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The objective is to investigate tumour prognostic factors versus breast density in screen-detected cancers and interval cancers. The results may highlight the need for more personalised screening protocols based on breast density in organized screening programmes.A retrospective study was performed of tumour characteristics of screen-detected cancers (n=468) and interval cancers (n=515) of 983 women who participated in the Flemish Breast Cancer Screening Programme in 2009-2010. Breast density was obtained from the screening programme data. Information on nodal invasion and histological grading was taken from the Belgian Cancer Registry. Tumour size and proliferation and receptor expression status were retrieved from pathology reports. The differences in tumour characteristics between screen-detected and interval cancers as well as the variation in these variables with breast density in both groups were studied by logistic regression.A comparison of tumour characteristics between screen-detected cancers and interval cancers systematically showed features of more aggressive tumours in interval cancers: larger tumour size, nodal invasion, grade 3 tumours, and hormone receptor negative phenotype (p0.05). The analysis of tumour characteristics versus breast density in screen-detected cancers showed higher numbers of aggressive grade 3 tumours in low-density breasts and of the luminal A subtype with good prognosis in high-density breasts (p0.05). This analysis for interval cancers highlights a high proportion of the difficult-to-treat triple-negative subtype in low-density breasts compared with high-density breasts. In conclusion, the study data support arguments against changes in breast cancer screening programmes with prolongation of screening intervals in low-density breasts.

Purpose: Feasability of a no-reference image quality metric was assessed on patient-like images using a patient-specific phantom simulating a frame of a coronary angiogram. Methods: One background and one contrast-filled frame of a coronary angiogram, acquired using a clinical imaging protocol, were selected from a Philips Integris Allura FD (Philips Healthcare, Best, The Netherlands). The background frame's pixels were extruded to a thickness proportional to their grey value. One phantom was 3D printed using composite 80% bronze filament (max. thickness of 5.1 mm), the other was a custom PMMA cast (max thickness of 8.5 cm). A vessel mold was created from the contrast-filled frame and injected with a solution of 320 mg I/ml contrast fluid (75%), water and gelatin. Still X-ray frames of the vessel mold + background phantom + 16 cm PMMA were acquired at manually selected different exposure settings using a Philips Azurion (Philips Healthcare, Best, The Netherlands) in User Quality Control Mode and were exportedas RAW images. The signal-difference-to-noise-ratio-squared (SDNR2) and a spatial-domain-equivalent of the noise equivalent quanta (NEQSDE) were calculated. The Spearman's correlation of the latter parameters with a no-reference perceptual image quality metric (NIQE) was investigated. Results: The bronze phantom showed better resemblance to the original patient frame selected from a coronary angiogram of an actual patient, with better contrast and less blur than the PMMA phantom. Both phantoms were imaged using a comparable imaging protocol to the one used to acquire the original frame. The bronze phantom was hence used together with the vessel mold for image quality measurements on the 165 still phantom frames. A strong correlation was noted between NEQSDE and NIQE (SROCC = –0.99, p < 0.0005) and between SDNR2 and NIQE (SROCC = –0.97, p < 0.0005). Conclusion: Using a cost-effective and easy to realize patient-specific phantom we were able to generate patient-like X-ray frames. NIQE as a no-reference image quality model has the potential to predict physical image quality from patient images.

Purpose In laparoscopy, the Operating Room Black Box® (ORBB) provides insights into operative performance to improve patient safety. This technology may also enhance endovascular surgical practice; however, the use of a C-arm and X-rays pose important challenges, hindering transferability to an endovascular context. We describe the first implementation of ORBB technology in a hybrid angiosuite and illustrate its value in evaluating surgeons’ radiation safety, technical and non-technical performance. Methods Team members (surgeons, nurses, anaesthesiologists) and stakeholders were informed during several information sessions. Together with teams from Surgical Safety Technologies (Toronto, Canada), an implementation plan was developed, and video-evaluation frameworks were chosen. Radiation safety was assessed using dose measurements and video-evaluation of safety-related behaviours. Technical performance was assessed using ‘global’ (GRS) and ‘procedure-specific’ (PRS) rating scales and the ‘EndoVascular Aortic Repair Assessment of Technical Expertise’ (EVARATE) framework. Surgeons’ non-technical skills were assessed with the NOTSS framework. Results The system captures Audio-visual data from four ceiling-mounted cameras, three ceiling-array microphones, the fluoroscopy screen and anaesthesia monitor. After patient and team consent, an elective endovascular aneurysm repair was successfully analysed. Dose-Area-Product and Air Kerma were 71094 mGy.cm2 and 270 mGy, respectively. Behavioural analysis revealed deficiencies in stepping back and radiation safety communication. Technical skill assessment was feasible: GRS: 29/40; ‘PRS’: 27/35; EVARATE: 29/35. Non-technical analysis highlighted surgeons’ leadership qualities. Conclusion An innovative data capture platform has been successfully installed to evaluate overall performance during endovascular procedures. This technology may facilitate identification of (radiation) safety-related errors and instigate educational interventions based on real-world issues.

Mobile radiography systems are commonly used in the intensive care unit. The use of a physical antiscatter grid with these systems is uncommon because of drawbacks. In 2015, Virtual Grid (Fujifilm, Tokyo, Japan) became available for chest and abdomen examinations. In this study, we compared image quality (IQ) with a contrast-detail phantom (CDRAD 2.0; Artinis Medical Systems, Zetten, the Netherlands) of digital radiographs acquired without any grid (gridless) with those corrected for scatter by either software (SW)-based scatter correction (Virtual Grid) or a physical grid (grid). Furthermore, we determined the optimal Virtual Grid settings that lead to the best contrast-detail IQ score (inverse IQ figure). MATERIALS AND METHODS Images were obtained with a cassette spot film device with an inserted portable flat-panel detector (Fujifilm, Tokyo, Japan). The CDRAD phantom was sandwiched between polymethylmethacrylate (PMMA) with total thicknesses of 12, 16, 21, and 26 cm to simulate patient attenuation and scatter. Tube voltages of 81, 90, 109, and 125 kVp were used to make the radiographs. In total, 12 different Virtual Grid settings (grid ratio, line pairs (lp)/cm, and type of interstitial material) were applied for every phantom thickness and tube voltage. RESULTS An average increase of 32% in IQ was obtained when Virtual Grid images with a SW grid ratio 10:1 were compared with gridless images (P < 0.001). Increasing the SW grid ratio to 20:1 resulted in a further increased IQ. With a phantom thickness of 12 cm PMMA, Virtual Grid outperformed the removable physical grid presented in the cassette spot film device. The linear mixed-effects model showed that IQ is mainly affected by PMMA, tube voltage, and the SW grid ratio. CONCLUSIONS Virtual Grid improves images obtained without physical grid for a wide range of experimental conditions. Despite the different possible settings of the Virtual Grid SW, the most important parameter affecting IQ is the SW grid ratio.

Objectives Bedside radiographs are usually obtained gridless, without a physical scatter correction grid because of several limitations. Therefore, multiple manufacturers of mobile radiography systems provide the possibility to apply scatter correction software (SC SW) on those images. The purpose of this study was to characterize different series of radiographs-gridless, SC SW, and physical grid-with an image quality assessment algorithm (IQAA). Furthermore, we investigated the potential dose reduction and the correlation between the output of the IQAA and the human observers. Materials and Methods We obtained different series of radiographs with an anthropomorphic phantom (multipurpose chest phantom N1 "Lungman," Kyoto Kagaku, Kyoto, Japan). All radiographs were obtained with flat-panel detectors of 5 different manufacturers in a wall bucky system. An IQAA to analyze the radiographs was implemented in our department but was originally developed by the research group of the Duke University Medical Center. Seven physical quantities were calculated by the IQAA: rib-lung contrast (RLcontrast), subdiaphragm-lung contrast (SLcontrast), lung detail (L-detail), mediastinum detail (M-detail), lung noise (L-noise), mediastinum noise (M-noise), and rib-lung sharpness (RLsharpness). In a proof of concept, the results of the IQAA were validated by 3 experienced radiologists. Results Regression coefficients (b) of the linear regression model indicate that the human observer results correlate well with the IQAA (b >= 0.89, R-2 >= 0.83). All manufacturers have SC SW that increases the 7 physical quantities of the gridless images. However, several manufacturers have SC SW that increases the physical metrics to the same level as the physical grid images. The SC SW radiographs obtained with a reduced tube load have an increased level of contrast, detail, sharpness, and noise compared with the gridless images obtained with the higher tube load. Conclusions We have proven in a proof of concept that the originally developed IQAA can be used to characterize different series of images of different manufacturers. Based on the physical quantities, SC SW increases the contrast, detail, sharpness, and noise. The experimental results in this study assume a patient dose reduction could be possible when SC SW is applied.

