Bai Bao Desing Pacs

7/26/2019 Bai Bao Desing Pacs

1/13

Jou rnal o f ig ita l Im aging

V O L 9 , N O 2

M A Y 9 9 6

D e s i g n a n d I m p l e m e n t a t i o n o f a P i c t u r e A r c h i v i n g a n d

C o m m u n i c a t i o n S y s te m T h e S e c o n d T i m e

H .K . H u a n g , K a t h e r i n e A n d r i o l e , T o d d B a z z il l, S .L . L ou , A l b e r t W . K . W o n g , a n d R o n a l d L. A r e n s o n

T h i s re p o r t d e s c r i b e s t h e a u t h o r s e x p e r i e n c e in t h e

d e s i g n a n d i m p l e m e n t a t i o n o f t w o l a r g e s c a l e p i c t u r e

a r c h i v i n g a n d c o m m u n i c a t i o n s y s t e m s ( P A C S ) d u r i n g

t h e p a s t 1 0 y e a r s . T h e f i r s t s y s t e m , w h i c h i s i n d a i l y

c l in i c al o p e r a t i o n w a s d e v e l o p e d a t U n i v e r s i t y o f C a l i -

f o r n i a , Lo s A n g e l e s f r o m 1 9 8 3 t o 1 9 9 2 . T h e s e c o n d

s y s t e m , w h i c h c o n t i n u e s e v o l v i n g , h a s b e e n i n d e v e l o p -

m e n t a t U n i v e r s i t y o f C a l i f o r n ia , S a n F r a n c i s c o ( U C S F )

s i n c e 1 9 9 2 . T h e r e p o r t h i g h i i g h t s t h e d i f f e r e n c e s b e -

t w e e n t h e t w o s y s t e m s a n d p o i n ts o u t th e g r a d u a l

c h a n g e i n t h e P A C S d e s i g n c o n c e p t d u r i n g t h e p a s t 1 0

y e a r s f r o m a c l o s e d a r c h i t e c t u r e t o a n o p e n h o s p i t a l -

i n t e g r a t e d s y s t e m . B o t h s y s t e m s f o c u s o n s y s t e m

r e l i a b i l i t y a n d d a t a i n t e g r i t y , w i t h 2 4 - h o u r o n - l i n e

s e r v i c e a n d n o I o s s o f i m a g e s . T h e m a j o r d i f f e r e n c e

b e t w e e n t h e t w o s y s t e m s i s t h a t t h e U C S F P A C S

i n f r a s tr u c t u r e d e s i g n i s a c o m p l e t e l y o p e n a r c h i t e c t u r e

a n d t h e s y s t e m i m p l e m e n t a t i o n u s e s m o r e a d v a n c e d

t e c h n o l o g i e s in c o m p u t e r s o f t w a r e , d i g i ta l c o m m u n i c a -

t i o n , s y s t e m i n t e r f a c e , a n d s t a b l e i n d u s t r y s t a n d a r d s .

S u c h a P A C S c a n w i t h s t a n d f u t u r e t e c h n o l o g y c h a n g e s

w i t h o u t r e n d e r i n g t h e s y s t e m o b s o l e t e , a n e s s e n t i a l

c r i t e r i o n i n a n y P A C S d e s i g n .

C o p y r i g h t 9 1 9 9 6 b y W . B . S a u n d e r s C o m p a n y

K E Y W O R D S : p i c tu r e a r ch i vi n g a n d c o m m u n i c a t i o n

s y s t e m { P A C S ) , c o m m u n i c a t io n n e t w o r k s , i n f r a st r u c -

t u r e d e s i g n , o p e n a r c h i t e c t u r e , d i s p la y w o r k s t a t i o n .

H E R E A R E g e ne ra ll y t h re e m e t h o d s o f

a p p r o a c h t o d e si g n a nd i m p l e m e n t a t i o n o f

a p i c t u r e a r c h i v i n g a n d c o m m u n i c a t i o n s y s t e m

P A C S ) . ~ I n t h e f i rs t a p p r o a c h , s y s t e m s i n t e g r a -

t i o n , a m u l t i d i s c i p l i n a r y t e a m w i t h t e c h n i c a l

k n o w - h o w is a s s e m b l e d b y t h e r a d i o l o g y d e p a r t -

m e n t o r t h e h o s p i t a l . T h e t e a m b e c o m e s a

s y s t e m i n t e g r a t o r , s e l e c t i n g P A C S c o m p o n e n t 5

f r o m v ar i ou s m a n u f a c t u r e r s . T h e t e a m d e v e l o p s

s y s te m i n t e r f a c e s a n d w r i t e s th e P A C S s o f t w a r e

a c c o r d i n g t o t h e c l in i ca l r e q u i r e m e n t s o f t h e

h o s p i t a l . I n t h e s e c o n d a p p r o a c h , r e q u i r e m e n t s

s p e c i f i c a t i o n a n d c o n t r a c t i n g , a t e a m o f e x p e r t s ,

f r o m b o t h o u t s i d e a n d i n s i d e t h e h o s p i t a l , is

a s s e m b l e d t o w r i t e d e t a i l e d s p e c i f i c a t i o n s f o r

t h e P A C S f o r a c e r t a i n c li n ic a l e n v i r o n m e n t . A

m a n u f a c t u r e r i s c o n t r a c t e d t o i m p l e m e n t t h e

s y s t e m . I n t h e t h i r d , o r t u r n k e y a p p r o a c h , t h e

m a n u f a c t u r e r d e v e l o p s a t u r n k e y P A C S a n d

i n s t a l l s i t i n a d e p a r t m e n t f o r c l i n i c a l u s e . E a c h

o f t h e s e a p p r o a c h e s h a s a d v a n t a g e s a n d d i sa d -

v a n t a g e s . O n e a d v a n t a g e o f t h e f ir st , o r s y s t em s

i n t e g r a t i o n a p p r o a c h , i s t h a t t h e r e s e a r c h t e a m

c a n c o n t i n u o u s l y u p g r a d e t h e s y s t e m w i th s t a t e -

o f - t h e - a r t c o m p o n e n t s a n d t h e r e f o r e , t h e s y s -

t e m w i l l n o t b e c o m e o b s o l e t e . T h e s y s t e m s o

d e s i g n e d is ta i l o r e d t o t h e c l in i ca l e n v i r o n m e n t

a n d c a n b e u p g r a d e d w i t h o u t d e p e n d i n g o n t h e

s c h e d u l e o f t h e m a n u f a c t u r e r . O n e d i sa d v a n-

t a g e is t h a t i t r e q u i r e s a s u b s t a n t i a l c o m m i t m e n t

b y t h e h o s p i t a l t o a s s e m b l e a m u l t i d i s c i p l i n a r y

t e a m . I n a d d i t i o n , t h e s y s t e m d e v e l o p e d w ill b e

o n e o f a k i n d , a n d t h e r e f o r e , s e r v ic e a n d m a i n t e -

n a n c e w i ll b e d i f f i cu l t b e c a u s e i t c o n s i s t s o f

c o m p o n e n t s f r o m d i f f e r e n t m a n u f a c t u r e r s .

T h e p r i m a r y a d v a n t a g e o f t h e s e c o n d a p -

p r o a c h r e q u i r e m e n t s sp e c i fi c a ti o n a n d c o n t r a c t -

i n g ) i s t h a t t h e P A C S s p e c i f i c a t i o n s a r e t a i l o r e d

t o a c e r t a i n c l in i c al e n v i r o n m e n t , y e t t h e r e s p o n -

s ib i li ty f o r i m p l e m e n t i n g t h e P A C S is d e l e g a t e d

t o t h e m a n u f a c t u r e r . T h e d e p a r t m e n t a c t s a s a

p u r c h a s i n g a g e n t a n d d o e s n o t h a v e t o b e

From the Laboratory for Radiological Informatics, Depart-

m ent of Radiology, University of Califomia, San Fran cisco

94143-0628.

Part ial ly supported by PH S grant RO l CA 51198, Nat ional

Librar) ' of Medicine contract NO1-LM-4-3508, Cal RE N grant

ATMN-O07, Fuj i Medical Systems USA, Lumisys, and Abe

Sekkei.

Address reprint requests to H.K . Huang, DSc, Laboratory for

Radiological lnformatics, Department of Radiology, Un iversity

of California, San Francisco, CA 94143-0628.

R.L .A. contributes to the design of the U CS F PA CS.

Copyright 9 1996 by H 91 Saunders Com pany

0897-1889 / 96 / 0902-000153. O0 0

Journa/ofDigita//maglng Vol 9, No 2 May ), 1996: pp 47-59 47


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8 HUANG ET AL

c o n c e r n e d w i t h t h e i n s ta l l at i o n . T h e d i s a d v a n -

t a g e s a r e t h a t t h e s p e c i f i c a t i o n s t e n d t o b e

o v e r l y a m b i t i o u s . T h e e x p e r t s m a y n o t b e f a m i l -

i a r w i t h t h e c l i ni c al e n v i r o n m e n t , a n d t h e y m a y

u n d e r e s t i m a t e t h e t e c h n i c a l a n d o p e r a t i o n a l

d i ff ic u lt y . T h e d e s i g n a t e d m a n u f a c t u r e r , w h o

m a y l a c k cl in i ca l e x p e r i e n c e , t e n d s t o o v e r e s t i -

m a t e t h e p e r f o r m a n c e o f e a c h P A C S c o m p o -

n e n t . A s a r e su l t, t he c o m p l e t e d P A C S m a y n o t

m e e t t h e o v e r a l l s p e c i f i c a t i o n s . T h e c o s t o f

c o n t r a c t i n g t h e m a n u f a c t u r e r t o d e v e l o p a s p e c i-

f ie d P A C S is a l so h i g h b e c a u s e o f th e m a n u f a c -

t u r e r s n a r r o w p r o f i t m a r g i n i n b u il d i n g o n l y

o n e s y s te m .

