regions can make it difficult to accumulate
sufficient quantity of data for a reliable audit. A
solution is to accumulate data over longer periods
of time; perhaps two years instead of annually.
CRIS did not capture all of the information
needed, resulting in a reliance on paper records
being transcribed for analysis electronically. This
is a very time-consuming process and can result
in possible transcription errors. Another potential
problem with paper records is inaccurate or
inconsistent naming conventions, especially for
body regions. For instance, some technologists
might write ‘lumbar spine’ and others ‘L-spine’,
meaning that any automated analysis will treat
these as separate. A significant amount of
manual interrogation of data is therefore
required to ensure data is recorded correctly
and consistently, a very time consuming and
inefficient process.
Following on from the initial audit, we have
been able to implement improved local systems to
facilitate routine audit in a more efficient manner.
These include collecting SPECT/CT over a two-year
audit period to ensure enough data are included to
be confident in it. Additional CRIS entries have
been found to record dose mode, and a free text
box is used to record body region, removing the
need for paper records. Principal technologists also
developed guidance on naming conventions to
help achieve consistency and reduce the burden
of manually correcting entries retrospectively.
Finally, a monthly CRIS download is performed
and reviewed by a nuclear medicine assistant
practitioner to check adherence to naming
conventions, confirm the scanner used and body
region, and check any ambiguous or suspicious
data. These monthly checks are essentially a tidy
and quality check of the data, with monthly
numbers being found to be more manageable.
Therefore the system is not fully automated, but
much less labour intensive than previously and
with practices improving over time, routine audit
can be made sustainable in the long term.
In summary, it is certainly possible to develop
systems for patient dosimetry audit in nuclear
medicine CT, but auditors must be aware of the
additional complications that might not be
familiar to those primarily working in diagnostic
radiology. Careful thought is needed on how
these complications will be managed in an
efficient way to allow for ongoing audit.
The challenges
were much
more practical
than analytical
in this case
(radiotherapy
planning CT),
meaning that
most of the
work involved
in setting up
local audit is in
finding efficient
ways to reliably
collect data on
a large scale
Radiotherapy planning CT
For radiotherapy planning CT, data were analysed
for adult patients on two Philips Brilliance Big Bore
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CT scanners over the 2017 calendar year. The task
was found to be very similar to that for diagnostic
radiology CT, in that there were no separate dose
modes and the protocols were standardised in terms
of the body region scanned. Once the data were
acquired, it was therefore simple to analyse using
established methods, but there were challenges
with the practicalities of acquiring the data.
Radiotherapy systems are not interfaced with CRIS,
as the scans are not taken to be reported on but to
facilitate treatment. Instead, radiotherapy systems
include treatment planning and record and verify
systems. These systems do not appear to be
designed with patient dosimetry audit in mind. It is
a simple matter to look up the records of individual
patients, but these systems are not set up for
outputting large-scale patient dose information in
the format facilitating audit (such as a spreadsheet).
So a solution is needed to avoid manually combing
individual patient records one at a time for data, an
extremely inefficient proposal.
An initial audit showed that radiographers had
been keeping paper records of all CT scan dose
information (largely for historical reasons) and
so these data were transcribed for analysis. These
records did not specify the protocol used but the
examination purpose and so there could be issues
with naming conventions, with different
description actually referring to the same type
of scan. Knowing the protocol would allow such
cases to be identified and merged for more reliable
audit. To help resolve this, a simple in-house
software was developed to search the data and
extract the protocol information based on
keywords in examination information. This
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manual descriptions and in discussion with
radiographers, datasets can be merged where
similar protocols are used. The hope in future
is that the in-house software will be usable more
widely to allow the need for manual transcription
and interrogation of the data to be reduced and the
data simply extracted.
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