To study number and type of imaging techniques, cumulative radiation exposure and radiation-induced risk from repeated imaging of cervical and lumbar spine attained after traffic or occupational accident.The study cohort comprised of 500 patients after traffic or occupational accident. Amount of radiography, CT and MRI procedures and injury severity were tallied for each patient. Cumulative effective dose (CED), expressed in millisieverts (mSv), was estimated by summing up typical effective dose values. Total lifetime cancer risks and associated risk category were estimated by using risk coefficients, specified according to sex, age at exposure and exposed region.A total of 2,107 imaging procedures were performed of which 30% were radiographs (n = 631), 21% were CT (n = 438) and 49% were MRI (n = 1,038). Abbreviated Injury Scale was low (1-2) in all cases (except one). The cohort included 352 patients after traffic accident and 148 after occupational accident. Mean CED of these two groups were 4.4 mSv and 9.4 mSv, respectively. No patient had a CED higher than 100 mSv. Nineteen patients fell into the 'moderate risk' group, meaning that the additional risk of fatal cancer from accumulated radiation exposure lies between 1 in 1,000 and 1 in 100.MRI was the most used imaging technique. No CED from repeated imaging procedures after minor or moderate traffic or occupational accident exceeded 100 mSv. However, nineteen patients fell into the 'moderate risk' group of developing radiation-induced cancer. Tracking radiation exposure can be beneficial in identifying those with high CED, although education on its proper use is necessary.

Objectives We evaluated the different Virtual Grid software ratios (Fujifilm, Tokyo, Japan) on gridless clinical chest radiographs with visual grading analysis (VGA). In addition, we investigated the 2 image quality assessment algorithms (IQAAs). Materials and Methods Gridless chest radiographs of 50 different intensive care unit patients were collected and afterward processed with Virtual Grid software. Different software (SW) grid ratios-6:1, 10:1, 13:1, 17:1, and 20:1-were applied to investigate the image quality (IQ) improvement. Image quality improvement was assessed by 4 radiologists in a relative VGA study where the reference image was processed with SW grid ratio of 10:1. One of the IQAAs used to analyze the radiographs was implemented in our department but was originally developed by the research group of the Duke University Medical Center. A general IQ score (IQS) was calculated based on contrast, detail, and noise. Another IQAA-NIQE (naturalness image quality evaluator)-available in Matlab (MATLAB Research R2019b; the MathWorks, Inc) was evaluated. Both methods were compared with VGA. Results Visual grading analysis scores of gridless radiographs are significantly lower (P < 0.001). Image quality increases with increasing SW grid ratios, up to grid ratio of 17:1. However, some anatomical structures-spine and ribs-are negatively affected by the higher grid ratios. A correlation coefficient of 0.99 between the VGA and the IQS was observed. The correlation coefficient between VGA and NIQE was 1.00. Conclusions Virtual Grid with SW grid ratio of 6:1 improves the IQ of gridless chest bedside radiographs. The grid ratios 17:1 and 20:1 should be considered carefully as the SW negatively affects parts of the ribs and spine. Therefore, grid ratios up to 13:1 can be advised. The IQAAs are promising and could be used to detect differences in IQ when different scatter correction SW settings are used.

Background Dual axis rotational coronary angiography ( DARCA ) reduces radiation exposure during coronary angiography on older x‐ray systems. The purpose of the current study is to quantify patient and staff radiation exposure using DARCA on a modality already equipped with dose‐reducing technology. Additionally, we assessed applicability of 1 dose area product to effective dose conversion factor for both DARCA and conventional coronary angiography ( CCA ) procedures. Methods and Results Twenty patients were examined using DARCA and were compared with 20 age‐, sex‐, and body mass index–matched patients selected from a prior study using CCA on the same x‐ray modality. All irradiation events are simulated using PCXMC ( STUK , Finland) to determine organ and effective doses. Moreover, for DARCA each frame is simulated. Staff dose is measured using active personal dosimeters (DoseAware, Philips Healthcare, The Netherlands). With DARCA , median cumulative dose area product is reduced by 57% (ie, 7.41 versus 17.19 Gy·cm 2 ). Effective dose conversion factors of CCA and DARCA are slightly different, yet this difference is not statistically significant. The occupational dose at physician's chest, leg, and collar level are reduced by 60%, 56%, and 16%, respectively, of which the first 2 reached statistical significance. Median effective dose is reduced from 4.75 mSv in CCA to 2.22 mSv in DARCA procedures, where the latter is further reduced to 1.79 mSv when excluding ventriculography. Conclusions During invasive coronary angiography, DARCA reduces radiation exposure even further toward low‐dose values on a system already equipped with advanced image processing and noise reduction algorithms. For both DARCA and CCA procedures, using 1 effective dose conversion factor of 0.30 mSv·Gy −1 ·cm −2 is feasible.

Objectives This study aims to evaluate the radiation exposure to patients undergoing an abdominopelvic or a chest and abdominopelvic (trunk) CT examination and to assess compliance to imaging referral guidelines. Methods To this end, 357 standard abdominopelvic and trunk CT scans were collected from 8 Belgian institutions in 2011 and 2015. Effective dose (E) and collective dose were calculated using CT dose descriptors (CTDIvol and DLP), which were obtained from dose reports generated by the CT scanner. Subsequently, these CT requests were compared against the national referral guidelines to assess compliance. Population estimates for dose and compliance were obtained using multilevel linear regression and generalized estimating equation models. Results Between 2011 and 2015, a significant decrease of 28% in CTDIvol and DLP was found for abdominopelvic CT. The corresponding E decreased by 27%, and the collective dose by 23%. For trunk CT, a non-significant decrease of 6% was found in CTDIvol and a significant decrease of 14% in both DLP and E. However, the collective dose of trunk examinations increased by 39%. In 2011, 24% of the abdominopelvic examinations were not compliant with the guidelines, whereas this percentage dropped to 17% in 2015. Non-justified examinations accounted for 8% and 12% of all trunk CT scans in 2011 and 2015, respectively. Conclusion Between 2011 and 2015, there was a decrease in dose for patients undergoing abdominopelvic or trunk CT in Belgium. However, a fraction of the estimated doses are linked to unnecessary CT examinations, which should be avoided.

INTRODUCTION Cardiac catheterization procedures result in high patient radiation exposure and corresponding staff doses are reported to be among the highest for medical staff. The purpose of current randomized controlled study was to quantify the potential radiation dose reduction for both patient and staff, enabled by recent X-ray technology. This technology is equipped with advanced image processing algorithms, real-time dose monitoring, and an acquisition chain optimized for cardiac catheterization applications. METHODS A total of 122 adult patients were randomly assigned to one of two cath labs, either the reference X-ray modality (Allura Xper FD10, Philips Healthcare, the Netherlands) or the new X-ray system (AlluraClarity FD20/10 Philips Healthcare, the Netherlands). Exposure parameters and staff dosimeter readings were recorded for each exposure. Technical measurements were performed to define the radiation scatter behavior. RESULTS With the newer equipment, patient radiation dose is reduced (as total dose-area product) by 67% based on geometric means with 95%CI of 53%, 77% for diagnostic and interventional procedures. The C-arm and leg dosimeter readings were both reduced with 65% (P

Prostate-specific membrane antigen (PSMA) is highly overexpressed in prostate cancer. Many PSMA analog radiotracers for PET/CT prostate cancer staging have been developed, such as

Purpose To assess compliance of lumbar spine imaging referrals with national imaging recommendations and to evaluate the impact of inappropriate imaging on the collective radiation dose and health insurance costs. Method In 2011 and 2015, 633 lumbar spine imaging referrals were evaluated across 9 Belgian hospitals. For each patient, a new clinical anamnesis and physical examination were performed. Together with the referral, this data were confronted with the national imaging recommendations. Collective radiation dose was estimated for the radiography and CT procedures. Cost analysis was based on national reimbursement fees. Statistical analysis was performed using multilevel linear and logistic regression models. Results The fraction of unjustified imaging referrals decreased from 50 % in 2011 to 41 % in 2015 (p = 0.255). The odds of a justified examination are 3.1 times higher when the referral is done by a specialist instead of a general practitioner. The highest percentage of unjustified examinations was found for CT (85 % in 2011, 81 % in 2015; p = 0.044). Seventy-five percent of the collective dose of both the 2011 and the 2015 study population was not justified. Adherence to the recommendations could result in an estimated 16 % and 5 % cost reduction for the 2011 and 2015 study samples, respectively. Conclusions Between 2011 and 2015, no significant improvement was found in requesting justified lumbar spine imaging procedures, although a positive trend was observed for CT. A shift from CT to MRI is necessary to improve the appropriateness of lumbar spine imaging referrals and to reduce the collective radiation dose.

On 5 December 2013 the European Council promulgated Directive 2013/59/EURATOM. This Directive is important for Medical Physicists and Medical Physics Experts as it puts the profession on solid foundations and describes it more comprehensively. Much commentary regarding the role and competences has been developed in the context of the European Commission project “European Guidelines on the Medical Physics Expert” published as Radiation Protection Report RP174. The guidelines elaborate on the role and responsibilities under 2013/59/EURATOM in terms of a mission statement and competence profile in the specialty areas of Medical Physics relating to medical radiological services, namely Diagnostic and Interventional Radiology, Radiation Oncology and Nuclear Medicine. The present policy statement summarises the provisions of Directive 2013/59/EURATOM regarding the role and competences, reiterates the results of the European Guidelines on the Medical Physics Expert document relating to role and competences of the profession and provides additional commentary regarding further issues arising following the publication of the RP174 guidelines.