T h e a d v a n t a g e o f t h e t h i r d o r t u r n k e y a p -

p r o a c h i s t h a t i t i s a g e n e r a l i z e d p r o d u c t i o n

s y s t e m , t h e r e f o r e , t h e c o s t t e n d s t o b e l o w e r .

H o w e v e r , i n t h is a p p r o a c h , t h e m a n u f a c t u r e r

n e e d s a c o u p l e o f y e a r s to c o m p l e t e t h e p r o d u c -

t i o n c y cl e . B y th e t i m e t h e s y s te m i s c o m m e r -

c i al ly a v a i la b l e , s o m e c o m p o n e n t s m a y h a v e

a l r e a d y b e c o m e o b s o l e t e b e c a u s e o f t h e f a s t

m o v i n g c o m p u t e r a n d c o m m u n i c a t i o n te c h n o l o -

g i e s . A l s o , i t i s d o u b t f u l w h e t h e r a g e n e r a l i z e d

P A C S c a n b e u s e d b y e v e r y s p e c i a lt y in a

d e p a r t m e n t a n d b y e v e r y r a d io l o g y d e p a r t m e n t .

I n t h e p a s t s e v e r a l y e a r s , t h e s e t h r e e a p -

p r o a c h e s g r a d u a l l y m e r g e a s a d d i t i o n a l c l i n i c a l

d a t a i n P A C S b e c o m e a v a il a b le . A s a r e s u lt , t h e

d i s ti n c ti o n a m o n g t h e m h a s b e c o m e b l u r r e d .

T h i s r e p o r t d e s c r i b e s t h e a u t h o r s e x p e r i e n c e

o f d e s ig n a n d i m p l e m e n t a t i o n o f tw o P A C S , o n e

a t U n i v e r s i t y o f C a l i f o r n i a a t L o s A n g e l e s

( U C L A ) a n d t h e o t h e r a t U n i v e r s i ty o f C a l i f o r-

n i a at S a n F r a n c i s c o ( U C S F ) d u r i n g t h e p a s t 1 0

y e a r s . T h e f i r s t s y s t e m w a s b a s e d o n t h e f i r s t

a p p r o a c h a n d t h e s e c o n d w a s b a s e d o n c o m b i n -

i n g t h e f i r st a n d s e c o n d a p p r o a c h e s . S e c t i o n s 2

a n d 3 d e s c r ib e th e U C L A a n d t h e U C S F P A C S ,

r e s p e ct i v e ly . S e c t i o n 4 c o m p a r e s t h e d i f f e r e n c e s

b e t w e e n t h e s e t w o s y s te m s .

T H E F IR S T P C S S Y S T E M T U C L

W e b e g a n t h e d e s ig n o f t h e U C L A P A C S in

1 98 3. 2 I ts i m p l e m e n t a t i o n w e n t t h r o u g h t h r e e

p h a s e s . P h a s e 1 , f r o m 1 9 84 t o 1 9 9 0, e n c o m -

p a s se d t h e d e m o n s t r a t i o n o f t h e c o n c e p t o f

P A C S a n d t h e d e s i g n o f t h e P A C S i n f r a s tr u c -

t u r e . P h a s e 2 , f r o m 1 9 9 0 t o 1 9 9 1 , c o m p r i s e d

c l in i ca l i m p l e m e n t a t i o n o f s e v e r a l P A C S m o d -

u l e s . P h a s e 3 , f r o m 1 9 9 2 o n , i n c l u d e d t h e

s y s t e m s r e f i n e m e n t , m a i n t e n a n c e , a n d a p p l i c a -

t io n s . T h i s P A C S w a s d e s i g n e d f o r t h e r a d i o l o g y

d e p a r t m e n t o p e r a t i o n w i t h o u t c o n s i d e r a t i o n o f

a h o s p i t a l i n t e g r a t e d P A C S .

Phase 1: Demonstration o f Concept and Design

o f PA CS Infrastructure

T o s h o w t h e c o n c e p t o f P A C S t o p h y s i c i a n s ,

i n 19 87 w e i m p l e m e n t e d t w o P A C S m o d u l e s ;

o n e i n t h e p e d i a t r i c r a d i o l o g y s e c t i o n w i t h i n t h e

d e p a r t m e n t , 3 a n d t h e o t h e r i n th e c o r o n a r y c a r e

u n i t . 4 T h e p e d i a t r i c r a d i o l o g y s e c t i o n w a s s e -

l e c t ed b e c a u s e i t o p e r a t e s i n d e p e n d e n t l y f r o m

o t h e r r a d i o l o g y s p ec i a l ti e s a n d r e s e m b l e s a m i n i

r a d i o l o g y d e p a r t m e n t . I r is a n e x c e l le n t m o d e l

t o s tu d y th e i m p l e m e n t a t i o n o f a P A C S f o r t h e

e n t i r e r a d i o l o g y d e p a r t m e n t . I n t h is m o d u l e ,

i m a g e s w e r e d i s p l a y e d o n t w o 2 , 0 4 8 - 1 i n e m o n i -

t o r s. T h e m o d u l e w a s u s e d f o r d ai ly c o n f e r e n c e s

a n d c a s e r e vi ew s . T h e c o r o n a r y c a r e u n i t w as

c h o s e n f o r t h e s e c o n d P A C S m o d u l e b e c a u s e it

e x p l o r e d t h e a p p l i c a t i o n o f P A C S o u t s i d e o f t h e

r a d i o l o g y d e p a r t m e n t . I n th i s m o d u l e , i m a g e s

w e r e d i s p l a y e d o n t h r e e 1 , 0 2 4 - 1 i n e m o n i t o r s .

B o t h m o d u l e s w e r e i n c l i n i c a l o p e r a t i o n 2 4

h o u r s a d a y , 7 d a y s a w e e k . T h e r e a c t i o n s f r o m

b o t h r a d i o l o g i s t s a n d c l i n i c i a n s w h o u s e d t h e s e

t w o s y s t e m s w a s v e r y p o s i ti v e .

F r o m 1 98 8 t o 1 99 0, 5 w e c o n c e n t r a t e d o n t h e

d e s ig n o f t h e P A C S i n f r a s t r u c t u r e . T h e c r i ti c al

c o m p o n e n t s i n t h e i n f r a st r u c t u re w e r e t h e c o m -

m u n i c a t i o n s y s te m , P A C S c o n t r o l l e r s , d a t a b a s e

d e s i g n , f a u l t t o l e r a n c e c o n s i d e r a t i o n , a n d s y s -

t e t a i n t e g r a t i o n s o f t w a r e . T h i s i n f r a s t r u c t u r e

s u p p o r t e d a d i g it a l -b a s e d r a d i o l o g y o p e r a t i o n .

T h e i n f r a s t r u c t u r e w a s i m p l e m e n t e d f r o m

1 9 90 t o 1 9 91 . 6 T h e r e w e .r e 64 m u l t i m o d e a n d 4 8

s i n g l e - m o d e f i b e r o p t i c c a b l e s c o n n e c t i n g t h e

t h r e e b u i l d i n g s ( C e n t e r f o r t h e H e a l t h S c i e n c e s

[ C H S ] , M e d i c a l P l a z a , a n d T a p e r B u i l d i n g )

h o u s in g t h e r a d i o to g y d e p a r t m e n t . T h e r e w e r e

t w o P A C S c o n t r o l l e r s , o n e a t t h e C H S a n d o n e

a t t h e M e d i c a l P l a z a . T h e i n f r a s t r u c t u r e w a s

o n - l i n e i n t h e b e g i n n i n g o f 1 9 91 .

Communica t ion sys tem W e d e s i g n e d a

t h r e e - t i e r e d f i b e r o p t i c c o m m u n i c a t i o n s y s t e m

w i t h E t h e r n e t , F D D I ( f ib e r d i s t r i b u t e d d a ta

i n t e r f a c e ) , a n d U l t r a n e t ( a p r o p r i e t a r y 1 g b i t /

s e c n e t w o r k ) . 7 E t h e r n e t w a s u s e d t o t r a n s m i t

i m a g e s f r o m a c q u i s i t i o n d e v i c e s t o t h e a c q u i si -

t i o n c o m p u t e r . B e c a u s e t h e a c q u i s i t i o n d e v i c e


3/13

PACS SECOND TIME 49

w a s s l o w i n g e n e r a t i n g i m a g e s , t h e t r a n s m i s s i o n

s p e e d b e t w e e n t h e s e t w o n o d e s w a s n o t c r u c ia l .

I m a g e s w e r e r e f o r m a t t e d a t t h e a c q u i s i t i o n

c o m p u t e r a n d s e n t t o th e P A C S c o n t r o l l e r b y

m e a n s o f F D D I . I m a g e s w e r e a r c h iv e d o n t o

o p t i c a l d i s k s a n d d i s t r i b u t e d t o t h e i m a g e d i s -

p l a y s t a ti o n s w i th t h e U l t r a n e t . T h e t h r e e c o m -

m u n i c a t i o n n e t w o r k s w e r e c o e x i s t e n t i n t h e

i n f r a s t r u c t u r e a n d s e r v e d a s b a c k u p s f o r e a c h

o t h e r .

