Experimental characterization of two-dimensional pencil beam scanning proton spot profiles.


:Dose calculations of pencil beam scanning treatment plans rely on the accuracy of proton spot profiles; not only the primary component but also the broad tail components. Four films are placed at several locations in air and multiple depths in Solidwater® for six selected energies. The films used for the primary components are exposed to 50-200 MU to avoid saturation; the films used for the tail components are exposed to 800, 8000 and 80,000 MU. By applying a pair/magnification method and merging these data, dose kernels down to 10(-4) of the central spot dose can be generated. From these kernels one can calculate the dose-per-MU for different field sizes and shapes. Measurements agree within 1% of dose-kernel-based calculations for output versus field size comparisons. Asymmetric, comet-shaped profile tails have a bigger impact at superficial depths and low energies: the output difference between two orientations at the surface of a rectangular field of 40 mm×200 mm is about 2% at the isocentre at 100 MeV. Integration of these dose kernels from 0 to 40 mm radius shows that the charge deficit in the Bragg peak chamber varies <2% from entrance to the end of range for energies <180 MeV, but exceeds 5% at 225 MeV.


Phys Med Biol


Lin L,Ainsley CG,McDonough JE




Has Abstract


2013-09-07 00:00:00












  • Hybrid scatter correction applied to quantitative holmium-166 SPECT.

    abstract::Ho-166 is a combined beta-gamma emitter of which the betas can be used therapeutically. From the 81 keV gammas of Ho-166, SPECT images can be obtained, which give opportunities to guide Ho-166 therapy. Accurate reconstruction of Ho-166 images is currently hampered by photopeak-scatter in the patient, down-scatter in t...

    journal_title:Physics in medicine and biology

    pub_type: 杂志文章


    authors: de Wit TC,Xiao J,Nijsen JF,van het Schip FD,Staelens SG,van Rijk PP,Beekman FJ

    更新日期:2006-10-07 00:00:00

  • Dosimetry for the MRI accelerator: the impact of a magnetic field on the response of a Farmer NE2571 ionization chamber.

    abstract::The UMC Utrecht is constructing a 1.5 T MRI scanner integrated with a linear accelerator (Lagendijk et al 2008 Radiother. Oncol. 86 25-9). The goal of this device is to facilitate soft-tissue contrast based image-guided radiotherapy, in order to escalate the dose to the tumour while sparing surrounding normal tissues....

    journal_title:Physics in medicine and biology

    pub_type: 杂志文章


    authors: Meijsing I,Raaymakers BW,Raaijmakers AJ,Kok JG,Hogeweg L,Liu B,Lagendijk JJ

    更新日期:2009-05-21 00:00:00

  • Coupled thermo-electro-mechanical models for thermal ablation of biological tissues and heat relaxation time effects.

    abstract::Thermal ablation is a widely applied electrosurgical process in medical treatment of soft biological tissues. Numerical modeling and simulations play an important role in prediction of temperature distribution and damage volume during the treatment planning stage of associated therapies. In this contribution we report...

    journal_title:Physics in medicine and biology

    pub_type: 杂志文章


    authors: Singh S,Melnik R

    更新日期:2019-12-13 00:00:00

  • Near real-time automated dose restoration in IMPT to compensate for daily tissue density variations in prostate cancer.

    abstract::Proton therapy is very sensitive to daily density changes along the pencil beam paths. The purpose of this study is to develop and evaluate an automated method for adaptation of IMPT plans to compensate for these daily tissue density variations. A two-step restoration method for 'densities-of-the-day' was created: (1)...

    journal_title:Physics in medicine and biology

    pub_type: 杂志文章


    authors: Jagt T,Breedveld S,van de Water S,Heijmen B,Hoogeman M

    更新日期:2017-06-07 00:00:00

  • Photon quality correction factors for ionization chambers in an epithermal neutron beam.

    abstract::Photon quality correction factors (kQy) for ionization chamber photon dosimetry in an epithermal neutron beam were determined according to a modified absorbed dose to water formalism which was extended to mixed radiation fields. We have studied two commercially available ionization chambers in the epithermal neutron b...

    journal_title:Physics in medicine and biology

    pub_type: 杂志文章


    authors: Munck af Rosenschöld PM,Ceberg CP,Giusti V,Andreo P

    更新日期:2002-07-21 00:00:00

  • Front-illuminated versus back-illuminated photon-counting CCD-based gamma camera: important consequences for spatial resolution and energy resolution.

    abstract::Charge-coupled devices (CCDs) coupled to scintillation crystals can be used for high-resolution imaging with x-rays and gamma rays. When the CCD images can be read out fast enough, the energy and interaction position of individual gamma quanta can be estimated by a real-time image analysis of the scintillation light f...

