： Yan J,Zhao B,Curran S,Zelenetz A,Schwartz LH

更新日期：2007-01-01 00:00:00

abstract：PURPOSE:To quantify detector perturbation effects in megavoltage small photon fields and support the theoretical explanation on the nature of quality correction factors in these conditions. METHODS:In this second paper, a modern approach to radiation dosimetry is defined for any detector and applied to small photon fi...

journal_title：Medical physics

authors： Bouchard H,Kamio Y,Palmans H,Seuntjens J,Duane S

更新日期：2015-10-01 00:00:00

abstract：:Positron emission tomography (PET) is increasingly considered as an effective imaging method to support several stages of radiation therapy. The combined usage of functional and morphological imaging in state-of-the-art PET/CT scanners is rapidly emerging to support the treatment planning process in terms of improved ...

journal_title：Medical physics

authors： Parodi K

更新日期：2015-12-01 00:00:00

abstract：:The bremsstrahlung spectrum from an 8-MeV linear accelerator has been measured using a NaI(T1) spectrometer system. The spectrum shows a low-energy cutoff at 0.4 MeV and the maximum photon energy to be approximately 6% greater than the nominal energy. The maximum emission of energy fluence was 1.6 and 1.8 MeV for meas...

journal_title：Medical physics

authors： Levy LB,Waggener RG,Wright AE

更新日期：1976-05-01 00:00:00

abstract：:A method is developed to smooth intensity-modulated beam delivery while considering hardware constraints. The method uses matrix algebra to model MLC leaf motion and hardware constraints such as interleaf digitization, synchronization requirements, and intersegment field abutment to deliver intensity modulated beam se...

journal_title：Medical physics

authors： Ma L

更新日期：2002-12-01 00:00:00

abstract：PURPOSE:To investigate image-registration errors when using fiducial markers with a manual method and the point-based rigid-body registration (PRBR) algorithm in accelerated partial breast irradiation (APBI) patients, with accompanying fiducial deviations. METHODS:Twenty-two consecutive patients were enrolled in a pro...

journal_title：Medical physics

authors： Inoue M,Yoshimura M,Sato S,Nakamura M,Yamada M,Hirata K,Sasaki M,Fujimoto T,Ogura M,Hiraoka M

更新日期：2015-04-01 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：:Hyperthermia, as an adjuvant with radiation and chemotherapy, has shown promise in the treatment of cancer. The relevant biological effects of a hyperthermia treatment are both time and temperature-dependent, creating a need for accurate thermometry. We present a novel noninvasive thermometry modality that combines a ...

journal_title：Medical physics

authors： Dreher MR,Elas M,Ichikawa K,Barth ED,Chilkoti A,Rosen GM,Halpern HJ,Dewhirst M

更新日期：2004-10-01 00:00:00

abstract：PURPOSE:To characterize a new air vented ionization chamber technology, suitable to build detector arrays with small pixel pitch and independence of sensitivity on dose per pulse. METHODS:The prototype under test is a linear array of air vented ionization chambers, consisting of 80 pixels with 3.5 mm pixel pitch dista...

journal_title：Medical physics

authors： Togno M,Wilkens JJ,Menichelli D,Oechsner M,Perez-Andujar A,Morin O

更新日期：2016-05-01 00:00:00

abstract：PURPOSE:The image quality of dedicated cone beam breast CT (CBBCT) is limited by substantial scatter contamination, resulting in cupping artifacts and contrast-loss in reconstructed images. Such effects obscure the visibility of soft-tissue lesions and calcifications, which hinders breast cancer detection and diagnosis...

journal_title：Medical physics

authors： Shi L,Vedantham S,Karellas A,Zhu L

更新日期：2016-08-01 00:00:00

abstract：PURPOSE:Flattening filters (FFs) have been considered as an integral part of the treatment head of a medical accelerator for more than 50 years. The reasons for the longstanding use are, however, historical ones. Advanced treatment techniques, such as stereotactic radiotherapy or intensity modulated radiotherapy have s...

journal_title：Medical physics

authors： Georg D,Knöös T,McClean B

更新日期：2011-03-01 00:00:00

abstract：PURPOSE:One technical barrier to patient-specific computed tomography (CT) dosimetry has been the lack of computational tools for the automatic patient-specific multi-organ segmentation of CT images and rapid organ dose quantification. When previous CT images are available for the same body region of the patient, the a...

journal_title：Medical physics

authors： Peng Z,Fang X,Yan P,Shan H,Liu T,Pei X,Wang G,Liu B,Kalra MK,Xu XG

更新日期：2020-06-01 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

authors： Anderson LL

更新日期：1976-01-01 00:00:00

abstract：:To more accurately and precisely delineate a tumor in a 3D PET image, we proposed a novel, semi-automatic, two-stage method by utilizing an adaptive region-growing algorithm and a dual-front active contour model. First, a rough region of interest (ROI) is manually drawn by a radiation oncologist that encloses a tumor....

journal_title：Medical physics

authors： Li H,Thorstad WL,Biehl KJ,Laforest R,Su Y,Shoghi KI,Donnelly ED,Low DA,Lu W