PACS con t ro l l e r s .

T h e r e w e r e t w o P A C S

c o n t r o l l e r s i n t h e i n f r a s t r u c t u r e . 8 E a c h c o n t r o l -

l e r w a s c o m p o s e d o f a n i m a g e s e r v e r 4 / 4 9 0

S P A R C ; S u n M i c r o s y s t e m s , M o u n t a i n V i e w ,

C A ) w i t h 4 - G b y t e m a g n e t i c d i s k s t o r a g e , a

1 Tbyte

o p t i c a [ d i sk l i b r a r y w i t h w r i t e o n c e r e a d

m a n y W O R M ) d i s ks f o r a r c h iv i n g i m a g e s , a n d

a S un 4 / 4 9 0 S P A R C s e r ve r r u n n i n g t h e d a t a

b a s e S y b a s e , E m e r y v i l l e , C A ) f o r p a t i e n t d i r e c -

t o r y a n d t e x t i n f o r m a t i o n . T h e a r c h i t e c t u r e o f

e a c h c o n t r o l l e r w a s i d e n ti c a l a n d c o u l d b e u s e d

a s t h e b a c k u p f o r t h e o t h e r . T h e P A C S c o n t r o l -

l e rs w e r e c o n n e c t e d w i th t h e U l t r a n e t . I m a g e s

c o u l d b e t r a n s m i t t e d b e t w e e n t h e P A C S c o n t r o l -

l e r s a n d d i s p l a y w o r k s t a t i o n s a t 4 t o 8 M b y t e s /

s ec

Data base .

T w o i d e n t i c a l S y b a s e d a t a b a s e s

e x i s te d i n e a c h P A C S c o n t r o l l e r a n d s e r v e d a s a

m i r r o r e d s y st em . C u r r e n t p a t i e n t i m a g e i n f o r m a -

t i o n w a s u p d a t e d c o n t i n u o u s l y o n t h e d a t a b a s e

o f e a c h c o n t r o l l e r .

Fault tolerance consideration.

I n t h e i n f r a -

s t r u c t u r e , e v e r y c r i ti c a l c o m p o n e n t h a d a b a c k u p .

T h e r e w e r e t w o id e n t i c a l d a t a b a s e s o n e i n e a c h

P A C S c o n t r o l le r . E a c h P A C S c o n t r o l l e r w a s

l o c a t e d i n a s e p a r a t e b u i l d i n g t o a v o i d p o t e n t i a l

d i s a s t e r . T h e t h r e e c o m m u n i c a t i o n n e t w o r k s

b a c k e d u p e a c h o t h e r , a n d a ll a c ti v e fi b e r o p t i c

c a b le s h a d s p a re s . E a c h P A C S c o n t r o l l e r w a s

p o w e r e d b y an u n i n t e r r u p t a b l e p o w e r s u p p l y

w i t h u p to 20 m i n u t e s o f u n i n t e r r u p t e d p o w e r .

Systems integration sof tware.

T h e p r e v i o u s l y

d e s c r ib e d c o m p o n e n t s w e r e i n t e g r a t e d a s t h e

P A C S i n f r as t r u c tu r e b y m e a n s o f an e l a b o r a t e

s y s te m s o f t w a r e . T h e s y s te m s o f t w a r e w a s w r i t -

t e n in C p r o g r a m m i n g l a n g u a g e a n d r a n u n d e r

t h e U N I X o p e r a t i n g s ys te m .

Phase 2 : Implementa tion o f PA CS Modules

T o i m p [ e m e n t P A C S m o d u l e s i n t h e c l i n i c a l

e n v i r o n m e n t , tw o a d d i t i o n a l ta s k s w e r e n e e d e d .

T h e f i r s t t a s k , c o m p l e t e d i n P h a s e 2 , w a s t o

c o n n e c t i m a g e a c q u i s i t i o n d e v i c e s t o t h e P A C S

c o n t r o l l e r t h r o u g h t h e i n f r a s t r u c t u r e . T h e s e c -

o n d w a s t o d e si g n a n d i m p l e m e n t d i s p l a y w o r k -

s t a t i o n s i n t h e d e p a r t m e n t a n d c l i n i c s i n t h e

t h i r d p h a s e . I n i m a g e a c q u i s it i o n , w e c o n n e c t e d

t h r ee c o m p u t e d to m o g r a p h y C T ) a nd t hr e e

m a g n e t i c r e s o n a n c e M R ) s c a n n e r s w i t h d i r e c t

d i g i t a l i n t e r f a c e s , a s w e l l a s t h r e e c o m p u t e d

r a d i o g r a p h y C R ) u n i t s a n d tw o fi lm di g i ti z e rs

t o t h e i n f r a s t r u c t u r e .

Pha se 3: Systems Refinemen t Training

Maintenance and App lications

P h a s e 3 w a s c o m p r i s e d i n t w o s t a g e s. 9 S t a g e 1

w a s t h e d e v e l o p m e n t o f d i s p la y w o r k s t a t i o n s

a n d t h e i r c l i n i c a l i m p l e m e n t a t i o n . S t a g e 2 c o n -

s i st e d o f re f i n in g t h e P A C S ; u p g r a d i n g t h e

d i s p l a y w o r k s t a t i o n s o f t w a r e ; a n d e s t a b l i s h i n g

t r a in i n g , m a i n t e n a n c e , a n d s e r v i c e.

Stage 1: Display stations an d clinical implernen-

tation.

I n t h i s s t a g e , f o u r s t a t i o n s , e a c h w i t h

t w o 2 , 0 4 8 - 1 i n e m o n i t o r s , w e r e d e p l o y e d i n t h e

p e d i a t r i c ra d i o l o g y t w o st a t io n s ) , n e u r o r a d i o l -

o g y , a n d g e n i t o u r i n a r y r a d i o l o g y s e c t io n . A l s o ,

o n e l a s e r i m a g e r p r i n t i n g s t a t i o n w a s i n s t a l l e d

a s a h a r d c o p y de v i c e . I n a d d i t i o n , t w o t h r e e -

m o n i t o r s t a ti o n s w i t h 1 K m o n i t o r s w e r e i n -

s t a ll e d i n th e c o r o n a r y c a r e u n i t a n d p e d i a t r i c

i n t e n s iv e c a r e u n it I C U ) . F i g u r e 1 s h o w s t h e

U C L A P A C S i n f r a s tr u c t u r e a n d i m a g e a cq u is i-

t i o n a n d d i s p l a y s ta t i o n s a s o f O c t o b e r 1 99 2.

Stage 2: Systems ref inem ent and training m ain-

tenance andservice.

D u r i n g c l in i ca l i m p l e m e n -

t a t io n , w e s e t u p p r o c e d u r e s f o r t r a in i n g , s y s t e m

m a i n t e n a n c e , a n d s e rv i ce . T h r e e g r o u p s o f p er -

s o n n e l w e r e t r a i n e d . T h e f ir st g r o u p w a s r a d i o l o -

g i s t s a n d c l i n i c i a n s t o u s e t h e d i s p l a y s t a t i o n s .

T h e s e c o n d g r o u p i n c lu d e d t h e P A C S c o o r d i n a -

t o r , t e c h n o l o g i s t s , a n d c l e r i c a l p e r s o n n e l . T h i s

t r a i n i n g w a s e x t e n si v e a n d c o v e r e d i m a g e q u a l -

i ty a s s u r a n c e , u p d a t i n g t h e p a t i e n t d i r e c t o r y ,

a n d f i r s t - l i n e t r o u b l e s h o o t i n g . T h e t h i r d g r o u p

w a s t h e P A C S e n g i n e e r s . T h i s tr a i n i n g w a s m o s t

e l a b o r a t e . I t i n c l u d e d a l l o p e r a t i o n a l a s p e c t s o f

t h e P A C S .

I n S e p t e m b e r 1 9 9 2 , t h e a u t h o r s t r a n s f e r r e d

t h e r e s p o n s i b i l i t y o f d a i l y o p e r a t i o n t o a n e w

P A C S m a n a g e m e n t t e a m a t U C L A , a n d w e

r e l o c a t e d t o U C S F t o d e v e lo p a s e co n d g e n e r a -

t i o n P A C S . T h i s r e p o r t o n l y s u m m a r i z e s t h e


4/13

Global Ethernet

9 s ,

Central Node CHS)

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PACS

Con~oller

PACS

Damb~ Se~er

FDDI

To Medical Plaza

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Global Ethernet

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5/13

PACS-SECOND TIME 51

UCLA system up to September 1992. Further

development of the UCLA system has since

been done by the new management team.

THE SECOND TIME UCSF

We started to plan the second generation

PACS at UCSF in October 1992. In addition to

following our previous PACS design philosophy

at UCLA, we have redesigned the PACS asa

hospital-integrated system, o and built the frame-

work in the infrastructure for future PACS-

based radiology research, la

There are several major differences between

the UCSF and the previous UCLA PACS de-

sign, among them intelligent image archiving

and distribution; integration of hospital informa-

tion system (HIS), radiology information system

(RIS), 12 and other manufacturer s PACS compo-

nents; new network architecture and technol-

ogy; and collaboration with manufacturers to

develop new display workstations. This section

describes these major features.

Intelligent Im age Arc hive an d D is tr ibution

The UCLA PACS was designed with focus on

system reliability and data integrity, promising

24-hour on-line service and no loss of images.

