Practical Applications of the Internet of Things in Radiation Oncology SA–CME REVIEW in radiation oncology. Table 1 lists a brief description of each application, although many others exist. Research purposes require a more nuanced framework using a 5-layer architecture. The 5-layer architec- ture adds a transport layer, which transfers the sensor data to and from the perception layer to the process- ing layer; the processing layer, which stores, analyzes, and processes huge amounts of data that come from the transport layer; and the business layer, which manages applications, business models, and user data/pri- vacy (Figure 1B). IoT Applications in Cancer Care Augmented Reality Therapeutic augmented reality (or extended reality) includes augment- ed reality (AR), mixed reality (MR), and virtual reality (VR) that can visu- alize data collected from sensors that are part of the IoT. This technology combines high-quality stereoscop- ic computer displays such as with goggles to display an immersive 3D environment, with 6 degrees-of-free- dom spatial tracking to capture the movements of the user and con- trollers, and interact with virtual or augmented surroundings. 22 Exam- ples have included a broad range of inpatient and outpatient applications to learn about anatomy, anesthesia, central vein catheterization, 23 mental health and anxiety disorders, 24 stroke, 25 pain management, 26, 27 and obesity. 28 Augmented reality may aid oncologic surgeries, 29-31 education for patients undergoing radiation therapy, 32,33 immersive virtual reality to reduce patient anxiety and psycho- logical symptoms, 26,34 practitioner training, 35,36 and brachytherapy. 37 Within radiation oncology, AR can provide 3D and 360-degree views to simulate the entire process of radia- tion therapy, from clinics to simulation rooms and treatment rooms. 38 AR will also provide 360-degree views of the treatment room to correct positioning in real-time. 39,40 A projector-based display has already been used to sim- ulate controlling a linac for training and education. 41 Physicians, dosim- etrists, physicists and even patients can explore spatial relationships of dosimetric distribution. For example, a patient with a meningioma may be considering stereotactic radiation therapy and may want to utilize AR to understand the concepts of how the brain and adjacent critical organs at risk may be exposed to radiation due to its proximity to the primary target. Sensor Technology Sensor technologies are devic- es placed on equipment or worn by a user that connect to sensors, apps (such as on a smartphone), or web portals, through wireless connections. Although only 21% of adults and fewer elderly people own wearable devices, the majority of US adults own a smartphone, allowing smartphone technology to rapid- ly scale IoT-based interventions. 42 Applications include continuous glucose monitors, smart insulin pens, loneliness detectors, sleep track- ers, smartwatches and Fitbits, fall detectors, wireless electrocardiogram monitors, wearable blood pressure monitors, and others. 43-45 Bluetooth inhalers are a related technology that use a Bluetooth sensor paired to a mo- bile app that provides analytics and patient/practitioner feedback. 46 Commonly, wearable devices have been used to assess physical activity levels, as these levels before, during, and aſter cancer treatment have been established as robust predictors of clinical outcomes as well as quality of life. 42,47,48 Interest- ingly, lower levels of activity during chemoradiation (head and neck, lung, and gastrointestinal cancer) as measured with Garmin devices were associated with greater hos- pitalization risk, lower likelihood of completing treatment without delays, and shorter survival. 49,50 Simi- larly, daily step count for abdominal cancer patients on postoperative day 7 was inversely correlated with the postoperative complication index. 51 Published prospective studies incorporating mobile sensor data with clinical outcomes have focused mostly on patient-reported outcomes, toxicity and symptom burden, 51-54 quality of life, 55 hospital- izations or readmissions, 49,50,56,57 or postoperative events. 58 Smart monitors are also being deployed on linear accelerators. Such technology allows for continuous background analytic data monitoring that provides feedback for equip- ment maintenance, proactive service and fault prevention for field service technicians. 59 This application has already helped technicians identify early trends in equipment malfunc- tion – such as couch faults or slow multileaf collimator motors – and order and install replacement parts before machine downtime. IoT offers an opportunity to maximize machine uptime and provide personalized, continuous remote support for radi- ation oncology clinics. Analytics can also be applied to the continuously monitored historical logs and con- figuration files using machine-learn- ing algorithms. Smart Patches Smart patches such as vital sign patches are designed to wirelessly track and monitor heart rate, respi- ratory rate, sleep cycle, stress levels, temperature, step counts, and falls/ incapacitation. 60 Temperature-track- ing smart patches (TempTraq) are being used in CAR T cell therapy clin- ical trials. 61 In a recent proof-of-con- cept study, smart patches were used to monitor dyspnea in the palliative care setting. 62 Transdermal delivery of chemotherapeutics utilizing smart patches may be a possibility in the future. 63 Smart patches have also been used to biopsy skin cells on the Applied Radiation Oncology 11 September 2022