Technology and Health Care - Volume 11, issue 1

Authors: Kavadias, C.D. | Koutsopoulos, K.A. | Vlachos, M.P. | Bourka, A. | Kollias, V. | Stassinopoulos, G.

Article Type: Research Article

Abstract: This paper analyzes the SSL/TLS procedures and defines the functionality of a monitoring/auditing entity running in parallel with the protocol, which is decoding, checking the certificate and permitting session establishment based on the decoded certificate information, the network addresses of the endpoints and a predefined access list. Finally, this paper discusses how such a facility can be used for detection impersonation attempts in Health Care applications and provides case studies to show the effectiveness and applicability of the proposed method.

Keywords: SSL/TLS, protocol analysis, public key cryptography, PKI, healthcare applications, case studies

DOI: 10.3233/THC-2003-11101

Citation: Technology and Health Care, vol. 11, no. 1, pp. 1-9, 2003

Authors: Andersson, Roger | Loyd, Dan | Ask, Per

Article Type: Research Article

Abstract: This study aims at investigating the radial dimensional changes, as a result of an applied intraluminal pressure for an elastic tube with non-uniform cross section. The study is related to a method for non-invasive pressure measurement using the extracorporeal tube as part of the sensor. The intended application is for monitoring of pressure in the blood and dialysate tubes during haemodialysis. The intention is to find a tube cross-section geometry that results in an expansion of the tube so that it is suitable to use as a component in a pressure sensor. The tube should have high radial compliance and …expand in a well-defined manner to be able to transfer the intraluminal pressure to a transducer element sensing the radial force. Radial expansion was studied experimentally for tubes with different cross-section geometries. For small tube expansions the resolution in the experimental measurements was not sufficient to study the radial expansion. In this case, numerical simulation was performed. We conclude that a tube with essentially elliptic outer surface and circular inner surface, with a relation of 1:2 between the size of the thin and thick wall, results in a radial expansion upon application of pressure indicating that this tube is suitable for use as part of a sensor. Show more

Keywords: non-invasive pressure measurement, elastic tube, modified cross-section, dialysis, extracorporeal tube

DOI: 10.3233/THC-2003-11102

Citation: Technology and Health Care, vol. 11, no. 1, pp. 11-20, 2003

Authors: Anayiotos, Andreas S. | Pedroso, Pedro | Advincula, Maria A. | Venugopalan, Ramakrishna | Eleftheriou, Evangelos C. | Holman, William L.

Article Type: Research Article

Abstract: Flow Streamlining Devices is a new tool in Coronary Artery Bypass Grafting (CABG). They aim in: a) Performing a sutureless anastomosis to reduce thrombosis at the veno-arterial junction, and b) Providing a hemodynamically efficient scaffolding to reduce secondary flow disturbances. Thrombosis and flow disturbances are factors that have been reported as contributing factors to the development of intimal hyperplasia (IH) and failure of the graft. By reducing thrombosis and flow disturbances, it is expected that IH will be inhibited and the lifetime of the graft extended. To evaluate the hemodynamic benefits of such an implant, two models were designed …and fabricated. One simulated the geometry of the conventional anastomosis without an implant, and the other simulated an anastomosis with a flow streamlining implant. Identical flow conditions relevant to a coronary anastomosis were imposed on both models and flow visualization was performed with dye injection and a digital camera. Results showed reduction of disturbances in the presence of the implant. This reduction seems to be favorable to hemodynamic streamlining which may create conditions that may inhibit the initialization of IH. However, the compliance and geometric mismatch between the anastomosis and the implant created a disturbance at the rigid compliant wall interface, which should be eliminated prior to clinical applications. Show more

Keywords: CABG, hemodynamics, flow visualization, vascular flow modeling

DOI: 10.3233/THC-2003-11103

Citation: Technology and Health Care, vol. 11, no. 1, pp. 21-39, 2003

Authors: Ntasis, Efthymios | Maniatis, Theofanis A. | Nikita, Konstantina S.

