Patient exposure and diagnostic reference levels in operating rooms: a multi-centric retrospective study in over 150 private and public French clinics.

To investigate patient exposure in operating rooms and establish Diagnostic Reference Levels (DRLs), fifteen different procedures and nearly 4500 surgeries performed between January 2017 and December 2019 at over 150 different private (79% of data) and public (21% of data) French clinics were recorded. Collected information include the used C-arm equipment, exposure parameters (kVp, mAs, Fluoroscopy Time - FT and Air Kerma-Area Product - PKA) and patient Body Mass Index (BMI) whenever available. Multi-centric DRLs were derived as the 75th percentile of the median exposure data collected in more than 10 different hospitals. For the less frequent procedures, DRLs were determined as the 75th percentile of pooled exposure data with a minimum of 4 centres and 100 patients. Patient exposure proved to be significantly different among the centres. Highest DRLs were found for Abdominal Aortic Aneurysm Endoprosthesis (18 min, 81 Gy cm2), Iliac Angioplasty (6 min, 24 Gy cm2) and Flutter Ablation surgeries (17 min, 14 Gy cm2). In opposition, lowest DRLs were obtained for Hallux Valgus (0.4 min, 0.04 Gy cm2), Hand/Wrist Fracture (0.6 min, 0.16 Gy cm2), and Venous Access Device Implantation surgeries (0.3 min, 0.36 Gy cm2). Similar exposure levels are registered in private clinics and public hospitals. Multi-centric DRLs for fifteen surgical procedures including six new reference values were established to help optimise patients' radiation protection.

Full model-based iterative reconstruction (MBIR) in abdominal CT increases objective image quality, but decreases subjective acceptance.

OBJECTIVE: Evaluate and compare the image quality and acceptance of a full MBIR algorithm to that of an earlier full IR hybrid algorithm and filtered back projection (FBP). METHODS: Acquisitions were performed with a 320 detector-row CT scanner with seven different dose levels. Images were reconstructed with three algorithms: FBP, full hybrid iterative reconstruction (HIR), and a full model-based iterative reconstruction algorithm (full MBIR). The sensitometry, spatial resolution, image texture, and low-contrast detectability of these algorithms were compared. Subjective analysis of low-contrast detectability was performed. Ten radiologists answered a questionnaire on image quality and confidence in full MBIR images in clinical practice. RESULTS: The contrast-to-noise ratio of full MBIR was significantly higher than in the other algorithms (p < 0.0015). The spatial resolution was also higher with full MBIR at high frequencies (> 0.3 lp/mm). Full MBIR at low dose levels led to better low-contrast detectability and more inserts being identified with a higher confidence (p < 0.0001). Full MBIR was associated with a change in image texture compared to HIR and FBP. Eighty percent of radiologists judged general appearance and texture of full MBIR images worse than HIR. Moreover, compared with HIR, for 50% of radiologists, the diagnostic confidence on full MBIR images was worse. Questionnaire reliability was considered acceptable (Cronbach alpha 0.7). CONCLUSION: Compared to conventional iterative reconstruction algorithms, full MBMIR presented a higher image quality and low-contrast detectability and a worse acceptance among radiologists. KEY POINTS: • Full MBIR used led to an overall improvement in image quality compared with FBP and HIR. • Full MBIR leads to image texture change which reduces the confidence in these images among radiologists. • Awareness of the image texture change and improved quality of full MBIR reconstructed images could improve the acceptance of this technique in clinical practice.

The political and fiscal determinants of public health and curative care expenditures: evidence from the Canadian provinces, 1980-2018.

OBJECTIVES: Public health systems have been centre stage during the COVID-19 pandemic, but governments invest relatively little in public health as compared to curative care. Previous research has shown that public health expenditures are under pressure during recessions and could be politically determined, but very few studies analyze quantitatively their determinants. This study investigates the political and fiscal determinants of public health and curative care expenditures. METHODS: After constructing a dataset building on disaggregated health expenditures in the Canadian provinces from 1975 to 2018, we use error correction models to study the short-run and long-run influence of fiscal and political determinants on public health expenditures and on curative expenditures. Fiscal determinants include measures of public debt charges and federal transfers. Political determinants include government partisanship and election cycles. We also explore whether curative expenditures crowd out public health expenditures. RESULTS: We find no difference between left and right governments in curative care expenditures but show that left governments spend more on public health if we control for past spending decisions in favour of curative care. Fiscal austerity reduces both public health and curative expenditures, and provincial governments use additional intergovernmental transfers to increase their curative care budgets. A growth in the proportion of curative care relative to total health budgets is associated with a decline in public health expenditures. CONCLUSION: Even though they have low political salience, public health expenditures remain driven by partisanship and electoral concerns. Despite their widely acknowledged importance, public health programs develop in the shadow of curative care priorities.

