Abstract:
:Positron emission tomography is one of the most mature techniques for monitoring the particles range in hadron therapy, aiming to reduce treatment uncertainties and therefore the extent of safety margins in the treatment plan. In-beam PET monitoring has been already performed using inter-spill and post-irradiation data, i.e. while the particle beam is off or paused. The full beam acquisition procedure is commonly discarded because the particle spills abruptly increase the random coincidence rates and therefore the image noise. This is because random coincidences cannot be separated by annihilation photons originating from radioactive decays and cannot be corrected with standard random coincidence techniques due to the time correlation of the beam-induced background with the ion beam microstructure. The aim of this paper is to provide a new method to recover in-spill data to improve the images obtained with full-beam PET acquisitions. This is done by estimating the temporal microstructure of the beam and thus selecting input PET events that are less likely to be random ones. The PET detector we used was the one developed within the INSIDE project and tested at the CNAO synchrotron-based facility. The data were taken on a PMMA phantom irradiated with 72 MeV proton pencil beams. The obtained results confirm the possibility of improving the acquired PET data without any external signal coming from the synchrotron or ad hoc detectors.
journal_name
Phys Med Bioljournal_title
Physics in medicine and biologyauthors
Kostara E,Sportelli G,Belcari N,Camarlinghi N,Cerello P,Del Guerra A,Ferrero V,Fiorina E,Giraudo G,Morrocchi M,Pennazio F,Pullia M,Rivetti A,Rolo MD,Rosso V,Wheadon R,Bisogni MGdoi
10.1088/1361-6560/aafa28subject
Has Abstractpub_date
2019-01-21 00:00:00pages
035001issue
3eissn
0031-9155issn
1361-6560journal_volume
64pub_type
杂志文章abstract::A method is presented to predict beam profiles and outputs for wedged asymmetric fields defined by independent collimator jaws allowing fast generation of beam profiles whilst requiring very little additional data to that already used by most treatment planning systems in generating symmetric field isodoses. Symmetric...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/39/1/004
更新日期:1994-01-01 00:00:00
abstract::The feasibility of detecting gamma rays with energies below 1.5 MeV by means of a large-volume liquid-filled Cerenkov counter has been examined, together with the characteristics and limitations of an experimental counter. Various liquids (water, glycerol, sodium iodide solution; and glycerol plus a wavelength shifter...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/23/3/007
更新日期:1978-05-01 00:00:00
abstract::The radiation used in hadrontherapy treatments interacts with the patient body producing secondary particles, either neutral or charged, that can be used for dose and Bragg peak monitoring and to provide a fast feedback on the treatment plans. Recent results obtained from the authors on simplified setups (mono-energet...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/59/7/1857
更新日期:2014-04-07 00:00:00
abstract::This study introduces a practical four-dimensional (4D) planning scheme of IMAT using 4D computed tomography (4D CT) for planning tumor tracking with dynamic multileaf beam collimation. We assume that patients can breathe regularly, i.e. the same way as during 4D CT with an unchanged period and amplitude, and that the...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/1361-6560/aa56b7
更新日期:2017-02-21 00:00:00
abstract::The dielectric properties of glycerol, propylene glycol, ethylene glycol and dimethyl sulphoxide have been measured in various aqueous concentrations generally sufficient to allow supercooling rather than freezing. The temperature range investigated is from -80 degrees C to +20 degrees C and the frequency range is 100...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/41/10/014
更新日期:1996-10-01 00:00:00
abstract::Spectral x-ray imaging using novel photon counting x-ray detectors (PCDs) with energy resolving abilities is capable of providing energy-selective images. PCDs have energy thresholds, enabling the classification of photons into multiple energy bins. The extra energy information provided may allow materials such as iod...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/56/18/012
更新日期:2011-09-21 00:00:00
abstract::This paper describes end-to-end test procedures as the last fundamental step of medical commissioning before starting clinical operation of the MedAustron synchrotron-based pencil beam scanning (PBS) therapy facility with protons. One in-house homogeneous phantom and two anthropomorphic heterogeneous (head and pelvis)...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/1361-6560/aaac23
更新日期:2018-02-26 00:00:00
