<p>A bench-top dual cone-beam computed tomography (CBCT) system was developed consisting of two orthogonally placed 40x30 cm<super>2</super> flat-panel detectors and two conventional X-ray tubes with two individual high-voltage generators sharing the same rotational axis. The X-ray source to detector distance is 150 cm and X-ray source to rotational axis distance is 100 cm for both subsystems. The objects are scanned through 200° of rotation. The dual CBCT (DCBCT) system utilized 110° of projection data from one detector and 90° from the other while the two individual single CBCTs utilized 200° data from each detector. The system performance was characterized in terms of uniformity, contrast, spatial resolution, noise power spectrum and CT number linearity. The uniformity, within the axial slice and along the longitudinal direction, and noise power spectrum were assessed by scanning a water bucket; the contrast and CT number linearity were measured using the Catphan phantom; and the spatial resolution was evaluated using a tungsten wire phantom. A skull phantom and a ham were also scanned to provide qualitative evaluation of high- and low-contrast resolution. Each measurement was compared between dual and single CBCT systems.</p><p>Compared with single CBCT, the DCBCT presented: 1) a decrease in uniformity by 1.9% in axial view and 1.1% in the longitudinal view, as averaged for four energies (80, 100, 125 and 150 kVp); 2) comparable or slightly better contrast to noise ratio (CNR) for low-contrast objects and comparable contrast for high-contrast objects; 3) comparable spatial resolution; 4) comparable CT number linearity with R<super>2</super> &#8805; 0.99 for all four tested energies; 5) lower noise power spectrum in magnitude. DCBCT images of the skull phantom and the ham demonstrated both high-contrast resolution and good soft-tissue contrast.</p><p>One of the major challenges for clinical implementation of four-dimensional (4D) CBCT is the long scan time. To investigate the 4D imaging capabilities of the DCBCT system, motion phantom studies were conducted to validate the efficiency by comparing 4D images generated from 4D-DCBCT and 4D-CBCT. First, a simple sinusoidal profile was used to confirm the scan time reduction. Next, both irregular sinusoidal and patient-derived profiles were used to investigate the advantage of temporally correlated orthogonal projections due to a reduced scan time. Normalized mutual information (NMI) between 4D-DCBCT and 4D-CBCT was used for quantitative evaluation.</p><p>For the simple sinusoidal profile, the average NMI for ten phases between two single 4D-CBCTs was 0.336, indicating the maximum NMI that can be achieved for this study. The average NMIs between 4D-DCBCT and each single 4D-CBCT were 0.331 and 0.320. For both irregular sinusoidal and patient-derived profiles, 4D-DCBCT generated phase images with less motion blurring when compared with single 4D-CBCT.</p><p>For dual kV energy imaging, we acquired 80kVp projections and 150 kVp projections, with an additional 0.8 mm tin filtration. The virtual monochromatic (VM) technique was implemented, by first decomposing these projections into acrylic and aluminum basis material projections to synthesize VM projections, which were then used to reconstruct VM CBCTs. The effect of the VM CBCT on metal artifact reduction was evaluated with an in-house titanium-BB phantom. The optimal VM energy to maximize CNR for iodine contrast and minimize beam hardening in VM CBCT was determined using a water phantom containing two iodine concentrations. The linearly-mixed (LM) technique was implemented by linearly combining the low- (80kVp) and high-energy (150kVp) CBCTs. The dose partitioning between low- and high-energy CBCTs was varied (20%, 40%, 60% and 80% for low-energy) while keeping total dose approximately equal to single-energy CBCTs, measured using an ion chamber. Noise levels and CNRs for four tissue types were investigated for dual-energy LM CBCTs in comparison with single-energy CBCTs at 80, 100, 125 and 150kVp.</p><p>The VM technique showed a substantial reduction of metal artifacts at 100 keV with a 40% reduction in the background standard deviation compared with a 125 kVp single-energy scan of equal dose. The VM energy to maximize CNR for both iodine concentrations and minimize beam hardening in the metal-free object was 50 keV and 60 keV, respectively. The difference in average noise levels measured in the phantom background was 1.2% for dual-energy LM CBCTs and equivalent-dose single-energy CBCTs. CNR values in the LM CBCTs of any dose partitioning were better than those of 150 kVp single-energy CBCTs. The average CNRs for four tissue types with 80% dose fraction at low-energy showed 9.0% and 4.1% improvement relative to 100 kVp and 125 kVp single-energy CBCTs, respectively. CNRs for low contrast objects improved as dose partitioning was more heavily weighted towards low-energy (80kVp) for LM CBCTs.