RéSUMé: OBJECTIFS: Bien que les systèmes de santé publique aient occupé le devant de la scène pendant la pandémie de COVID-19, les gouvernements investissent relativement peu dans la santé publique par rapport aux soins de santé curatifs. Des recherches antérieures ont montré que les dépenses de santé publique sont vulnérables aux récessions économiques et pourraient être influencées par la politique, mais très peu d'études analysent quantitativement les déterminants des dépenses de santé publique. Cette étude examine les déterminants politiques et fiscaux des dépenses de santé publique et de soins curatifs. MéTHODES: Nous avons assemblé une base de données regroupant les dépenses de santé désagrégées dans les provinces canadiennes de 1975 à 2018. Nous utilisons des modèles de correction d'erreurs pour étudier l'influence à court et long terme des déterminants fiscaux et politiques des dépenses de santé publique et des dépenses de santé curatives. Les déterminants fiscaux comprennent des mesures des intérêts sur la dette publique et des transferts fédéraux. Les déterminants politiques comprennent l'idéologie du gouvernement et les cycles électoraux. Nous examinons également si la croissance des dépenses curatives entraîne un effet d'éviction sur les dépenses de santé publique. RéSULTATS: Nous ne trouvons aucune différence entre les dépenses en soins curatifs effectuées par les gouvernements de gauche et de droite, mais nous montrons que les gouvernements de gauche dépensent plus en santé publique si nous contrôlons pour les décisions passées en faveur des soins curatifs. L'austérité fiscale réduit à la fois les dépenses de santé publique et les dépenses en soins curatifs, et les gouvernements provinciaux utilisent les transferts intergouvernementaux supplémentaires pour augmenter leurs budgets de soins curatifs. Une augmentation de la proportion des budgets de santé alloués aux soins curatifs est associée à une baisse des dépenses de santé publique. CONCLUSION: Même si elles ont une faible saillance politique, les dépenses de santé publique restent guidées par la partisanerie et les préoccupations électorales. Malgré leur importance largement reconnue, les programmes de santé publique se développent à l'ombre de la priorité donnée aux soins curatifs.

CT image quality improvement using Adaptive Iterative Dose Reduction with wide-volume acquisition on 320-detector CT.

OBJECTIVES: To evaluate the impact of Adaptive Iterative Dose Reduction (AIDR) on image quality and radiation dose in phantom and patient studies. METHODS: A phantom was examined in volumetric mode on a 320-detector CT at different tube currents from 25 to 550 mAs. CT images were reconstructed with AIDR and with Filtered Back Projection (FBP) reconstruction algorithm. Image noise, Contrast-to-Noise Ratio (CNR), Signal-to-Noise Ratio (SNR) and spatial resolution were compared between FBP and AIDR images. AIDR was then tested on 15 CT examinations of the lumbar spine in a prospective study. Again, FBP and AIDR images were compared. Image noise and SNR were analysed using a Wilcoxon signed-rank test. RESULTS: In the phantom, spatial resolution assessment showed no significant difference between FBP and AIDR reconstructions. Image noise was lower with AIDR than with FBP images with a mean reduction of 40%. CNR and SNR were also improved with AIDR. In patients, quantitative and subjective evaluation showed that image noise was significantly lower with AIDR than with FBP. SNR was also greater with AIDR than with FBP. CONCLUSION: Compared to traditional FBP reconstruction techniques, AIDR significantly improves image quality and has the potential to decrease radiation dose. KEY POINTS: This study showed that Adaptive Iterative Dose Reduction (AIDR) reduces image noise. In a phantom image noise was reduced without altering spatial resolution. In patients AIDR reduced the image noise in lumbar spine CT. AIDR can potentially reduce the dose for lumbar spine CT by 52%.

Evaluation of the diagnostic performance of tomosynthesis in fractures of the wrist.