Images were managed in the individual PACS

component on a first come-first serve basis,

which resulted in inefficient image distribution

and retrieval.

The second generation UCSF PACS design

includes more intelligent and thereby minimizes

access time for both current and historical

images. The system is hospital-integrated and

based on a composite staging mechanism using

multiple storage media, HIS and RIS, and the

client server concept.

Two major aspects are considered in the

implementation of the second-generation UCSF

PACS: data integrity, which promises no loss of

images once the PACS receives the images from

Fig 1. A) U C L A P A C S n e t w o r k a t t h e C e n t e r f o r H e a l t h

S c ie nc e s , a nd r e m ot e M R s i t e . ( B ) U C LA P A C S ne t wor k a t

M e dic a l P la z a . The y a r e c onne c t e d t oge t he r . C H S , C e nt e r f o r

t he H e a l t h S c ie nc e s ; Ge nU n , ge n i t our ina r y r a d io logy ;

PCR,

P hi lips c om put e d r a d iogr a phy ; P e ds , pe d ia t r i c r a d io logy ; RIS,

r a d i o l o g y i n f o rm a t i o n s y s te rn ( R e p r i n te d f r o m C o m p u t e r i z e d

M e d ic a l Im a g ing Gr a ph ic s ,

V o l 17 , Huang HK , T a i r a RK , Lou

SL, e t a l , Im p le m e nt a t ion o f a la r ge s ca le p ic t u r e a r ch iv ing a nd

comrnunicat ion sys tem, pp 1-11, 1993, w i t h p e r m i s s i o n f r o m

E ls ev ier S c ie nc e L t d , The B ou le v a r d , La n gf or d La ne , K id l ing t on

OX 5 1GB, UK. 9)

the radiologic imaging system and system effi-

ciency, which minimizes access time for images

at the display stations. The following describes

some major components.

L o ca l stor ag e ma n a g eme n t v ia P A CS in ter co m

p o n en t co mmu n ica t io n .

To ensure data integ-

rity, the UCSF PACS always retains two copies

of an individual image on separate storage

devices until a successful archive of the image to

the long-term optical disk library has been

made. This backup scheme is achieved via the

PACS intercomponent communication:

(1) At the radiologic imaging system: Images

are not dele ted from the imaging devices unless

technologists have verified the successful archiv-

ing of individual images via the PACS terminals.

Should any failure of the acquisition process or

the archival process occur, images can be resent

from these imaging systems to the PACS; (2) At

the acquisition subsystem: Images acquired in

the acquisition subsystem remain on its local

magnetic disks until the archive subsystem ac-

knowledges back to the acquisition subsystem a

successful archive. These images are then de-

leted from the magnetic disks so that storage

space from these disks can be reclaimed; (3) At

the archive subsystem: Images received in the

archive server from various acquisition nodes

are not deleted before their successful archiving

to the optical storage. On the other hand, all

archived images are stacked in the archive

server s cache magnetic disks and will be de-

leted based on their aging criteria (eg, number

of days an examination is performed, discharge

or transfer of a patient, etc).

Mu ltiple s torage m edia.

The storage manage-

ment system features three levels of user-

accessible storage media: (1) redundant array of

inexpensive disks (RAID) in the display station

for immediate access for current images; (2)

magnetic disks in the archive server for fast

retrieval of cached images; and (3) erasable

magneto-optical disks and WORM disks in the

optical disk library for retrieval of any historical

images. On the other hand, all local magnetic

disks in the radiologic imaging systems and the

acquisition subsystem are used for storing newly

acquired images. These images are deleted once

they have been successfully archived to the

optical disks. Table 1 illustrates the configura-

tion of these multiple level storage media.


6/13

52 HUA N G E T A L

T a b t e 1 M u l t i p l e S t o r a g e D e v i c e s f o r I m a g e s in t h e S t o r a g e M a n a g e m e n t S y s t e m

Storage Media Location Purpose

Level 1

Level 2

Level 3

Redundan t a r r ay o f i nexpens i ve d i sks

t e m p o r a r y s t o ra g e )

Ma gne t i c d i sks t emp or a r y s t o r age )

Ma gne to - o p t i ca l d i sks I onge r - t e r m

s to r age )

W O R M d i sk s p e r m a n e n t s t o ra g e )

D isp lay subsys tem d i sp lay hos t )

A r ch i ve subsys tem a r ch i ve se r ve r )

A r ch i ve subsy s tem op t i ca l d i sk l ib r a r y )

A r ch i ve subsys tem op t i ca l d i sk l i b ra r y )

P r ov ides imme d ia te access to bo th

cu r r en t and se lec ted h i s t o r i ca l images

P r ov ides f as t r e t r ieva l o f cu r r en t images

P r ov ides r e t r i eva l o f h i s t o r i ca l images

P r ov ides r e t r i eva l o f h i s t o r ica l im ages

RAI D t ech n o l o g y a p p l i ed t o PACS s t o r a g e .

All h igh- reso lu t ion (2 ,048 x 2 ,048 p ixe l s ) d i s -

p l a y s t a ti o n s i n t h e U C S F P A C S a r e c o n f i g u r e d

w i t h 5 - G b y t e h i g h - p e r f o r m a n c e R A I D . W i t h

th i s co nf ig ura t ion , a 2 ,048 2 ,048 x 10-b it

( 8 - M b y t e ) C R i m a g e c a n b e d i s p l a y e d i n l e s s

t h a n 2 s e c o n d s .

Fo l d er ma n a g er .

T h e s t o r a g e m a n a g e m e n t

s y s t e m i s c h a r a c t e r i z e d b y i t s o n - l i n e p a t i e n t

f o l d e r m a n a g e m e n t . 13 W h e n t h e f ir st r a d i o l o g i-

c a l e x a m i n a t i o n i s s c h e d u l e d , a p a t i e n t f o l d e r i s

c r e a t e d i n t h e P A C S c o n t r o l l e r f o r t h e g i v e n

p a t i e n t . D u r i n g t h e p a t i e n t s h o s p i t a l s ta y , t h i s

f o l d e r r e m a i n s i n t h e d i s p l a y s t a t i o n ( s ) f o r

i m m e d i a t e a c c e s s u n t i l t h e p a t i e n t i s d i s -

c h a r g e d , t r a n s f e r r e d , o r o t h e r a g i n g c r i t e r i o n

( e g , t w o d a y s a f t e r a n o u t - p a t i e n t v i s i t ) i s m e t .

T h e p a t i e n t s a d m i s s i o n , d i s c h a r g e , a n d t r a n s f e r

( A D T ) i n f o r m a t i o n i s o b t a i n e d d i r ec t ly fr o m

t h e H I S a n d R I S . I m a g e s a n d a s s o c i a t e d d a t a

f r o m a n y n e w e x a m i n a t i o n s o f t h e p a t i e n t a r e

c o n t i n u a l l y a d d e d t o t h e e x i s t i n g f o l d e r s o t h a t

n o r e d u n d a n t p r e f e t c h i n g p r o c e d u r e s w i l l b e

p e r f o r m e d . B y a p p l y i n g t h e f o l d e r m a n a g e r

c o n c e p t , t h e p r e f e t c h m e c h a n i s m is o n l y p e r -

f o r m e d o n c e p e r h o s p i t a l s t a y o f a n i n d i v i d u a l

p a t i e n t .

Im p lem en ta t io n o f the In te l ligen t Arc h ive Server

H I S / R I S / P A C S i n t e r f a c i n g . I n t e r f a c i n g t h e

H I S a l l o w s t h e s t o r a g e m a n a g e m e n t s y s t e m t o

r e c ei v e p a t ie n t A D T m e s s a g e s. I n t e r f a c i n g th e

R I S , o n t h e o t h e r h a n d , a l l o w s t h e s t o r a g e

m a n a g e m e n t s y s t e m to r e c e iv e i n f o r m a t i o n s u c h

a s p a t i e n t a r r i v a l , e x a m i n a t i o n s c h e d u l i n g , e x -

a m i n a t i o n c a n c e l l a t i o n , e x a m i n a t i o n c o m p l e -

t i o n , e t c . T h e s e e v e n t s t r ig g e r t h e s t o r a g e m a n -

a g e m e n t s y s t em t o p e r f o r m t h e p r e f e t c h , s t u d ie s

g r o u p i n g , a n d p l a t t e r m a n a g e m e n t m e c h a -

n i sm s . E x c h a n g e o f m e s s a g es a m o n g t h e s e h e t -

e r o g e n e o u s c o m p u t e r s y s t e m s i s c o n d u c t e d i n

t h e H e a l t h L e v e l S e v e n ( H L 7 ) s t a n d a r d d a t a

f o r m a t 14 w i t h t h e u s e o f T r a n s m i s s i o n C o n t r o l

P r o t o c o l / I n t e r n e t P r o t o c o l ( T C P / I P ) p r o t o c o l s

o n a c l i e n t / s e r v e r b a s i s .

I n teg r a ti o n w i t h o t h er ma n u f a c t u r er s P A C S

co mp o n en t s .

T h e U C S F s e c o n d g e n e r a t i o n

P A C S c a n i n t e g r a te w i t h o t h e r m a n u f a c t u r e r s

P A C S c o m p o n e n t s u s i n g t h e D i g i t a l I m a g i n g

a n d C o m m u n i c a t i o n s i n M e d i c i n e ( D I C O M )

3 . 0 s t a n d a r d . A n e x a m p l e i s t h e A e g i s u l t r a -

s o u n d P A C S ( A c u s o n , M o u n t a i n V i e w , C A ) . 15

I n th i s c a se , P A C S t r e a ts t h e A e g i s a s a P A C S

a c q u i s i t i o n d e v i c e a n d c o o r d i n a t e s t h e U S i m -

a g e s th e s a m e w a y a s C T a n d M R i m a g e s in t h e

p a t i e n t s i m a g e f o l d e r .

