Using Discrete Event Simulation to Improve Diagnostic
Imaging Resource Utilization
Pheba Philip
Ashley Robinson
June 2014
Outline

MD Anderson & the Breast Diagnostic Center

Problem & Aim Statement

Simulation Preparation

Building the Simulation

Initial Results

Next Steps

Challenges
Background on MD Anderson

Located in Houston, TX

Found in 1941

20,000 Employees (1,600 faculty)

650 inpatient beds

1.3 M outpatient visits

Provided care to 120,000 patients in 2013

Ranked Number 1 in cancer care by U.S. News and
World Report
Background Breast Diagnostic Imaging

Sub-specialty of the Department of Diagnostic
Radiology

Biopsies performed and Images taken of the
breast to identify cancer

Over 54,000 procedure performed
Why use Simulation?
•
Understanding of complex systems
•
Identification of constraints in the system (patient
flow, staff utilization, resource management)
•
Testing & experimentation
•
Visual tool to enhance communication
•
FlexSim Healthcare used for the simulation model
Problem & Aim Statement
Patients are experiencing long wait times and resources are
under utilized in the breast diagnostic center.
The aim is to build a simulation model that identifies
opportunities to reduce patient wait time and better
utilize resources by April 2014.
SIMULATION PREPARATION
Simulation Preparation
Identify the Scope
1. Wait time of patients with appointments in
Mammo and US
2. Utilization of labor and equipment
3. Scheduling of patients, radiologist, and techs
Simulation Preparation
Center Information
•
Two Modalities: Diagnostic Mammo & Ultrasound (US)
•
9 US Techs / 9 Mammo Techs
•
3 US Radiologist / 2 Diagnostic Mammo Radiologist
•
2 Diagnostic Assistants
•
3 RNs
•
8 Breast US Rooms/ 8 Diagnostic Mammo Rooms
Simulation Preparation
Four Patient Flow Charts
•
Diagnostic Mammo
•
Ultrasound
•
Diagnostic to Mammo
•
Stereotactic
Simulation Preparation
Process Flow
Simulation Preparation
Simulation Preparation
Data Collection
Activities captured for
•
Electronic Data Validation
•
Simulation
Simulation Preparation
Data Collection
Baseline
63.4 (min)
34%
42%
24%
Simulation Preparation
Data Collection
BUILDING THE SIMULATION
Building the Simulation
Building the Simulation
Insert the schedule
of all labor
resources
represented in the
model
Building the Simulation
Diagnostic Mammo
Ultrasound
Wait Area
Diagnostic Mammo
Radiologist Reading Room
Entrance & Exit
Patient Path
Building the Simulation
Building the Simulation
Initial Results
Next Steps
•
Validate simulation results
•
Recommend changes based on simulation output
•
Create new simulation with recommended changes
Before you begin…
•
What are you simulating?
•
Are you simulating something you can’t change?
•
Are you attempting to simulate EVERYTHING? EEK!
•
Validate, Validate, VALIDATE
Supplementary
MD Anderson Volume of Clinical Activity2
Supplementary
Modality
Description
X-rays
Common method of sending beams to
be absorbed through the body to
creating images
Magnetic Resonance Imaging (MRI)
Accurate test that uses a magnetic field
to make computer images of the body’s
soft tissue, large blood vessels and
major organs
Computed Tomography (CT) Scan
Test that uses radiographic beams to
make detailed computerized pictures
taken with a special X-ray machine;
more precise than a standard X-ray
Mammography
An x-ray image specifically of the
breast for both screening and
diagnostic purposes
Nuclear medicine
Specialized technology that uses
radioactive materials
(radiopharmaceuticals) in diagnosis
and therapy
Positron Emission Tomography (PET)
Similar to a CT Scan, but patient takes
a small dose of radioactive sugar which
provides information about tissue
function
Ultrasound
High-frequency sound waves
transmitted into the body and
converted into a computerized image to
determine if a suspicious lump is solid
or fluid.
Supplementary
Ultrasound Procedures
Mammography Procedures
Ultrasound Guided Needle Biopsy
Mammography, Ductography
/Galactography, SIN S&I or Multiple
Ultrasound Pre-op Needle
Unilateral Digital Screen Mammogram
Localization
and/or with TOMO
US, Breast with Fine Needle
Unilat Digital Screen Mammogram
Aspiration
with implant and/or with TOMO
US, Radiation Seed 76942
Digital Screening Mammogram and/or
with TOMO
Intra-operative Ultrasound
Digital Screening mammogram with
implants and/or with TOMO
Ultrasound Breast Unilateral
Digital Bilateral Diag Mammogram
and/or with TOMO
Ultrasound Breast Bilateral
Digital Unilateral Diag Mammogram
and/or with TOMO
Ultrasound Chest
Mammogram Guide For Needle
Placement
Ultrasound, Extremity Limited
Mammogram guided Seed
Localization
Molecular Breast Imaging
Supplementary
-
-
Projected
Demand
DI Processes &
Service Times
Key Stats
Simulation
Model
-
Evaluation
-
Facility Layout
-
LOS
Average Wait Times
Volumes
Operating Hours (closing time)
Modality concerns
Bottlenecks?
Space Sufficient?
Utilization
What-If Scenarios