Productivity Comparison CR vs. DR

The Economic Reason for CR & DR

CR Defined

CR Equipment

DR DefinedDR Equipment

Introduction

Workflow: CR-based

Workflow: DR-based

Assumptions

The comparison will look at radiographic imaging, not the production of cross-sectional imaging on film, nor imaging for interventional radiology

Assumptions

CR and DR operation An RIS and PACS are in place The systems support DICOM MWL and

PPS Reading is done on PACS diagnostic

workstations

Fundamental Steps in the Process

End the examination Move the patient out of the

examination room Move images to the radiologist to be

read

CR-based Workflow (Steps 1-2)

From the reception desk or inpatient schedule, determine the next patient to be examined

Call for the patient from the waiting room or floor

CR-based Workflow (Steps 3-4)

While the patient is changing or being put into the room, call up the worklist on the CR workstation

Select the appropriate patient and exam from the worklist

CR-based Workflow (Steps 5-8)

ID the plate Position the patient and the CR plate Set the generator and make the

exposure If there is more than one view, repeat

the above three steps until done

CR-based Workflow (Steps 9-11)

Carry the CR plates to the plate reader

Stack the plates in the reader input View the images on the CR reader

workstation to be sure of correct position and exposure

CR-based Workflow (Steps 12-14)

If the images are not acceptable, return to re-take the necessary views

If the images are acceptable, check the patient ID and request number

If correct, send the study to PACS

CR-based Workflow (Steps 15-16)

If not correct, edit as needed, then send the study to PACS

Return to the exam room and have the patient dress or move to the holding area

CR-based Workflow

16 steps No film library steps The major change is eliminating

separate interaction with the RIS

CR-based Workflow: Variations

Some systems have the technologist select the patient and exam at the plate reader

Others use the ID and information recorded on the cassette to associate the images with the patient and exam

This changes where a step is done; it does not add a step

CR Alternatives

Dedicated chest and rapid-type rooms

Many CR Vendors are setting up relationships with DR vendors to meet this need

DR-based Workflow (Steps 1-3)

From the reception desk or inpatient schedule, determine the next patient to be examined

Call for the patient from the waiting room or floor

Have the patient change or moved into the exam room; log into the DR system

DR-based Workflow (Steps 4-7)

Select the patient and examination from the worklist

Position the patient Set the generator and make the

exposure If more than one view is needed, repeat

the above two steps

DR-based Workflow (Steps 8-11)

On the DR system or a QC workstation, view the images taken

If not acceptable (photon starvation/positioning), repeat the needed views

If acceptable, end the examination on the DR system

Discharge patient

DR-based Workflow

Reduced to 10 to 11 steps

No file room tasks No interaction with

cassettes

DR-based Workflow

A single system for capture, QC, and sending to PACS

Uses DICOM MWL and PPS to eliminate technologist interactions with the RIS

Eliminates carrying cassettes or plates Eliminates a separate ID step

Additional Pros for DR TechnologyDirect capture means:

No phosphors No scintillators No intermediate steps No light to diffuse or scatter Nothing to degrade the quality of the digital signal

Downside of DR

Replace existing tables/wall Buckys May have to replace the generator if

the system cannot be integrated with it

Not having DICOM MWL and PPS obviates many of the advantages

Portable?

Schematic of Workflows

Find study to do

Get paperwork

Get patient

Begin exam RIS

Position patient

Expose

Add views?

Flash ID

Carry cassettes

Process films

Reload film

Pick up films

QC films

Films OK?

Films to FL

Log into RIS

Complete exam

Log exam

Discharge Pt

Log exam in RIS

Locate master

Make exam folder

Put in TBR slot

Load alternator

Log loc in RIS

Find study to do

Get patient

Expose

Position patient

Call up WL

Pick from WL

ID Plate

Add views?

Carry plates

Run plates

View images

Images OK?

ID OK? Edit info

Images to PACS

Discharge Pt

Find study to do

Get patient

Pick from WL

Add views?

Position patient

View images

Login to DR

Expose

Images OK?

End DR examDischarge Pt

Film-based CR-based DR-based

Other Workflow Considerations

Poor planning can defeat the advantages of CR and DR

If you design a department for technologist and patient movement as though you were using film, you may create problems

Planning Considerations

For CR, a rate-limiting step may be how far the plate readers are from the examination rooms

Technologist walking time may become significant

Planning Considerations

For DR, poor layout may make moving patients into and out of the rooms a rate-limiting step

Don’t just consider space when designing for film replacement; plan around “traffic flow” as well26

Additional Workflow

These workflow examples stop at the step at which the radiologist would interpret the exam

There are additional workflow improvements for PACS over film, but there is less of an impact from particular imaging methods

CR vs. DR

An objective assessment and comparison of computed radiography (CR) versus digital radiography (DR) and screen-film for performing upright chest examinations on outpatients is presented in terms of: Workflow Productivity Speed of service Potential cost justification

How Was The Study Conducted

Perceived ease of use and workflow of each device was collected via a technologist opinion survey.

Productivity is measured as the rate of patient throughput from normalized timing studies.

The overall speed of service is calculated from the time of examination ordering as stamped in the RIS, to the time of image availability on the PACS, to the time of interpretation rendered (from the Transcription System).

A cost comparison is discussed in terms of potential productivity gains and device expenditures. Comparative results of a screen-film (analog) dedicated chest unit versus a CR reader and a DR dedicated chest unit show a higher patient throughput for the digital systems.

The Statistics

A mean of 8.2 patients were moved through the analog chest room per hour, versus 9.2 patients per hour using the CR system and 10.7 patients per hour with the DR system. This represents a 12% increase in patient

throughput for CR over screen-film; a 30% increase in patient throughput for DR

over screen-film, which is statistically significant; and

a 16% increase in patient throughput for DR over CR, which is not statistically significant.

Measurements

Measured time to image availability for interpretation is much faster for both CR and DR versus screen-film: With the mean minutes to image availability calculated as 29.2 ± 14.3 min for

screen-film 6.7 ± 1.5 min for CR 5.7 ± 2.5 min for DR

This represents an improved time to image availability of: 77% for CR over screen-film 80% for DR over screen-film 15% for DR over CR

These results are statistically significant (P < .0001) for both CR over screen-film and DR over screen-film but not statistically

significant for DR over CR.

Conclusion

A comparison of the digital technology costs illustrates that the high cost of DR may not be justifiable unless a facility has a steady high patient volume to run the device at or near 100% productivity.

Both CR and DR can improve workflow and productivity over analog screen-film in a PACS for delivery of projection radiography services in an outpatient environment.

Cost justification for DR over CR appears to be tied predominantly to high-patient volume and continuous rather than sporadic use patterns.

Additional Notes

There is a potential for workflow improvement in moving from film to CR and from CR to DR

These improvements require integration with HIS, RIS as well as the Transcription/Dictations Systems

Don’t forget department layout effects on workflow (location, location, location)