OBJECTIVE: The purpose of our study was to define the diagnostic value of tomosynthesis compared with standard radiography and CT in wrist injuries. MATERIALS AND METHODS: One hundred consecutive patients with acute wrist trauma were investigated with standard radiography, tomosynthesis, and CT. Reference results were those obtained with CT; follow-up monitoring of the patients; and, in some cases, MRI (n=13). Three readers interpreted the findings independently, each using a PACS workstation, and categorized the cases into four groups: fracture of the radius, fracture of the scaphoid, fracture of another bone, and absence of fracture. RESULTS: Fifty-seven percent of the patients had a fracture. The interobserver kappa value varied between 0.54 and 0.59 for standard radiography, between 0.66 and 0.69 for tomosynthesis, and between 0.84 and 0.89 for CT. The sensitivity of standard radiography varied between 61% and 80% and specificity between 65% and 83%. The sensitivity of tomosynthesis ranged between 77% and 87%, and specificity between 76% and 82%. Ranges of sensitivity and specificity for CT were 93-95%, and 86-95%, respectively. CONCLUSION: The diagnostic value of tomosynthesis is superior to that of standard radiography but inferior to that of CT.

The politics of public health investments.

Public health investments help to prevent mortality and reduce health care costs. Yet very few studies have examined the determinants of preventive care investments across countries and over time. We develop a theory of health spending priorities contrasting preventive and curative care. Preventive care is particularly unlikely to be prioritized by governments since it is a public good that requires the allocation of scarce resources in the present to generate diffuse benefits that unfold only in the long-term. As such, public health is a "quiet" policy that is not supported by interest groups or public opinion. These characteristics have two implications: like other long-term investments, public health programs are particularly vulnerable to fiscal austerity, and prevention expenditures are not influenced by government partisanship since parties cannot attract votes with such low visibility, long term investments. We use a dataset covering 25 OECD countries from 1970 to 2018 to demonstrate that fiscal consolidations are negatively associated with the absolute level of preventive care and with its proportion relative to curative care. We also confirm that left-wing governments are not more likely to invest in public health than right-wing governments. Finally, contributing to the literature on comparative health care systems, we show that National Health Services systems maintain higher preventive care investments than Social Health Insurance systems.

Welfare state decommodification and population health.

A generous welfare state decommodifies social relations and frees citizens from relying excessively on markets. We argue that decommodification is associated with population health in two ways: directly, as it provides better social protection to households and indirectly, as it mitigates health-damaging labour market polarization and reduces the incidence of labour market risks. Using time-series cross-sectional quantitative analysis for 21 OECD countries from 1971 to 2010, we observe a negative relationship between decommodification and the age-standardized death rate. We then analyze three correlates of decommodification-income redistribution, labour market polarization and the reduction of labour market risk incidence-and find that only the latter two are associated with population health. Higher labour market polarization, measured by the share of market income allocated to the richest decile relative to the share of the poorest decile, is associated with a higher death rate. A new measure of risk reduction, the degree to which the welfare state reduces the prevalence of large income losses, is also associated with lower death rates, especially for men. Welfare state decommodification thus contributes to population health directly, and indirectly, via the attenuation of labour market polarization and the mitigation of labour market risks.

Technical note: Design and initial evaluation of a novel physical breast phantom to monitor image quality in digital breast tomosynthesis.

PURPOSE: To describe the creation process of a new breast phantom specifically designed to monitor quality control (QC) metrics consistency over several months in digital breast tomosynthesis (DBT). METHODS: The semi-anthropomorphic Tomomam® phantom was designed and evaluated twice monthly on a single Hologic Selenia Dimensions® unit over 5 months. The phantom is manufactured in a one-piece epoxy resin homogeneous material as the basis for manufacturing, simulating breast tissue as 50% equivalent glandular (GL)/50% equivalent adipose (AD) and compressed thickness of 60 mm. The distribution of test objects on different planes inside the phantom should allow the quantification of 10 image quality metrics: reproducibility, signal difference-to-noise ratio (SDNR), geometric distortions in the plane, missing or added tissue at chest wall, at the top and bottom of images stack and lateral sides, in-plane homogeneity, image scoring, artifact spread function (ASF), geometric distortions in the volume. SDNR was quantified according to GL and AD tissues. Tolerance criteria per parameter were described to analyze results over the study time. RESULTS: Mean scores were equal to 15.4, 15.0, and 11.6 for masses, microcalcifications, and fibers, respectively. A large difference between GL and AD tissues for SDNR metrics was noted over the study time: the best results were obtained from GL tissues. Both geometric distortions and local homogeneity in the plane conformed to expected values. The mean volume value of the triangular prism was 11.3% greater than the expected value due to a reconstruction height equal to 66 mm instead of 60 mm. CONCLUSIONS: In this study, we monitored several QC metrics discriminating GL and AD tissues by using a new breast phantom developed by us. The preliminary clinical tests demonstrated that the Tomomam® phantom could be used to reliably and efficiently track 10 QC metrics with a single acquisition. More data need to be acquired to refine tolerance criteria for some metrics.

