Assessment of the added value of the Twente Photoacoustic Mammoscope in breast cancer diagnosis\ud

Purpose: Photoacoustic (PA) imaging is a recently developed breast cancer imaging technique. In order to enhance successful clinical implementation, we quantified the potential clinical value of different scenarios incorporating PA imaging by means of multi-criteria analysis. From this analysis, the most promising area of application for PA imaging in breast cancer diagnosis is determined, and recommendations are provided to optimize the design of PA imaging. - \ud Methods: The added value of PA imaging was assessed in two areas of application in the diagnostic track. These areas include PA imaging as an alternative to x-ray mammography and ultrasonography in early stage diagnosis, and PA imaging as an alternative to Magnetic Resonance Imaging (MRI) in later stage diagnosis. The added value of PA imaging was assessed with respect to four main criteria (costs, diagnostic performance, patient comfort and risks). An expert panel composed of medical, technical and management experts was asked to assess the relative importance of the criteria in comparing the alternative diagnostic devices. The judgments of the experts were quantified based on the validated pairwise comparison technique of the Analytic Hierarchy Process, a technique for multi-criteria analysis. Sensitivity analysis was applied to account for the uncertainty of the outcomes. - \ud Results: Among the considered alternatives, PA imaging is the preferred technique due to its non-invasiveness, low cost and low risks. However, the experts do not expect large differences in diagnostic performance. The outcomes suggest that design changes to improve the diagnostic performance of PA imaging should focus on the quality of the reconstruction algorithm, detector sensitivity, detector bandwidth and the number of wavelengths used. - \ud Conclusion: The AHP method was useful in recommending the most promising area of application in the diagnostic track for which PA imaging can be implemented, this being early diagnosis, as a substitute for the combined use of x-ray mammography and ultrasonography

Analytical modeling of light transport in scattering materials with strong absorption

We have investigated the transport of light through slabs that both scatter and strongly absorb, a situation that occurs in diverse application fields ranging from biomedical optics, powder technology, to solid-state lighting. In particular, we study the transport of light in the visible wavelength range between $420$ and $700$ nm through silicone plates filled with YAG:Ce$^{3+}$ phosphor particles, that even re-emit absorbed light at different wavelengths. We measure the total transmission, the total reflection, and the ballistic transmission of light through these plates. We obtain average single particle properties namely the scattering cross-section $\sigma_s$, the absorption cross-section $\sigma_a$, and the anisotropy factor $\mu$ using an analytical approach, namely the P3 approximation to the radiative transfer equation. We verify the extracted transport parameters using Monte-Carlo simulations of the light transport. Our approach fully describes the light propagation in phosphor diffuser plates that are used in white LEDs and that reveal a strong absorption ($L/\ell_{\mathrm{a}} > 1$) up to $L/\ell_{\mathrm{a}} = 4$, where $L$ is the slab thickness, $\ell_{\mathrm{a}}$ is the absorption mean free path. In contrast, the widely used diffusion theory fails to describe this parameter range. Our approach is a suitable analytical tool for industry, since it provides a fast yet accurate determination of key transport parameters, and since it introduces predictive power into the design process of white light emitting diodes

PHP4 - Patient references toward health services provided by the general practioner

OBJECTIVES: In the Dutch health care system, like many other countries, the general practitioner (GP) plays a key role in securing equity and effectiveness in delivering health care. Nowadays, GPs are often part of primary care centers and it is foreseen that these centers will play an even more important role in future health service delivery. A European comparison in nine different countries concluded patients favour small practices and full time GPs. The percentage of GPs working in small practices varies between countries. In the UK the percentage is 16% whereas in Belgium the percentage is 69% and in Netherlands the percentage is 39%. Continuity of care and access is highly appreciated by patients. For instance, it has been shown that patients are more satisfied with primary care if they always have the same GP and if they experience short waiting times. Given the development of larger primary care centers, people are hesitant if the current GP service levels can be maintained. On the other hand, an advantage of primary care centers is that they do offer multiple medical services like pharmacy and physiotherapy. The\ud purpose of this study was two-fold. First, it was questioned which type of services is preferred by patients in three different GP settings and if people would be willing to pay for these services. Second, we wish to investigate differences between patients in different GP settings. The selected GP settings were 1) a single person GP practice (SP); 2) a healthservice with multiple\ud independent GPs (GP); and 3) a multi-disciplinary and comprehensive primary care center supervised by one management (PCC).\ud \ud METHODS:\ud A discrete choice experiment (DCE) was carried out among 164 patients in the three different GP settings. The DCE comprised 6 attributes including 1) time to appointment; 2) choice of time; 3) access by telephone; 4) consultation time; 5) availability of other medical services and; 6) WTP. Sample size for the DCE was estimated at about 45 patients in each GP setting. The DCE included 6 attributes. The maximum number of levels for an attribute was three, allowing 72 choice combinations. The DCE survey used 15 random and 2 fixed choicesets. Following the DCE, all 164 and an extra group of 114 patients (278 in total) were interviewed by a research assistent. Sampling was carried out to obtain equal group sizes (approx. 55) in each of the GP settings (SP, GP and PCC). DCE data were analyzed using sawtooth software. This abstract reports the first preliminary analyses of the complete dataset.\ud \ud RESULTS:\ud Socioeconomic (income and education) and demographic data (age and gender) of patients in each of the GP settings were comparable. The DCE showed preference for improved telephone services and time to appointment as most important attributes. Except for “time to appointment” no large differences were found between the GP settings. Only patients in the GP group accepted longer waiting times compared to SP and PCC. SP and PCC patients did prefer to have access within 24 hours, whereas GP patients accepted longer waiting times. Overall, most important attributes were “time to appointment”, “access of service by telephone” and “WTP”. The availability of pharmacy services was preferred by all patients. About 50% of all patients werent willing to pay for additional services. However, some 35% was willing to pay an extra amount of €9 for each consult if they would receive additional services.\ud \ud CONCLUSIONS:\ud This study shows a similar outcome compared to previous studies on access to GP services. “Time to first appointment” and “access by telephone” are most important factors to consider by patients. However, an interesting finding was that one third of all patients were willing to pay for improved services. The DCE study didn’t show big differences in preferences between patients in the different GP settings. In some aspects (e.g. accessability) the SP scored better compared to PCC and GP

