Medical Robert

E. Nelson,

BS,

RTR

John

#{149}

G. Stears,

RT

Acceptance Testing Experience in Testing at Two Major Medical The problems encountered in acceptance testing of newly installed imaging equipment at two major medical institutions over a 10-year period are presented. Acceptance tests were conducted in 129 newly installed imaging systems with conventional acceptance testing methods. A total of 1,132 problems were documented. Problems were classified as major or minor; there were 772 major problems and 360 minor problems. An average of six major and three minor problems were documented in each new equipment installation tested. In some instances, final payment was withheld for several months or more to ensure correction of the problems identified. This experience confirms the need of thorough acceptance testing of new imaging equipment before final payment is made to the vendor. Index terms: Acceptance testing #{149}Radiology and radiologists, departmental management Radiology

and

radiologists,

design

of radiologi-

cal facilities 1992;

183:563-567

health

ODERN

standards

production of high

care requires of quality, and

of radiologic technical

Joel

#{149}

inations

requires

optimal

skilled

ment quality maintenance in such ceptance

control program.

a program tests on

achieved

to operate,

with equip-

and

preventive The first step

is to perform newly installed

equipment. That is, verify new equipment operates signed

consisexam-

performance.

The latter can only be the aid of a comprehensive

ac-

that the as it is de-

complies

with

the

baseline

for

future

quality control evaluations. The objective of this article is to review the acceptance testing experience and the problems encountered at two major medical facilities-the Mayo

Clinic,

Rochester,

the University and Clinics, Birmingham. publications tance testing 7); however, type

and

countered We address From the Department of Radiology, Univerof Alabama Hospitals and Clinics, University of Alabama at Birmingham, Birmingham, AL 35294 (R.E.N., G.T.B.), and Department of Diagnostic Radiology, Mayo Clinic and Foundahon. Rochester, Minn (J.G.S., J.E.G.). From the

Minn,

and

of Alabama Hospital University of Alabama at There have been several concerned with accepand quality control (1to our knowledge, the

frequency

of problems

en-

have not been reviewed. those issues herein.

standards

are

met, and high-quality images are obtamed. At both institutions, acceptance tests are performed when the vendor cornpletes the installation and the equipment is ready for clinical use. Thus, problems in equipment function and performance are identified and corrected before clinical use. The results of acceptance tests in 129 new equipment installations over a 10year period were evaluated. Seventy-six pieces of equipment were installed at the Mayo Clinic and 53 at the University of Alabama at Birmingham. The 129 installa-

lions were equipment

reg-

ulatory standards, and produces high-quality images. This in turn mmimizes radiation exposure to patients and staff. Furthermore, when acceptance tests are performed on new equipment, it ensures that all contract (bid) requirements are satisfactorily met between the vendor and institution before clinical use. Also of importance is that data from acceptance provide

with the manufacturer’s specsU.S. Food and Drug Administra-

tion (FDA) performance in

personnel

equipment

PhD

accordance fications,

high the

is essential

objective. The of high-quality

E. Gray,

Systems: Systems

examinations

quality

achieving this tent production and

PhD

T. Barnes,

ofRadiologic 129 Imaging Facilities’

M

tests

Radiology

#{149} Gary

Physics

divided into seven general classifications. Equipment

from

20 different equipment manufacturers were included in the evaluation. These manufacturers

are

listed

in Table

I and

represent a broad cross-section of the medical x-ray imaging industry. Thirteen categories of radiologic compo-

nents

were

developed

for problem

fication.

Problems

were

further

as major

or minor,

depending

identi-

classified on

the

se-

verity of the problem. Major problems (a) interfered with the desired patient examinafions and equipment operation or resulted in a hazard to the patient, (b) noticeably compromised image quality, (c)

resulted

from

FDA

standards, hour meet

in a 10% or greater regulations

or

(d)

and

required

deviation

performance

more

than

I

to repair. Minor problems (a) did not the required bid specifications or

performance

standards

and,

in the

judg-

ment of the authors, did not interfere with patient examinations and equipment operation or result in a hazard to the patient; (b) resulted in less than a 10% deviation from FDA regulations and performance standards; or (c) required less than 1 hour to repair.