To develop a clinically applicable method to estimate patient-specific organ and blood doses and lifetime attributable risks (LAR) from paediatric torso CT examinations. Individualized voxel models were created from full-body CT data of 10 paediatric patients (2–18 years). Patient-specific dose distributions of chest and abdominopelvic CT scans were simulated using Monte Carlo methods. Blood dose was calculated as a weighted sum of simulated organ doses. LAR of cancer incidence and mortality were estimated, according to BEIR-VII. A second simulation and blood dose calculation was performed using only the thoracic and abdominopelvic region of the original voxel models. For each simulation, the size-specific dose estimate (SSDE) was calculated. SSDE showed a significant strong linear correlation with organ dose (r > 0.8) and blood dose (r > 0.9) and LAR (r > 0.9). No significant differences were found between blood dose calculations with the full-body voxel models and the thoracic or abdominopelvic models. Even though clinical CT images mostly do not cover the whole body of the patient, they can be used as a voxel model for blood dose calculation. In addition, SSDE can estimate patient-specific organ and blood doses and LAR in paediatric torso CT examinations. • Blood dose can be simulated using the patient’s clinical CT images. • SSDE estimates patient-specific organ/blood dose and LAR in paediatric CAP CT-examinations. • SSDE makes on-the-spot dose and LAR estimations possible in routine clinical practice.

IntroductionCardiac catheterization procedures result in high radiation doses and often multiple procedures are necessary for congenital heart disease patients. However, diagnostic reference levels (DRL) remain scarce. Our first goal was finding the optimal DRL parameter and determining appropriate DRLs. The second goal was to calculate organ doses (OD), effective doses (ED) and lifetime attributable risks (LAR) per procedure and to provide conversion factors based on dose area product (DAP).Materials and methodsDRLs are calculated for each procedure type, as the 75th percentile of the cumulative value per procedure from the corresponding parameter. All irradiation events in the DICOM Structured Reports were automatically processed and simulated using PCXMC, resulting in OD, ED and LAR. Using a Kruskal Wallis H test and subsequent pairwise comparisons, differences in median values of the DRL parameter between procedure types were assessed.ResultsLinear regression showed a strong correlation and narrow confidence interval between DAP and product of body weight and fluoroscopy time (BWxFT), even when all procedures (diagnostic and interventional) are combined. Only 15% of the pairwise comparisons were statistically significant for DAP normalized to BWxFT (DAPBWxFT). The latter pairs contained less frequent procedure types with significant outliers. For DAP normalized to BW (DAPBW), 38% of the pairwise comparisons showed statistically significant differences. Conversion factors from DAPBW to OD and ED were reported for various weight groups, due to the higher correlation between DAPBW and both OD and ED than between DAP and both OD and ED.ConclusionsThe P75 of DAPBWxFT for all procedures combined serves as an appropriate DRL value. This facilitates local DRL determination in smaller paediatric centres, which often have insufficient data to produce appropriate DRLs for different procedure types. Conversion factors are more reliable starting from DAPBW instead of DAP and should be used according to the appropriate BW group.

Purpose The evaluation of clinical image quality (IQ) is important to optimize CT protocols and to keep patient doses as low as reasonably achievable. Considering the significant amount of effort needed for human observer studies, automatic IQ tools are a promising alternative. The purpose of this study was to evaluate automatic IQ assessment in chest CT using Thiel embalmed cadavers. Methods Chest CT’s of Thiel embalmed cadavers were acquired at different exposures. Clinical IQ was determined by performing a visual grading analysis. Physical-technical IQ (noise, contrast-to-noise and contrast-detail) was assessed in a Catphan phantom. Soft and sharp reconstructions were made with filtered back projection and two strengths of iterative reconstruction. In addition to the classical IQ metrics, an automatic algorithm was used to calculate image quality scores (IQs). To be able to compare datasets reconstructed with different kernels, the IQs values were normalized. Results Good correlations were found between IQs and the measured physical-technical image quality: noise (ρ = −1.00), contrast-to-noise (ρ = 1.00) and contrast-detail (ρ = 0.96). The correlation coefficients between IQs and the observed clinical image quality of soft and sharp reconstructions were 0.88 and 0.93, respectively. Conclusions The automatic scoring algorithm is a promising tool for the evaluation of thoracic CT scans in daily clinical practice. It allows monitoring of the image quality of a chest protocol over time, without human intervention. Different reconstruction kernels can be compared after normalization of the IQs.

To investigate if direct radiography (DR) performs better than screen-film mammography (SF) and computed radiography (CR) in dense breasts in a decentralized organised Breast Cancer Screening Programme. To this end, screen-detected versus interval cancers were studied in different BI-RADS density classes for these imaging modalities. The study cohort consisted of 351,532 women who participated in the Flemish Breast Cancer Screening Programme in 2009 and 2010. Information on screen-detected and interval cancers, breast density scores of radiologist second readers, and imaging modality was obtained by linkage of the databases of the Centre of Cancer Detection and the Belgian Cancer Registry. Overall, 67% of occurring breast cancers are screen detected and 33% are interval cancers, with DR performing better than SF and CR. The interval cancer rate increases gradually with breast density, regardless of modality. In the high-density class, the interval cancer rate exceeds the cancer detection rate for SF and CR, but not for DR. DR is superior to SF and CR with respect to cancer detection rates for high-density breasts. To reduce the high interval cancer rate in dense breasts, use of an additional imaging technique in screening can be taken into consideration. • Interval cancer rate increases gradually with breast density, regardless of modality. • Cancer detection rate in high-density breasts is superior in DR. • IC rate exceeds CDR for SF and CR in high-density breasts. • DR performs better in high-density breasts for third readings and false-positives.

The purpose of this study was to investigate the influence of the localizer and scan direction on the dose-reducing efficacy of the automatic tube current modulation (ATCM) in computed tomography (CT). Craniocaudal and caudocranial chest CT scans, based on anterior-posterior (AP), posterior-anterior (PA), lateral (LAT) or dual AP/LAT localizers, of an anthropomorphic phantom containing thermoluminescent dosimeters (TLDs), were made on three Siemens systems. TLD readings were converted to lung and thyroid doses. A second dose estimation was performed based on Monte Carlo simulations. In addition, the ATCM behaviour of GE and Toshiba was evaluated based on AP, PA and LAT localizers. Compared with AP, tube currents of PA and AP/LAT scans were on average 20 % higher and 40 % lower, respectively, for the Siemens systems. Consequently, thyroid and lung doses increased with 60 % with a PA instead of an AP/LAT scan, with significant differences in image noise. Moreover, the thyroid dose halves by taking the scan in caudocranial direction. Noise values were not significantly different when changing scan direction.

Computed tomography (CT) exams contribute for a large part to the population's radiation burden. This study addresses the question if dose settings of scanners expressed by dose-length product (DLP) are correlated with directly measurable biological effects in patients.DLP, blood dose, effective dose and DNA damage were analyzed for patients undergoing a thoracic or abdominal contrast CT scan on two CT scanners with different dose settings. The DNA damage was assessed by scoring γ-H2AX foci representing DNA double-strand breaks (DSBs) in patient's lymphocytes. Blood dose was calculated using the ImPACT software.The CT system operating at higher dose settings represented by higher DLP values, resulted in a significantly higher number of radiation-induced γ-H2AX foci in patient's lymphocytes (DLP: 2.1 times higher; γ-H2AX foci: 2.3 times higher; p0.05). Plotting γ-H2AX foci versus blood dose showed a systematic increase of DNA damage with dose. In vitro experiments ruled out a possible X-ray enhancement of DNA damage effect by contrast agent.Present study demonstrates that optimization of DLP setting of scanners results in a reduction of X-ray effects in patients.

To determine the correlation between the clinical and physical image quality of chest images by using cadavers embalmed with the Thiel technique and a contrast-detail phantom.The use of human cadavers fulfilled the requirements of the institutional ethics committee. Clinical image quality was assessed by using three human cadavers embalmed with the Thiel technique, which results in excellent preservation of the flexibility and plasticity of organs and tissues. As a result, lungs can be inflated during image acquisition to simulate the pulmonary anatomy seen on a chest radiograph. Both contrast-detail phantom images and chest images of the Thiel-embalmed bodies were acquired with an amorphous silicon flat-panel detector. Tube voltage (70, 81, 90, 100, 113, 125 kVp), copper filtration (0.1, 0.2, 0.3 mm Cu), and exposure settings (200, 280, 400, 560, 800 speed class) were altered to simulate different quality levels. Four experienced radiologists assessed the image quality by using a visual grading analysis (VGA) technique based on European Quality Criteria for Chest Radiology. The phantom images were scored manually and automatically with use of dedicated software, both resulting in an inverse image quality figure (IQF). Spearman rank correlations between inverse IQFs and VGA scores were calculated.A statistically significant correlation (r = 0.80, P.01) was observed between the VGA scores and the manually obtained inverse IQFs. Comparison of the VGA scores and the automated evaluated phantom images showed an even better correlation (r = 0.92, P.001).The results support the value of contrast-detail phantom analysis for evaluating clinical image quality in chest radiography.

