Bouwman R.W.,Radboud University Nijmegen |
Visser R.,Radboud University Nijmegen |
Young K.C.,University of Surrey |
Dance D.R.,University of Surrey |
And 4 more authors.
Progress in Biomedical Optics and Imaging - Proceedings of SPIE | Year: 2010
Breast tomosynthesis is an imaging modality that recently became available for breast examination. For conventional Projection mammography qualify control procedures are well described. For breast tomosynthesis on the other hand, Such procedures hate not yet been established. In this paper we propose a simple method and phantom for daily quality control (DQC). With DQC image quality problems arising after acceptance of the system should be detected. Therefore, the DQC procedure needs to monitor the stability of the most critical components of the system over tune. For breast tomosynthesis we assume that the most critical items are the image receptor, X-ray tube and the tomosynthesis motion. The proposed procedure the image receptor homogeneity and system stability are evaluated using an image of a homogeneous block of PMMA. The z-resolution is assumed to be dependent on the tomosynthesis motion. To momtor this motion the nominal z-resolution using the slice sensitive profile is measured Shading artefacts that arise due to objects with high attenuation are also typical for tomosynthesis systems. Analysing those artefacts may provide additional information about the tomosynthesis motion. The proposed DQC procedure has been evaluated on two Afferent breast tomosynthesis systems: A multi slit scanning system and a system using a stationary a-Se detector. Preliminary results indicate that the proposed method is useful for DQC, although some minor advised. To verify that this method detects image quality problems sufficiently, more experience with different DBT systems, over longer periods of time are needed. © 2010 SPIE.
PubMed | Philips, University of Michigan, University of Houston, LRCB and 11 more.
Type: Journal Article | Journal: Medical physics | Year: 2017
Spatial resolution in digital breast tomosynthesis (DBT) is affected by inherent/binned detector resolution, oblique entry of x-rays, and focal spot size/motion; the limited angular range further limits spatial resolution in the depth-direction. While DBT is being widely adopted clinically, imaging performance metrics and quality control protocols have not been standardized. AAPM Task Group 245 on Tomosynthesis Quality Control has been formed to address this deficiency.Methods of measuring spatial resolution are evaluated using two prototype quality control phantoms for DBT. Spatial resolution in the detector plane is measured in projection and reconstruction domains using edge-spread function (ESF), point-spread function (PSF) and modulation transfer function (MTF). Spatial resolution in the depth-direction and effective slice thickness are measured in the reconstruction domain using slice sensitivity profile (SSP) and artifact spread function (ASF). An oversampled PSF in the depth-direction is measured using a 50 m angulated tungsten wire, from which the MTF is computed. Object-dependent PSF is derived and compared with ASF. Sensitivity of these measurements to phantom positioning, imaging conditions and reconstruction algorithms is evaluated. Results are compared from systems of varying acquisition geometry (9-25 projections over 15-60). Dependence of measurements on feature size is investigated.Measurements of spatial resolution using PSF and LSF are shown to depend on feature size; depth-direction spatial resolution measurements are shown to similarly depend on feature size for ASF, though deconvolution with an object function removes feature size-dependence. A slanted wire may be used to measure oversampled PSFs, from which MTFs may be computed for both in-plane and depth-direction resolution.Spatial resolution measured using PSF is object-independent with sufficiently small object; MTF is object-independent. Depth-direction spatial resolution may be measured directly using MTF or indirectly using ASF or SSP as surrogate measurements. While MTF is object-independent, it is invalid for nonlinear reconstructions.
Sancho-Garnier H.,Regional Cancer Center |
Tamalet C.,Virology Unit |
Halfon P.,Alphabio Laboratory |
Leandri F.X.,ARCADES |
And 5 more authors.
International Journal of Cancer | Year: 2013
Today in France, low attendance to cervical screening by Papanicolaou cytology (Pap-smear) is a major contributor to the 3,000 new cervical cancer cases and 1,000 deaths that occur from this disease every year. Nonattenders are mostly from lower socioeconomic groups and testing of self-obtained samples for high-risk Human Papilloma virus (HPV) types has been proposed as a method to increase screening participation in these groups. In 2011, we conducted a randomized study of women aged 35-69 from very low-income populations around Marseille who had not responded to an initial invitation for a free Pap-smear. After randomization, one group received a second invitation for a free Pap-smear and the other group was offered a free self-sampling kit for HPV testing. Participation rates were significantly different between the two groups with only 2.0% of women attending for a Pap-smear while 18.3% of women returned a self-sample for HPV testing (p ≤ 0.001). The detection rate of high-grade lesions (≥CIN2) was 0.2‰ in the Pap-smear group and 1.25‰ in the self-sampling group (p = 0.01). Offering self-sampling increased participation rates while the use of HPV testing increased the detection of cervical lesions (≥CIN2) in comparison to the group of women receiving a second invitation for a Pap-smear. However, low compliance to follow-up in the self-sampling group reduces the effectiveness of this screening approach in nonattenders women and must be carefully managed. Copyright © 2013 UICC.
