Influence of cold walls on PET image quantification and volume segmentation: a phantom study.


PURPOSE:Commercially available fillable plastic inserts used in positron emission tomography phantoms usually have thick plastic walls, separating their content from the background activity. These "cold" walls can modify the intensity values of neighboring active regions due to the partial volume effect, resulting in errors in the estimation of standardized uptake values. Numerous papers suggest that this is an issue for phantom work simulating tumor tissue, quality control, and calibration work. This study aims to investigate the influence of the cold plastic wall thickness on the quantification of 18F-fluorodeoxyglucose on the image activity recovery and on the performance of advanced automatic segmentation algorithms for the delineation of active regions delimited by plastic walls. METHODS:A commercial set of six spheres of different diameters was replicated using a manufacturing technique which achieves a reduction in plastic walls thickness of up to 90%, while keeping the same internal volume. Both sets of thin- and thick-wall inserts were imaged simultaneously in a custom phantom for six different tumor-to-background ratios. Intensity values were compared in terms of mean and maximum standardized uptake values (SUVs) in the spheres and mean SUV of the hottest 1 ml region (SUVmax, SUVmean, and SUVpeak). The recovery coefficient (RC) was also derived for each sphere. The results were compared against the values predicted by a theoretical model of the PET-intensity profiles for the same tumor-to-background ratios (TBRs), sphere sizes, and wall thicknesses. In addition, ten automatic segmentation methods, written in house, were applied to both thin- and thick-wall inserts. The contours obtained were compared to computed tomography derived gold standard ("ground truth"), using five different accuracy metrics. RESULTS:The authors' results showed that thin-wall inserts achieved significantly higher SUVmean, SUVmax, and RC values (up to 25%, 16%, and 25% higher, respectively) compared to thick-wall inserts, which was in agreement with the theory. This effect decreased with increasing sphere size and TBR, and resulted in substantial (>5%) differences between thin- and thick-wall inserts for spheres up to 30 mm diameter and TBR up to 4. Thinner plastic walls were also shown to significantly improve the delineation accuracy for the majority of the segmentation methods tested, by increasing the proportion of lesion voxels detected, although the errors in image quantification remained non-negligible. CONCLUSIONS:This study quantified the significant effect of a 90% reduction in the thickness of insert walls on SUV quantification and PET-based boundary detection. Mean SUVs inside the inserts and recovery coefficients were particularly affected by the presence of thick cold walls, as predicted by a theoretical approach. The accuracy of some delineation algorithms was also significantly improved by the introduction of thin wall inserts instead of thick wall inserts. This study demonstrates the risk of errors deriving from the use of cold wall inserts to assess and compare the performance of PET segmentation methods.


Med Phys


Medical physics


Berthon B,Marshall C,Edwards A,Evans M,Spezi E




Has Abstract


2013-08-01 00:00:00












  • Linear motion correction in three dimensions applied to dynamic gadolinium enhanced breast imaging.

    abstract::Quantitative analysis of dynamic gadolinium-DTPA (diethylenetriamine pentaacetic acid) enhanced magnetic resonance imaging (MRI) is emerging as a highly sensitive tool for detecting malignant breast tissue. Three-dimensional rapid imaging techniques, such as keyhole MRI, yield high temporal sampling rates to accuratel...

    journal_title:Medical physics

    pub_type: 杂志文章


    authors: Krishnan S,Chenevert TL,Helvie MA,Londy FL

    更新日期:1999-05-01 00:00:00

  • Segmentation of bone CT images and assessment of bone structure using measures of complexity.

    abstract::A nondestructive and noninvasive method for numeric characterization (quantification) of the structural composition of human bone tissue has been developed and tested. In order to quantify and to compare the structural composition of bones from 2D computed tomography (CT) images acquired at different skeletal location...

    journal_title:Medical physics

    pub_type: 杂志文章


    authors: Saparin P,Thomsen JS,Kurths J,Beller G,Gowin W

    更新日期:2006-10-01 00:00:00

  • Effect of T1-mapping technique and diminished image resolution on quantification of infarct mass and its ability in predicting appropriate ICD therapy.