Background: Cone beam computed tomography (CBCT) has become an extremely useful technique for dentomaxillofacial imaging because it provides clear images of highly contrasted structures. Previous studies evaluating the applicability of this technique in otologic imaging were very encouraging but were only performed in vitro on temporal bone specimens. The intracochlear positioning of the individual electrodes after cochlear implantation by means of CBCT has not yet been shown in vivo. Objective: We describe a protocol for in vivo postoperative imaging of cochlear implants by CBCT. Moreover, the effective dose was measured and compared with the effective dose used on 4- and 16-slice multislice computed tomography (MSCT) by using a RANDO-phantom. Main Outcome Measure: Developing a protocol for in vivo postoperative imaging of cochlear implants by CBCT. Results: CBCT provides high-resolution and almost artifact-free multiplanar reconstruction images allowing assessment of the precise intracochlear position of the electrode and visualization of each of the individual contacts. The calculated effective dose of the used CBCT and MSCT acquisitions is 80 mu sv for the CBCT, 3,600 mu sv for the 16-slice computed tomography, and 4,800 mu sv for the 4-slice computed tomography. Conclusion: These preliminary results suggests that, for in vivo postoperative evaluation of cochlear implants, CBCT can provide at least the same information as conventional radiography, digital radiograph, and MSCT but in a more comfortable and a much more safer way.

In this paper, a large-scale multicentre patient dose study performed in eight Belgian interventional cardiology departments is presented. Effective dose (E) was calculated based on a detailed dose-area product (DAP)-registration during each procedure and by using conversion coefficients generated by the Monte Carlo-based computer program PCXMC. Conversion coefficients were found to be 0.177 mSv Gycm −2 for systems that do not use any additional copper filtration in cineradiography and 0.207 mSv Gycm −2 for systems that use additional copper filtration in cineradiography. Mean E values of 9.6 and 15.3 mSv for diagnostic and therapeutic procedures, respectively, were obtained. DAP distributions were investigated in order to derive dose reference levels: 71 and 106 Gycm 2 for diagnostic and therapeutic procedures, respectively, are proposed. Significant differences were observed in DAP distributions taking into account whether additional copper filtration was used in the cineradiography mode. Apart from the skin, the organs most at risk are lungs and heart. The probability of fatal cancer for the studied population amounted to 1.1 × 10 −4 and 2.1 × 10 −4 for diagnostic and therapeutic procedures, respectively, for the age distribution of the patients considered in this multicentre study.

Background: The first aim of this study was to evaluate the correlation between clinical and physical-technical image quality applied to different strengths of iterative reconstruction in chest CT images using Thiel cadaver acquisitions and Catphan images. The second aim was to determine the potential dose reduction of iterative reconstruction compared to conventional filtered back projection based on different clinical and physical-technical image quality parameters. Methods: Clinical image quality was assessed using three Thiel embalmed human cadavers. A Catphan phantom was used to assess physical-technical image quality parameters such as noise, contrast-detail and contrast-to-noise ratio (CNR). Both Catphan and chest Thiel CT images were acquired on a multislice CT scanner at 120 kVp and 0.9 pitch. Six different refmAs settings were applied (12, 30, 60, 90, 120 and 150refmAs) and each scan was reconstructed using filtered back projection (FBP) and iterative reconstruction (SAFIRE) algorithms (1,3 and 5 strengths) using a sharp kernel, resulting in 24 image series. Four radiologists assessed the clinical image quality, using a visual grading analysis (VGA) technique based on the European Quality Criteria for Chest CT. Results: Correlation coefficients between clinical and physical-technical image quality varied from 0.88 to 0.92, depending on the selected physical-technical parameter. Depending on the strength of SAFIRE, the potential dose reduction based on noise, CNR and the inverse image quality figure (IQF(inv)) varied from 14.0 to 67.8 %, 16.0 to 71.5 % and 22.7 to 50.6 % respectively. Potential dose reduction based on clinical image quality varied from 27 to 37.4 %, depending on the strength of SAFIRE. Conclusion: Our results demonstrate that noise assessments in a uniform phantom overestimate the potential dose reduction for the SAFIRE IR algorithm. Since the IQF(inv) based dose reduction is quite consistent with the clinical based dose reduction, an optimised contrast-detail phantom could improve the use of contrast-detail analysis for image quality assessment in chest CT imaging. In conclusion, one should be cautious to evaluate the performance of CT equipment taking into account only physical-technical parameters as noise and CNR, as this might give an incomplete representation of the actual clinical image quality performance.

Objective : To compare the organ doses and lifetime-attributable risk of cancer for electrocardiogram-triggered sequential and high-pitch helical scanning in a clinical patient population. Methods : Phantom thermoluminiscence dosimeter measurements were used as a model for the organ dose assessment of 314 individual patients who underwent coronary computed tomographic angiography. Patient-specific lifetime-attributable cancer risks were calculated. Results : Phantom measurements showed that heart rate had a significant influence on the delivered radiation exposure in sequential mode, and calcium scoring and contrast bolus tracking scans make a nonnegligible contribution to patients' dose. Therefore, they should be taken into account for patients' organ dose estimations. Median cancer induction risks are low, with 0.008% (0.0016%) and 0.022% (0.056%) for high-pitch and sequential scanning for men (women), respectively. Conclusions : The use of high-pitch helical scanning leads to 65% and 72% lower lifetime-attributable risk values for men and women, respectively, compared with sequential scanning.

Metal artifacts may negatively affect radiologic assessment in the oral cavity. The aim of this study was to evaluate different metal artifact reduction techniques for metal artifacts induced by dental hardware in CT scans of the oral cavity. Clinical image quality was assessed using a Thiel-embalmed cadaver. A Catphan phantom and a polymethylmethacrylate (PMMA) phantom were used to evaluate physical-technical image quality parameters such as artifact area, artifact index (AI), and contrast detail (IQFinv). Metal cylinders were inserted in each phantom to create metal artifacts. CT images of both phantoms and the Thiel-embalmed cadaver were acquired on a multislice CT scanner using 80, 100, 120, and 140 kVp; model-based iterative reconstruction (Veo); and synthesized monochromatic keV images with and without metal artifact reduction software (MARs). Four radiologists assessed the clinical image quality, using an image criteria score (ICS). Significant influence of increasing kVp and the use of Veo was found on clinical image quality (p = 0.007 and p = 0.014, respectively). Application of MARs resulted in a smaller artifact area (p

The aim of this study was to compare the image quality and radiation dose in chest imaging using an amorphous silicon flat-panel detector system and an amorphous selenium flat-panel detector system. In addition, the low-contrast performance of both systems with standard and low radiation doses was compared.In two groups of 100 patients each, digital chest radiographs were acquired with either an amorphous silicon or an amorphous selenium flat-panel system. The effective dose of the examination was measured using thermoluminescent dosimeters placed in an anthropomorphic Rando phantom. The image quality of the digital chest radiographs was assessed by five experienced radiologists using the European Guidelines on Quality Criteria for Diagnostic Radiographic Images. In addition, a contrast-detail phantom study was set up to assess the low-contrast performance of both systems at different radiation dose levels. Differences between the two groups were tested for significance using the two-tailed Mann-Whitney test.The amorphous silicon flat-panel system allowed an important and significant reduction in effective dose in comparison with the amorphous selenium flat-panel system (p0.0001) for both the posteroanterior and lateral views. In addition, clinical image quality analysis showed that the dose reduction was not detrimental to image quality. Compared with the amorphous selenium flat-panel detector system, the amorphous silicon flat-panel detector system performed significantly better in the low-contrast phantom study, with phantom entrance dose values of up to 135 muGy.Chest radiographs can be acquired with a significantly lower patient radiation dose using an amorphous silicon flat-panel system than using an amorphous selenium flat-panel system, thereby producing images that are equal or even superior in quality to those of the amorphous selenium flat-panel detector system.

