WORK IN PROGRESS:
Some attempts to aid skin
lesion diagnosis
jonathan rees (dermatology)
bob fisher (informatics)
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The problem
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scale and perspective
catchment area one million
1.5 x 106 m2 of skin
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signal -> noise
250 millenium stadium rugby pitches
trying to find 120 melanomas/yr
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for a GP
sees 1 melanoma only every five years &
will need to examine 2 pitches to find
one
1~2 lesions per week
1 melanoma death every 25 years
~ 42, 000 other lesions / year
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cognitive issues
average medical student spends around 5
days on clinical dermatology
>90% of GPs no postgraduate training in
dermatology
base rates very low
12% of persons report a change in a
mole in the previous six months
little timely feedback
sensitive but low specificity
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present solutions
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teledermatology
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send patient -> photography
automated 2D systems (neural nets)
sell gadgets that look flash, make
doctors feel clever, and pass cost onto
patient
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Criticisms:
often hyped as solving some health care problem
(abolish waiting list...)
little real understanding / interest in what is
going on
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expertise
we know little of the basis of
expertise in this area
although we teach based on a specialist
vocabulary, not clear this is how
experts behave
some evidence for reinterpretation of
what you see based on prior knowledge
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Q: how do people see things as alike
A: [often] they don’t know formal rules
and they have difficulty in using words
what is the basis of ‘alike’--how can
we learn more?
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our approach
‘matching’
3D representation
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3D imaging
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matching
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thought experiment
take an index patient and an infinite
library of images
can you match correctly?
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index image->words->word index->diagnosis
index image->image index->diagnosis
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we don’t impose a structure we discover it
is there a structure to how people move
through the search space?
can we discover such structure and does it
allow a library of workable size?
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moving forward
(ethics / governance in place)
image collection.............->
some simple matching experiments /
psychophysics
prototype of interface and database
iterations of database structure
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