Table 5.

Interview answers grouped by theme

Theme	Software	Quotes	Prevalence
Performance discrepancy across tumours	ImFusion	‘Very good for clear-cut, simple tumours... [those which were] highly contrast enhancing, homogeneous, with well-defined boundaries and minimal adjacent blood vessels.’	All five participants (100%)
		‘Complex tumours threw up errors which required a complete restart.’
Compromise between thoroughness and timing	ITK-SNAP	‘I am a perfectionist... if we weren’t timed it would take me much longer.’	Four out of five (80%)
		‘I made lots of small mistakes... but it would have taken too long to correct.’
		‘It was very fiddly.’
Unpredictable outcome after drawing labels	ImFusion	‘a one-trick pony...if you make alterations to the initial segmentation you may worsen it.’	Three out of five (60%)
		‘if we wanted perfection...we would have to go back again and again.’
		‘I do not know if the changes I make will improve of worsen the segmentation.’
Speed of segmentation	ImFusion	‘Much faster so it would be great for my work.’	Four out of five (80%)
		‘The algorithm works very quickly.’
UI and tools	Both	‘[Using ImFusion] was a much nicer experience...and a sleek UI.’	-
		‘[ImFusion] is better for visualization.’
		‘[In ImFusion] I would like to have a paintbrush tool which draws and erases exactly what I want it to...there is too much prediction required...scribbles I make should not affect the whole segmentation.’
Study design	–	‘It was helpful to have someone here to explain and provide feedback.’	-
		‘Would have been good to define the goal more clearly...do we want a very accurate segmentation or a rough volume estimate.’
		‘You could have gone through all the tools I might need during the training phase.’