</p><p>For application of the dual-energy technique in the kilovoltage (kV) and megavoltage (MV) range, we acquired both MV projections (from gantry angle of 0° to 100°) and kV projections (90° to 200°) with the current orthogonal kV/MV imaging hardware equipped in modern linear accelerators, as gantry rotated a total of 110°. A selected range of overlap projections between 90° to 100° were then decomposed into two material projections using experimentally determined parameters from orthogonally stacked aluminum and acrylic step-wedges. Given attenuation coefficients of aluminum and acrylic at a predetermined energy, one set of VM projections could be synthesized from two corresponding sets of decomposed projections. Two linear functions were generated using projection information at overlap angles to convert kV and MV projections at non-overlap angles to approximate VM projections for CBCT reconstruction. The CNRs were calculated for different inserts in VM CBCTs of a CatPhan phantom with various selected energies and compared with those in kV and MV CBCTs. The effect of overlap projection number on CNR was evaluated. Additionally, the effect of beam orientation was studied by scanning the CatPhan sandwiched with two 5 cm solid-water phantoms on both lateral sides and an electronic density phantom with two metal bolt inserts.</p><p>Proper selection of VM energy (30keV and 40keV for low-density polyethylene (LDPE), polymethylpentene (PMP), 2MeV for Delrin) provided comparable or even better CNR results as compared with kV or MV CBCT. An increased number of overlap between kV and MV projections demonstrated only marginal improvements of CNR for different inserts (with the exception of LDPE) and therefore one projection overlap was found to be sufficient for the CatPhan study. It was also evident that the optimal CBCT image quality was achieved when MV beams penetrated through the heavy attenuation direction of the object. </p><p>In conclusion, the performance of a bench-top DCBCT imaging system has been characterized and is comparable to that of a single CBCT. The 4D-DCBCT provides an efficient 4D imaging technique for motion management. The scan time is reduced by approximately a factor of two. The temporally correlated orthogonal projections improved the image blur across 4D phase images. Dual-energy CBCT imaging techniques were implemented to synthesize VM CBCT and LM CBCTs. VM CBCT was effective at achieving metal artifact reduction. Depending on the dose-partitioning scheme, LM CBCT demonstrated the potential to improve CNR for low contrast objects compared with single-energy CBCT acquired with equivalent dose. A novel technique was developed to generate VM CBCTs from kV/MV projections. This technique has the potential to improve CNR at selected VM energies and to suppress artifacts at appropriate beam orientations.</p> / Dissertation

<p>Tissue stiffness can be an indicator of various types of ailments. However, no standard diagnostic imaging modality has the capability to depict the stiffness of tissue. To overcome this deficiency, various elasticity imaging methods have been proposed over the past 20 years. A promising technique for elasticity imaging is acoustic radiation force impulse (ARFI) based shear wave imaging. Spatially localized acoustic radiation force excitation is applied impulsively to generate shear waves in tissue and its stiffness is quantified by measuring the shear wave speed (SWS).</p><p>The aim of this thesis is to contribute to both the clinical application of ARFI shear wave imaging and its technical development using the latest advancements in ultrasound imaging capabilities.</p><p>To achieve the first of these two goals, a pilot imaging study was conducted to evaluate the suitability of ARFI shear wave imaging for the assessment of liver fibrosis using a rodent model of the disease. The stiffness of severely fibrotic rat livers were found to be significantly higher than healthy livers. In addition, liver stiffness was correlated with fibrosis as quantified using collagen content.</p><p>Based on these findings, an imaging study was conducted on patients undergoing liver biopsy at the Duke University Medical Center. A robust SWS estimation algorithm was implemented to deal with noisy patient shear wave data using the random sample consensus (RANSAC) approach. RANSAC estimated liver stiffness was found to be higher in severely fibrotic and cirrhotic livers, suggesting that ARFI shear wave imaging may potentially be useful for the staging of severe</p><p>fibrosis in humans.</p><p>To achieve the second aim of this thesis, a system capable of monitoring ARFI induced shear wave propagation in 3D was implemented using a 2D matrix array transducer. This capability was previously unavailable with conventional 1D arrays. This system was used to study the precision of time-of-flight (TOF) based SWS estimation. It was found that by placing tracking beam locations at the edges of the SWS measurement region of interest using the 2D matrix array, TOF SWS precision could be improved in a homogeneous medium.</p><p>The 3D shear wave imaging system was also used to measure the SWS in muscle, which does not conform to the isotropic mechanical behavior usually assumed for tissue, due to the parallel arrangement of muscle fibers. It is shown that the SWS along and across the fibers, as well as the 3D fiber orientation can be estimated from a single 3D shear wave data-set. In addition, these measurements can be made independent of the probe orientation relative to the fibers. This suggests that 3D shear wave imaging can be useful for characterizing anisotropic mechanical properties of tissue.</p> / Dissertation