Lack of association between putative transporter gene polymorphisms in Plasmodium falciparum and chloroquine resistance in imported malaria isolates from Africa.

BACKGROUND: Plasmodium falciparum drug resistance represents a major health problem in malaria endemic countries. The mechanisms of resistance are not fully elucidated. Recently, an association between putative transporter gene polymorphisms and in vitro response to chloroquine (CQ) and quinine has been reported in culture-adapted, cloned isolates from various geographical origins. However, this was not confirmed in another study performed on isolates from a defined region in Thailand. METHODS: This study tried to find an association between putative transporters gene polymorphisms with in vitro response to CQ and pfcrt genotype in isolates originating from various African countries. To avoid biases of parasites adaptation in culture, fresh isolates obtained from symptomatic, malaria-infected travellers returning from Africa to France were used. Monoclonal isolates included in the study were selected using a msp-2 fragment analysis method. In vitro susceptibility to CQ, single nucleotide polymorphisms and microsatellite polymorphisms in pfcrt, pfmdr1 and six putative transporter genes were established in 27 isolates and three reference strains. RESULTS: Polymorphism of pfcrt at positions 76 and 220 showed a significant association with in vitro chloroquine resistance (P < .02 and P < .05 respectively). Polymorphism of pfmdr1 at position 86 showed an equally significant association with in vitro chloroquine response (P < .05). No association was found between SNPs or microsatellite polymorphisms of putative transporter genes and in vitro CQR or pfcrt genotype in imported malaria isolates from Africa. CONCLUSION: The previously described association between putative transporter gene polymorphisms and in vitro response to chloroquine (CQ) was not confirmed in the present study.

Qualitative estimation of pelvic organ interactions and their consequences on prostate motion: study on a deceased person.

In an attempt to have better targeting of the prostate during radiotherapy it is necessary to understand the mechanical interactions between bladder, rectum, and prostate and estimate their consequences on prostate motion. For this, the volumes of bladder, rectum, and lungs were modified concomitantly on a deceased person. A CT acquisition was performed for each of these different pelvic configurations (36 acquisitions). An increase in the volume of the bladder or lungs induces a compression of tissues of the pelvic area from its supero-anterior (S-A) to infero-posterior (I-P) side. Conversely, an increase of rectum volume induces a compression from the I-P to the S-A side of the pelvic region. These compressive actions can be added or subtracted from each other, depending on their amplitudes and directions. Prostate motion occurs when a movement of the rectum is observed (this movement depends, itself, on lungs and bladder volume). The maximum movement of prostate is 9 mm considering maximal bladder or rectal action, and 11 mm considering maximum lung action. In some other cases, opposition of compressive effects can lead to stasis of the prostate. Based on the volumes of bladder, rectum, and lungs, it is possible to qualitatively estimate the movement of organs of the pelvic area. The best way to reduce prostate movement is to recommend the patient to have an empty rectum, with either full bladder and/or full lungs.

Assessment of a Monte-Carlo simulation of SPECT recordings from a new-generation heart-centric semiconductor camera: from point sources to human images.