I

RESULTS

sity

MATERIALS

AND

The acceptance

METHODS

tests performed

at both

RSNA scientific assembly. Received September 9, 1991; revision requested October 10; revision received December 13; accepted De-

institutions were similar and comparable in scope. The protocols employed have been previously described elsewhere (1-

cember

5). Newly

installed

to ensure

that

1990

C

23. Address

RSNA,

1992

reprint

requests

to G.T.B.

equipment

it functions

Table problems

and

and

problems

found

number of major

in

and

360 were

minor.

of

for each

the seven types of equipment stalled. A total of 1,132 problems identified. Of these, 772 were

is evaluated

properly

minor

2 shows the total and the number

of

inwere

major In general, the 563

more complex the system, the greater the number of problems. The major problems in the different equipment component categories are listed in Table 3, and the minor problems are listed in Table 4. Lack of compliance with FDA performance standards was responsible

for

at least

one

problem

in

each number in the x-ray beam

of the 13 categories. The largest of major problems occurred calibration and operation of generators. Collimation and alignment and equipment integrity categories were also high in deficiencies. Most minor problems occurred in installation and equipment integrity. For both the major and minor problems,

collimation

accounted lems.

and

beam

for 171 of the

The

x-ray

alignment

1,132

generator

prob-

category

are present during most of the acceptance testing. However, problems are not corrected when identified. Rather, acceptance testing is completed, and a

in the

acceptance

types

of equipment,

list

Classification of the data in major and minor problems in ferent component categories completely indicate the range

of all problems

is provided

as the

initial

list

to the

of problems,

that the dates the rected satisfactorily highlighting

This lems this

problems.

are

that

problems

are

documented and acceptance can be performed efficiently interruption. Disadvantages with

less-effective

philosophies, documented

had

to be replaced.

Of

tubes,

image

intensifiers,

the

grids

pickup tubes, high tension transformers, and tabletops were also replaced. One portable radiography unit was rejected as a result of evaluation. Tables 5 and 6 identify components that were replaced.

The

philosophies differ

slightly

involvement

of the

two

instituto the

of the

vendor’s service Clinic, both inhouse and vendor service engineers are present during acceptance testing, and minor problems are corrected at that time if possible. If problems cannot be corrected immediately, the acceptance testing is continued and completed to the degree possible. Capabilities not tested during this initial phase are tested at a later date when the equipment should be functioning engineers.

correctly.

At Mayo

Advantages

of this

while

repairs

are

being

564

#{149} Radiology

(four

However,

major,

both

were at the

Table Types

Studied

assem-

ifi)

Inc (Chicago)

Imaging

GE Medical

(Rochester, NJ)

Corporation

Systems

Jamieson Film Liebel-Flarsheim nati)

(Denver)

(Milwaukee)

Company Company

(Dallas) (Cincin-

Philips Medical Systems (Shelton, Conn) Picker International, Inc (Highland Heights, Ohio) Schimadzu

X-Ray

Corporation

land Heights, Ohio) Siemens Medical Systems, NJ)

test-

(High-

Inc (Iselin,

Tecnomed USA (Bay Shore, NY) Thomson CGRt Transworld X-Ray Corporation (Charlotte, NC) Varian Associates (Palo Alto, Calif) Xerox Medical Systems*

helped

2 of Equipment

Bucky

and equipment inGrid and Bucky often overlooked dur-

Manufacturers

Fischer

minor)

acceptance

and

terms of the difdoes not of prob-

as illusproblems

Inc* Eastman Kodak Company NY) Elscinct, Inc (Hackensack,

testing

one

is

testing and, therefore, is of practical impor-

Amerisys, Amrad,

for

identify a surprisingly large number of problems with new equipment installations. Ultrasound, computed tomographic, and magnetic resonance imagers were not included in this study because we have been less involved

*

t

and Associated

No longer Purchased

Major

and

in business. by GE in 1988.