Purpose: To investigate the association between six transforming growth factor β1 gene ( TGFβ1 ) polymorphisms (-1.552delAGG, -800G>A, -509C>T, Leu10Pro, Arg25Pro, Thr263Ile) and the occurrence of late normal tissue reactions after gynecologic radiotherapy (RT). Methods and Materials: Seventy-eight women with cervical or endometrial cancer and 140 control individuals were included in the study. According to the Common Terminology Criteria for Adverse Events version 3.0 (CTCAEv3.0) scale, 25 patients showed late adverse RT reactions (CTC2+), of whom 11 had severe complications (CTC3+). Polymerase chain reaction–restriction fragment length polymorphism (PCR-RFLP), single base extension and genotyping assays were performed to examine the polymorphic sites in TGFβ1 . Results: Homozygous variant -1.552delAGG, -509TT, and 10Pro genotypes were associated with the risk of developing late severe RT reactions. Triple (variant) homozygous patients had a 3.6 times increased risk to develop severe RT reactions ( p = 0.26). Neither the -800A allele, nor the 25Pro allele or the 263Ile allele were associated with clinical radiosensitivity. There was perfect linkage disequilibrium (LD) between the -1.552delAGG and the -509C>T polymorphisms, and tight LD between the -1.552/-509 and the Leu10Pro polymorphisms. Haplotype analysis revealed two major haplotypes but could not distinguish radiosensitive from nonradiosensitive patients. Conclusions: The present study shows that homozygous variant TGFβ1 -1.552delAGG, -509TT, and 10Pro genotypes may be associated with severe clinical radiosensitivity after gynecologic RT.

The aim of this study was to investigate the feasibility of administering increasing activities of (188)Re-4-hexadecyl-1-2,9,9-tetramethyl-4,7-diaza-1,10-decanethiol/lipiodol ((188)Re-HDD/lipiodol) for the treatment of hepatocellular carcinoma (HCC) in patients with well-compensated cirrhosis.The activity levels were increased by 1.1 GBq/step after a 6-week interval without unacceptable adverse events in at least five consecutive patients. Absorbed doses to the various organs were calculated according to the MIRD formalism, based on three gamma-scintigraphic studies. Response was assessed by means of MRI and alpha-fetoprotein (AFP) monitoring.Thirty-five treatments were carried out in 28 patients. Activities from 4.8 to 7.0 GBq (188)Re-HDD/lipiodol were administered via a transfemoral catheter. The mean absorbed dose to the liver (including tumour) was 7.6+/-2.2, 9.8+/-4.9 and 15.2+/-4.9 Gy for the 4.8-, 5.9- and 7.0-GBq groups, respectively. Treatment was well tolerated at all activity levels. Further escalation of the administered activity was not feasible owing to limitations related to the radiolabelling procedure. Response assessment on MRI showed partial response, stable disease and disease progression in 1, 28 and 2 assessable treatments, respectively. In 8 of 17 treatment sessions with an initially elevated AFP, a reduction ranging from 19% to 97% was observed 6 weeks later.Following the intra-arterial administration of 4.8-7.0 GBq (188)Re-HDD/lipiodol in patients with HCC and well-compensated liver cirrhosis, no severe adverse events occurred. Further escalation was not feasible owing to limitations in the radiolabelling procedure.

An evaluation of the image quality of an amorphous silicon flat-panel detector system and a computed radiology system compared with a screen-film system was performed by means of contrast-detail phantom images. Hard and soft copy images were evaluated. Although patient dose at clinical settings was strongly decreased with the amorphous silicon system, the low-contrast visibility with this system was still significantly better than with the screen-film system. For the computed radiology system, low-contrast visibility was comparable to the screen-film system. Best results were obtained by soft copy reading at full resolution with adaptation of contrast and brightness. Changing tube voltage (102-133 kV), or additional filtration, did not significantly affect image quality. However, low-contrast visibility improved significantly with increasing exposure. It was clearly demonstrated that, in chest imaging, the amorphous silicon system has superior imaging characteristics compared to the screen-film and the computed radiology system.

The importance and methodology of contemporary patient dosimetry in well-established radionuclide therapies are reviewed. The different protocols used for radioiodine treatment of thyrotoxicosis are discussed. Special attention is paid to patient dosimetry in the largest safe dose approach for curative radioiodine therapy of thyroid remnants and metastases in the post-surgical treatment of differentiated thyroid cancer. Nowadays, meta-[131I]iodobenzylguanidine (131I-MIBG) therapy for neuroblastoma relies on bone marrow dose levels. Issues related to whole-body and tumour dosimetry in this type of radionuclide therapy, where, traditionally, dosimetry has played an important role, are discussed. A relatively large number of patients are treated with radiolabelled Lipiodol for hepatocellular carcinoma. Administered activities are restricted to 2.22 GBq (60 mCi) when using 131I-lipiodol because of the radioprotection measures to be taken. These radiation protection issues can be avoided by using 188Re labelled Lipiodol allowing further dose escalation. The follow-up of these patients also necessitates whole-body dosimetry. It is concluded that for treatment of malignant diseases reliable patient dosimetry is now a keystone of high quality radionuclide therapy. Where dosimetry of present medical applications focuses generally on the critical organs, in the near future accurate 3-dimensional tumour dosimetry also will become feasible by the introduction of the combined SPECT-CT and PET-CT imaging systems in the dosimetric methodology. This will allow treatment protocols based on tumour dose prescriptions as performed in external beam radiotherapy.

The aim of this study was twofold: firstly, to determine whether the European Association of Nuclear Medicine (EANM) dosage card results in weight-independent effective doses or weight-independent count rates; secondly, to determine whether one dosage card is sufficient for 95 different radiopharmaceuticals, and, if not, how many cards we reasonably need to take into account inter-tracer variability.Normalisation factors for count rate and effective dose were calculated as a function of body weight, with 70 kg as standard. Calculations were performed, using whole-body absorption fractions and MIRDOSE 3 software, for seven anthropomorphic phantoms and ten radionuclides. An analytic function for both relations was proposed. Normalisation factors for effective dose for 95 radiopharmaceuticals were investigated using cluster analysis.Normalisation factors for count rate and effective dose can be estimated accurately as a function of body weight W by (W/70)a holding only one parameter, called the a value. The a values for 95 radiopharmaceuticals were classified into three clusters (nA=7, nB=76, nC=12). Cluster A contains tracers for renal studies. Cluster B contains all remaining tracers, except iodine-labelled tracers for thyroid studies and 89Sr for therapy, which belong to cluster C.Correction factors proposed by the EANM task group mainly correct for effective dose. They are very similar to the factors obtained for cluster A. Using the EANM factors for tracers belonging to clusters B and C results in significantly higher effective doses to children. We suggest using three tracer-dependent dosage cards for which the correction factors have been calculated to obtain weight-independent effective doses.

Background External beam radiotherapy and beta radioimmunotherapy (RIT) are effective treatments for lymphoid malignancies. The development of RIT with alpha emitters is attractive because of the high linear energy transfer (LET) and short path length, allowing higher tumour cell kill and lower toxicity to healthy tissues. Aim To assess the binding of rituximab to samples of B cell chronic lymphocytic leukaemia (B-CLL) and splenic lymphoma with villous lymphocytes (SLVL), and to evaluate the induction of apoptosis by conventional therapies as well as with 2 1 3 Bi conjugated to rituximab. Method 2 1 3 Bi was eluted from a 2 2 5 Ac generator and conjugated to CD20 antibody (rituximab) with CHX-A"-DTPA as chelator. Binding assays with 2 1 3 Bi-rituximab were correlated to antibody binding capacity obtained by flow cytometry. Apoptosis was scored by flow cytometric analyses of the cells stained with annexin V-FITC and 7-amino-actinomycin D. Results Binding of 2 1 3 Bi-rituximab was significantly lower for B-CLL compared to SLVL samples (12 ′ 3 and 42 ′ 10 2 1 3 Bi atoms per cell, respectively, at 370 kBq.ml - 1 ). The induction of apoptosis did not differ significantly between the two groups (B-CLL and SLVL) after external gamma irradiation or treatment with methylprednisolone and fludarabine (17 ′ 12% and 18 ′ 11%; 23 ′ 14% and 21 ′ 12%; 9 ′ 9% and 11 ′ 8%, respectively; all results expressed as percentages of all cells). Rituximab conjugated or not to 2 1 3 Bi induced significantly more apoptosis in SLVL (42 ′ 19% and 42 ′ 17%) compared to B-CLL samples (27 ′ 12% and 6 ′ 8%). Conclusion Binding assays confirm that SLVL samples present more CD20 antigens compared to B-CLL samples. Conventional therapies such as fludarabine, methylprednisolone or external gamma irradiation induce similar responses in the two populations but SLVL samples present higher sensitivity towards 2 1 3 Bi-rituximab. These data are in favour of alpha-RIT in SLVL patients.

Purpose To determine accurately the radiation burden of both patients and staff from intracoronary radiotherapy (IRT) with 192 Ir and to investigate the importance of IRT in the patient dose compared with interventional X-rays. Methods and materials The Radiation Burden Assessment Study (RABAS) population consisted of 9 patients undergoing γ-IRT after percutaneous transluminal coronary angioplasty and 14 patients undergoing percutaneous transluminal coronary angioplasty only as the control group. For each patient, the dose to the organs and tissues from the internal and external exposure was determined in detail by Monte Carlo N-particle simulations. Patient skin dose measurements with thermoluminescence dosimeters served as verification. Staff dosimetry was performed with electronic dosimeters, thermoluminescence dosimeters, and double film badge dosimetry. Results With respect to the patient dose from IRT, the critical organs are the thymus (58 mGy), lungs (31 mGy), and esophagus (27 mGy). The mean effective dose from IRT was 8 mSv. The effective dose values from interventional X-rays showed a broad range (2–28 mSv), with mean values of 8 mSv for the IRT patients and 13 mSv for the control group. The mean dose received by the radiotherapist from IRT was 4 μSv/treatment. The doses to the other staff members were completely negligible. Conclusion Our results have shown that the patient and personnel doses in γ-IRT remain at an acceptable level. The patient dose from IRT was within the variations in dose from the accompanying interventional X-rays.