Image rout ing. B e f o r e s u c c e s s f u l a r c h i v i n g

t o l o n g - t e r m o p t i c a l s t o r a g e , a ll c u r r e n t i m a g e s

a r r i v e d a t t h e a r c h i v e s e r v e r f r o m v a r i o u s a c q u i -

s i ti o n n o d e s a r e i m m e d i a t e l y r o u t e d t o t h e i r

d e s t i n a t i o n d i s p l a y s ta t i o n ( s ) . T h i s r o u t i n g m e c h -

a n i s m m i n i m i z e s a c c e ss t i m e f o r c u r r e n t i m a g e s

a t t h e d i s p l a y s t a t i o n s . T h e r o u t i n g p r o c e s s i s

d r i v e n b y a p r e d e f i n e d r o u t i n g t a b l e c o m p o s e d

o f p a r a m e t e r s i n c l u d i n g e x a m i n a t i o n t y p e , d i s -

p l a y s t a t i o n s i t e , ra d i o l o g i s t , a n d r e f e r r i n g p h y s i -

c i a n . T h e r o u t i n g a l g o r i t h m p e r f o r m s t a b l e

l o o k - u p b a s e d o n t h e s e p a r a m e t e r s a n d d e t e r -

m i n e s w h e r e a n i m a g e s h o u l d go .

Image s tacking.

S t a c k i n g c u r r e n t i m a g e s i n

t h e a r c h i v e s e r v e r s c a c h e m a g n e t i c d i s k s a ll o w s

t h e s e i m a g e s t o b e r e t r i e v e d f r o m t h e h i g h -

s p e e d m a g n e t i c d i s k s i n s t e a d o f t h e l o w - s p e e d

o p t i c a l d i s k s . T h e a r c h i v e s e r v e r h o l d s a s m a n y

i m a g e s i n i t s m a g n e t i c d i s k s a s p o s s i b l e a n d

m a n a g e s t h e s e i m a g e s o n t h e b a s is o f t h e i r a g i n g

c r i t e r i a . D u r i n g a h o s p i t a l s t a y , f o r e x a m p l e ,

i m a g e s b e l o n g i n g t o a g i v e n p a t i e n t r e m a i n o n

t h e m a g n e t i c d i s k s o f t h e a r c h i v e s e r v e r u n t i l t h e

p a t i e n t i s d i s c h a r g e d o r t r a n s f e r r e d .

I m a g e a g i n g .

A g i n g c r i t e r i a s u c h a s n u m b e r

o f d a y s s i n c e a n e x a m i n a t i o n w a s p e r f o r m e d ,

d i s c h a r g e o r t r a n s f e r o f a p a t i e n t , o r c l as s o f t h e

p a t i e n t ( i n - p a t i e n t o r o u t - p a t i e n t ) a r e u s e d b y


7/13

PACS SECOND TIME 53

t h e s t o r a g e m a n a g e m e n t s y s t e m t o c o n t r o l t h e

m i g r a t i o n o f im a g e s f r o m o n e s t o r a g e d e v i c e to

a n o t h e r ( e g , f r o m a m a g n e t o - o p t i c a l d i s k t o a

W O R M d is k) o r th e d e l e t i o n o f i m a g e s f r o m

t h e i r r e s i d e n t s t o r a g e d e v i c e s .

Image prefetching

T h e p r e f e t c h i n g m e c h a -

n i s m 16 is t r i g g e r e d b y m e a n s o f a p a t i e n t a r r i v a l

m e s s a g e f r o m t h e R I S . S e l e c t e d h i s t o r i c a l i m -

a g e s a r e r e t r i e v e d f r o m t h e l o n g - t e r m o p t i c a l

s t o r a g e . T h e s e i m a g e s a r e t h e n d i s t r i b u t e d t o

t h e d e s t i n a t i o n d i s p l a y s t a t io n ( s ) b e f o r e c o m p l e -

t i on o f t h e p a t i e n t s c u r r e n t e x a m i n a t i o n .

P r e f e t c h i n g h i s t o r i c a l i m a g e s t o t h e d i s p l a y

s t a t io n s m i n i m i z e s o n - l f n e i m a g e r e t r i e v a l , h e n c e

r e li e v in g p e a k - h o u r w o r k l o a d o f th e a r c h i v e

s u b s y s te m a n d t h e n e t w o r k s . T h e p r e f e t c h a l go -

r i t h m is b a s e d o n p r e d e f i n e d p a r a m e t e r s s u c h a s

e x a m i n a t i o n t y p e , d i s e a s e c a t e g o r y , r a d i o l o g i s t ,

r e f e r r i n g p h y s i c i a n , l o c a t i o n o f d i s p l a y s t a t i o n ,

a n d t h e n u m b e r a n d a g e o f t h e p a t i e n t s a r -

c h i v e d i m a g e s . T h e s e p a r a m e t e r s d e t e r m i n e

w h i c h h i s t o r i c a l i m a g e s s h o u l d b e r e t r i e v e d

f r o m t h e l o n g - t e r m a r c h iv e .

Studies grouping

D u r i n g a h o s p i t a l s t a y , a

p a t i e n t m a y u n d e r g o d i f fe r e n t e x a m i n a t io n s o n

d i f f e r e n t d a y s. I m a g e s f r o m t h e s e e x a m i n a t i o n s

a r e a r c h i v e d t o t h e e r a s a b l e m a g n e t o - o p t i c a l

d is ks , w h e r e t h e y a r e s c a t t e r e d a c r o s s d i f f e r e n t

p l a t te r s . W h e n a p a t i e n t i s d i s c h a r g e d o r t r an s -

f e r r e d , t h e s e i m a g e s a r e t h e n g r o u p e d f r o m t h e

m a g n e t o - o p t i c a l d i s k s a n d c o p i e d c o n t i g u o u s l y

t o a s in g le W O R M d i sk o r t o c o n s e c u t i v e

W O R M d is ks f o r p e r m a n e n t s to r a ge . O n c e

t h e s e i m a g e s h a v e b e e n a r c h i v e d p e r m a n e n t l y ,

t h e y a r e r e m o v e d f r o m t h e m a g n e t o - o p t i c a l

d i s k s s o t h a t s t o r a g e s p a c e i n t h e m a g n e t o -

o p t i c a l d i s k s c a n b e r e c l a i m e d . S t u d i e s g r o u p i n g

a l l o w s a l l i m a g e s f r o m a p a t i e n t d u r i n g a h o s p i -

t a l s t a y t o b e a r c h i v e d c o n t i g u o u s l y t o o p t i c a l

d i s k ( s ) , h e n c e o p t i m i z i n g f u t u r e r e t r i e v a l o f a

p a t i e n t s i m a g e s fr o m m u l t i p l e e x a m i n a t i o n s .

Plattermanagement P l a t t e r m a n a g e m e n t a l -

l o c a te s t h e s t o r a g e s p ac e r e s e r v e d in t h e W O R M

d i sk s f o r f u t u r e i m a g e s i n c a s e a p a t i e n t r e v is i ts

o r i s r e a d m i t t e d t o t h e h o s p i t a l . I n t h i s w a y ,

i m a g e s o f a p a t i e n t f r o m m u l t i p l e h o s p i t a l v i s i t s

c a n b e a c c u m u l a t e d i n a s in g le W O R M d i s k o r

i n c o n s e c u t i v e d i s ks , r e d u c i n g e x c e s s d i sk s w a p -

p i n g a n d c o n s e q u e n t l y m i n i m i z i n g r e t r ie v a l t i m e

f o r t h e se i m a g e s. H o w e v e r , p r e a l l o c a t i n g s t o r -

a g e s p a c e i n a n o p t i c a l d i s k f o r a p a r t i c u l a r

p a t i e n t i s e x p e n s i v e . L o g i c a l ly g r o u p i n g c o n s e c u -

t iv e o p t ic a l d i sk s i n t o o n e v o l u m e , o n t h e o t h e r

h a n d , c a n r e d u c e d i s k s w a p p i n g t i m e a n d h e n c e

m i n i m i z e s t h e r e t r i e v a l t i m e f o r i m a g e s s t o r e d

i n d i f f e r e n t di sk s w i t h i n t h e s a m e v o l u m e .

Networking

O n e d i s ti n c t d i f f e r e n c e in n e t w o r k i n g b e -

t w e e n th e U C S F a n d th e U C L A P A C S is t h e

a v a i la b i li ty o f a s y n c h r o n o u s t r a n s f e r m o d e

( A T M ) t e c h n o l o g y in th e U C S F s y st em . T h e

U C L A n e t w o r k s w e r e m a i n l y a l o c a l a r e a n e t -

w o r k ( L A N ) w i t h E t h e r n e t , F D D I , a n d U l t ra -

n e t. I n t h e U C S F P A C S n e t w o r k s , A T M is u s e d

b o t h in w i d e a r e a n e t w o r k ( W A N ) a n d L A N

w i t h t h e c o n v e n t i o n a l T - 1 a n d E t h e r n e t a s

b a c k - u p , r e s p e c t i v e l y . 17 F i g u r e 2 s h o w s t h e l o gi -

c a l n e t w o r k c o n n e c t i o n a n d F i g 3 s h o w s t h e

p h y si c al A T M c o n n e c t i o n .