PRM113 - Timed Automata Modeling of The Personalized Treatment Decisions In Metastatic Castration Resistant Prostate Cancer

Objectives\ud The Timed Automata modeling paradigm has emerged from Computer Science as a mature tool for the functional analysis and performance evaluation of timed distributed systems. This study is a first exploration of the suitability of Timed Automata for health economic modeling, using a case study on personalized treatment for metastatic Castration Resistant Prostate Cancer (mCRPC).\ud \ud Methods\ud The treatment process has been modeled by creating several independent timed automata, where an automaton represents a patient, a physician, a test, or a treatment/testing guideline schedule. These automata interact via message passing and are fully parameterized with quantitative information. Messages can be passed, asynchronously, from one automaton to one or more other automata, at any point in time, thereby triggering events and decisions in the treatment process. In the automata time is continuous, and both QALYs and costs can be incorporated using (assignable) local clocks. Uncertainty can be modeled using probabilities and timing intervals that can be uniformly or exponentially distributed. Software for building timed automata is freely available for academic use and includes procedures for statistical model checking (SMC) to validate the (internal) behavior and results of the model.\ud \ud Results\ud In several days a Timed Automata model has been produced that is compositional, easy to understand and easy to update. The behavior and results of the model have been assessed using the SMC tool. Actual results for the mCRPC case study obtained from the Timed Automata model are compared with results of a Discrete Event Simulation model in a separate study.\ud \ud Conclusions\ud The Timed Automata paradigm can be successfully applied to evaluate the potential benefits of a personalized treatment process of mCRPC. The compositional nature of the resulting model provides a good separation of all relevant components. This leads to models that are easy to formulate, validate, understand, maintain and update

The association between birth weight and plasma fibrinogen is abolished after the elimination of genetic influences

Low birth weight is associated with an increased risk of atherothrombosis, which may be related in part to the association between low birth weight and high plasma fibrinogen. The association between birth weight and fibrinogen may be explained by intrauterine, socio-economic or genetic factors. We examined birth weight and fibrinogen in 52 dizygotic and 56 adolescent monozygotic (genetically identical) twin pairs. The dizygotic but not the monozygotic twins with the lowest birth weight from each pair had a fibrinogen level that was higher compared with their co-twins with the highest birth weight [dizygotic twins: 2.62±0.46 g

Cost Effectiveness of Molecular Diagnostic Testing Algorithms for the Treatment Selection of Frontline Ibrutinib for Patients with Chronic Lymphocytic Leukemia in Australia

BACKGROUND: Clinical indications for ibrutinib reimbursement in Australia should consider the inclusion of patients with chronic lymphocytic leukemia (CLL) harboring prognostically unfavorable TP53/IGHV genomic aberrations. This study assessed the cost effectiveness of five first-line treatment strategies in CLL for young (aged ≤ 65 years), fit patients without significant comorbidities: (1) no testing (fludarabine, cyclophosphamide and rituximab [FCR] for all), (2) test for del(17p) only, (3) test for TP53 gene mutation status, (4) test for TP53 and IGHV gene mutation status and (5) no testing (ibrutinib for all).METHOD: A decision analytic model (decision tree and partitioned survival model) was developed from the Australian healthcare system perspective with a lifetime horizon. Comparative treatment effects were estimated from indirect treatment comparisons and survival analysis using several studies. Costs, utility and adverse events were derived from public literature sources. Deterministic and probabilistic sensitivity analyses explored the impact of modeling uncertainties on outcomes.RESULTS: Strategy 1 was associated with 5.69 quality-adjusted life-years (QALYs) and cost 458,836 Australian dollars (AUD). All other strategies had greater effectiveness but were more expensive than Strategy 1. At the willingness-to-pay (WTP) threshold of 100,000 AUD per QALY gained, Strategy 1 was most cost effective with an estimated probability of 68.8%. Strategy 4 was cost effective between thresholds 155,000-432,300 AUD per QALY gained, and Strategy 5 &gt;432,300 AUD per QALY gained.CONCLUSION: Population targeting using mutation testing for TP53 and IGHV when performed with del(17p) testing specifically in the context of frontline ibrutinib choice does not make a cost-ineffective treatment into a cost-effective treatment.</p