Modelling a Computed Tomography service using mixed Operational Research methods

Figures & data

Figure 1. Three stage framework.

Figure 2. Group model of factors affecting CT service.

Table 1. Process validation using mean time in system (minutes).

Exam categories	Mean time in system − 95% CI	Mean error − 95% CI
Overall	54.4±1.2	3.36±0.64
IV	33.2±1.6	−1.81±1.76
IV and Oral	118.6±0.8	8.55±1.20
None	20.5±0.6	1.76±0.81
Oral	113.0±3.3	7.30±4.33
Procedure	48.7±2.7	2.81±3.01

Figure 3. Factors affecting CT service.

Table 2. Comparison of process metrics for mixed IP/OP and OP only services.

Process metrics (daily average)	Mixed IP/OP scenario	Outpatient only scenario
Scanner utilisation 9-5	61.2%	69.8%
Radiographer utilisation 9-5	57%	53%
HCA utilisation 9-5	38.2%	43.7%
Daily flexible staff requests	14.6	1
Total daily tasks completed	144	121
IP work perturbations (minutes)	11.9	N/A
OP work perturbations (minutes)	0.15	<1
Average number patients scanned	21	24

Figure 4. Consumed staff time (minutes) for each exam type.

Figure 5. Variation in daily radiographer utilisation.

Figure 6. Comparison of resource utilisation for mixed versus outpatient only scanner.

Figure 7. Decision tree for presentation of results from DES model.