Image Display

T h e U C S F P A C S i m a g e d is p la y s ys t em is

b a s e d o n t h r e e i m p l e m e n t a t i o n m e t h o d s : u s i n g

e x i s t i n g i n - h o u s e w o r k s t a t i o n s , w o r k i n g w i t h

m a n u f a c t u r e r s t o d e v e l o p n e w w o r k s t a t i o n s ,

a n d d i s t r i b u t in g i m a g e s a n d p a t i e n t t e x t u a l d a t a

t o e xi s ti n g l o w - e n d d e s k t o p M a c i n t o s h c o m p u t -

e r s ( A p p l e C o m p u t e r s , C u p e r t i n o , C A ) . I n t h e

f ir st t y p e , w e m o d i t h e t w o - m o n i t o r 2 K

d i sp l ay w o r k s ta t i o n s d e v e l o p e d a t U C L A b y

a d d i ng t h e H I S / R I S i n t e r f a c e a n d s o m e e x t r a

d i s p l a y f u n c t i o n s . A n e x a m p l e i s t h e M o n t a g e

f u n c t i o n t h a t a l lo w s t h e a s s e m b l y o f im a g e s

f r o m d i f f e r e n t e x a m i n a t i o n s i n t o o n e f il e. T h e s e

w o r k s t a t i o n s a r e u s e d in t h e n e u r o r a d i o l o g y a n d

p e d i a t r i c r a d i o l o g y s e ct i o ns . S e c o n d , w e w o r k e d

F ig 2 . D e p a r t m e n t o f R a d i o l o g y U C S F L o g i ca l N e t w o r k

A r c h i t e c tu r e w h i c h i n c l u de s W A N a n d L A N . T h e e x t e rn a l

n e t w o r k i s o p e n w h e r e a s t h e i n t e rn a l n e t w o r k h a s a f i r e w a l l

p r o t e c t i o n .


8/13

54 HUANG ET AL

I ~ I u ''~ 17 6x~0.ioh

, OM ~ , , ,- - ~ , ./ /I \ \ \

A T M S w i t c h

A S X 2 0 0

UCSF

Siemens

G E 5X G E S X G E 5X G E 5X I m a tr onGE9800

G E S p i r a f G E S p i r a l G E S p i r a l I m p ac t

LP P I M RS C UCI C1 UC lC2 Lo ng Long Long UC lC CT M ZH M ZH

~CQ

U V U T P

I LAN Acr I

S w i t c h

LAX 20

Mt. Z i o n

Sing~ e Mode Fibers

Switch

O a k l a n d

F i g 3 . F i rs t p h a s e A T M c o n n e c t io n b e t w e e n U C S F a n d M t Z i o n H o s p i t al ; - - ) c o m p l e t e d , . . . . . ) s e c o n d p h a s e . W A N a n d L A N A T M

155 m b i t s / s e c ) N e t w o r k P h y s ic a l C o n n e c t i o n a t U C S F . F o r t h o s e o l d e r c o m p o n e n t s t h a t d o n o t support ATM, a n A T M t o L A N s w i t c h

i s u s e d w h i c h

supports 10

m b i t s / s e c f o r e v e r y n o d e c o n n e c t e d t o t h e s w i t c h .

with ISG Technologies Inc Toronto, Ontario,

Canada) to develop the two-monitor 1,600-1ine

display stations for ICU applications. Figure 4

shows such a workstation.

The third method is to develop a file server to

distribute integrated PACS images and textual

data to the Macintosh desk top computers for

individual review, teaching, and research.~8 Fig-

ure 5 shows the distributed network and Fig 6

depicts a page on the Macintosh screen.

M J O R D I F FE R E N C E S B E T W E E N T H E U C S F

N D T H E U C L P C S

This section summarizes some major differ-

ences between the UCSF and the UCLA PACS.

P C S C o n t r o ll e r

The PACS controller is an intelligent ma-

chine that controls the flow of data within the

entire PACS from acquisition data input) to

archiving long-term and short-term storage)

and display data output) . The primary func-

tions of the PACS controller include: 1) accept-

ing images from acquisition nodes; 2) accept-

ing HIS /RIS data; 3) updating global PACS

data base; 4) archiving images to optical disks;

5) routing images and HIS/RIS data to display

workstations; 6) handling retrieval requests

from display stations.

The PACS controller implemented in the

UCLA PACS was a single-processor Sun

SPARCserver 490 computer, from which a one

terabyte optical disk library based on 14 inch

platters was attached. A three-tiered communi-

cation network comprising Ethernet, FDDI,

and the proprietary fiber-optic UltraNet net-

work was used to provide independent paths for

data transmission between the PACS controller

and other PACS computers. Images acquired

from radiologic imaging devices were trans-

ferred from various acquisition nodes to the

PACS controller, where they were then routed

to destination display stations and were ar-

chived chronologically on WORM optical disks.

With its fault-tolerant design, the PACS control-

ler focused on system reliability and data integ-

rity, promising 24-hour on-line service and no

loss of images.

The PACS controller developed at UCSF

includes more intelligence and thereby mini-

mizes access time for both current and previous

imaging studies. The computer system is based


9/13

PACS-SECOND TIME 55

Fig 4. A 1,600-1ine tw o moni tor wo rkst ati on fo r ICUs. This station consists of a SPARC 20 with 128 Mbytes m emory and two

TurboGXplus cards, all off-the-shelf components. The display soft ware w s d e v e l o p e d by ISG Technologies Inc based on UCSF

specific ations The communication interface between workst atio ns and the PACS contro ller was codeveloped by both parties b s e d

on the DICOM standard.

on the SUN 690 Sun Microsystems) with four

central processing units CPUs), which allows

multiple processes to run simultaneously with

minimal shared CPU time. Two standard net-

work interfaces, the Ethernet and the 155-bit

~ ~ ~ . ~

~ V

Fig 5. Distributed image file servers connected to the PACS

controller. Eac h server provides specific applications for a

given cluster of users. One of this clusters is to serve the

Macintosh users in the department to access PACS data.

sec bandwidth ATM, OC 3 networks, are used

for receiving and distributing images. The opti-

cal disk library attached to the PACS controiler

supports both erasable magneto-optical disks

and WORM disks. A composite staging mecha-

nism is implemented in the PACS controller to

manage images stored in its multiple storage

media: magnetic disks immediate-access tempo-

rary storage), crasable magneto-optical disks

Ionger-tcrm archive data cache), and WORM

disks permanent storage). This second-genera-

tion PACS controller differs from the first-

generation system in severai of its new features:

multiple storage media, image stacking, auto-

mated image prefetching, studies grouping, plat-

ter management, and HIS/RIS/PACS interfac-

ing. Table 2 shows the major differences in the

infrastructure design between the two systems.

In Table 2 there are several items that were

not considered in the original UCLA design, for

example, integration to the HIS/RIS and other


10/13

5 6 H U A N G E T A L

v e n d o r s P A C S . T h e r e a s o n w a s b e c a u s e t h e

h o s p i t a l -i n t e g r a te d c o n c e p t w a s n o t i n t r o d u c e d

u n t il 1 99 2. A l so , t h e A m e r i c a n C o l l e g e o f R a d i -

o l o g y - N a t i o n a l E l e c t r i c a l M a n u f a c t u r e r s A s s o -

c ia ti on ( A C R - N E M A ) a n d D I C O M w e r e n o t

r e a d y f o r i m p l e m e n t a t i o n i n 19 91 . O n t h e o t h e r

h a n d , t h e U C S F P A C S d o e s n o t h a v e a d u p l i -

c a t e P A C S c o n t r o l l e r a n d a l l a r c h i v i n g i s d o n e

w i t h i n o n e s i t e a r e b e c a u s e o f l im i t e d s p a c e a n d

f i n a n c i a l r e s o u r c e .

T a b l e 2 . D i f f e re n c e s i n t h e I n f r a s t r u c t u r e D e s i g n

UCLA

as of

September

1992) UCSF

O p e n a r ch i t e c t u re l i m i t e d Y

C o n n e c t i v i t y l ir n i te d Y

S t a n d a r d i z a t i o n

A C R - N E M A , D I C O M N Y

H L 7 N Y

T C P / I P Y Y

I n t e r f a ce t o H I S / R I S N Y

I n te r f a c e t o o t h e r v e n d o r P A C S

m o d u l e s N Y

M i r r o r e d d a t a b a s e Y Y

D u p l i c a te P A C S c o n t r o l a n d a r c h i v i n g Y N

D i f f e re n t s i te s f o r a r ch i v i n g Y N

A u t o r o u t i n g u Y

I m a g e p r e f e t c h i n g N Y

I m a g e s e q u e n c i n g N i n p r o g r e s s

A b b r e v i a t i o n s : Y , Y e s ; N , N o .

Fig

6. A

p a g e o n t h e M a c i n

tosh screen. T he user can

d i -

r e c t l y

access both images and

t e x t u a l

i n f o r m a t i o n i n c l u d i n g

d i -

a g n o s t i c

r e p o r t s f r o m P A C S . T h e

' T o o l s ' k i t

a l l o w s u s e r t o m a

n i p u l a t e i n d i v i d u a l i m a g e s w h i c h

inc ludes programs l ike Na t iona l

I n s t i t u t e s o f H e a l t h I m a g e , e t c.

