TY - CHAP A1 - Ese, Zehra A1 - Qamhiyeh, Sima A1 - Kreutner, Jakob A1 - Schaefers, Gregor A1 - Erni, Daniel A1 - Zylka, Waldemar ED - Lhotska, Lenka ED - Sukupova, Lucie ED - Lacković, Igor ED - Ibbott, Geoffrey S. T1 - CT Extended Hounsfield Unit Range in Radiotherapy Treatment Planning for Patients with Implantable Medical Devices T2 - World Congress on Medical Physics and Biomedical Engineering 2018. June 3-8, 2018, Prague, Czech Republic (Vol.3) N2 - Radiotherapy (RT) treatment planning is based on computed tomography (CT) images and traditionally uses the conventional Hounsfield unit (CHU) range. This HU range is suited for human tissue but inappropriate for metallic materials. To guarantee safety of patient carrying implants precise HU quantification is beneficial for accurate dose calculations in planning software. Some modern CT systems offer an extended HU range (EHU). This study focuses the suitability of these two HU ranges for the quantification of metallic components of active implantable medical devices (AIMD). CT acquisitions of various metallic and non-metallic materials aligned in a water phantom were investigated. From our acquisitions we calculated that materials with mass-density ρ > 3.0 g/cm3 cannot be represented in the CHU range. For these materials the EHU range could be used for accurate HU quantification. Since the EHU range does not effect the HU values for materials ρ < 3.0 g/cm3, it can be used as a standard for RT treatment planning for patient with and without implants. Y1 - 2018 SN - 978-981-10-9022-6 U6 - https://doi.org/10.1007/978-981-10-9023-3_111 SP - 599 EP - 603 PB - Springer CY - Singapore ER - TY - JOUR A1 - Ese, Zehra A1 - Kressmann, Marcel A1 - Kreutner, Jakob A1 - Schaefers, Gregor A1 - Erni, Daniel A1 - Zylka, Waldemar T1 - Influence of conventional and extended CT scale range on quantification of Hounsfield units of medical implants and metallic objects JF - Technisches Messen (tm). Plattform für Methoden, Systeme und Anwendungen der Messtechnik N2 - We report on the suitability of two different ranges of Hounsfield units (HU) in computed tomography (CT) for the quantification of metallic components of active implantable medical devices (AIMD). The conventional Hounsfield units (CHU) range, which is traditionally used in radiology, is well suited for tissue but suspected inappropriate for metallic materials. Precise HU values are notably beneficial in radiotherapy (RT) for accurate dose calculations, thus for the safety of patient carrying implants. Some of today’s CT machines offers an extended Hounsfield units (EHU) range. This study presents CT acquisitions of a water phantom containing various metallic discs and an implantable-cardioverter defibrillator (IPG). We show that the comparison of HU values at EHU and CHU ranges clearly reveals the superiority and accuracy of EHU. Some geometrical discrepancies perpendicular to slices are observed. At EHU metal artifact reduction algorithms (MAR) underestimates HU values rendering MAR potentially inappropriate for RT. Y1 - 2018 U6 - https://doi.org/10.1515/teme-2017-0122 SN - 0171-8096 VL - 85 IS - 5 SP - 343 EP - 350 ER - TY - CHAP A1 - Ese, Zehra A1 - Tuma, Lara A1 - Qamhiyeh, Sima A1 - Kreutner, Jakob A1 - Schaefers, Gregor A1 - Erni, Daniel A1 - Zylka, Waldemar T1 - Extended CT Hounsfield values scale as a method to improve radiotherapy for patients with active and metallic implants T2 - Biomedical engineering = Biomedizinische Technik. Joint journal of the German Society for Biomedical Engineering in VDE and the Austrian and Swiss Societies for Biomedical Engineering Y1 - 2018 U6 - https://doi.org/10.1515/bmt-2018-6051 SN - 0013-5585 VL - 63 IS - S1 SP - 303 ER - TY - JOUR A1 - Zylka, Waldemar A1 - Wassenberg, Jörg T1 - Investigation of avascular tumor–immune system interactions using a CA–PDE model JF - Current directions in biomedical engineering N2 - We report on investigations that illustrate the interaction between the specific immune system and a young avascular tumor growing due to a diffusive nutrient supply. We formulate a hybrid cellular automata-partial differential equation (CA-PDE) model which includes cell cycle dynamics and allows for tracking the spatial and temporal evolution of this elaborate biological system. We present results of two dimensional numerical simulations that, specifically in this work, include special cases of the spherical and papillary tumor growth, the infiltration of immune system cells into the tumor and the escape of tumor cells from the regime of the immune cells. Y1 - 2018 U6 - https://doi.org/10.1515/cdbme-2018-0148 SN - 2364-5504 VL - 4 IS - 1 SP - 615 EP - 619 ER - TY - CHAP A1 - Ese, Zehra A1 - Qamhiyeh, Sima A1 - Kreutner, Jakob A1 - Schaefers, Gregor A1 - Erni, Daniel A1 - Zylka, Waldemar T1 - Erweiterte CT Hounsfield Werte Skala als eine Methode zu Verbesserung der Strahlentherapie für Patienten mit aktiven und metallischen Implantaten T2 - Konferenz: 49. Jahrestagung der DGMP und 21. Jahrestagung der Deutschen Sektion der ISMRM, 19.-22. September 2018 in Nürnberg Y1 - 2018 ER -