Minor

Problems No. of Problems

Type

of

No. of Units

Equipment

ap-

Radiography

and

fluoroscopy*

Radiographyt Mobile radiography

Processors and darkrooms Mammography Special procedures, heart ters

Includes

add-on

7,3

106

169

99

344 268

24 21

93 18

38 11

131 29

12

74

27

101

17

173 7

74 5

247 12

129 general radiography and tomography and trauma, digital

Total

27

2

Total Indudes t Includes

Minor

cathe-

Miscellaneous*

*

Major

and fluoros-

copy

made.

At the University of Alabama Hospitals and Clinics, the vendor’s service engineers are not essential to the acceptance testing process. They are invited to be present and, in general,

different

problems

Acoma X-ray Company (Wheeling, Advanced Medical Systems, Inc (Geneva, Ohio) Alpha Imaging (Wffloughby, Ohio)

the

equipment

fewer problems per installation

approaches

proach are that problems are easily communicated and corrected when identified, and, as a result, follow-up measurements are minimized. Disadvantages are that many problems are not documented and that the staff has to wait

in delaying

of the of the

Clinic

ing

in regard

result

grid

acceptance category

than at the University of Alabama Hospitals and Clinics (nine major, six minor). Other factors that may have affected the number of problems documented at the two institutions are the difference in location and service groups involved, and that different personnel performed the acceptance tests.

DISCUSSION

tions

As a result

Mayo

video

can

in the

Table 1 Equipment

communica-

subsystems

This

testing

well

tion about certain types of problems, and additional vendor visits may be required to resolve a problem or probfinal acceptance clinical use.

ing the

testing without may re-

accounted for 152 problems and equipment integrity for 145. Problems in equipment integrity included parts or subsystems that were not delivered or were nonoperational and shipment of the wrong equipment or parts. As a result, a number of components or

lems.

documenta-

found in a category, by reviewing the

bly, mechanical, tegrity categories. assemblies are

until all probadvantages of

of these

and

or incomplete.

found

except

uncorrected

system

lems trated

problems were corare noted, thereby

process is repeated are resolved. The

of acceptance

lacking

vendor’s service organization. When the problems have been corrected, evaluations are performed and a revised list of problems developed. The revised list is essentially the same

sult

operational components tested, were replaced most often. X-ray

tion

testing

fluoroscopy head, and

772

and urologic radiography dedicated chest units.

360 and

1,132

fluoroscopy.

units.

May

1992

Table 3 Major Problems

Found

with Acceptance

Testing

(n

772) No. of

Parameter X-ray source assembly Focal spot size

(n

=

Tested

Problems

37)

12 8 6 11

Alignment

Half-value layer Miscellaneous X-ray generator

calibration

Kilovolt peak Milliampere

and

and operation

kilovoltage

Time, milliampere Line compensator

(it

=

125)

36 28 8 3 22 11 17

waveform

seconds

Hand switch Exposure Output

waveform

Collimation

and

beam

light field

Radiography Radiography Indicators Source-to-image

image cassette

Positive

(n

alignment

Radiography

=

119) 25 10 22 12

intensifier

distance

beam

12

28 10

limitation

Detents

Grid and Grid

Bucky assembly

(n

59)

=

41 18

Bucky Automatic

exposure

Density

control

performance

(n

Tube potential and patient thickness Sensing cell variations Miscellaneous Fluoroscopic

automatic

rates (n

brightness

brightness

Maximum 5-minute

5

control

control

Input

tabletop timer

and

exposure

image

Image

quality

rate

rate (n

=

84)

intensifier

Monitor

31

performance

Video

29

camera (n

Mechnical

24 72)

=

Table

31 11

Tubecrane

Image Image

intensifier intensifier

tower tower

movements alignment

13 6

11

Miscellaneous

(n

Tomography

=

25)

Operation

12

Alignment Fulcrum Speed and

2 7

exposure

2 2

Miscellaneous

and darkroom

Imaging, processing, Processors Multiformat

cameras (n

Installation Corridor

=

0 0 0 0 0 0 0

lights

location

Equipment aesthetics Room aesthetics Painting

Miscellaneous integrity type

Wrong on

order

Volume

183

Number

#{149}

=

104)