Geant4 application for tomographic emission (GATE), a Monte-Carlo simulation platform, has previously been used for optimizing tomoscintigraphic images recorded with scintillation Anger cameras but not with the new-generation heart-centric cadmium-zinc-telluride (CZT) cameras. Using the GATE platform, this study aimed at simulating the SPECT recordings from one of these new CZT cameras and to assess this simulation by direct comparison between simulated and actual recorded data, ranging from point sources to human images. Geometry and movement of detectors, as well as their respective energy responses, were modeled for the CZT 'D.SPECT' camera in the GATE platform. Both simulated and actual recorded data were obtained from: (1) point and linear sources of (99m)Tc for compared assessments of detection sensitivity and spatial resolution, (2) a cardiac insert filled with a (99m)Tc solution for compared assessments of contrast-to-noise ratio and sharpness of myocardial borders and (3) in a patient with myocardial infarction using segmented cardiac magnetic resonance imaging images. Most of the data from the simulated images exhibited high concordance with the results of actual images with relative differences of only: (1) 0.5% for detection sensitivity, (2) 6.7% for spatial resolution, (3) 2.6% for contrast-to-noise ratio and 5.0% for sharpness index on the cardiac insert placed in a diffusing environment. There was also good concordance between actual and simulated gated-SPECT patient images for the delineation of the myocardial infarction area, although the quality of the simulated images was clearly superior with increases around 50% for both contrast-to-noise ratio and sharpness index. SPECT recordings from a new heart-centric CZT camera can be simulated with the GATE software with high concordance relative to the actual physical properties of this camera. These simulations may be conducted up to the stage of human SPECT-images even if further refinement is needed in this setting.

Influence of dose point and inverse optimization on interstitial cervical and oropharyngeal carcinoma brachytherapy.

BACKGROUND AND PURPOSE: Evaluation of the use of optimization methods in interstitial cervical and oropharyngeal brachytherapy; evaluation of the conformal index (COIN) and the natural dose ratio (NDR) to quantify the implant quality. MATERIAL AND METHODS: CT-based dose distributions were obtained for seven implants according to the Paris system. CT-based implants were used to assess the dose point and inverse optimization methods. To compare the results of these planning methods, the coverage index (CI), normal tissue irradiation (NTI), and the protection of organs at risk (OARs) were evaluated using cumulative dose volume histograms (CDVH). RESULTS: In regular cervical implants, a CI of 94 and 96%; a NTI of 35 and 28% resulted for non-optimized and optimized implants, respectively. In irregular cervical implants, a CI of 88, 96, and 90%; a NTI of 44, 37, and 44% resulted for non-optimized, dose point optimized, and inverse optimized implants, respectively. Compared to the non-optimized implants; both optimization methods resulted in better protection for the bladder wall. As for the protection of the rectal wall, only the inverse optimization gave a better result. In oropharyngeal implants, a better CI resulted after dose point optimization. Irradiation of the contralateral parotid were improved after both optimization methods. The maximum change in COIN that could have been achieved by optimization was 3%, as CI and NTI increased similarly. For the same value of COIN, an underdosage of PTV was avoided by the optimization methods as NDR increased from 0.86 to 1.01. CONCLUSION: CT-based optimized implant allows conformation of the dose distribution to the PTV while sparing normal tissue and organs at risk. COIN and NDR should be used together to evaluate both doses to normal tissue and organs at risk, and an under- or overdose inside the PTV.

Validation of a digital mammographic unit model for an objective and highly automated clinical image quality assessment.

In mammography, image quality assessment has to be directly related to breast cancer indicator (e.g. microcalcifications) detectability. Recently, we proposed an X-ray source/digital detector (XRS/DD) model leading to such an assessment. This model simulates very realistic contrast-detail phantom (CDMAM) images leading to gold disc (representing microcalcifications) detectability thresholds that are very close to those of real images taken under the simulated acquisition conditions. The detection step was performed with a mathematical observer. The aim of this contribution is to include human observers into the disc detection process in real and virtual images to validate the simulation framework based on the XRS/DD model. Mathematical criteria (contrast-detail curves, image quality factor, etc.) are used to assess and to compare, from the statistical point of view, the cancer indicator detectability in real and virtual images. The quantitative results given in this paper show that the images simulated by the XRS/DD model are useful for image quality assessment in the case of all studied exposure conditions using either human or automated scoring. Also, this paper confirms that with the XRS/DD model the image quality assessment can be automated and the whole time of the procedure can be drastically reduced. Compared to standard quality assessment methods, the number of images to be acquired is divided by a factor of eight.

Compared performance of high-sensitivity cameras dedicated to myocardial perfusion SPECT: a comprehensive analysis of phantom and human images.

