Asian Journal Of Medical Technology

HIGH PERFORMANCE THROUGH WALL HUMAN ACTIVITY RECOGNITION USING WIFI

2023-05-02T11:28:30+00:00

ABSTRACT: Passive human activity recognition without requiring a device is crucial in various fields, including smart homes, health care, and identification. However, current systems for human activity recognition require a dedicated device, or they need to be more suitable for scenarios where signals are transmitted through walls. To address this challenge, we propose a system for device-free, passive recognition of human activity that utilizes CSI-based Wi-Fi signals and does not require any dedicated devices. The proposed approach uses two techniques to distinguish different human activities. First, we introduce an opposite robust method to eliminate the influence of the background environment on correlation extraction and to obtain the correlation between human activity and its resulting changes in channel state information values. Second, we propose a normalized variance sliding windows algorithm to segment the time of human action from the waveforms, which can differentiate human actions' start and end times. We also implemented a model CSI based using Nexmon with an LSTM algorithm with commodity Wi-Fi devices and evaluated it in several environments. Our experimental results demonstrate that we achieve an average accuracy of 95% when signals pass through concrete walls.

PRECISION AND RELIABILITY: CALIBRATION COEFFICIENTS AND LONG-TERM STABILITY ANALYSIS OF RADIOTHERAPY DOSIMETERS CALIBRATED BY SSDL, NUKLEAR MALAYSIA

2023-06-22T03:24:10+00:00

One of the main objectives of the Secondary Standard Dosimetry Laboratory (SSDL) in radiotherapy dosimetry is verifying the radiation dose provided to patients is accurate and meets globally recognised standards. Properly calibrating the therapy dosimeters used in the radiotherapy centres is the first step the SSDL must take to ensure this goal is attained. This study analyses the calibration coefficients and long-term stability of therapy dosimeters calibrated by Nuklear Malaysia's SSDL. The dosimeters were calibrated in the absorbed dose to water using 60Co gamma rays, following the procedure described in IAEA TRS No. 398 and IAEA TRS No. 469. Two hundred therapy dosimeters from 33 radiotherapy centres were evaluated for the percentage deviation of the calibration coefficients provided by the SSDL and the manufacturer. Furthermore, the variation in calibration coefficient and the long-term stability of therapy dosimeters from 2011 to 2021 were examined. The percentage deviation of calibration coefficients between the SSDL and manufacturers found that most (82%) user dosimeters were within the IAEA's acceptance limit of ± 1.5%. Overall, the stability of calibration coefficient values ranged between 33.25% and -27.24%, with an average of 0.03%. As predicted, only 15% of the therapy dosimeters fulfill the criteria for long-term stability of 0.5%. In conclusion, proper maintenance and annual calibration of therapy dosimeters are very important to improve accuracy, minimise measurement uncertainty, and thus reduce the likelihood of errors in radiotherapy dosimetry.

DEVELOPMENT OF AN IoT-BASED KNEE EXOSKELETON DEVICE FOR REHABILITATION THERAPY MONITORING

2023-07-03T01:38:47+00:00

The COVID-19 pandemic has presented a multitude of challenges pertaining to medical treatments and patient care, creating a pressing need for innovative solutions. Constrained outdoor activities have hindered patients' ability to access essential healthcare, while healthcare professionals encounter difficulties in remotely monitoring and administering treatments. This study aims to address these pressing issues by proposing an Internet of Things (IoT)-based exoskeleton system designed for the monitoring of knee rehabilitation therapy. Through the utilization of the IoT platform ThingSpeak, this developed system enables patients to remotely monitor the status of their knee recovery from the comfort of their homes. The collected data is securely stored and made accessible to healthcare professionals, facilitating remote analysis and the formulation of treatment recommendations. This pioneering solution amalgamates advancements in exoskeleton technology with seamless IoT integration, establishing a dependable and easily accessible framework for the monitoring of knee rehabilitation. By empowering patients to actively participate in their own recovery process and enabling remote monitoring by healthcare providers, this system effectively surmounts the limitations imposed by the pandemic and financial constraints. The proposed IoT-based exoskeleton system possesses the potential to revolutionize knee rehabilitation therapy, thereby enhancing patient engagement, optimizing treatment outcomes, and circumventing traditional healthcare barriers.

DOSE MAP BLOOD IRRADIATOR DOSIMETRY SYSTEM: CUSTOMIZED BLOOD EQUIVALENT PHANTOM AND GAFCHROMIC EBT-XD FILM

2023-07-27T09:08:27+00:00

Blood irradiation is done to sterilize and cease donor T-lymphocytes functionality to avoid Transfusion Associated-Graft Versus Host Disease (TA-GVHD). Dose mapping is the primary means of ensuring that the irradiation process is being conducted correctly. The aim of this study is to measure the minimum, maximum and central absorbed gamma radiation dose delivered at the newly customized blood equivalent phantom using a Gafchromic EBT-XD film. A Gammacell 3000 Elan Blood Irradiator with Cesium-137 source was used. To obtain the dose calibration curves, the films were placed at the center of a phantom and irradiated with the dose range from 5 Gy to 35 Gy with one unirradiated film as a control. The dose calibration curve was plotted using red, green and blue channels. While, for the dose mapping measurement, the irradiation exposure of 9.03 minutes was used to deliver a central dose of 25 Gy to the film. The response of the film will be compared with the GC Dose Mapping Report 2022 which used a water equivalent medium as a phantom. For the calibration curve, the red channel of the film was utilized in this study as it had a higher signal than the other channel. The doses obtained at central, minimum and maximum using EBT-XD film with customized blood equivalent phantom were in agreement with that obtained from GC Dose Mapping Report 2022 to be within ±7.6%, ±8.51% and ±9.95% respectively. We concluded that the customized blood equivalent phantom together with EBT-XD film has a potential to map the dose in blood irradiator accurately. The doses obtained from EBT-XD film were in the range of doses needed to inhibit the proliferation of the T-lymphocytes with central, minimum and maximum doses were 26.9 Gy, 17.2 Gy and 35.7 Gy respectively.