Van Engen R.E.,National Expert and Training Center for Breast Cancer Screening |
Bosmans H.,University Hospitals Leuven |
Bouwman R.W.,National Expert and Training Center for Breast Cancer Screening |
Dance D.R.,Royal Surrey County Hospital |
And 7 more authors.
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2014
Quality control (QC) procedures for digital breast tomosynthesis (DBT) systems are a crucial part of the acceptance of a new modality. In contrast to the situation in the US, the European approach is to provide a device independent protocol with limiting values that should be applied to all systems. A European QC protocol that deals with this challenge is being developed and is currently work-in-progress. In this paper four specific QC tests for DBT, which have reached an (almost) final stage, are presented: reproducibility, system projection MTF, z-resolution and missed tissue at the top and bottom of the reconstructed volume. The proposed tests have been evaluated on several DBT systems. The encouraging results show that these tests will form an appropriate and necessary part of QC procedures for DBT. © 2014 Springer International Publishing.
Tamalet C.,Center Hospitalo University Timone |
Richet H.,Center Hospitalo University Timone |
Carcopino X.,Service de Gynecologie Obstetrique |
Henry M.,Center Hospitalo University Timone |
And 5 more authors.
Journal of Medical Virology | Year: 2010
Self-sampling using vaginal swabs could be a valuable alternative to screen for cervical cancer for women who do not attend regular cytological screening. The aim of this study was to determine the prevalence of high and low-risk HPV types and of HPV type 16 and 18 DNA load in self-collected vaginal swabs from 35- to 69-year-old Southern French women of low socioeconomic level or migrant populations who do not attend regular cervical screening. A good concordance (93.1%) was found between cervical brush and vaginal swabs in 29 samples. Self-collected vaginal swabs were examined from 120 women. HPV infection was found in 28 women (23.3%; median age 48 years), 17 (14.1%) of whom harbored high-risk HPV types. HPV type 16 was the high risk type found most frequently, followed by types 53, 31, 18, 58, and 66. The low-risk type detected most frequently was HPV type 6, followed by types 61, 70, and 81. The mean HPV 16 and 18 load was 6.3 log10 copies/106 cells and 2.4 log 10 copies/106 cells, respectively. These results suggest that vaginal self-swabs can be a reliable tool for cervical cancer screening in non-attending and inadequately screened elderly women. © 2010 Wiley-Liss, Inc.
Tamalet C.,Marseille University Hospital Center |
Le Retraite L.,Arcades |
Leandri F.-X.,Arcades |
Heid P.,Arcades |
And 2 more authors.
Clinical Microbiology and Infection | Year: 2013
In France, about 40% of women aged 25-65 years do not participate in regular screening and thus are at high risk (HR) of cervical cancer. Human papillomavirus (HPV) vaginal self-sampling is a valuable alternative in this population. This study aimed to assess the prevalence of HR and LR (low-risk) HPV infection in 3767 women aged >35 years from mid-socioeconomic backgrounds who carried out HPV vaginal self-sampling at home. HPV vaginal self-sampling was better accepted than the Pap-test in women aged 35-69 years who were previously non-responders to individual invitation. From the 933 self-collected swabs studied (24.7%), 62 were HPV-infected (6.6%), and 73 HPV types were found. HPV 16 was the most frequently found (43.5%), followed by 53 (23.2%), 18 (12.3%), 66 (12.3%), 31 (6.8%), 33 (5.4%) and 58 (2.7%). Ten women (16.2%) were infected by multiple HR-HPV types. Median HPV 16 load was 104.000 copies/106 cells and median HPV 18 load was 833 copies/106 cells. Six women (9.3%) harboured LR-HPV types. The 12-month follow-up of 43 HR-HPV positive women (69.3%) revealed CIN2-3 lesions in three women (6.9%), all HPV 16 infected, and harbouring an HPV 16 load >5 log10 copies/106 cells. Women harbouring HR-HPV types other than HPV 16/18 were older than women harbouring HPV 16/18 types (55 years vs. 46.9 years, p 0.0008). The high frequency of HR-HPV types in women >50 years deserves further investigation to elucidate the mechanism involved (re-infection or reactivation). © 2012 The Authors Clinical Microbiology and Infection © 2012 European Society of Clinical Microbiology and Infectious Diseases.