    journal_title:Physics in medicine and biology

    pub_type: 杂志文章


    authors: Heemskerk JW,Westra AH,Linotte PM,Ligtvoet KM,Zbijewski W,Beekman FJ

    更新日期:2007-04-21 00:00:00

  • Direct determination of cone-beam geometric parameters using the helical phantom.

    abstract::Estimation of a set of parameters that describe the geometry of the cone-beam computed tomography system plays an important role in the geometrical calibration. In the calibration process, the helical phantom consisting of spherical markers arranged on a helical trajectory has been widely applied. To directly determin...

    journal_title:Physics in medicine and biology

    pub_type: 杂志文章


    authors: Xu M,Zhang C,Liu X,Li D

    更新日期:2014-10-07 00:00:00

  • Fundamental study on diffuse reflective optical tomography.

    abstract::We report a simulation study on diffuse reflective optical computed tomography, in which continuous-wave sources and detectors are placed on the plane surface of a semi-infinite body. We adopted a simple Tikhonov regularization in the inverse problem and demonstrated the feasibility of three-dimensional reconstruction...

    journal_title:Physics in medicine and biology

    pub_type: 杂志文章


    authors: Endoh R,Suzuki A,Fujii M,Nakayama K

    更新日期:2004-05-21 00:00:00

  • Diagnostic imaging over the last 50 years: research and development in medical imaging science and technology.

    abstract::Over the last 50 years, diagnostic imaging has grown from a state of infancy to a high level of maturity. Many new imaging modalities have been developed. However, modern medical imaging includes not only image production but also image processing, computer-aided diagnosis (CAD), image recording and storage, and image...

    journal_title:Physics in medicine and biology

    pub_type: 杂志文章,评审


    authors: Doi K

    更新日期:2006-07-07 00:00:00

  • Glandular dose in breast computed tomography with synchrotron radiation.

    abstract::The purpose of this work is to provide an evaluation of the mean glandular dose (MGD) for breast computed tomography (CT) with synchrotron radiation in an axial scanning configuration with a partial or total organ volume irradiation, for the in vivo program of breast CT ongoing at the ELETTRA facility (Trieste, Italy)...

    journal_title:Physics in medicine and biology

    pub_type: 杂志文章


    authors: Mettivier G,Fedon C,Di Lillo F,Longo R,Sarno A,Tromba G,Russo P

    更新日期:2016-01-21 00:00:00

  • Scheduling cisplatin and radiotherapy in the treatment of squamous cell carcinomas of the head and neck: a modelling approach.

    abstract::The aim of the present work was to implement the kinetics of cisplatin into a previously developed tumour growth model and to simulate the combined cisplatin-radiotherapy treatment with the emphasis on time sequencing and scheduling of drug and radiation. An investigation into whether the effect of cisplatin-radiation...

    journal_title:Physics in medicine and biology

    pub_type: 杂志文章


    authors: Marcu L,Bezak E,Olver I

    更新日期:2006-08-07 00:00:00

  • Dosimetry of biological irradiations using radiochromic films.

    abstract::Delivering accurate radiation dose to blood specimens during biological irradiations is essential in quantifying damage of ionizing radiation. To estimate dose to blood samples as accurately as possible, pieces of EBT2 model GAFCHROMIC™ film were placed within an approximately 10 mm finely ground rice layer that was u...

    journal_title:Physics in medicine and biology

    pub_type: 杂志文章


    authors: Aldelaijan S,Nobah A,Alsbeih G,Moftah B,Aldahlawi I,Alzahrany A,Tomic N,Devic S

    更新日期:2013-05-21 00:00:00

  • A modular Geant4 model of Leksell Gamma Knife Perfexion™.

    abstract::This work presents a Monte Carlo model of Leksell Gamma Knife Perfexion as well as the main parameters of the dose distribution in the standard phantom obtained using this model. The model is developed in the Geant4 simulation toolkit in a modular way which enables its reuse in other Perfexion studies. Large phase spa...

    journal_title:Physics in medicine and biology

    pub_type: 杂志文章


    authors: Pipek J,Novotný J,Novotný J,Kozubíková P

    更新日期:2014-12-21 00:00:00

  • Sensitivity of different dose scoring methods on organ-specific neutron dose calculations in proton therapy.

    abstract::Scattered doses, e.g. neutron doses in proton therapy, are of concern in radiation therapy. Although measured data are the gold standard, Monte Carlo simulations allow a more realistic consideration of patient anatomy via whole-body phantoms. When calculating neutron doses with Monte Carlo techniques, the dose can be ...

    journal_title:Physics in medicine and biology

    pub_type: 杂志文章


    authors: Jarlskog CZ,Paganetti H

    更新日期:2008-09-07 00:00:00

  • Measurement of cone beam CT coincidence with megavoltage isocentre and image sharpness using the QUASAR Penta-Guide phantom.