    abstract:PURPOSE:Myocardial infarct (MI) may consist of an infarct core (IC) and a heterogeneous, semi-viable border zone (BZ). Patients with chronic MI in the left ventricular (LV) myocardium are at increased risk of developing ventricular arrhythmias, and may therefore qualify for implantable cardioverter defibrillator (ICD) ...

    journal_title:Medical physics

    pub_type: 杂志文章


    authors: Farrag NA,Ramanan V,Wright GA,Ukwatta E

    更新日期:2018-04-01 00:00:00

  • Technical note: the calibration of 90Y-labeled SIR-Spheres using a nondestructive spectroscopic assay.

    abstract::90Y-labeled SIR-Spheres are currently used to treat patients with hepatic metastases secondary to colorectal adenocarcinoma. In general, the prescribed activity is based on empirical data collected during clinical trials. The activity of the source vial is labeled by the manufacturer as 3.0 GBq +/- 10% and is not inde...

    journal_title:Medical physics

    pub_type: 杂志文章


    authors: Selwyn R,Micka J,DeWerd L,Nickles R,Thomadsen B

    更新日期:2008-04-01 00:00:00

  • Technical Note: Identification of an optimal electromagnetic sensor for in vivo electromagnetic-tracked scintillation dosimeter for HDR brachytherapy.

    abstract:PURPOSE:Brachytherapy is a treatment modality which delivers large doses of radiation in a reduced number of visits. Since a small number of large dose-per-fraction is administered in high dose rate brachytherapy, ensuring the right dose is delivered is highly critical. In this work, a scintillation detector is coupled...

    journal_title:Medical physics

    pub_type: 杂志文章


    authors: Tho D,Beaulieu L

    更新日期:2019-05-01 00:00:00

  • Dosimetric characteristics of the Leipzig surface applicators used in the high dose rate brachy radiotherapy.

    abstract::The nucletron Leipzig applicator is designed for (HDR) 192Ir brachy radiotherapy of surface lesions. The dosimetric characteristics of this applicator were investigated using simulation method based on Monte Carlo N-particle (MCNP) code and phantom measurements. The simulation method was validated by comparing calcula...

    journal_title:Medical physics

    pub_type: 杂志文章


    authors: Niu H,Hsi WC,Chu JC,Kirk MC,Kouwenhoven E

    更新日期:2004-12-01 00:00:00

  • Dose-averaged LET calculation for proton track segments using microdosimetric Monte Carlo simulations.

    abstract:PURPOSE:There is an increasing interest in calculating linear energy transfer (LET) distributions for proton therapy treatments in order to assess the influence of this quantity in biological terms. Microdosimetric Monte Carlo (MC) simulations are useful tools to calculate dose-averaged LET, as this has been broadly pr...

    journal_title:Medical physics

    pub_type: 杂志文章


    authors: Bertolet A,Baratto-Roldán A,Barbieri S,Baiocco G,Carabe A,Cortés-Giraldo MA

    更新日期:2019-09-01 00:00:00

  • Balancing dose and image registration accuracy for cone beam tomosynthesis (CBTS) for breast patient setup.

    abstract:PURPOSE:To balance dose reduction and image registration accuracy in breast setup imaging. In particular, the authors demonstrate the relationship between scan angle and dose delivery for cone beam tomosynthesis (CBTS) when employed for setup verification of breast cancer patients with surgical clips. METHODS:The dose...

    journal_title:Medical physics

    pub_type: 杂志文章


    authors: Winey BA,Zygmanski P,Cormack RA,Lyatskaya Y

    更新日期:2010-08-01 00:00:00

  • SU-E-T-619: A Network-Flow Solution Approach to VMAT Treatment Plan Optimization.

    abstract:PURPOSE:To add mathematical rigor to the merging phase of the recently published two-stage VMAT optimization method called VMERGE. Using an exact merging method, we are able to better characterize the tradeoff between delivery efficiency and dose quality. METHODS:VMERGE begins with an IMRT plan that uses 180 equi-spac...