abstract::In modern radiotherapy, it is vitally important to monitor the performance of all linac components including the collimation system. In this study, a simple measurement method and accurate algorithm are introduced for investigation of the secondary and tertiary collimator sag during radiotherapy arc treatments. The me...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/57/12/N209
更新日期:2012-06-21 00:00:00
abstract::The measurement of beam data for dynamic wedge dosimetry requires the integration of radiation dose at points across the radiation field during the dose delivery. The different measurement techniques required when using a linear diode array to measure beam profiles and when using ionization chambers to measure depth d...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/40/3/005
更新日期:1995-03-01 00:00:00
abstract::Positron emission tomography (PET) has become an important modality in medical and molecular imaging. However, in most PET applications, the resolution is still mainly limited by the physical crystal sizes or the detector's intrinsic spatial resolution. To achieve images with better spatial resolution in a central reg...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/60/2/647
更新日期:2015-01-21 00:00:00
abstract::In the IAEA TRS-381 protocol, k(cel) and p(cel) account for the central electrode perturbation during the air kerma chamber calibration and the in-phantom measurements. The values of these correction factors are based mainly on Monte Carlo simulations. In the present work experimental data on k(cel) and p(cel) for the...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/44/5/315
更新日期:1999-05-01 00:00:00
abstract::Echocardiography (echo) is a widely available method to obtain images of the heart; however, echo can suffer due to the presence of artefacts, high noise and a restricted field of view. One method to overcome these limitations is to use multiple images, using the 'best' parts from each image to produce a higher qualit...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/56/18/020
更新日期:2011-09-21 00:00:00
abstract::Diffuse optical imaging using non-ionizing radiation is a non-invasive method that shows promise towards breast cancer diagnosis. Hand-held optical imagers show potential for clinical translation of the technology, yet they have not been used towards 3D tomography. Herein, 3D tomography of human breast tissue in vivo ...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/58/5/1563
更新日期:2013-03-07 00:00:00
abstract::The local noise property of a 3D PET reconstructed image is investigated for a uniform-activity sphere distributed in a constantly attenuating spherical object. The positional dependence of the statistical noise is approximately derived and calculated for some special cases. It is suggested that a larger diameter of t...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/42/1/015
更新日期:1997-01-01 00:00:00
abstract::Quantitative Yttrium-90 ((90)Y) bremsstrahlung single photon emission computed tomography (SPECT) imaging has shown great potential to provide reliable estimates of (90)Y activity distribution for targeted radionuclide therapy dosimetry applications. One factor that potentially affects the reliability of the activity ...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/57/12/3711
更新日期:2012-06-21 00:00:00
abstract::For renal dynamic studies, the COST B2 hybrid phantom is an example of an artificially created software phantom. Although this phantom is useful, it is not possible to implement the phantom in a self-consistent fashion to produce, for example, a collection of tracer in the bladder which is related to the flow from the...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/44/2/008
更新日期:1999-02-01 00:00:00
abstract::It was observed that the radiation output of x-ray tubes falls off exponentially during an exposure with a time constant of about 120 ms. The equilibrium value is approximately 15% lower than that at the beginning of the exposure. The clinically noticeable consequences are discrepancies in x-ray generator calibration,...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/25/2/004
更新日期:1980-03-01 00:00:00
abstract::In this study, the quantitative accuracy of different attenuation correction strategies presently available for the High Resolution Research Tomograph (HRRT) was investigated. These attenuation correction methods differ in reconstruction and processing (segmentation) algorithms used for generating a micro-image from m...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/53/1/007
更新日期:2008-01-07 00:00:00
abstract::We examine how the choice of CT x-ray beam filtration and phantom size influences patient dose (D) to computed tomography dose index (CTDI) conversion factors (i.e. D/CTDI). The ratio of head to body phantom CTDI(w) for a defined scan technique is alpha, and the ratio of organ dose when the body filter is changed to t...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/55/2/014