    abstract::For image-guided radiotherapy (IGRT) systems based on cone beam CT (CBCT) integrated into a linear accelerator, the reproducible alignment of imager to x-ray source is critical to the registration of both the x-ray-volumetric image with the megavoltage (MV) beam isocentre and image sharpness. An enhanced method of det...

    journal_title:Physics in medicine and biology

    pub_type: 杂志文章


    authors: Sykes JR,Lindsay R,Dean CJ,Brettle DS,Magee DR,Thwaites DI

    更新日期:2008-10-07 00:00:00

  • Systematic investigation of the signal properties of polycrystalline HgI2 detectors under mammographic, radiographic, fluoroscopic and radiotherapy irradiation conditions.

    abstract::The signal properties of polycrystalline mercuric iodide (HgI2) film detectors, under irradiation conditions relevant to mammographic, radiographic, fluoroscopic and radiotherapy x-ray imaging, are reported. Each film detector consists of an approximately 230 to approximately 460 microm thick layer of HgI2 (fabricated...

    journal_title:Physics in medicine and biology

    pub_type: 杂志文章


    authors: Su Z,Antonuk LE,El-Mohri Y,Hu L,Du H,Sawant A,Li Y,Wang Y,Yamamoto J,Zhao Q

    更新日期:2005-06-21 00:00:00

  • Inverse planning for functional image-guided intensity-modulated radiation therapy.

    abstract::Radiation therapy is an image-guided process whose success critically depends on the imaging modality used for treatment planning and the level of integration of the available imaging information. In this work, we establish a dose optimization framework for incorporating metabolic information from functional imaging m...

    journal_title:Physics in medicine and biology

    pub_type: 杂志文章


    authors: Xing L,Cotrutz C,Hunjan S,Boyer AL,Adalsteinsson E,Spielman D

    更新日期:2002-10-21 00:00:00

  • High-energy x-ray Talbot-Lau radiography of a human knee.

    abstract::We report on a radiographic measurement of an ex vivo human knee using a grating-based phase-contrast imaging setup and a medical x-ray tube at a tube voltage of 70 kV. The measurement has been carried out using a Talbot-Lau setup that is suitable to achieve a high visibility in the energy regime of medical imaging. I...

    journal_title:Physics in medicine and biology

    pub_type: 杂志文章


    authors: Horn F,Gelse K,Jabari S,Hauke C,Kaeppler S,Ludwig V,Meyer P,Michel T,Mohr J,Pelzer G,Rieger J,Riess C,Seifert M,Anton G

    更新日期:2017-08-01 00:00:00

  • Automated detection of clustered microcalcifications on mammograms: CAD system application to MIAS database.

    abstract::To investigate the detection performance of our automated detection scheme for clustered microcalcifications on mammograms, we applied our computer-aided diagnosis (CAD) system to the database of the Mammographic Image Analysis Society (MIAS) in the UK. Forty-three mammograms from this database were used in this study...

    journal_title:Physics in medicine and biology

    pub_type: 杂志文章


    authors: Ibrahim N,Fujita H,Hara T,Endo T

    更新日期:1997-12-01 00:00:00

  • Synchrotron microangiography with no contrast agent.

    abstract::Coherent x-rays from synchrotron sources are increasingly used in non-conventional radiological techniques ('phase-contrast' radiology). Our experiments demonstrate that by using white (unmonochromatic) radiation and a time-resolving system, it is possible to image microscopic details of moving blood vessels in differ...

    journal_title:Physics in medicine and biology

    pub_type: 杂志文章


    authors: Hwu Y,Tsai WL,Je JH,Seol SK,Kim B,Groso A,Margaritondo G,Lee KH,Seong JK

    更新日期:2004-02-21 00:00:00

  • Role of skin tissue layers and ultra-structure in transcutaneous electrical stimulation including tDCS.

    abstract:BACKGROUND:During transcranial electrical stimulation (tES), including transcranial direct current stimulation (tDCS) and transcranial alternating current stimulation (tACS), current density concentration around the electrode edges that is predicted by simplistic skin models does not match experimental observations of ...

    journal_title:Physics in medicine and biology

    pub_type: 杂志文章


    authors: Khadka N,Bikson M

    更新日期:2020-09-11 00:00:00

  • Measuring optical temperature coefficients of Intralipid.

    abstract::The temperature sensitivities of absorption and reduced scattering coefficients in the range 700-1000 nm are determined for the liquid phantom Intralipid using spatially resolved continuous wave measurements. The measurements were conducted on a 10 L heated volume of 1% Intralipid subjected to a 40-30 degrees C coolin...

    journal_title:Physics in medicine and biology

    pub_type: 杂志文章


    authors: McGlone VA,Martinsen P,Künnemeyer R,Jordan B,Cletus B

    更新日期:2007-05-07 00:00:00

  • NTCP modelling and pulmonary function tests evaluation for the prediction of radiation induced pneumonitis in non-small-cell lung cancer radiotherapy.

