NHS Grampian – Using modelling and simulation to evaluate future capacity requirements for CT and MRI scanners due to potential growth in demand.

Problem
NHS Grampian wanted to understand what effect demographic change and new clinical practice would have on the potential demand for CT and MRI scanners over the next 5 and 10 years and whether their current capacity would be sufficient to meet this demand.

In addition, as a result of new clinical practice it was expected that the annual demand for CT Scanners in Grampian would increase by an additional 30% over the coming years. NHS Grampian wanted to know if their current capacity would be adequate to meet this demand and if not what capacity would be required to do so.

Approach
The Scenario Generator was used to model the expected growth in demand for scans and the effect this would have on capacity looking at 3 different scenarios.

1. Growth in scans due to natural demographic change.
2. Growth in scans due to expected annual increase.
3. Growth in scans due to effects of new clinical practice on top of expected annual increase.

The Scenario Generator model was calibrated to ensure that the baseline reflected the current use of the Grampian Health Service.

The model was then modified to include CT and MRI Scanners in the appropriate pathways and was further calibrated to ensure that the activity in these steps represented the current demand.

For scenarios 2 and 3 annual projections were added to the model over the ten year period to reflect the growth in demand for CT and MRI scans. Grampian’s current CT and MRI weekly scanner capacity was then modelled as a constraint.

The results produced from this high level analysis were used to aid NHS Grampian in making informed decisions regarding future capacity planning for scanners.

Results
The results showed the varying levels of demand likely to be produced for each scenario;

There was a clear indication of when additional capacity would be required as queues would start to build when Grampian’s current capacity could no longer cope with the demand.

Further scenarios were run to test the impact of adding additional scanners when existing capacity was fully utilised, and to observe whether this additional capacity would be able to sustain the growing demand.

It was found that no additional capacity would be required over the ten year period if only Grampian’s demographic change were modelled. However for both scenarios 2 and 3 (additional clinical processes requiring scans) it was found that additional capacity would be required at several periods over the ten years to cope with the demand.

Scenario 2
The graphs show when extra capacity should be added to enable demand to be met.

Scenario 3

Further modelling was then undertaken to show what effect altering the current capacity would have on the results. This involved running scenarios where

• Current capacity reflected all Scanners operating 7 days a week.
• The additional capacity added (CT Scanners only) was capable of mirroring the highest performing scanner, in terms of number of scans per week.

The results showed that both cases had a significant impact on the point at which additional capacity would be needed over the ten year period.

Scanners operational 7 Days per Week (effect on Sc.2)

Scanners operational 7 Days per Week
Effect on Scenario 3

Effect on Scenario 3

Benefits
Scenario generator provided Grampian with a means of understanding the effects of forecasted increases in demand for scanners on their current capacity. It showed,

• The volume of scans likely to occur over ten years over 3 different scenarios.
• Where their capacity would fail to meet demand and so where additional capacity is likely to be required.
• The impact of scanners operating 7 days a week has on the results.
• The effect the capability of a new scanner has on the results.

Furthermore the initial modelling raised interesting questions giving Grampian a basis to further explore:

• The impact of changing maximum capacity utilisation.
• The impact of additional capacity being added only in specific areas, such as planned outpatient services.
• The impact forecasted demand has on particular types of scanner such as Body or Neuro.