Several authors have demonstrated the good tolerance of hepatic intra-arterial 131 I-Lipiodol therapy and report survival rates of 21-25% after 1 year in inoperable patients. This study explored the possibility that more selective hepatic arterial instillation could be a strategy for increasing tumoural uptake and response of 131 I-Lipiodol. Between June 1999 and September 2001 we selected 24 patients: 14 received a selective instillation of 131 I-Lipiodol to the proper hepatic artery (SEL group); and 10 received a hyperselective instillation in the right or left hepatic artery (HYP-SEL group). The individual 131 I-Lipiodol activity as a per cent of the injected activity per millilitre of tumour (%IA/ml tumour) was correlated with the selectivity of instillation in 28 tumours and with tumour response in 24 tumours. Differences in tumour response or tumour uptake between the SEL and HYP-SEL groups were not significant. In general, we observed a %IA/ml tumour of 0.05-2.6% for the uptake of 131 I-Lipiodol. The uptake was significantly higher in responsive disease than in stable or progressive disease (P = 0.002). A large tumour volume was invariably related to low uptake of 131 I-Lipiodol and progressive disease (P = 0.008). In conclusion, our study does not support the general use of hyper-selective or super-selective intra-arterial administration of 131 I-Lipiodol. This result may be extrapolated to similar types of intra-arterial, loco-regional hepatic radionuclide therapy.

Patient dosimetry data for intra-arterial()iodine-131 lipiodol therapy for hepatocellular carcinoma (HCC) are scarce. The aim of this study was to determine the absorbed dose (D) to the tumour and healthy tissues, as well as the effective dose (E), by different methods for 17 therapies in 15 patients who received a mean activity of 1.9 GBq (SD 0.2) (131)I-lipiodol. Eight patients received thyroid blocking by potassium iodide (KI). Patient dosimetry was performed based on bi-planar total body scans using the Monte Carlo simulation program MCNP-4B and the MIRDOSE-3 standard software program. CT images of each patient were used to determine liver and tumour volume and position. The total body dose to the patient was also determined by biological dosimetry with the in vitro micronucleus (MN) assay. From the increase in micronucleus yield after therapy, the equivalent total body dose (ETBD) was calculated. Results for D and E were comparable between MCNP and MIRDOSE (liver: mean 7.8 Gy, SD 1.8, lungs: 6.8 Gy, SD 2.9, E: 2.01 Gy, SD 0.58). MIRDOSE gave a systematic overestimation for the tumour dose, especially for tumours3 cm (15%). The MCNP method is more accurate since the dose contributions from tumour to organs and vice versa can be accounted for. The absorbed dose to the thyroid was significantly lower for patients who received KI (7.2 Gy, SD 2.2) than for the other patients (13.8 Gy, SD 5.0). MN yields could be obtained for only 12 of the 17 therapies due to hypersplenism. A mean ETBD of 1.66 Gy (SD 0.73) was obtained, but the MN results showed no correlation between the ETBD and the total body dose values of the physical dosimetry. Also, in all except one of the patients, no further reduction in the number of thrombocytes was observed after therapy, probably due to the existing hypersplenism. It is concluded that in view of the high E values, patient dosimetry is necessary for patients receiving (131)I-lipiodol therapy. Except in the case of the smaller tumours, comparable results were obtained with MCNP and MIRDOSE. Due to hypersplenism, biological dosimetry results based on the MN assay are not reliable.

Objectives The purpose of this study was to quantify the reduction in patient radiation dose during coronary angiography (CA) by a new X-ray technology, and to assess its impact on diagnostic image quality. Background Recently, a novel X-ray imaging technology has become available for interventional cardiology, using advanced image processing and an optimized acquisition chain for radiation dose reduction. Methods 70 adult patients were randomly assigned to a reference X-ray system or the novel X-ray system. Patient demographics were registered and exposure parameters were recorded for each radiation event. Clinical image quality was assessed for both patient groups. Results With the same angiographic technique and a comparable patient population, the new imaging technology was associated with a 75% reduction in total kerma-area product (KAP) value (decrease from 47 Gycm2 to 12 Gycm2, P

To investigate the impact of digitalisation on performance parameters and breast dose of the Flemish Breast Cancer Screening Programme. Both computed (CR) and direct radiography (DR) are compared with screen-film mammography (SFM).Data from 975,673 mammographic examinations were collected from units which underwent digitalisation from SFM to CR (41 units) or DR (72 units) in the period 2005-2011. Performance indicators were obtained by consulting the Screening Programme database. Phantom and patient dosimetry data were acquired from the physical technical quality assurance of the programme.Digitalisation induced no significant change in cancer detection rate (CDR), percentage of ductal carcinomas in situ and percentage of breast cancers smaller than 1 cm. A decrease in false-positive results and third readings was observed, which was a time-related observation. After digitalisation, positive predictive value (PPV) increased and recall rates decreased. Compared with SFM, an increase of 30% in mean glandular dose (MGD) was found for CR, while a similar change in the opposite direction was found for DR.No major differences in performance parameters after digitalisation were found. Transition of SFM to CR resulted in a higher MGD and associated lower detection-over-induction ratio (DIR), while the change to DR induced an improvement of DIR.• Performance parameters showed no major differences after digitalisation to CR or DR. • Transition from SFM to CR results in a higher mean glandular dose. • Transition from SFM to DR results in a lower mean glandular dose.

The purpose of this study was to assess patient-specific organ doses and cancer risk with 3D-rotational acquisitions versus the current standard of multiple single-plane coronary angiography (CA).Catheter-based CA remains one of the most commonly performed diagnostic invasive procedures delivering a relatively high radiation dose to the patient. With the introduction of flat-panel technology, three-dimensional rotational angiography became an alternative for the conventional two-dimensional angiography. However, limited information is available on the difference in patient radiation exposure with both acquisition techniques.Eighty adult patients (45 males, age 38-93 years) were randomly assigned to the rotational or standard angiography group. Exposure parameters were registered and skin dose distribution was measured during the procedure. Patient-specific organ doses and related cancer risks were assessed with dedicated software.Rotational angiograms were associated with 33% lower KAP-values (decrease from 49.99 Gycm(2) to 33.37 Gycm(2), P0.001). A significant (P0.001) lower peak skin dose was measured with rotational acquisitions (80 mGy, median) versus planar imaging (172 mGy, median). Moreover, the skin dose was smoothed over the whole chest of the patient. Contrast medium consumption decreased from 104 mL to 73 mL (P0.001) with the use of 3D-imaging. The reduction in radiation exposure resulted in a corresponding decrease of organ doses. The latter contributed to an overall cancer risk reduction of 21% for males and 50% for females.The current study demonstrates that in CA radiation risk reduction is feasible by using a rotational acquisition technique.

Purpose The impact on patients’ health of radiopharmaceuticals in nuclear medicine diagnostics has not until now been evaluated systematically in a European context. Therefore, as part of the EU-funded Project PEDDOSE.NET (www.peddose.net), we review and summarize the current knowledge on biokinetics and dosimetry of commonly used diagnostic radiopharmaceuticals. Methods A detailed literature search on published biokinetic and dosimetric data was performed mostly via PubMed (www.ncbi.nlm.nih.gov/pubmed). In principle the criteria for inclusion of data followed the EANM Dosimetry Committee guidance document on good clinical reporting. Results Data on dosimetry and biokinetics can be difficult to find, are scattered in various journals and, especially in paediatric nuclear medicine, are very scarce. The data collection and calculation methods vary with respect to the time-points, bladder voiding, dose assessment after the last data point and the way the effective dose was calculated. In many studies the number of subjects included for obtaining biokinetic and dosimetry data was fewer than ten, and some of the biokinetic data were acquired more than 20 years ago. Conclusion It would be of interest to generate new data on biokinetics and dosimetry in diagnostic nuclear medicine using state-of-the-art equipment and more uniform dosimetry protocols. For easier public access to dosimetry data for diagnostic radiopharmaceuticals, a database containing these data should be created and maintained. Electronic supplementary material The online version of this article (doi:10.1007/s00259-011-1904-z) contains supplementary material, which is available to authorized users.