<p>The rupture of arterial plaques is the most common cause of ischemic complications including stroke, the fourth leading cause of death and number one cause of long term disability in the United States. Unfortunately, because conventional diagnostic tools fail to identify plaques that confer the highest risk, often a disabling stroke and/or sudden death is the first sign of disease. A diagnostic method capable of characterizing plaque vulnerability would likely enhance the predictive ability and ultimately the treatment of stroke before the onset of clinical events.</p><p>This dissertation evaluates the hypothesis that Acoustic Radiation Force Impulse (ARFI) imaging can noninvasively identify lipid regions, that have been shown to increase a plaque's propensity to rupture, within carotid artery plaques <italic>in vivo</italic>. The work detailed herein describes development efforts and results from simulations and experiments that were performed to evaluate this hypothesis.</p><p>To first demonstrate feasibility and evaluate potential safety concerns, finite-element method simulations are used to model the response of carotid artery plaques to an acoustic radiation force excitation. Lipid pool visualization is shown to vary as a function of lipid pool geometry and stiffness. A comparison of the resulting Von Mises stresses indicates that stresses induced by an ARFI excitation are three orders of magnitude lower than those induced by blood pressure. This thesis also presents the development of a novel pulse inversion harmonic tracking method to reduce clutter-imposed errors in ultrasound-based tissue displacement estimates. This method is validated in phantoms and was found to reduce bias and jitter displacement errors for a marked improvement in image quality <italic>in vivo</italic>. Lastly, this dissertation presents results from a preliminary <italic>in vivo</italic> study that compares ARFI imaging derived plaque stiffness with spatially registered composition determined by a Magnetic Resonance Imaging (MRI) gold standard in human carotid artery plaques. It is shown in this capstone experiment that lipid filled regions in MRI correspond to areas of increased displacement in ARFI imaging while calcium and loose matrix components in MRI correspond to uniformly low displacements in ARFI imaging.</p><p>This dissertation provides evidence to support that ARFI imaging may provide important prognostic and diagnostic information regarding stroke risk via measurements of plaque stiffness. More generally, the results have important implications for all acoustic radiation force based imaging methods used clinically.</p> / Dissertation

The use of beamlets as a dose calculation tool in Intensity Modulated Radiation Therapy (IMRT) treatment planning is widespread and well documented. A beamlet can simply be defined as the contribution of radiation passing through a particular geometrically defined subdivision of a given linear accelerator's emerging radiation field. The most common classes of algorithms used today to calculate the dose distributions deposited by beamlets are the pencil beam convolution and col-lapsed cone classes of algorithms. Using BEAMnrc [1], a Monte Carlo (MC) based radiation transport simulation software package, this thesis presents a novel method of calculating MC beamlet dose distributions with a level of accuracy not achievable using the above analytic dose calculation methods. In a first application, the MC beamlet dose distributions generated in this thesis are used to fine-tune the output of the MC or "virtual" linear accelerator from which they are produced. This is achieved through the adjustment of individual beamlet weights to align the output of the virtual accelerator to the experimentally measured output of the modeled accelerator in water. In a second application, MC beamlets are used to derive corrections to particular Multileaf Collimator (MLC) leaf sequences of IMRT treatment plans that have been miscalculated by a convolution-based dose calculation algorithm. These calculation inaccuracies (up to as much as 15%) arise due to the well known fact that convolution-based algorithms do not accurately model dose deposition in inhomoge¬neous media, such as lung [2] [3] [4]. In a final application, the MC beamlet generation method described in this thesis is implemented into a direct aperture optimization (DAO) algorithm. The implementation of MC beamlet generation in DAO forms the basis for a purely MC based inverse treatment planning system.