Networking

T a b l e 3 s h o w s t h e m a j o r d i f f e r e n c e s in n e t -

w o r k d e s i g n b e t w e e n t h e s e t w o s y s t e m s . T h e

U C L A n e t w o r k w a s m a in l y a L A N w i th v e ry

l o n g f ib e r o p t i c c a b le c o n n e c t i o n s b e t w e e n b u i ld -

i n g s , w h e r e a s t h e U C S F s y s t e m i n c l u d e s b o t h

W A N a n d L A N .

I t i s s e e n i n T a b l e 3 t h a t t h e U C S F n e t w o r k

d e s i g n i s m o r e s o p h i s t i c a t e d w i t h u p - t o - d a t e

n e t w o r k t e c h n o l o g y . O n t h e o t h e r h a n d , t h e

U C L A s y s te m h a d t h e h i g h e r s p e e d p r o p r i e t a r y

U l t r a n e t f o r h i g h s p e e d i m a g e c o m m u n i c a t i o n s .

T h e U C L A s y st e m h a d n o f i re w a ll p r o te c t i o n

f o r d a t a i n t e g r i t y a n d s e c u r i t y , w h i c h w a s a m a i n

d r a w - b a c k in n e t w o r k d e s ig n .

lmage Acquisition Component

CT a n d M R T h e U C L A C T / M R im a g e

a c q u i s it i o n s y s te m s w e r e a l l m a d e b y G e n e r a l

E l e c t r i c M e d i c a l S y s t e m s ( M i l w a u k e e , W I ) . I n

t h i s r e g a r d , t h e G E 9 , 8 0 0 C T s c a n n e r s u s e d G E

I D N E T - 1 c o n f i g u r a t i o n f o r i n t e rf a c i n g , a n d t h e

i m a g e a c q u i s i t io n p r o c e s s e s o f G E h i g h - s p e e d

C T s c a n n e r s a n d S ig n a 5 x M R s c a n n e rs w e r e

b a s e d o n G E p r o p r i e t a r y c o m m u n i c a t i o n p ro t o -

c o ls . T h e a c q u i s i ti o n p r o c e s s e s i n t h e P A C S d i d

n o t h a v e p a t i e n t I D v e r i f i ca t i o n a l g o r it h m , n o

a u t o m a t i c p r o c e s s r e c o v e r y m e c h a n i s m , a n d n o


11/13

PACS-SECOND TIME 57

T a b l e 3 D i f fe r e n c e s B e t w e e n t h e T w o N e t w o r k s

UCLA* UCSF

9 Fibers were used to connect remote buildings, but the back-

bone primarily consisted of Thicknet Ethernet (copper) that

stretched through multiple buildings and levels.

9 Clinical acquisition, Research, and Distr ibut ion networks

were all physically connected to the same subnet. Ultranet

used for 2K distribution only.

9 AUI cables were connected d irectly to the backbone as

opposed to CAT 5 UTP cables. Radiology Dept did not have

a direct connection to the Internet.

9 Ultranet was used fo r transfer of images from the PACS Con-

trolle r to the 2K display stations at a tate of 125 Mb/s. The

transfer of information between the two Ultranet hubs in

CHS and Medical Plaza was striped between fou r 250 Mb/s

fibers giving a total transfer rate of 1,000 Mb/s or 1 Gb/s.

9 No routers or firewa lls were used.

9 No WAN connections.

9 Only Med Plaza hada UPS.

9 The backbone consists of primari ly fibe r optics, but CAT 5

UTP is the media used for station connections.

9 ATM via fiber used for acquisition and distribution.

9 The design is a distributed star configu ration with multiple

subnets. For examples, Genesis ne twork is used to connect

the digital modalities le, CT, MR to the PACS controller. The

departmental network is used to distribute images to Macin-

tosh's users, etc.

9 PACS External network is used fo r transferring image data

from the imaging modalities to the acquisition computers.

The internal network, with a firewall protection is used to

transfer data from the acquisition computers to the PACS

Controller.

9 The External ne twork is also used asa backup network for

the display systems.

9 Distribution to the 1K stations is done via ATM, which uses a

dedicated 155 MB/s fiber optic connection directly to the

PACS Controller.

9 Distribution to the 2K systems is done through an ATM to

Ethernet switch, which has dedicated 10 Mb/s connections

to each station.

9 Radiology has direct connections to the Internet via the

departmental network which has over 100 connections to

faculty and staff offices.

9 Routers and gateways are used to divide subnets and insure

security among the networks.

9 The network has T1 and ATM WAN connections to two aff ili-

ated hospitals. Network hubs are backed up by UPS's.

*As o f September 1992.

Abbrevia tions: AUI, attachment unit interface; CAT UTP, category 5 unshielded twis t pair; UPS, uninterrupted power supply.

a u t o m a t i c p a g i n g s y s t e m f o r e n g i n e e r i n g s e r -

v i c e . T h e i m a g e h e a d e r f o r m a t w a s b a s e d o n a

U C L A i n te r n a l d e s ig n a n d w a s n o t st a n d a rd .

T h e U C S F C T / M R i m a g e a c q u i s it i on sy s-

t e m s c o n s is t o f m u l t iv e n d o r e q u i p m e n t i n c lu d -

i n g G E , S i e m e n s E r l a n g e n , G e r m a n y ) , a n d

I m a t r on S o u t h S a n F r a n c i sc o , C A ) . T h e G E

9 8 0 0 C T s c a n n e r u s e s G E I D N E T - I I c o n f ig u r a -

t i o n f o r i n t e r f a c i n g , a n d i m a g e a c q u i s i t i o n p r o -

c e s s e s o f G E s p ir a l C T s c a n n e r s a n d S i g n a 5

M R s c a n n e rs a re b a s e d o n D I C O M s ta n d a rd

c o m m u n i c a t i o n p r o t o c o l u p p e r le v e l f o r T C P /

I P ). T h e S i e m e n s a n d I m a t r o n u s e t h e ir o w n

p r o p r i e t a ry i n t e r f a c e p r o t o c o l s .

T h e P A C S a c q u i s i t i o n c o m p u t e r s h a v e a

p a t i e n t I D v e r i f i c a t i o n a l g o r i t h m t o c o r r e c t

t y p o g r a p h i c a l e r r or s b y im a g i n g m o d a l i t y t e c h n i -

c i an s , a m e c h a n i s m t o a u t o m a t i c a l l y r e c o v e r

i m a g e a c q u i s i t i o n p r o c e s s e s , a n d a c e n t r a l p a g -

i n g s c h e m e t o a u t o m a t i c a l l y p a g e s e r v i c e e n g i -

n e e r s f o r s y s te m f a t a l e r r or s . T h e P A C S u s e s

b o th A C R / N E M A 2 .0 a s w e l l as D I C O M 3 .0

h e a d e r i n f o r m a t i o n f o r m a t .

CR The UCLA PACS used earlier versions

of CR technology: Philips 901 and two Philips

7000 laser plate readers Philips Medical Sys-

tems, Shelton, CT), and ST-III type photostimu-

lable phosphor plates; while the UCSF PACS

incorporates the latest in CR technology: Fuji

FCR AC2 and FCR 9,000 plate readers Stam-

ford, CT), and ST-V standard) and HR-V

high-resolution) photostimulable phosphor

plates. The interfacing of the CR devices to

PACS required three different methods: two

different methods for the two different models

of Philips CRs and one method compatible with

both Fuji CRs. The Philips 901 digital interface

consisted of a RS-422 connection to a Data

Interception Circuitry buffer) board and a

DR-11W link over which the image data was

transmitted to the SUN acquisition computer;

textual information demographic and image

header data) carne over an RS-232 cable connec-

tion. The Philips 7,000 interface device included

a PCR interface processor PIP) which con-

tained an auto data transfer board, memory


12/13

5 8 H U A N G E T A L

b u f f e r b o a r d a n d E t h e r n e t b o a r d a n d t r a n sm i t -

t e d b o t h i m a g e s a n d t e x t t o t h e S U N a c q u i s i ti o n

c o m p u t e r o v e r E t h e r n e t . T h e d ig it al i n t e r fa c e

t o P A C S f o r b o t h t h e F u j i A C 2 a n d t h e 9 ,0 0 0

c o n s i st s o f a D M S B u s w i t h a R S - 4 8 5 c a b l e

( w h i c h i s a c o m b i n a t i o n R S - 2 3 2 s e r i a l b u s f o r

m e s s a g e s a n d t e x t u a l i n f o r m a t i o n a n d a n R S -

4 2 2 p a r a l l e l b u s f o r i m a g e d a t a ) c o n n e c t i o n t o

t h e d a t a a c q u i si t io n s y s te m m a n a g e r ( D A S M ) .

T h e D A S M i s b a s i c a l l y a r i n g - b u f f e r e d s m a l l

c o m p u t e r s y s t e m i n t e r f a c e ( S C S I ) d i s k t h a t

t r a n s m i t s b o t h t e x t u a l a n d i m a g e d a t a t o t h e

S U N a c q u i s i t i o n c o m p u t e r o v e r S C S I c a b l e .

T a b l e 4 s u m m a r i z e s t h e d i f f e r e n c e s i n C R

b e t w e e n t h e s e t w o P A C S s y s t e m s .

