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Determination of a Quality Index for Stereotactic Radiosurgery Based On FMEA Risk Analysis

F Teixeira1,2*, C de Almeida2, M Huq3, (1) Brazilian National Nuclear Energy Commission, Rio De Janeiro, RJ, BR, (2) Universidade do Estado do Rio de Janei, Maracana V Isabel, RJ,BR, (3) UPMC Hillman Cancer Center and University of Pittsburgh School of Medicine, Pittsburgh, PA


(Sunday, 7/12/2020)   [Eastern Time (GMT-4)]

Room: AAPM ePoster Library

Purpose: To determine a Quality Index for Stereotactic Radiosurgery (QISRS) that will facilitate quantitative evaluation of the quality of stereotactic radiosurgery (SRS) process.

Methods: A Quality Index QI, based on risk analysis, was determined from Severity Index and RPN values obtained from FMEA analysis for SRS process performed at three radiotherapy centers in Brazil. The scale of severity S was divided into 4 groups and a weighting factor (Wg) was assigned to each group(g). The severity index for each subprocess (SIsp) was determined from the sum of the product of the number (Ng) of failure modes (FM) belonging to each group and their respective Wg. The quality index QIsp for each subprocess was determined from the product of SIsp and the number of FM within that subprocess with a value of RPN=100. The quality index for the entire SRS process, QISRS was obtained from the sum of all QIsp.

Results: For the three radiotherapy centers the QIsp for Treatment Planning was the highest, even though the highest RPN of FMEA ranking belongs to subprocesses that are different from treatment planning. For all 3 centers the QIsp is higher when the number of FM with S = 7 is greater, even if the number of FM with RPN = 100 is the same or very close.

Conclusion: QISRS is a measure of correlation between RPN and severity of a process and thus represents a better measure of the risk of a process. Values of QISRS for the three centers ranged from 5078 – 38503. Centers with high values of QISRS can lower risks by improving detectability of FM or lowering the occurrence of FM.


Risk, Radiosurgery, Quality Assurance


TH- External Beam- Photons: extracranial stereotactic/SBRT

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