<p>In 2011, an estimated 230,480 new cases of invasive breast cancer were diagnosed among women, as well as an estimated 57,650 additional cases of in situ breast cancer [1]. Breast conserving surgery (BCS) is a recommended surgical choice for women with early stage breast cancer (stages 0, I, II) and for those with Stage II-III disease who undergo successful neo-adjuvant treatment to reduce their tumor burden [2, 3]. Cancer within 2mm of a margin following BCS increases the risk of local recurrence and mortality [4-6]. Margin assessment presents an unmet clinical need. Breast tissue is markedly heterogeneous which makes identifying cancer foci within benign tissue challenging. Optical spectroscopy can provide surgeons with intra-operative diagnostic tools. Here, ex-vivo breast tissue is evaluated to determine which sources of optical contrast have the potential to detect malignancy at the margins in women of differing breast composition. Then, H&E images of ex-vivo breast tissue sites are quantified to further deconstruct the relationship between optical scattering and the underlying tissue morphology. </p><p>Diffuse reflectance spectra were measured from benign and malignant sites from the margins of lumpectomy specimens. Benign and malignant sites were compared and then stratified by tissue type and depth. The median and median absolute deviance (MAD) was calculated for each category. The frequencies of the benign tissue types were separated by menopausal status and compared to the corresponding optical properties. </p><p>H&E images were then taken of the malignant and benign sites and quantified to describe the % adipose, % collagen and % glands. Adipose sites, images at 10x, were predominantly fatty and quantified according to adipocyte morphology. H&E-stained adipose tissue sections were analyzed with an automated image processing algorithm to extract average cell area and cell density. Non-adipose sites were imaged with a 2.5x objective. Grids of 200µm boxes corresponding to the 3mm x 2mm area were overlaid on each non-adipose image. The non-adipose images were classified as the following: adipose and collagen (fibroadipose); collagen and glands (fibroglandular); adipose, collagen and glands (mixed); and malignant sites. Correlations between <&mus&#8242;> and % collagen in were determined in benign sites. Age, BMI, and MBD were then correlated to <&mus&#8242;> in the adipose and non-adipose sites. Variability in <&mus&#8242;> was determined to be related to collagen and not adipose content. In order to further investigate this relationship, the importance of age, BMI and MBD was analyzed after adjusting for the % collagen. Lastly, the relationship between % collagen and % glands was analyzed to determine the relative contributions of % collagen and % glands <&mus&#8242;>. Statistics were calculated using Wilcoxon rank-sum tests, Pearson correlation coefficients and linear fits in R. </p><p> The diagnostic ability of the optical parameters was linked to the distance of tumor from the margin as well as menopausal status. [THb] showed statistical differences from <&mus&#8242;> between malignant (<&mus&#8242;>: 8.96cm-1±2.24MAD, [THb]: 42.70&muM±29.31MAD) compared to benign sites (<&mus&#8242;>: 7.29cm-1±2.15MAD, [THb]: 32.09&muM±16.73MAD) (p<0.05). Fibroglandular (FG) sites exhibited increased <&mus&#8242;> while adipose sites showed increased [&beta-carotene] within benign tissues. Scattering differentiated between ductal carcinoma in situ (DCIS) (9.46cm-1±1.06MAD) and invasive ductal carcinoma (IDC) (8.00cm-1±1.81MAD), versus adipose sites (6.50cm-1±1.95MAD). [&beta-carotene] showed marginal differences between DCIS (19.00&muM±6.93MAD, and FG (15.30&muM±5.64MAD). [THb] exhibited statistical differences between positive sites (92.57&muM±18.46MAD) and FG (34.12&muM±22.77MAD), FA (28.63&muM±14.19MAD), and A (30.36&muM±14.86MAD). Due to decreased fibrous content and increased adipose content, benign sites in post-menopausal patients exhibited lower <&mus&#8242;>, but higher [&beta-carotene] than pre-menopausal patients.</p><p>Further deconstructing the relationship between optical scattering and tissue morphology resulted in a positive relationship between <&mus&#8242;> and % collagen (r=0.28, p=0.00034). Increased variability was observed in sites with a higher percentage of collagen. In adipose tissues MBD was negatively correlated with age (r=-0.19, p=0.006), BMI (r=-0.33, p=2.3e-6) and average cell area (r=-0.15, p=0.032) but positively related to the log of the average cell density (r=0.17, p=0.12). In addition, BMI was positively correlated to average cell area (r=0.31, p=1.2e-5) and negatively related to log of the cell density (r=-0.28, p=7.6e-5). In non-adipose sites, age was negatively correlated to <&mus&#8242;> in benign (r=-0.32, p=4.7e-5) and malignant (r=-0.32, p=1.4e-5) sites and this correlation varied significantly by the collagen level (r=-0.40 vs. -0.13). BMI was negatively correlated to <&mus&#8242;> in benign (r=-0.32, p=4e-5) and malignant (r=-0.31, p=2.8e-5) sites but this relationship did not vary by collagen level. MBD was positively correlated to <&mus&#8242;> in benign (r=0.22, p=0.01) and malignant (r=0.21, p=4.6e-3) sites. Optical scattering was shown to be tied to patient demographics. Lastly, the analysis of collagen vs. glands was narrowed to investigate sites with glands between 0-40% (the dynamic range of the data), the linear model reflected an equivalent relationship to scattering from % glands and the % collagen in benign sites (r=0.18 vs. r=0.17). In addition, the malignant sites showed a stronger positive relationship (r=0.64, p=0.005) to <&mus&#8242;> compared to the benign sites (r=0.52, p=0.03).