    journal_title:Medical physics

    pub_type: 杂志文章


    authors: Salari E,Craft D

    更新日期:2012-06-01 00:00:00

  • Dual-energy x-ray projection imaging: two sampling schemes for the correction of scattered radiation.

    abstract::In addition to the familiar problems of reduced contrast and signal-to-noise ratio (SNR) in the single energy case, dual-energy subtractions in the presence of scattered radiation suffer further degradations from: (1) artifacts due to nonuniform subtraction of scatter, and (2) a serious deterioration of the signal of ...

    journal_title:Medical physics

    pub_type: 杂志文章


    authors: Wagner FC,Macovski A,Nishimura DG

    更新日期:1988-09-01 00:00:00

  • Motion tracking of low-activity fiducial markers using adaptive region of interest with list-mode positron emission tomography.

    abstract:PURPOSE:Motion compensated positron emission tomography (PET) imaging requires detecting and monitoring of patient body motion. We developed a semiautomatic list-mode method to track the three-dimensional (3D) motion of fiducial positron-emitting markers during PET imaging. METHODS:A previously developed motion tracki...

    journal_title:Medical physics

    pub_type: 杂志文章


    authors: Chamberland MJP,deKemp RA,Xu T

    更新日期:2020-08-01 00:00:00

  • Medical applications of shortwave FM radar: remote monitoring of cardiac and respiratory motion.

    abstract:PURPOSE:This article introduces the use of low power continuous wave frequency modulated radar for medical applications, specifically for remote monitoring of vital signs in patients. METHODS:Gigahertz frequency radar measures the electromagnetic wave signal reflected from the surface of a human body and from tissue b...

    journal_title:Medical physics

    pub_type: 杂志文章


    authors: Mostov K,Liptsen E,Boutchko R

    更新日期:2010-03-01 00:00:00

  • Monte Carlo simulation of diagnostic x-ray scatter.

    abstract::A Monte Carlo method was developed and implemented to simulate x-ray photon transport. Simulations consisted of a pencil beam of monoenergetic photons with energies from 50 to 110 keV incident on water and aluminum slabs. The dependence of scatter fraction and multiple scattering on x-ray energy, scatterer thickness, ...

    journal_title:Medical physics

    pub_type: 杂志文章


    authors: Papin PJ,Rielly PS

    更新日期:1988-11-01 00:00:00

  • SU-E-J-81: Beveled Needle Tip Detection Error in Ultrasound-Guided Prostate Brachytherapy.

    abstract:PURPOSE:To quantify the needle tip detection errors in ultrasound images due to bevel-tip orientation in relation to the location on template grid. METHODS:Transrectal ultrasound (TRUS) system (BK Medical) with physical template grid and 18-gauge bevel-tip (20-deg beveled angle) brachytherapy needle (Bard Medical, Cov...

    journal_title:Medical physics

    pub_type: 杂志文章


    authors: Leu S,Ruiz B,Podder T

    更新日期:2012-06-01 00:00:00

  • Energy spectra due to the intrinsic radiation of LYSO/LSO scintillators for a wide range of crystal sizes.

    abstract::Most detectors in current positron emission tomography (PET) scanners and prototypes use lutetium oxyorthosilicate (LSO) or lutetium yttrium oxyorthosilicate (LYSO) scintillators. The aim of this work is to provide a complete set of background energy spectra, due to the scintillator intrinsic radioactivity, for a wide...

    journal_title:Medical physics

    pub_type: 杂志文章


    authors: Domínguez-Jiménez DY,Alva-Sánchez H

    更新日期:2021-01-21 00:00:00

  • Comparison of quantitative Y-90 SPECT and non-time-of-flight PET imaging in post-therapy radioembolization of liver cancer.

    abstract:PURPOSE:Radioembolization with yttrium-90 microspheres may be optimized with patient-specific pretherapy treatment planning. Dose verification and validation of treatment planning methods require quantitative imaging of the post-therapy distribution of yttrium-90 (Y-90). Methods for quantitative imaging of Y-90 using b...