Article Type: Research Article

Abstract: A secure framework is described for real-time tele-collaboration on Virtual Simulation procedure of Radiation Treatment Planning. An integrated approach is followed clustering the security issues faced by the system into organizational issues, security issues over the LAN and security issues over the LAN-to-LAN connection. The design and the implementation of the security services are performed according to the identified security requirements, along with the need for real time communication between the collaborating health care professionals. A detailed description of the implementation is given, presenting a solution, which can directly be tailored to other tele-collaboration services in the field of health …care. The pilot study of the proposed security components proves the feasibility of the secure environment, and the consistency with the high performance demands of the application. Show more

DOI: 10.3233/THC-2003-11104

Citation: Technology and Health Care, vol. 11, no. 1, pp. 41-52, 2003

Authors: Klaessens, J.H.G.M. | Thijssen, J.M. | Hopman, J.C.W. | Liem, K.D.

Article Type: Research Article

Abstract: Objectives: in vitro assessment of the reproducibility and the optimal separation and position of the optodes in continuous wave (CW-) NIRS measurement of local inhomogeneities in absorption and/or scattering. Methods: a CW- NIRS system (OXYMON) was used with laser diodes at wavelengths of 767 nm, 845 nm, 905 nm, 945 nm and 975 nm. For practical considerations (dimensions of neonatal head) the measurements were performed on a cylindrical tissue-equivalent phantom (70 mm diameter of base material with μ a = 0.01 mm − 1 (800 nm) and μ …s ′ = 1.00 mm − 1 (800 nm)), containing rods with 10 × absorption, or 10 × scattering, and 5 × both Monte Carlo simulations were carried out of a cylinder with transport scattering coefficient μ s ′ = 0.525 mm − 1 and absorption coefficient μ a = 0.075 mm − 1 and two optode positions. Results: reproducibility of repeated measurements (n = 10 ) was ± 0.005 OD. Maximum OD in case of absorbing rod, and of absorbing + scattering rod was measured with optodes separated by 90° and rod position angle symmetrically (45°) in between. Minimum OD for these rods was obtained with optodes at 150° angle and rod position at 240° (i.e. relative to transmitting optode position at 0°). A second maximum OD was obtained at an optode angle 180° and rod position at 180°. Maximum OD (i.e. attenuation) for the scattering rod was at optode separation angle of 90° and rod at 0°. Minimum OD for this case was obtained with optode angle of 180° and rod positions around 80° and 280°. Maximum OD changes by absorbing rod were in the order of +0.12 OD and −0.04 OD, respectively. Simulations at an optode separation angle of 90° showed a spatial sensitivity path enclosing the rod position at maximum absorption found experimentally. Conclusions: when considering the phantom as a realistic geometrical model for the neonatal head, it can be concluded that the optode position at 90° angle would be optimal for detecting an inhomogeneity at 15 mm depth, i.e. the location of the periventricular white matter. Since the rods are relatively strongly different from the base material the question remains to be answered whether local ischemia, which might lead to irreversible brain damage, can be detected by CW-NIRS Show more

Keywords: near infrared spectroscopy, phantom, optode, position, simulation

DOI: 10.3233/THC-2003-11105

Citation: Technology and Health Care, vol. 11, no. 1, pp. 53-60, 2003

Authors: Bourka, A. | Kaliontzoglou, A. | Polemi, D. | Georgoulas, A. | Sklavos, P.

Article Type: Research Article

Abstract: The paper presents the enrichment of an existing e-referral / e-prescription application within a Regional Healthcare Information Network with security functionality, solving current authentication, integrity, non-repudiation and confidentiality issues and thus significantly enhancing the overall system security, operability, applicability and user acceptance. The application makes use of an underlying PKI framework, in order to provide strong authentication, digital signature, encryption and time-stamping services. XML is used for the representation of the healthcare data itself, the encrypted form of this data, as well as the relevant data security information, following W3C standards.

Keywords: healthcare information, electronic document communication, security, PKI, XML

DOI: 10.3233/THC-2003-11106

Citation: Technology and Health Care, vol. 11, no. 1, pp. 61-76, 2003