</p><p>The data indicate that the ability of an optical parameter to differentiate benign from malignant breast tissues is dictated by patient demographics. Scattering differentiated between malignant and adipose sites and would be most effective in post-menopausal women. [&beta-carotene] or [THb] may be more applicable in pre-menopausal women to differentiate malignant from fibrous sites. Patient demographics are therefore an important component to incorporate into optical characterization of breast specimens. Through the subsequent stepwise analysis of tissue morphology, <&mus&#8242;> was positively correlated to collagen and negatively correlated to age and BMI. Increased variability of <&mus&#8242;> with collagen level was not dependent on the adipose contribution. A stronger correlation between age and <&mus&#8242;> was seen in high collagen sites compared to low collagen sites. Contributions from collagen and glands to <&mus&#8242;> were independent and equivalent in benign sites; glands showed a stronger correlation to <&mus&#8242;> in malignant sites than collagen. This information will help develop improved scattering models and additional technologies from separating fibroglandular sites from malignant sites and ultimately improve margin assessment.</p> / Dissertation

PURPOSE: To determine the management performance indicators most frequently utilized in academic radiology departments in the United States. MATERIALS AND METHODS: This investigation met the criteria for an exemption from institutional review board approval. A cross-sectional study in which a validated national survey was sent to members of the Society of Chairmen of Academic Radiology Departments (SCARD) was conducted. The survey was designed to examine the following six categories of 28 performance indicators: (a) general organization, (b) volume and productivity, (c) radiology reporting, (d) access to examinations, (e) customer satisfaction, and (f) finance. A total of 158 variables were included in the analysis. Summary statistics, the 2 test, rank correlation, multiple regression analysis, and analysis of variance were used. RESULTS: A response rate of 42% (55 of 132 SCARD members) was achieved. The mean number of performance indicators used by radiology departments was 16 ± 6.35 (standard deviation). The most frequently utilized performance indicators were as follows: (a) productivity, in terms of examination volume (78% [43 departments]) and examination volume per modality (78% [43 departments]); (b) reporting, in terms of report turnaround (82% [45 departments]) and transcription time (71% [39 departments]); (c) access, in terms of appointment access to magnetic resonance imaging (80% [44 departments]); (d) satisfaction, in terms of number of patient complaints (84% [46 departments]); and (e) finance, in terms of expenses (67% [37 departments]). Regression analysis revealed that the numbers of performance indicators in each category were statistically significant in predicting the total number of performance indicators used (P < .001 for all). Numbers of productivity and financial indicators were moderately correlated (r = 0.51). However, there were no statistically significant correlations between the numbers of performance indicators used and hospital location, hospital size, or department size (P > .4 for all). CONCLUSION: Assessing departmental performance with a wide range of management indicators is not yet an established and standardized practice in academic radiology departments in the United States. Among all indicators, productivity indicators are the most frequently used.

Lic.-avh. (sammanfattning) Stockholm : Karolinska institutet, 2007. / Härtill 2 uppsatser.

Thesis (MScEng (Mathematical Sciences. Applied Mathematics))--Stellenbosch University, 2008. / The medical radiation treatment facility at iThemba Labs requires a precise and robust patient positioning system. The current system makes use of an accurately calibrated multi-camera stereophotogrammetry (SPG) setup that is vulnerable to physical disruptions that invalidate system calibration. The task in this thesis is to design a vision system that can be used to verify the correct operation of the SPG system. We propose an unscented Kalman filter (UKF) based structure from motion (SFM) system for this purpose. Our SFM system does not rely on calibration information used by the SPG system and provides accurate reconstruction for verification purposes. The system is critically evaluated against a set of synthetic and real motion sequences.

