MAKING INVISIBLE LYMPHEDEMA VISIBLE
-A low-cost and easy-to-use tomography device can ensure early detection and proper understanding of lymphedema.
Research Keywords: Electrical Impedance Tomography (EIT), lymphedema, Cloud Computing
“Lymphedema,” or stagnant lymph flow and abnormal swelling of the arms and legs that may occur following the removal of lymph nodes by surgery or radiotherapy, occurs in about 30% of patients who had surgery for gynecological cancers such as breast cancer and uterine cancer. “It has been considered as an abandoned sequela for a long time and has only recently garnered the attention of researchers,” says Masahiro Takei. “The risk of lymphedema onset lasts for a lifetime, and the condition cannot be fully cured if detected late, so the patients are forced to have a significant psychological burden. For a good prognosis, early detection of stages 0 and 1 of lymphedema is critical, but there is still no effective detection device for this purpose.”
Takei is now forming a research team of engineering, medical, pharmaceutical, and scientific experts from Chiba University, aiming to improve the accuracy of detection by developing IoT lymphedema tomographic monitor with artificial intelligence (AI) system that can be used at home.
A SMALL ELECTRIC TOMOGRAPHY
As a mechanical engineer, Takei’s belief is “to make invisible things visible by using a machine.” So far, he has been working on developing hardware and software related to electrical tomography. Tomography refers to cross-section visualization measurement, as in computed tomography (CT). Medical CT is a large machine that costs hundreds of millions of yen, and it is impossible for patients themselves to use it easily at home. This challenge has been recognized around the world. In the 1990s, the theoretical construction of a new electric tomography began at the University of Manchester, UK.
Takei had also participated in this project called “European Action.” Several challenges occurred during this project, and the member researchers tried to solve these problems one by one. They developed the sensors, the electrical circuits to reduce noise and speeding up, the image reconstruction software with mathematical inverse problem-solving capability, and proceeded with developing the appropriate procedures for industrial and biological use. However, the prototype equipment had cost millions of yen, and the accuracy was not sufficient for practical use.
“At that time, I thought it would be innovative if we could easily see our inside of the body with a machine that costs around tens of thousands of yen,” says Takei. Thus emerged the breakthrough technology—a small electric tomography with diagnostic function. The new system works as follows: several electrodes are placed on the body, and a weak electric current is passed through the body. The system produces images showing the distribution of conductivity and dielectric constant in the body at each frequency using a wearable sensor to measure the potential, small hardware, and mathematical algorithms.
Currently, Takei’s research team is working on developing an easy-to-use IoT lymphedema tomographic monitor. First, with the monitor, impedance data measured by a small unit from the multi-electrode winded sensors are sent to the cloud computing unit. Next, 4D images of limb cross-sections are reconstructed at high speed on the cloud using specialized software. Finally, edema (including early-stage edema) is diagnosed using machine learning and big data analysis of the lymphedema images. With this device, patients can check their edema stage by themselves at home.
To elucidate the mechanism of development and progression of lymphedema, not only engineering and medical knowledge but also pharmaceutical and scientific considerations are crucial. By implementing the knowledge gained from such integrated research to the prototype, Takei’s team aim to improve the accuracy and convenience of the machine. “Ultimately, we want to visualize the medical condition in real-time on a mobile device and to reduce the pain of patients.”（CHIBA RESEARCH 2020）
|Name||Title, Affiliation||Research Themes|
|TAKEI Masahiro||Professor, Graduate School of Engineering||Multiphase Fluid Measurement Engineering|
|Name||Title, Affiliation||Research Themes|
|AKITA Shinsuke||Assistant Professor, Chiba University Hospital||Plastic Surgeny, Lymphatic Micro-sajari|
|SHIMOMURA Yoshihiro||Professor, Graduate School of Engineering||Humanity Rohmix Design|
|SUGAWARA Michiko||Associate Professor, Graduate School of Engineering||Cell Engineering|
|MITSUKAWA Nobuyuki||Professor, Graduate School of Medicine||Plastic Surgeny|
|HORIKOSHI Takuro||Associate Professor, Chiba University Hospital||Diagnostic Radiology|
|YAMAGUCHI Tadashi||Professor, Center for Frontier Medical Engineering||Bio-physical Properties Measurement|
|MANABE Ichiro||Professor, Graduate School of Medicine||Lymphedema|
|SUGA Mikio||Associate Professor, Center for Frontier Medical Engineering||Medical Imaging Technology|
|YOSHIDA Kenji||Associate Professor, Center for Frontier Medical Engineering||Ultrasonic Medical Engineering|
|FUJIMOTO Hiroshi||Assistant Professor, Chiba University Hospital||Breast surgery|
|NISHIKIMI Kyoko||Assistant Professor, Chiba University Hospital||Ovarian cancer|