    journal_title:Medical physics

    pub_type: 杂志文章


    authors: Yue J,Mauxion T,Reyes DK,Lodge MA,Hobbs RF,Rong X,Dong Y,Herman JM,Wahl RL,Geschwind JH,Frey EC

    更新日期:2016-10-01 00:00:00

  • Clinical Target Volume Segmentation for Stomach Cancer by Stochastic Width Deep Neural Network.

    abstract:PURPOSE:Precise segmentation of clinical target volume (CTV) is the key to stomach cancer radiotherapy. We proposed a novel stochastic width - deep neural network (SW-DNN) for better automatically contouring stomach CTV METHODS: SW-DNN was an end-to-end approach, of which the core component was a novel SW mechanism tha...

    journal_title:Medical physics

    pub_type: 杂志文章


    authors: Xu L,Hu J,Song Y,Bai S,Yi Z

    更新日期:2021-01-27 00:00:00

  • Automated segmentation of lungs with severe interstitial lung disease in CT.

    abstract:PURPOSE:Accurate segmentation of lungs with severe interstitial lung disease (ILD) in thoracic computed tomography (CT) is an important and difficult task in the development of computer-aided diagnosis (CAD) systems. Therefore, we developed in this study a texture analysis-based method for accurate segmentation of lung...

    journal_title:Medical physics

    pub_type: 杂志文章


    authors: Wang J,Li F,Li Q

    更新日期:2009-10-01 00:00:00

  • Calculating output factors for photon beam radiotherapy using a convolution/superposition method based on a dual source photon beam model.

    abstract::A realistic photon beam model based on Monte Carlo simulation of clinical linear accelerators was implemented in a convolution/superposition dose calculation algorithm. A primary and an extra-focal sources were used in this beam model to represent the direct photons from the target and the scattered photons from other...

    journal_title:Medical physics

    pub_type: 杂志文章


    authors: Liu HH,Mackie TR,McCullough EC

    更新日期:1997-12-01 00:00:00

  • The effect of dose calculation uncertainty on the evaluation of radiotherapy plans.

    abstract::Monte Carlo dose calculations will potentially reduce systematic errors that may be present in currently used dose calculation algorithms. However, Monte Carlo calculations inherently contain random errors, or statistical uncertainty, the level of which decreases inversely with the square root of computation time. Our...

    journal_title:Medical physics

    pub_type: 杂志文章


    authors: Keall PJ,Siebers JV,Jeraj R,Mohan R

    更新日期:2000-03-01 00:00:00

  • Definition of parameters for quality assurance of flattening filter free (FFF) photon beams in radiation therapy.

    abstract:PURPOSE:Flattening filter free (FFF) beams generated by medical linear accelerators have recently started to be used in radiotherapy clinical practice. Such beams present fundamental differences with respect to the standard filter flattened (FF) beams, making the generally used dosimetric parameters and definitions not...

    journal_title:Medical physics

    pub_type: 杂志文章


    authors: Fogliata A,Garcia R,Knoos T,Nicolini G,Clivio A,Vanetti E,Khamphan C,Cozzi L

    更新日期:2012-10-01 00:00:00

  • Experimental test of theoretical models for time-resolved reflectance.

    abstract::Four different expressions, derived from the diffusion theory or the random walk model, were used to fit time-resolved reflectance data for the evaluation of tissue optical properties. The experimental reflectance curves were obtained from phantoms of known optical parameters (absorption and transport scattering coeff...

    journal_title:Medical physics

    pub_type: 杂志文章


    authors: Cubeddu R,Pifferi A,Taroni P,Torricelli A,Valentini G

    更新日期:1996-09-01 00:00:00

  • Model-based optoacoustic inversion with arbitrary-shape detectors.

    abstract:PURPOSE:Optoacoustic imaging enables mapping the optical absorption of biological tissue using optical excitation and acoustic detection. Although most image-reconstruction algorithms are based on the assumption of a detector with an isotropic sensitivity, the geometry of the detector often leads to a response with spa...