    abstract::This work aims to evaluate the predictive strength of the relative seriality, parallel and Lyman-Kutcher-Burman (LKB) normal tissue complication probability (NTCP) models regarding the incidence of radiation pneumonitis (RP), in a group of patients following lung cancer radiotherapy and also to examine their correlati...

    journal_title:Physics in medicine and biology

    pub_type: 杂志文章


    authors: Tsougos I,Nilsson P,Theodorou K,Kjellén E,Ewers SB,Jarlman O,Lind BK,Kappas C,Mavroidis P

    更新日期:2007-02-21 00:00:00

  • Wavelet compression in medical terahertz pulsed imaging.

    abstract::This paper concerns the robustness of discrete wavelet transform (DWT) compression in terahertz pulsed imaging (TPI). TPI datasets consist of terahertz time-domain series which are sampled at each 'pixel' of the image, leading to file sizes which are typically of the order of several megabytes (MB) per image. This mak...

    journal_title:Physics in medicine and biology

    pub_type: 杂志文章


    authors: Handley JW,Fitzgerald AJ,Berry E,Boyle RD

    更新日期:2002-11-07 00:00:00

  • Characterization of a single LSO crystal layer high resolution research tomograph.

    abstract::The purpose of this study was to determine the performance of a single lutetium oxy-orthosilicate (LSO) crystal layer High Resolution Research Tomograph (HRRT) positron emission tomography (PET) scanner. The HRRT is a high resolution PET scanner designed for human brain and small animal imaging. The scanner consists o...

    journal_title:Physics in medicine and biology

    pub_type: 杂志文章


    authors: Boellaard R,Buijs F,de Jong HW,Lenox M,Gremillion T,Lammertsma AA

    更新日期:2003-02-21 00:00:00

  • The noise power spectrum of CT images.

    abstract::An expression for the noise power spectrum of images reconstructed by the discrete filtered backprojection algorithm has been derived. The formulation explicitly includes sampling within the projections, angular sampling, and the two-dimensional sampling implicit in the discrete representation of the image. The effect...

    journal_title:Physics in medicine and biology

    pub_type: 杂志文章


    authors: Kijewski MF,Judy PF

    更新日期:1987-05-01 00:00:00

  • Calculation of 10 MV x-ray spectra emitted by a medical linear accelerator using the BFGS quasi-Newton method.

    abstract::To calculate photon spectra for a 10 MV x-ray beam emitted by a medical linear accelerator, we performed numerical analysis using the aluminium transmission data obtained along the central axis of the beam under the narrow beam condition corresponding to a 3x3 cm2 field at a 100 cm distance from the source. We used th...

    journal_title:Physics in medicine and biology

    pub_type: 杂志文章


    authors: Shimozato T,Tabushi K,Kitoh S,Shiota Y,Hirayama C,Suzuki S

    更新日期:2007-01-21 00:00:00

  • Single and multiple cross sections for ionizing processes of biological molecules by protons and alpha-particle impact: a classical Monte Carlo approach.

    abstract::A classical trajectory model has been used to predict total cross sections of single and double ionizing processes (including capture processes) for several ion-biological molecule collisional systems in the intermediate and high energy range. In this work, the systems studied are water, adenine or cytosine targets io...

    journal_title:Physics in medicine and biology

    pub_type: 杂志文章


    authors: Abbas I,Champion C,Zarour B,Lasri B,Hanssen J

    更新日期:2008-02-21 00:00:00

  • In-bore setup and software for 3T MRI-guided transperineal prostate biopsy.

    abstract::MRI-guided prostate biopsy in conventional closed-bore scanners requires transferring the patient outside the bore during needle insertion due to the constrained in-bore space, causing a safety hazard and limiting image feedback. To address this issue, we present our custom-made in-bore setup and software to support M...

    journal_title:Physics in medicine and biology

    pub_type: 杂志文章


    authors: Tokuda J,Tuncali K,Iordachita I,Song SE,Fedorov A,Oguro S,Lasso A,Fennessy FM,Tempany CM,Hata N

    更新日期:2012-09-21 00:00:00

  • Truncation artifact suppression in cone-beam radionuclide transmission CT using maximum likelihood techniques: evaluation with human subjects.

    abstract::Transverse image truncation can be a serious problem for human imaging using cone-beam transmission CT (CB-CT) implemented on a conventional rotating gamma camera. If this problem can be solved, CB-CT will be useful for attenuation compensation of SPECT images. This paper presents a reconstruction method to reduce or ...

    journal_title:Physics in medicine and biology

    pub_type: 杂志文章


    authors: Manglos SH

    更新日期:1992-03-01 00:00:00