CNPq / Neste trabalho foram desenvolvidos phantoms para dois protótipos de tomografia com feixe de prótons (pCT). Um phantom foi desenvolvido para um protótipo de um mini tomógrafo utilizando um feixe de prótons de baixa energia, que está sendo desenvolvido na Universidade Tecnológica Federal do Paraná (UTFPR). O protótipo encontra-se em fase de teste no cíclotron CV-28 do Instituto de Engenharia Nuclear (IEN). Dois outros phantoms foram desenvolvidos para um protótipo de pCT no Centro Médico da Universidade de Loma Linda – CA, EUA (LLUMC). Os código GEANT4 e SRIM foram utilizados para simular todos os elementos que compõe os protótipos. Também foram feitos aprimoramentos no protótipo da UTFPR/IEN, entre eles um sistema de controle eletrônico do mecanismo, operado por um programa através de um computador, alteração no sistema de colimação para melhorar a resolução e a reconstrução de imagens obtidas por simulações. Foram realizados testes experimentais de perda de energia de prótons em polietileno de alta densidade (PEAD) no CV-28. Também foi feito experimentos de perda de energia de prótons em camadas de Poliestireno no LLUMC e comparação com dados simulados. Esses dois phantoms em PEAD foram construídos e testados no protótipo do LLUMC e um programa foi desenvolvido para a análise dos dados. / In this work phantoms were developed for two tomographic systems with proton beam (pCT). A phantom was developed for a mini scanner using a low energy proton beam, which is being developed at the Federal University of Technology - Parana (UTFPR) and tested at the CV-28 cyclotron at the Institute of Nuclear Engineering (IEN). Two additional phantoms were developed for the pCT prototype at Loma Linda University Medical Center – CA, USA (LLUMC). SRIM and Geant4 codes were used to simulate all the elements of the prototypes. Improvements were made in the UTFPR/IEN prototype such as electronic control system of mechanism, controlled by a computer program, upgrade in the collimation system to improve the resolution of reconstructed images obtained by simulations. Experimental energy loss tests were done with polyethylene protons of high density (PEAD) in CV-28. Experiments of energy loss in layers of polystyrene at the LLUMC were also done and compared with simulated data. Both phantoms were constructed and tested in the prototype of LLUMC and a program was developed for data analysis.

Objectives: This study identifies modern information technologies that can improve the clinical practice of Picture Archiving and Communication Systems (PACS) and determines the approaches that are needed to improve the functionality of current PACS to provide better next generation PACS and to improve the future of radiology practices and workflow with future PACS generations. Method: A parallel mixed method approach was adopted including qualitative method (semi-structured interviews), quantitative method (questionnaire survey) and observation of online discussion groups on PACS. Five databases were searched to find salient literature, including Science Direct, Springer Link, Scopus, CINAHL Plus and Google Scholar. Six radiologists were interviewed and questionnaires were collected from 120 radiologists. Four online discussion groups related to PACS were monitored via LinkedIn. The data were analysed thematically using the thematic analysis method. Finally, a focus group was held with a separate group of radiologists to validate the findings. Results: Eight themes emerged from the thematic analysis of the data: (1) limitations of traditional PACS; (2) user needs and requirements that can increase PACS functionality; (3) Web based solutions of PACS; (4) PACS on mobile phones; (5) Vendor Neutral Archive (VNA); (6) full integration of voice recognition in PACS; (7) backup solutions for the system and (8) continuous training for PACS users. Discussion: With the development of healthcare information and communication technology (ICT) and with the increased demands of the radiologists to expand PACS usability, traditional PACS must be updated to follow the changes. Modern technologies can provide better solutions to enhance the functionality of current PACS. The next generation of PACS can fulfil the future requirements of users. This study considers the issues between the needs and requirements of the users of a PACS system in the future and the developing solutions in ICT and the PACS industry. Moreover, highly developed PACS systems with advanced features will have a direct impact in changing and improving radiology workflow. Accordingly, a model has been developed that proposes new features for the next generation PACS system, which may be applied to the next generation radiology practice. The model was validated with the focus group and, by using a separate group of radiologists in another country, was determined to be generalisable. Conclusion: It is widely recognised that traditional PACS must be updated to adopt recent advances in ICT. This research has identified themes that, when incorporated, will enhance the functionality of PACS and radiology workflow and provide better quality clinical practice. The findings from this empirical research can be used: as recommendations to vendors; for technology development; and by medical institutes to consider aspects when undertaking implementation of PACS and training future radiologists. Keywords: 'Picture archiving and communication system’, PACS, Future trends, next generation, Organisational efficiency, Productivity, Clinical practice, Ubiquitous.