Application of Failure Modes and Effects Analysis: An example of 2100 C-series Linear Accelerator

Radiation Oncology-21st Century Oncology of California, USA.

^*Corresponding Author

Aime M Gloi PhD, DABR

21st Century Oncology of California

1316 Nelson Avenue, Modesto, CA 95350

USA

Phone:209-575-5870

Fax:209-575-5872

Email: agloi7288@gmail.com

Abstract

Purpose: We apply Failure Mode and Effects Analysis (FMEA) to investigate and alleviate linear accelerator (linac) downtime issues due to various mechanical and electrical interlocks.

Methods: A working group filled out questionnaires to identify different linac failure modes and assign severity, occurrence, and detectability scores to six frequent interlocks. The three scores were multiplied to obtain an overall risk probability number (RPN) for each interlock. The consistency of scores assigned by the therapists was evaluated using Cronbach’s Alpha. 

Results: A total of 61 failure modes were identified. Six recurring interlocks were analyzed over a study period of three months, by five therapists. A fault tree was generated for a generic interlock and for the complex hardware (HFWA) interlock. The Cronbach’s Alpha statistics show generally poor agreement among the scores assigned by therapists.

Conclusions: On the basis of these findings, the clinic proposed novel solutions for mitigating the risk of linac failures, thus reducing linac downtime and improving patient satisfaction.

Keywords: Failure mode and effects analysis (FMEA), Linear accelerator (linac), Risk probability number (RPN)

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