The purpose of this study was to evaluate the diagnostic performance of digital tomosynthesis in comparison with digital radiography in the detection of urinary stones with MDCT as the reference standard.Fifty consecutively enrolled patients (32 men, 18 women; mean age, 51.5 years; range, 19-83 years) referred for unenhanced MDCT of the abdomen with suspicion of urinary stones also underwent digital tomosynthesis and digital radiography (anteroposterior and bladder inlet views). Images from all examinations were randomly read by three blinded radiologists. The mean effective doses for digital tomosynthesis, digital radiography, and low- and high-dose MDCT were measured on a male phantom. Free-response receiver operating characteristics and receiver operating characteristics analyses were used to compare the diagnostic performance of digital radiography with that of digital tomosynthesis.Both types of analysis showed significantly better performance of tomosynthesis over digital radiography for all urinary stones (p0.05). No such improvement was found for ureteral stones. The gain in sensitivity with tomosynthesis was largest for stones between 2 and 5 mm in diameter. The mean effective dose was 0.5 mSv for digital radiography, 0.85 mSv for tomosynthesis, 2.5 mSv for low-dose MDCT, and 12.6 mSv for high-dose MDCT.Use of digital tomosynthesis of the abdomen results in improved detection of urinary stones in general over digital radiography with only a slight increase in effective dose. Use of tomosynthesis, however, was not associated with major improvement in the diagnosis of ureteral stones. The technique has potential as an alternative imaging technique in the detection and follow-up of urinary stones.

KEY WORDS cytology; webviewer; digital image; innovative microscopy; ultrastructureABSTRACT Virtual microscopy of histological glass slides can emulate conventional light mi-croscopy. Up till now, such a digital simulation does not exist for ultrathin electron microscopicslides. Because of the relative inaccessibility of electron microscopy, evaluation of subcellular struc-tures by (bio)medical students is performed with the aid of photographic prints. In this article, thegeneration and evaluation of virtual electron microscopic slides is discussed. AT-lymphoblastic cellwas used as an example. Electron microscopic pictures were taken at two magnifications (25,000and 50,000), processed in an analogue or digital way and stitched to reconstruct the image of thetotal cell. This image is viewed with a webviewer equipped with pan and zoom functions. The possi-bility of distinguishing the trilaminar structure of cellular membranes was the requisite. Virtualimages obtained at an original magnification of 25,000, scanned at a resolution of 800 ppi couldcompete with pictures developed directly from negatives obtained by electron microscopy. It is pos-sible to navigate and zoom into details in a way emulating electron microscopy. Virtual electron mi-croscopy is innovative and offers new perspectives to interpret cytological pictures and to teach cellbiology in an interactive and unique way. Microsc. Res. Tech. 74:251–256, 2011.

Background— A better knowledge of patient x-ray dose and the associated radiation risk in pediatric interventional cardiology is warranted in view of the extensive use of x-rays and the higher radiosensitivity of children. In the present study, γ-H2AX foci were used as a biomarker for radiation-induced effects. Patient-specific dose was assessed and radiation risks were estimated according to the linear-no-threshold model, commonly used in radiation protection, and the γ-H2AX foci data. Methods and Results— In 49 pediatric patients (median age, 0.75 years) with congenital heart disease who underwent cardiac catheterization procedures, blood samples were taken before and shortly after the procedure. γ-H2AX foci were determined in peripheral blood T lymphocytes. In each patient, a net increase in γ-H2AX foci, representing DNA double-strand breaks induced by interventional x-rays, was observed. In addition, a patient-specific Monte Carlo simulation of the procedure was performed, resulting in individual blood, organ, and tissue doses. Plotting of γ-H2AX foci versus blood dose indicated a low-dose hypersensitivity. Median effective doses calculated according to the International Commission on Radiological Protection 60 and 103 publications are 5.6 and 6.4 mSv, respectively. The lifetime-attributable risk of cancer mortality was calculated from the linear-no-threshold model and the γ-H2AX foci data. This resulted in lifetime-attributable risk values of 1% and 4%, respectively, for the patient population under study. Conclusions— γ-H2AX foci as a biomarker for DNA damage indicate that radiation risk estimates according to the linear-no-threshold hypothesis are possibly underestimates. Great care should be taken to minimize and optimize patient radiation exposure.

Alemtuzumab (Campath, Berlex) is a humanized IgG1 rat monoclonal antibody directed against the cell surface CD52 antigen, found on lymphocytes and monocytes. It is being developed for the treatment of chronic lymphocytic leukemia (CLL), autoinumme disease and for the prevention of transplant rejection. This study focused on synthesis, quality control, in vitro evaluation and biodistrubution of Re-188-labeled alemtuzumab for radioimmunotherapy of B-cell CLL.Re-188-alemtuzumab was synthesized using a direct radiolabeling method. Reduction of the intramolecular disulfide bonds of the antibody was performed with tris-(carboxyethyl)-phosphine (Pierce), using a 1:60 molar excess. Reaction took place at room temperature for 20 min. A PD-10 desalting column was used to purify the reduced antibody from excess phospine.Complexation and transchelation of (ReO4-)-Re-188 was achieved using sodium gluconate as weak chelator and SnCl2 as reducing agent. Quality control was done using instant thin-layer chromatography. Binding assays were performed on a CD52-positive cell line (HuT-78). Female NMRI mice were injected intravenously with 20 mu g radiolabeled alemtuzumab and killed at preset time intervals for biodistribution studies. Tissues were dissected, weighed and counted for determination of radioactivity. Data were expressed as percentage injected activity per gram of tissue (% IA/g tissue) or as percentage injected activity (%IA).Re-188-alemtuzumab was prepared achieving high radiochemical yields. Labeling efficiency of more than 95% can be obtained using optimal reaction conditions. Re-188-alemtuzumab showed good in vitro stability, remaining intact at 24 h after radiolabeling. In mice, Re-188-alemtuzumab showed high uptake in the blood (25.10 +/- 1.36% IA at 1 h p.i.), followed by a biexponential clearance (t(1/2 alpha) =4.790 h and t(1/2 beta)=55.45 h). Increased uptake was observed in kidneys and heart (9.29 +/- 0.46% IA/g in kidneys and 6.10 +/- 1.82% IA/g in heart at I p.i.). The highest absorbed radiation dose was received by the kidneys (0.159-3.26 mGy/MBq) and heart wall (0.0705-0.132 mGy/MBq). The predicted radiation dose for the total body was in the range of 0.0459-0.0529 mGy/MBq. The effective dose for the human reference adult was estimated to be approximately 0.0486-0.195 mSv/mBq.Re-188-alemtuzumab can be prepared with high radiochemical yield and purity and showed good in vitro behavior and favorable biodistribution. Therefore, Re-188-alemtuzumab would be an ideal candidate for radioimmunotherapy of chronic lymphocytic leukemia. (C) 2008 Elsevier Inc. All rights reserved.

Effective dose ( E), representing the risk of late radiation-induced effects, can be estimated by the use of conversion factors (CF), converting direct measurable quantities such as dose-area-product into E. Eight Belgian hospitals participated in the study with a total number of 318 procedures. E-values, calculated with PCXMC, were compared for the different hospitals for diagnostic and therapeutic procedures separately. E-values varied significantly depending on the hospital where the procedure was performed (P < 0.001), on filtration insertion (P < 0.001), on whether a centre is a training centre or not, the dose conscious action of the cardiologists and the complexity of the procedure ( P < 0.001). Hospital-specific CF were calculated. An average CF of 0.185 mSv Gycm(-2) was obtained with a satisfactory correlation (r = 0.966, P < 0.001). The differences in CF between hospitals were due to, a large extent, the availability of additional filtration in cinegraphy mode (P < 0.001) and not to the differences in irradiation geometries in the clinical protocol of the interventional procedures.

To investigate compliance with the acceptance criteria of the European guidelines for quality assurance in breast cancer screening, a typetesting programme of the physical characteristics of digital mammography systems based on direct readout (DR) technology or computed radiography (CR) was organised and executed within the Flemish breast cancer screening programme. While in general image quality/dose characteristics of flat panel DR systems passed the acceptance criteria more easily than CR systems, the slit-scanning direct photon counting system included in present study was outstanding in combining a very low dose with a good image quality. The data obtained up to now indicate the necessity of retuning the AEC for DR systems according to constant contrast to noise ratio (CNR) over the whole range of PMMA thicknesses (20–70 mm) to improve image quality in imaging breasts of large thickness at the cost of higher doses. For the two CR systems which passed the typetesting procedure dose levels do not allow a similar improvement of CNR for thick objects for these systems. The obtained results highlight the importance of the use of high Z target/filter combinations in X-ray generating systems for imaging thick objects to meet the image quality/dose criteria. With respect to image display aspects high-quality 3-megapixel LCD monitors succeeded also in the typetesting procedure in addition to 5-megapixel monitors. However, as zooming and scrolling are necessary for 3-megapixel monitors to get the full resolution capabilities of the image capture system, 5-megapixel monitors are preferred in a busy screening environment.