25 14 27

24)

Miscellaneous code

(n

38

Nonoperational Not provided =

20)

4

Tie wrapping

Equipment

=

0)

warning

Equipment

(n

5 11

Darkroom

(n

exposure

8 2 19 3 19

tracking

exposure

phosphor

Fluoroscopic

Error

36 10

tracking

Interlock

Other

52)

51)

=

Automatic

Parts

=

settings

problems

2

19 5

tance. Examples of problems include grids with the wrong ratio, grids not centered to the x-ray source, grids with the wrong focal range, Bucky assemblies demonstrating grid lines at more than 10-msec exposure times, and Bucky assemblies in which the grid would slow down or stop when minimal pressure was applied to the assembly cover. As noted

in Tables

3 and

4, 73 prob-

lems in the grid and Bucky assembly category were found at the two institutions during the past 10 years. Six grids

were

replaced

because

of radio-

graphically demonstrated defects, one fluoroscopic grid with a radiographically demonstrated defect at its periphery was accepted because the defect was outside the television and cine field of view, four grids were replaced because the wrong grid ratios were supplied, five grids with a 3640-inch (90-100-cm) focus were installed on units with a 44-inch (112cm) source-to-image distance, and three grid tunnels were found to have the incorrect focal length. The remaining 29 problems were associated with Bucky assemblies. In six cases, the moving grid was not centered to the x-ray source during an exposure (lateral decentering), and in seven cases the grid was not orthogonal to the x-ray beam (off-level decentenng). Other examples of Bucky assembly problems included grid lines evident at more than 10-msec exposure times, Bucky assemblies that were difficult to move and position, and wall Bucky assemblies that were not properly counterbalanced. The most common mechanical radiography table, tube crane, and image intensifier tower problems encountered were rough or difficult movement (due to binding, defective, or misaligned bearings), disturbing noise during

movement,

and

would not release release. Additional intensifier tower nonfunctional

locks

that

or only partially table and image problems included

limit

switches

that

per-

mitted the table to continue to drive or tilt beyond normal limits, nonfunctioning drives and power assist, dragging brakes, noisy drives, and the omission of or nonoperational interlocks. Additional tube crane problems were cables catching other equipment, cables and/or tie wraps that limited movement, and the omission of cushions, stops, and detents. The latter allowed unsatisfactory and destructive metal-to-metal collisions and collisions with walls, control booths, or delicate imaging components. The number of major problems asRadiology

565

#{149}

sociated with equipment integrity is large, approximately 13% of all major problems, which is somewhat surprising for new equipment installations. Included in this category are (a) yendor notification of parts or components on order at the time of acceptance testing, (b) missing parts or components that the vendor did not indicate, (c) incorrect parts or components supplied, and (d) nonoperational parts or components that were subsequently replaced. Many minor installation integrity problems (eg, room aesthetics, room painting) were associated

with

institution

rather

than

vendor responsibility. It is advantageous to specify in the purchase agreement that a substantial portion of the purchase price will be withheld until the equipment meets specifications. In several cases, final payment was withheld for several months. In two cases (one at each institution), final payment was withheld for more than 1 year before the problems were resolved. In one of those cases, the equipment manufacturer made several modifications to the installed equipment and, later, to production systems. The amount of money that should be withheld is negotiable but should be about 20% of the purchase price. As a result of acceptance testing, a number of expensive major and minor components were found to be defective or did not meet specifications and were subsequently replaced. Examples are listed in Tables 5 and 6 and include x-ray tubes, an x-ray generator (the wrong type was supplied), x-ray generator high-tension transformers, tabletops (bent), a digital image

processing

tubes, (those

intensifiers, television supplied

desired

degree

control

module,

video pickup monitors and stands would not allow the of movement

and

viewing flexibility), a mobile radiography unit, grids with the problems mentioned earlier, the grid-cassette mounting bracket and the lower section of a radiographic U-arm (because of poor design and/or manufacturing practices, the grid could not be aligned to the x-ray beam), and a large number of miscellaneous circuit boards. Many of these defective components (eg, high tension transformer, digital processing module, bent tabletop, and malfunctioning printed circuit boards) would have been detected during routine clinical use if the equipment was not acceptance tested. However, equipment failure or malfunction is likely to result in additional patient positioning, 566