    journal_title:Medical physics

    pub_type: 杂志文章


    authors: Rosenthal A,Ntziachristos V,Razansky D

    更新日期:2011-07-01 00:00:00

  • A K alpha dual energy x-ray source for coronary angiography.

    abstract::The use of characteristic-line radiation from rare-earth targets bombarded by high-energy (up to 1 MeV) electron beams has been evaluated as an x-ray source for dual energy K-edge subtraction imaging of the human coronary arteries. Two characteristic-line x-ray sources, one using the split K alpha 1 and K alpha 2 line...

    journal_title:Medical physics

    pub_type: 杂志文章


    authors: Manning HL,Shefer RE,Klinkowstein RE,Mistretta CA

    更新日期:1991-09-01 00:00:00

  • Pelvic multi-organ segmentation on cone-beam CT for prostate adaptive radiotherapy.

    abstract:BACKGROUND AND PURPOSE:The purpose of this study is to develop a deep learning-based approach to simultaneously segment five pelvic organs including prostate, bladder, rectum, left and right femoral heads on cone-beam CT (CBCT), as required elements for prostate adaptive radiotherapy planning. MATERIALS AND METHODS:We...

    journal_title:Medical physics

    pub_type: 杂志文章


    authors: Fu Y,Lei Y,Wang T,Tian S,Patel P,Jani AB,Curran WJ,Liu T,Yang X

    更新日期:2020-08-01 00:00:00

  • Evaluation of two methods of predicting MLC leaf positions using EPID measurements.

    abstract::In intensity modulated radiation treatments (IMRT), the position of the field edges and the modulation within the beam are often achieved with a multileaf collimator (MLC). During the MLC calibration process, due to the finite accuracy of leaf position measurements, a systematic error may be introduced to leaf positio...

    journal_title:Medical physics

    pub_type: 杂志文章


    authors: Parent L,Seco J,Evans PM,Dance DR,Fielding A

    更新日期:2006-09-01 00:00:00

  • Use of proximal operator graph solver for radiation therapy inverse treatment planning.

    abstract:PURPOSE:Most radiation therapy optimization problems can be formulated as an unconstrained problem and solved efficiently by quasi-Newton methods such as the Limited-memory Broyden-Fletcher-Goldfarb-Shanno (L-BFGS) algorithm. However, several next generation planning techniques such as total variation regularization- b...

    journal_title:Medical physics

    pub_type: 杂志文章


    authors: Liu X,Pelizzari C,Belcher AH,Grelewicz Z,Wiersma RD

    更新日期:2017-04-01 00:00:00

  • Electron beam water calorimetry measurements to obtain beam quality conversion factors.

    abstract:PURPOSE:To provide results of water calorimetry and ion chamber measurements in high-energy electron beams carried out at the National Research Council Canada (NRC). There are three main aspects to this work: (a) investigation of the behavior of ionization chambers in electron beams of different energies with focus on ...

    journal_title:Medical physics

    pub_type: 杂志文章


    authors: Muir BR,Cojocaru CD,McEwen MR,Ross CK

    更新日期:2017-10-01 00:00:00

  • First Measurements of Ionization Cluster-Size Distributions with a Compact Nanodosimeter.

    abstract:PURPOSE:A nanodosimeter is a type of detector which measures single ionizations in a small gaseous volume in order to obtain ionization cluster size probability distributions for characterization of radiation types. Working nanodosimeter detectors are usually bulky machines which require a lot of space. In this work, t...

    journal_title:Medical physics

    pub_type: 杂志文章


    authors: Vasi F,Schneider U

    更新日期:2021-01-28 00:00:00

  • Gadolinium neutron capture therapy for brain tumors: a computer study.

    abstract::A Monte Carlo computer study of the total dose distribution from neutrons and prompt gamma emissions (but excluding the contribution from conversion and Auger electrons) for gadolinium neutron capture therapy of brain tumors has been carried out in order to test the theoretic feasibility of this modality using commerc...

    journal_title:Medical physics

    pub_type: 杂志文章


    authors: Masiakowski JT,Horton JL,Peters LJ

    更新日期:1992-09-01 00:00:00