Investigation of a real-time EPID-based patient dose monitoring safety system using site-specific control limits

Radiation Oncology

Table 4 Sensitivity test of four test cases

Sensitivity test cases	Error parameters	# test fields	# error detection	^aDetection delay ± 1SD (seconds)
Wrong dose delivery (MU error)	+5 %	14	14	4.6 ± 1.5
	+7 %	14	14	3.3 ± 0.9
	+10 %	14	14	2.5 ± 0.6
Patient setup errors	Shift 5 mm	6	0	N/A
	Shift 7 mm	6	0	N/A
	Shift 10 mm	6	1	8.7 ± 0.0
Wrong patient treatment	Incorrect plan, same treatment site	10	10	Immediately detected after 2 s
Wrong gantry angle	Correct plan, incorrect field/gantry angle	10	10	Immediately detected after 2 s

^aDetection delay is the period from the start of treatment to the time that the system is able to detect the simulated errors. The system was designed not to take the first 2s into account; therefore, the detection delay must greater than 2s

ISSN: 1748-717X