Radiology

#{149}

Table

4

Minor

Found

Problems

Acceptance

with

Testing

(n

=

360)

No. of Parameter X-ray source assembly Focal spot size Alignment Half-value Miscellaneous

(n

Tested

Problems

30)

=

1 1 27 1

layer

X-ray

calibration and and kilovoltage

generator Kilovolt peak Milliampere

Time, milliampere Line compensator

operation waveform

(n

=

17)

I 2 2

seconds

1

5 1

Hand switch Exposure Output waveform

Collimation

5

and beam

alignment

(n

=

52)

field

Radiography

light

Radiography

image

Radiography Indicators

cassette

Source-to-image

15

intensifier

2 0 9 9 2

distance

limitation

Positive beam Detents

15

Grid and Bucky assembly

(ii

14)

=

Grid

5 9

Bucky

Automatic exposure control performance Density settings Tube potential and patient thickness

(n =4) 3 0 0 1

tracking

Sensing cell variations Miscellaneous Fluoroscopic

automatic

(n

rates

Automatic

brightness

control

and

brightness

control

0

tracking

Interlock

0

Maximum

tabletop

5-minute Input

exposure

phosphor

0 0 0

rate

exposure

image

Image Video

rate

timer

Fluoroscopic

(n

quality

=

12) 3 4 5

intensifier camera

Monitor

performance

(n

Mechnical

39)

=

Table Tubecrane Image intensifier

Image

intensifier

14 17 3 0 5

tower movements tower alignment

Miscellaneous

Tomography

(n =5)

Operation Alignment Fulcrum Speed and

0 0 2 1 2

exposure

Miscellaneous

Iinagmg, processing, Processors Darkroom Multiformat Installation Corridor

and darkroom

cameras

(n

warning

lights

=

15 5 14

aesthetics

19

4 10 5

Miscellaneous Equipment

integrity type Parts on order Nonoperational Wrong

Not provided =

code

(n

=

41) 3 1 16

21

55)

Miscellaneous Error

19)

location

Room aesthetics Painting

(n

=

72)

Tie wrapping Equipment

(n

11 3 5

integrity

Equipment

Other

exposure

0)

=

53 problems

2

May

1992

Our experience clearly demonstrates that acceptance testing should be routinely performed in newly installed equipment before it is used for clinical imaging and before final payment is made to the vendor. #{149} Acknowledgments: the assistance Chakraborty,

The authors Wu, PhD, Dewey Narkates,

acknowledge Dev P. PhD, Rich-

of Xizeng

PhD, ard L. Morin, PhD, CarolJ. Mount, RTR, Jerome P. Taubel, RTR, and Timothy R. Daly, RTR, in acceptance testing, and the assistance of Phyllis J. Roybal in preparing the manuscript.

References 1.

creased contrast grids,

from

patient discomfort, problems, additional injections,

or repeat

More

subtle

tube focal generous

tional ation, contrast

Vnliime

patient scheduling contrast media imaging.

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include

spots being specifications

Electrical Manufacturers image intensifiers with resolution,

is:;

#{149} Number

x-ray

larger than the of the Na-

grid

2

artifacts,

Associpoor in-

radiation associated decreased

and

with contrast

decreased

tected would ment

use

would

not

have

been

de-

during routine clinical use but result in suboptimal equipperformance, suboptimal image

quality,

and

to the

patient.

increased

2.

misaligned resulting

of a lower than commonly employed grid ratio, increased radiation dose resulting from the use of a high-ratio grid in low-scatter conditions, and poor image quality and repeat imaging because of improper calibration and performance in accordance with automatic exposure control standards. In most cases, these problems

the

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radiation

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JK, Rauch

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#{149} S67