更新日期:2010-01-21 00:00:00
abstract::Monte Carlo-based simulation of positron emission tomography (PET) data plays a key role in the design and optimization of data correction and processing methods. Our first aim was to adapt and configure the PET-SORTEO Monte Carlo simulation program for the geometry of the widely distributed Inveon PET preclinical sca...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/58/19/6749
更新日期:2013-10-07 00:00:00
abstract::The influence of artefacts due to metal implants on the range of ion beams is investigated, using a geometrically well-defined head and pelvic phantom together with inserts from steel, titanium and tungsten. The ranges along various beam paths including artefacts were calculated from the TPS and compared to known calc...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/52/3/007
更新日期:2007-02-07 00:00:00
abstract::Heating induced near deep brain stimulation (DBS) lead electrodes during magnetic resonance imaging with a 3 T transceive head coil was measured, modeled, and imaged in three cadaveric porcine heads (mean body weight = 85.47 ± 3.19 kg, mean head weight = 5.78 ± 0.32 kg). The effect of the placement of the extra-crania...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/57/17/5651
更新日期:2012-09-07 00:00:00
abstract::A general theory is presented for minimizing noise in linear dimension reduction of sequences of medical images when the factors and the covariance matrix and mean of the noise are given. A dimension reduction is optimal when all diagonal elements in the covariance matrix of the noise in the signal (factor) space are ...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/40/11/010
更新日期:1995-11-01 00:00:00
abstract::A silicon semiconductor photodiode was used to measure the TL-signal of TLD-300 (CaF2:Tm) detectors irradiated with 60Co gamma rays and 226Ra alpha particles. The applied dose values varied from 0.12 to 14.3 Gy for gamma rays and from about 50 to 300 Gy for alpha particles. Because of the infrared sensitivity of the p...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/33/12/006
更新日期:1988-12-01 00:00:00
abstract::A radiofrequency and field-gradient pulse sequence is presented permitting the non-invasive, volume-selective and spectroscopically resolved determination of incoherent transport parameters with the aid of an NMR field-gradient method. With proton NMR, diffusion or (quasi-incoherent) perfusion coefficients as low as 1...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/35/1/007
更新日期:1990-01-01 00:00:00
abstract::Multileaf collimator (MLC) calibration and quality control is a time-consuming procedure typically involving the processing, scanning and analysis of films to measure leaf and collimator positions. Faster and more reliable calibration procedures are required for these tasks, especially with the introduction of intensi...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/50/7/003
更新日期:2005-04-07 00:00:00
abstract::This work studies the effect of age on lung dose commitments arising from the inhalation of an atmosphere containing radionuclides of varying half-lives and physical sizes. This dependence is significant in many cases, approaching a ratio of 2 in several instances when the maximum dose at a given age is compared with ...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/27/4/005
更新日期:1982-04-01 00:00:00
abstract::Segmented attenuation correction is now a widely accepted technique to reduce noise propagation from transmission scanning in positron emission tomography (PET). In this paper, we present a new method for segmenting transmission images in whole-body scanning. This reduces the noise in the correction maps while still c...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/47/7/310
更新日期:2002-04-07 00:00:00
abstract::In modern radiotherapy the verification of complex treatments plans is often performed in inhomogeneous or even anthropomorphic phantoms. For dose verification small detectors are necessary and therefore alanine detectors are most suitable. Though the response of alanine for a wide range of clinical photon energies in...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/61/3/N70
更新日期:2016-02-07 00:00:00
abstract::Advanced radiotherapeutical techniques like intensity-modulated radiation therapy (IMRT) are based on an accurate knowledge of the location of the radiation target. An accurate dose delivery, therefore, requires a method to account for the inter- and intrafractional target motion and the target deformation occurring d...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/52/22/N01
更新日期:2007-11-21 00:00:00