Bangladesh Journal of Medical Physics The official journal of the Bangladesh Medical Physics Association (BMPA) (an affiliate of the International Organisation of Medical Physics - IOMP). Full text articles available. en-US (Professor K. Siddique-e Rabbani) (Md Fahmid Uddin Khondoker) Fri, 15 Nov 2019 08:30:33 +0000 OJS 60 Simple electrode configurations for probing deep organs using Electrical Bio-Impedance techniques <p>Tetrapolar Impedance Method (TPIM) and Focused Impedance Method (FIM) are two simple modalities of electrical bio-impedance measurement that could be employed to give useful physiological and diagnostic information of the human body. FIM is based on TPIM but uses a combination of two sets of TPIM, producing a focusing effect, which is useful to localize specific target organs. Most non-invasive electrical bio-impedance measurements based on TPIM and FIM use electrodes on one side of the body, outside the skin surface, which gives a shallow depth sensitivity. The sensitivity decreases with depth so that deep organs like lungs, heart, liver, stomach and bladder are not fully assessed through such measurements. Based on a long experience of studying electrical impedance methods, several qualitative ideas are presented in this article for probing deep organs using a few modified TPIM and FIM configurations. The suggestions are based on visualisations of both equipotentials and a popular sensitivity equation for transfer impedance, but not based on any quantitative analysis. Simulation and phantom studies based on these ideas may produce some practically useful electrode configurations for real life bio-impedance measurements.</p> <p>Bangladesh Journal of Medical Physics Vol.11 No.1 2018 P 1-15</p> K Siddique e Rabbani Copyright (c) 2018 Bangladesh Journal of Medical Physics Fri, 15 Nov 2019 00:00:00 +0000 Epileptic Seizure Prediction and Source Localization using Entropy Analysis of Scalp EEG <p>Epilepsy is one of most common neurological disorders that affects people of all ages and can cause unpredictable seizures which may even cause death. The prediction of epileptic activities thus can have a great impact in avoiding fatal injuries through early preparation with medicines and also in improving the efficacy of medicines. A technique for early prediction of epileptic seizure from EEG signal is proposed in this paper. The pre-ictal period of epileptic seizure clearly depicts a start of seizure and comparing the changes in entropy of EEG signals in different brain regions during the pre-seizure period, the proposed technique could successfully predict the seizure using entropy analysis. Moreover, the region of the epileptic activities was also localized by dividing the total brain into four topographic regions and by calculating the entropy from this four zones separately. Thus, this proposed technique has the potential to help the clinical neurologists to investigate seizure detection and treat the patient in a better way with less supervision and better accuracy.</p> <p>Bangladesh Journal of Medical Physics Vol.11 No.1 2018 P 16-25</p> Mohammad Ali Reza, ASM Shamsul Arefin Copyright (c) 2018 Bangladesh Journal of Medical Physics Fri, 15 Nov 2019 00:00:00 +0000 Design and Implementation of a Constant Tension Mid-Upper Arm Circumference (CT-MUAC) device for improved detection of malnutrition in children <p>Mid-upper arm circumference (MUAC) is an important indicator of the nutritional index, particularly of children in low resource countries of the world. It is a significant anthropometric tool with simple cut-off values which is easy to implement in large scale screening measurements. A conventional MUAC device is essentially an insertion strap and has many merits over other anthropometric measurements techniques, but a lack of reproducibility in measurements is its leading problem since the measurement depends on how strongly a person pulls the strap around an arm of the subject. The aim of the present study is to minimize this reproducibility problem. For this the existing MUAC device has been modified using a short length of an elastic band to provide a constant tension while measuring, making it a Constant Tension MUAC device. Using both the MUAC devices (conventional and CT-MUAC), data were collected from seven subjects by 70 observers (10 observers measuring one subject). Statistical analyses showed that the CT-MUAC device gives a significant improvement with less variability over the conventional device. Thus, the new CT-MUAC device has the potential for improved detection of malnutrition throughout the world.</p> <p>Bangladesh Journal of Medical Physics Vol.11 No.1 2018 P 26-37</p> Md Moiful Alam, Rashida Haque, K Siddique e Rabbani Copyright (c) 2018 Bangladesh Journal of Medical Physics Fri, 15 Nov 2019 00:00:00 +0000 A new mechanism controlling conduction in stretched myelinated nerves and a comprehensive nerve conduction model <p>Analysing published experimental findings this paper revealed that for myelinated nerves the conduction velocity (<em>CV</em>) increases on stretching out of the nerve, which has not been pointed out by anyone before. This apparently contradicts existing concepts since stretching out of a nerve fibre reduces its diameter which is expected to reduce the <em>CV</em>. Besides, the change is reversible and immediate, which cannot be explained with existing knowledge either. In order to explain this anomaly, the present work invoked a new resistance to ion flow between the nerve axon and the extracellular fluid created by interdigitated fingerlike processes of myelin sheaths coming from two sides of a node of Ranvier, analyzing published electron microscopic images. When stretched out, the gaps between the processes increase, decreasing the resistance to ion flow and thereby hastening depolarization, increasing <em>CV </em>in turn. The gaps close immediately on the release of the stretching force because of the pull of the elastic endoneurium, thus retrieving the original <em>CV</em>. To represent this new mechanism, a new resistive element has been added to the existing electrical model of a myelinated nerve, which is being claimed to be the dominant component that determines the conduction delay. Stretching also affects other nerve parameters and this paper developed a mathematical formulation involving all these parameters to show satisfactorily that <em>CV </em>indeed increases with stretching, in which the contribution of the proposed resistance dominates. The paper also proposed an appropriate modification of the representative schematic model commonly used to depict propagation of action potential in a myelinated nerve fibre. The suggested new mechanism and the resistance model is a breakthrough in the explanation of neural conduction and opens up the door for new study as well as for reviewing all previous experiments on myelinated nerves afresh.</p> <p>Bangladesh Journal of Medical Physics Vol.11 No.1 2018 P 38-56</p> K Siddique e Rabbani Copyright (c) 2018 Bangladesh Journal of Medical Physics Fri, 15 Nov 2019 00:00:00 +0000