UNLABELLED: Differences in the performance of cadmium-zinc-telluride (CZT) cameras or collimation systems that have recently been commercialized for myocardial SPECT remain unclear. In the present study, the performance of 3 of these systems was compared by a comprehensive analysis of phantom and human SPECT images. METHODS: We evaluated the Discovery NM 530c and DSPECT CZT cameras, as well as the Symbia Anger camera equipped with an astigmatic (IQ x SPECT) or parallel-hole (conventional SPECT) collimator. Physical performance was compared on reconstructed SPECT images from a phantom and from comparable groups of healthy subjects. RESULTS: Classifications were as follows, in order of performance. For count sensitivity on cardiac phantom images (counts x s(-1) x MBq(-1)), DSPECT had a sensitivity of 850; Discovery NM 530c, 460; IQ x SPECT, 390; and conventional SPECT, 130. This classification was similar to that of myocardial counts normalized to injected activities from human images (respective mean values, in counts x s(-1) x MBq(-1): 11.4 ± 2.6, 5.6 ± 1.4, 2.7 ± 0.7, and 0.6 ± 0.1). For central spatial resolution: Discovery NM 530c was 6.7 mm; DSPECT, 8.6 mm; IQ x SPECT, 15.0 mm; and conventional SPECT, 15.3 mm, also in accordance with the analysis of the sharpness of myocardial contours on human images (in cm(-1): 1.02 ± 0.17, 0.92 ± 0.11, 0.64 ± 0.12, and 0.65 ± 0.06, respectively). For contrast-to-noise ratio on the phantom: Discovery NM 530c had a ratio of 4.6; DSPECT, 4.1; IQ x SPECT, 3.9; and conventional SPECT, 3.5, similar to ratios documented on human images (5.2 ± 1.0, 4.5 ± 0.5, 3.9 ± 0.6, and 3.4 ± 0.3, respectively). CONCLUSION: The performance of CZT cameras is dramatically higher than that of Anger cameras, even for human SPECT images. However, CZT cameras differ in that spatial resolution and contrast-to-noise ratio are better with the Discovery NM 530c, whereas count sensitivity is markedly higher with the DSPECT.

Computation of realistic virtual phantom images for an objective lesion detectability assessment in digital mammography.

Image quality assessment is required for an optimal use of mammographic units. On the one hand, there are objective image quality assessment methods based on the measurement of technical parameters such as modulation transfer function (MTF), noise power spectrum (NPS) or detection quantum efficiency (DQE) describing performances of digital detectors. These parameters are, however, without direct relationship with lesion detectability in clinical practice. On the other hand, there are image quality assessment methods involving time consuming procedures, but presenting a direct relationship with lesion detectability. This contribution describes an X-ray source/digital detector model leading to the simulation of virtual contrast-detail phantom (CDMAM) images. The virtual image computation method requires the acquisition of only few real images and allows for an objective image quality assessment presenting a direct relationship with lesion detectability. The transfer function of the proposed model takes as input physical parameters (MTF* and noise) measured under clinical conditions on mammographic units. As presented in this contribution, MTF* is a modified MTF taking into account the effects due to X-ray scatter in the breast and magnification. Results obtained with the structural similarity index prove that the simulated images are quite realistic in terms of contrast and noise. Tests using contrast detail curves highlight the fact that the simulated and real images lead to very similar data quality in terms of lesion detectability. Finally, various statistical tests show that quality factors computed for both the simulated images and the real images are very close for the two data sets.

DNA double-strand breaks induced by mammographic screening procedures in human mammary epithelial cells.

PURPOSE: To assess in vitro mammographic radiation-induced DNA damage in mammary epithelial cells from 30 patients with low (LR) or high (HR) family risk of breast cancer. MATERIALS AND METHODS: Spontaneous and radiation-induced DNA double-strand breaks (DSB) were quantified by using immunofluorescence of the phosphorylated H2AX histone (γH2AX) in different conditions of mammography irradiation (2, 4, 2 + 2 mGy). RESULTS: HR patients showed significantly more spontaneous γH2AX foci than LR patients (p = 0.014). A significant dose-effect was observed, with an exacerbation in HR patients (p = 0.01). The dose repetition (2 + 2 mGy) provided more induced and more unrepaired DSB than 2 mGy and 4 mGy, and was exacerbated in HR (p = 0.006). CONCLUSIONS: This study highlights the existence of DSB induced by mammography and revealed by γH2AX assay with two major radiobiological effects occurring: A low-dose effect, and a LOw and Repeated Dose (LORD) effect. All these effects were exacerbated in HR patients. These findings may lead us to re-evaluate the number of views performed in screening using a single view (oblique) in women whose mammographic benefit has not properly been proved such as HR patients.