The Display ornponent

T h e U C L A P A C S d is pl ay c o m p o n e n t c o n-

s i s te d o f t h e 2 K d i s p l a y s ta t i o n s , 1 K d i s p la y

s t a ti o n s , a n d a f il m p r i n t i n g s ta t i on . T h e U C S F

d i s p l a y c o m p o n e n t i s c o m p r i s e d o f 2 K d i s p l a y

s t a t i o n s , 1 K d i s p l a y s t a t i o n s , a n d M a c i n t o s h

s t a ti o n s . B o t h 2 K s t a ti o n s i n t h e U C L A a n d

U C S F P A C S a r e o f t h e s am e h a r d w a r e p l a t-

f o r m . W e d e v e l o p e d t h e s o f t w a r e i n - h o u s e a t

U C L A , a n d c a r r i e d i t o v e r t o U C S F . C e r t a i n

e n h a n c e m e n t s h a v e b e e n a d d e d t o t h e s o ft w a r e

a t U C S F b a s e d o n u s e r s f e e d - b a c k . I n p a r t i c u -

l a r , t h e r e i s a l o c a l m o n t a g e f e a t u r e f o r u s e r s t o

s e l e c t i m a g e s f r o m d i f f e r e n t f i l e s f o r d i s p l a y . A

f e a t u r e w i t h 1 o n 1 f o r c u r r e n t i m a g e s a n d 4 o n 1

f o r h i s t o r i c a l i m a g e s w a s s p e c i f i c al l y d e s i g n e d

f o r p e d i a t r i c C R i m a g e v i e w i n g . T h e s t u d y l i s t

a u t o m a t i c u p d a t e f e a t u r e a l e r t s u s e r s t h a t t h e

a c t i v e ( s e l e c t e d ) p a t i e n t h a s a n e w i m a g e f i l e

j u s t a r r i v e d . A n o t h e r n e w f e a t u r e i s a w o r k s t a -

t i o n u s a g e s t a t i s t i c s o f t w a r e p a c k a g e t o t r a c k

s y s t em u s a g e . T h i s p a c k a g e a l lo w s r e f i n e m e n t o f

w o r k s t a t i o n s o f t w a r e b a s e d o n u s e r s w o r k i n g

h a b i t s .

T h e U C L A 1 K s y st e m w a s d e v e l o p e d b a se d

Table 4 Differences Between the CR Acquisition

Components

UCLA* UCSF

De vices Ph i l i ps 901 Fu ji AC 2

Phi l i ps 7 ,000 tw o) Fu ji 9 ,000

Ph os ph or p la te t yp e ST- II I ST-V , HR-V

I n te r f a ce D R -1 l W b o a r d t o D A S M t o A C 2 a n d

901 9 ,000

PIP to 7 ,000

* A s o f S e p t e m b e r 1 99 2 .

Table 5 Ma jor Differences in the Display Component

Between the Two PAC Systems

Types of

Workstat ion UCLA * UCSF

2 K S U N 4 / 4 7 0 , M e g a - S a m e w i t h n e w

s c a n d i s p l a y b o a r d s e n h a n c e m e n t

w i t h t w o m o n i t o r s s o f t w a r e 4 )

4)

1 K S UN 4 , i n -h o u se d i s - S P A RC 2 0 , T u b o r

p l a y b o a r d w i t h G X + b o a r d s s u p -

t h re e 1 , 0 2 4 m o n i - p o r t i n g 2 , 3 , o r 4

t o r s 2 ) m o n i t o r s 5 )

F i lm p r i n t i n g Y N

PC sta t ion N 100

* A s o f S e p t e m b e r 1 9 96 .

o n a n i n - h o u s e d e s i g n e d d i s p la y b o a r d w h i c h

s u p p o r t e d t h r e e 1 ,0 24 m o n i t o rs . T h e U C S F 1 K

s y s t e m i s d e v e l o p e d i n c o l l a b o r a t i o n w i t h I S G

T e c h n o l o g i e s I n c b a s e d o n o f f - th e - s h e lf c o m p o -

n e n t s . T h i s 1 K s y s te m c a n s u p p o r t e i t h e r 2 , 3 , o f

4 1 , 6 00 li n e m o n i t o r s , a n d h a s v e r y e a sy to u s e

u s e r i n t e r f a c e .

T h e U C S F s y st e m c u r re n t l y d o e s n o t s u p p o r t

a fi lm p r i n t i n g s t a t i o n , i n s t e a d , i t s u p p o r t s o v e r

1 0 0 M a c i n t o s h u s e r s t o r e t r i e v e i m a g e s a n d

r e l a t e d P A C S d a t a f o r re s e a r c h , t e a c h in g , a n d

c a s e r e v i e w . F r o m t h e s e M a c i n t o s h c o m p u t e r s ,

t h e u s e r s c a n s e l e c t o t h e r p r i n t i n g r e s o u r c e s i n

t h e d e p a r t m e n t f o r h a r d c o p y o u t p u t . T a b l e 5

s u m m a r i z e s t h e m a j o r d i f f e r e n c e s in t h e d i sp l ay

c o m p o n e n t s b e t w e e n t h e s e tw o P A C s y st em s .

D l S C U S S l O N

B o t h t h e U C L A a n d t h e U C S F P A C S a r e

d e s i g n e d i n - h o u s e b a s e d o n t h e S U N w o r k s t a -

t i o n p l a t f o r m . B e c a u s e o f t h e e v o l u t i o n o f t h e

P A C S c o n c e p t , t h e U C S F s y s t e m i s d e s i g n e d a s

a h o s p i t a l - i n t e g r a t e d P A C S w i t h t h e A C R -

N E M A a n d D I C O M a n d H L 7 s ta n da rd s . R e l-

e v a n t d a t a f r o m H I S a n d R I S i s a u t o m a t i c a l l y

i n c o r p o r a t e d i n t h e P A C S . O t h e r m a n u f a c t u r -

e r s P A C S c o m p o n e n t s t h a t c o n f o r m w i th t h e s e

s t a n d a r d s c a n b e e a s i l y i n t e g r a t e d i n t o t h e

s y s t e m . T h e U C S F s y s t e m a l s o t a k e s a d v a n t a g e

o f n e w e r c o m m u n i c a t i o n , s t o r ag e , a n d s o f tw a r e

t e c h n o l o g i e s i n A T M , m u l t i p l e s t o r a g e m e d i a ,

a n d a u t o m a t i c p r o g r a m m i n g f o r a b e t t e r c o st -

p e r f o r m a n c e s y st em .

T h e n e w c o n c e p t s o f a u t o - r o u t i n g , p r e f e t c h -

i n g , a n d a u t o - s e q u e n c i n g h a v e i n f l u e n c e d o u r

d e s i g n in t h e U C S F P A C S c o n t r o l l e r , w h i c h is


13/13

PACS SECOND TIME 59

q u i te a d ra s t ic d i f fe r e n c e f ro m t h e U C L A P A C S

c o n t r o l le r . W i t h t h e c l i e n t - s e r v e r c o n c e p t w e

a r e a b le t o i m p l e m e n t t h e M a c i n t o s h s e r v e r t o

d i s t r ib u t e P A C S i m a g e s a n d p a t i e n t t e x t u a l

d a t a t o e v e ry M a c i n t o s h u s e r i n t h e d e p a r t m e n t .

T h i s f e a t u r e w a s n o t a v a i l a b l e i n t h e U C L A

s y s t e m b e c a u s e o f a l a c k o f su c h k n o w l e d g e o n

o u r p a r t a s w e l l a s n o t u n d e r s t a n d i n g t h e

i m p o r t a n c e o f d a t a d i s t r ib u t i o n t o e v e r y r a d i o l o -

g i s t a n d c l i n i c ia n a t t h a t t i m e .

T o o u r d i s a p p o i n t m e n t w e h a v e n o t s e e n a n y

i m p r o v e m e n t i n t h e 2 K d i s p l a y t e c h n o l o g y i n 5

y e a rs . B o t h th e U C L A a n d U C S F 2 K d is p la y

s y s t e m s a r e p r a c t i c a l l y t h e s a m e i n t e r m s o f

h a r d w a r e p l a t f o r m a n d d i s p l a y s o f tw a r e . O n t h e

o t h e r h a n d 1 K d i s p l a y h a s i m p r o v e d in b o t h

p e r f o r m a n c e a n d c o s t .

T h e U C S F h o s p i t a l i n t e g r a t e d P A C S h a s

b e e n d e v e l o p e d t o s u c h a s t a g e t h a t t h e i n f r a -

s t r u c t u r e w i ll n o t b e c o m e o b s o l e t e a n d i t c a n

s u p p o r t a n y n e w P A C S c o m p o n e n t s a s w e l l a s

a d d i t i o n a l a c q u i s i t i o n m o d a l i t i e s a n d d i s p l a y

w o r k s t a t i o n s . P A C S s y s t e m r e f i n e m e n t w i ll c o n -

t i n u e e v o l v i n g f o r h i g h e r r e li a b il it y b e t t e r p e r -

f o r m a n c e a n d n e w a p p l i c a t i o n fu n c t i o n s a s i ts

d e v e l o p m e n t i s a c o n t in u o u s d y n a m i c p r o c e s s .

R E F E R E N E S

1 . H u a n g H K : T h r e e m e t h o d s o f P A C S r e s e a r c h , d e v e l -

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2 . H u a n g H K , M a n k o v i c h N J , B a r b a r i c Z , e t a l : D e s i g n

a n d i m p l e m e n t a t i o n o f m u l t i p l e d i g i t a l v i e w i n g s t a t i o n s .

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4 . Cho P S , Huang HK, T i l l i s ch J , e t a l : C l in ica l eva lua -

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