External beam radiotherapy and beta-radioimmunotherapy (RIT) are effective treatments for lymphoid malignancies. The development of RIT with alpha-emitters is attractive, owing to the high (LET) nature and short path length of alpha particles allowing for higher tumor cell kill and lower toxicity to healthy tissues.The aim of this study was to assess the response of B-Cell chronic lymphocytic leukemia (B-CLL) cells in vitro after treatment with chemotherapy (cisplatin, fludarabine, doxorubicin, or vincristine) or other pharmaceuticals (colchicine, simvastatin, or cyclosporin A) in combination with (60)Co-gamma or (213)Bi-alpha-irradiation.(213)Bi was eluted from a (225)Ac generator. Apoptosis was scored by flow cytometric analysis of the cells stained with Annexin-V and 7 amino actinomycin D. Metabolic activity was assessed by a MTT assay.The response induced by alpha- irradiation is systematically higher than the response induced by gamma-irradiation. The combination of drug treatment with alpha-irradiation induced a systematic, higher response, compared to treatment with drugs alone, even for the highest concentrations used. For all the drugs used in this study, synergism or additivity was demonstrated for the combination of drugs and radiotherapy with a stronger effect for alpha-particles.The results of this in vitro study highlight a potential benefit of alpha-irradiation in combination with the drugs considered in this study.

Earlier reports described the preferential uptake of d-amino acids in tumor-bearing mice. Moreover, it was shown that in tumor cells in vitro the L-amino acid transporter system seemed to lack stereospecificity. Because of the successful results with 123/125I-2-iodo-L-phenylalanine, 123/125I-2-iodo-D-phenylalanine was developed, and its tumor-detecting characteristics were evaluated in vivo.123I labeling of 2-iodo-D-phenylalanine was performed with a kit formulation by use of Cu1+-assisted nucleophilic exchange. 123I-2-Iodo-D-phenylalanine was evaluated in R1M tumor-bearing athymic mice by dynamic planar imaging (DPI) and dissection. The in vivo stability of the tracer was tested by high-performance liquid chromatography. Tumor tracer retention and tracer contrast were evaluated as a function of time. Two-compartment blood modeling from DPI results and dosimetric calculations from biodistribution results were carried out. Moreover, 125I-2-iodo-D-phenylalanine and 18F-FDG uptake in acute inflammation was investigated.123I-2-Iodo-D-phenylalanine was metabolically stable. Fast, high, and specific tumor retention was observed. Two-compartment modeling confirmed the fast clearance of the tracer through the kidneys to the bladder, as observed by DPI and dissection. Moreover, compared with the L-isomer, 123I-2-iodo-D-phenylalanine demonstrated faster clearance and faster uptake in the peripheral compartment. No accumulation in the abdomen or in the brain was noted. Dosimetry revealed that 123I-2-iodo-D-phenylalanine demonstrated a low radiation burden comparable to those of 123I-2-iodo-L-phenylalanine and 123I-2-iodo-L-tyrosine. Although 123I-2-iodo-D-phenylalanine showed a tumor retention of only 4%, the tumor contrast was increased up to 350% at 19 h after injection.123I-2-Iodo-D-phenylalanine is a promising tracer for diagnostic oncologic imaging because of its high, fast, and specific tumor uptake and fast clearance from blood.

This study aimed to investigate the feasibility of the intraarterial administration of 3.7 GBq (188)Re-4-hexadecyl-1-2,9,9-tetramethyl-4,7-diaza-1,10-decanethiol/lipiodol ((188)Re-HDD/lipiodol) for treatment of hepatocellular carcinoma (HCC) in patients with moderately advanced cirrhosis.Patients with HCC and underlying cirrhosis classified as Child-Pugh B in terms of severity were eligible. Whole-body scintigraphies were performed at 4 time points after injection. Absorbed doses to the various organs were calculated according to the MIRD formalism. Urine was collected for 52 h after injection. Toxicity was assessed until 6 wk after administration by means of the Common Toxicity Criteria for Adverse Events (version 3.0) scale. Responses were evaluated on MRI and by alpha-fetoprotein (AFP) monitoring.A mean activity +/- SD of 3.7 +/- 0.2 GBq (188)Re-HDD/lipiodol was administered in the hepatic artery to 12 patients; 36.2% +/- 5.7% of the activity was excreted in the urine 52 h after injection. The absorbed dose to the liver, lungs, kidney, and thyroid was 7.6 +/- 2.9, 4.8 +/- 2.6, 0.8 +/- 0.7, and 0.2 +/- 0.1 Gy (mean +/- SD), respectively. Two weeks after administration, 6 of 12 patients had adverse events consisting of aggravations of preexisting laboratory changes (3 patients), fatigue (2 patients), vomiting (1 patient), fever (1 patient), encephalopathy (1 patient), and ascites (1 patient). Toxicity assessment at week 6 revealed single cases of the worsening of hyperbilirubinemia, pleural effusion, thrombocytopenia, and dyspnea. Three patients dropped out of the study because of deterioration of their general condition. The response was assessable by MRI in 8 patients: 1 patient with a partial response and 7 patients with stable disease were reported. Nine patients with an initially elevated AFP were evaluated. Stable AFP was recorded in 1 patient and 3 showed a reduction, whereas a considerable increase was observed in 5 patients.After the administration of 3.7 GBq (188)Re-HDD/lipiodol, half of the Child-Pugh B patients in the present study had a worsening of their general condition or aggravation of preexisting symptoms. This was associated with a rise in AFP in a considerable number of patients. In the future, administration of the radiopharmaceutical as close to the tumor feeding arteries as possible might avoid further deterioration of the liver function and show enhanced antitumoral activity.

This paper reports on the biodistribution and dosimetry of (99m)Tc-depreotide in patients.Whole body planar images were acquired 30 minutes, 1, 2, 4, 9, and 24 hours after intravenous injection of 555-740MBq (99m)Tc-depreotide in 5 breast cancer patients. Urine was collected up to 24 hours after injection, allowing for a calculation of renal clearance and an interpretation of whole body clearance. Time activity curves were generated for the thyroid, lungs, liver, spleen, kidneys, colon, thoracic vertebrae/sternum, and whole body by fitting the organ-specific geometric mean counts, obtained from regions of interest (ROIs). The Medical Internal Radiation Dose (MIRD) formulation was applied to calculate the absorbed radiation dose for various organs.The whole body images show most of the activity distributed in the liver, spleen, and kidneys. Nearly all excretion of activity occurred by the renal system, and hepatobiliary excretion was negligible. Elimination of administered activity occurred predominantly through physical decay. The mean cumulative measured urinary excretion at 24 hours postinjection was 14.0% (standard deviation; 11.8%) of the administered activity. The highest absorbed dose was received by the kidneys, thyroid, and spleen. The average effective dose was estimated to be 1.15E-02mSv/MBq (standard deviation; 1.41E-03mSv/MBq).The biodistribution of (99m)Tc-depreotide demonstrated low lung and myocardial uptake allowing early imaging of the supradiaphragmatic region and this with a dosimetry favorable for clinical whole body and single photon emission computed tomography (SPECT) imaging.

The aim of this study was to investigate the pharmacokinetics, organ dosimetry, and toxicity after the intraarterial administration of (188)Re-labeled 4-hexadecyl-1,2,9,9-tetramethyl-4,7-diaza-1,10-decanethiol/lipiodol ((188)Re-HDD/lipiodol) for palliative treatment of hepatocellular carcinoma (HCC). A secondary objective was to document the response.A mean activity of 3.60 GBq (188)Re-HDD/lipiodol (range, 1.86-4.14 GBq) was administered to 11 patients (16 treatment sessions) via a transfemoral catheter. The pharmacokinetic and dosimetric data were collected by means of venous blood samples, urine collections, and 4 or 5 gamma-scintigraphies over 76 h. Absorbed doses to the various organs were calculated according to the MIRD formalism, using the MIRDOSE3.1 software. The toxicity was assessed until 6 wk after administration by means of the Common Toxicity Criteria scale. The response was evaluated on MRI and by monitoring of the tumor marker.A fast blood clearance of the injected activity was observed with a calculated effective half-life of 7.6 +/- 2.2 h (+/-SD) in blood. The predominant elimination of the activity was through urinary excretion with a mean renal clearance of 44.1% +/- 11.7% (+/-SD) of the injected activity within the 76 h after administration. Fecal elimination was negligible. The calculated whole-body effective half-life was 14.3 +/- 0.9 h (+/-SD). The absorbed dose to the liver tissue, the lungs, the kidneys, and the thyroid was 4.5 +/- 1.9, 4.1 +/- 1.2, 0.9 +/- 0.7, and 0.3 +/- 0.1 Gy, respectively. Treatment was well tolerated, except in 2 patients. One Child B patient experienced a worsening of his liver dysfunction (hyperbilirubinemia) and another patient experienced dyspnea and coughing. Response assessment on MRI showed 1 case of partial response, disease stabilization in 11 treatments, and progressive disease in 1 treatment. In 5 of 8 treatment sessions with an initially elevated alpha-fetoprotein, a reduction (range, 19%-90%) was observed 6 wk later.After the intraarterial administration of 3.60 GBq (188)Re-HDD/lipiodol, a fast clearance of the activity appearing in the blood is observed and the predominant elimination is through urinary excretion. The tolerance as well as the preliminary response rates of the present phase I study are encouraging.