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Pressure Monitoring at Two Clinics Using Calibrated Barometers Vs IPhone's Barometric Sensor

C Kumaran Nair

C Kumaran Nair1*, R Harder2 , S Dieterich1 , (1) University of California-Davis, Sacramento, CA, (2) Gene Upshaw Memorial Tahoe Forest Cancer Center, Truckee, CA


SU-I-GPD-T-463 (Sunday, July 30, 2017) 3:00 PM - 6:00 PM Room: Exhibit Hall

Purpose: The aim of this work is to evaluate the stability and reliability of using a third party application for recording the daily barometric pressure for dosimetry applications. Daily pressure was monitored for several months at two clinics at different altitudes.

Methods: Daily barometric pressure was recorded at two different clinics using an iPhone app and calibrated barometers. The scientific devices used include the BRA898 Long-Range Wireless Weather Station by Oregon Scientific (inter-compared yearly with a calibrated device) and the Control Company Model 4247 Barometer (calibrated). The barometric readings were compared to the daily recording using the iPhone app “My Altitude” (Bej Bej Apps, http://www.bejbej.info/app/myaltitude). This third party application calculates the barometric pressure based on a current location elevation determined from the device’s built-in sensor. The barometric data were recorded daily for the time period of October 2016 to March 2017. One of the clinics was at near sea level and the other at an altitude ~1800 m higher.

Results: Daily pressure recordings for Clinic 1 varied between 1012-1033 hPa and for Clinic 2 between 805-830 hPa. The daily readings for both clinics normalized to standard atmospheric pressure (1013.25 hPa) are given in figures 1 and 2 (see supporting document). For Clinic 1, the daily recordings using the “My Altitude” app is systematically lower by 2-3 hPa whereas for Clinic 2, the recordings are consistent between the calibrated device and the third party app. This demonstrates that the third party app could be used as a reliable alternative to recording the daily pressure for dosimetric analyses.

Conclusion: The scientific barometer pressure recordings have been compared against a third party iPhone app for several months. The app demonstrates as a reliable backup or alternative pressure recording device at the radiotherapy clinics for daily recording of pressure for clinical dosimetry.

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