更新日期：2008-08-01 00:00:00

abstract：PURPOSE:Intraoperative electron radiation therapy (IOERT) involves the delivery of a high radiation dose during tumor resection in a shorter time than other radiation techniques, thus improving local control of tumors. However, a linear accelerator device is needed to produce the beam safely. Mobile linear accelerators...

journal_title：Medical physics

authors： Marinetto E,Victores JG,García-Sevilla M,Muñoz M,Calvo FÁ,Balaguer C,Desco M,Pascau J

更新日期：2017-10-01 00:00:00

abstract：PURPOSE:To evaluate the dose distribution of a 120-MeV laser-plasma accelerated electron beam which may be of potential interest for high-energy electron radiation therapy. METHODS:In the interaction between an intense laser pulse and a helium gas jet, a well collimated electron beam with very high energy is produced....

journal_title：Medical physics

authors： Lundh O,Rechatin C,Faure J,Ben-Ismaïl A,Lim J,De Wagter C,De Neve W,Malka V

更新日期：2012-06-01 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

authors： Chen QS,Russell JL Jr,Macklis RR,Weinhous MS,Blair HF

更新日期：2006-07-01 00:00:00

abstract：PURPOSE:To develop and validate a multivariate statistical method to optimize scanning parameters for material quantification in spectral x-rayimaging. METHODS:An optimization metric was constructed by extensively sampling the thickness space for the expected number of counts for m (two or three) materials. This resul...

journal_title：Medical physics

authors： Nik SJ,Thing RS,Watts R,Meyer J

更新日期：2012-06-01 00:00:00

abstract：:Electron spectral reconstruction of medical accelerators from measured depth doses is a practical method for providing the input initial phase space distribution at the patient surface that is required by Monte Carlo treatment planning systems. The posed inverse problem of spectral reconstruction is ill conditioned an...

journal_title：Medical physics

authors： Wei J,Sandison GA,Chvetsov AV

更新日期：2006-02-01 00:00:00

abstract：PURPOSE:Experimental dosimetry of high-dose-rate (HDR) 192 Ir brachytherapy (BT) sources is complicated due to high dose and dose-rate gradients, and softening of photon energy spectrum with depth. A single crystal synthetic diamond detector microDiamond (PTW 60019, Freiburg, Germany) has a small active volume, high se...

journal_title：Medical physics

authors： Kaveckyte V,Malusek A,Benmakhlouf H,Alm Carlsson G,Carlsson Tedgren Å

更新日期：2018-01-01 00:00:00

abstract：PURPOSE:To provide a cascaded-systems framework based on the noise-power spectrum (NPS), modulation transfer function (MTF), and noise-equivalent number of quanta (NEQ) for quantitative evaluation of differential phase-contrast imaging (Talbot interferometry) in relation to conventional absorption contrast under equal-...

journal_title：Medical physics

authors： Fredenberg E,Danielsson M,Stayman JW,Siewerdsen JH,Aslund M

更新日期：2012-09-01 00:00:00

abstract：PURPOSE:Timely identification of systematic changes in radiation delivery of an imaging system can lead to a reduction in risk for the patients involved. However, existing quality assurance programs involving the routine testing of equipment performance using phantoms are limited in their ability to effectively carry o...

journal_title：Medical physics

authors： Stevens NT,Steiner SH,Smith IR,MacKay RJ

更新日期：2011-01-01 00:00:00

abstract：:Transthoracic electrical impedance Z consists of a constant baseline component Z0 and the time variable component delta Z such that Z = Z0 + delta Z. The first time derivative of Z has a negative peak, the magnitude of which is (dZ/dt)min. Measurements of 170 volunteers show that (dZ/dt)min is a function of the consta...

journal_title：Medical physics

authors： Djordjevich L,Sadove MS

更新日期：1981-01-01 00:00:00

abstract：:In this paper we examine the few-view reconstruction problem as it applies to imaging vascular trees. A fully automated reconstruction algorithm is described that circumvents the traditional "correspondence problem," using only notions of consistency and connectivity. It is assumed that the vascular tree is a connecte...

journal_title：Medical physics

authors： Henri CJ,Peters TM

更新日期：1996-02-01 00:00:00

abstract：:Computer-aided diagnosis (CAD) has been a major field of research for the past few decades. CAD uses machine learning methods to analyze imaging and/or nonimaging patient data and makes assessment of the patient's condition, which can then be used to assist clinicians in their decision-making process. The recent succe...

journal_title：Medical physics

authors： Chan HP,Hadjiiski LM,Samala RK

更新日期：2020-06-01 00:00:00

abstract：:This paper proposes a new respiratory gated radiation treatment system that allows real-time tumor localization while avoiding invasive operation to a patient. The proposed system employs a three-dimensional (3D) ultrasound device, a 3D digital localizer, and a real-time image processing system. At the planning time, ...

journal_title：Medical physics

authors： Sawada A,Yoda K,Kokubo M,Kunieda T,Nagata Y,Hiraoka M

更新日期：2004-02-01 00:00:00

abstract：:Projected light fields are used on treatment simulators and teletherapy treatment units to delineate the size and position of the radiation beam. Any discrepancy between these fields will lead to a systematic field placement error, with possibly serious implications with regard to the accuracy of the delivered dose di...

journal_title：Medical physics

authors： Luchka K,Chen D,Shalev S,Gluhchev G,Rajapakshe R

更新日期：1996-07-01 00:00:00