Fluoroplanigraphic system for rapid presentation of single plane body sections with reduced X ray exposure to patient

Bailey, N. A.

Crepeau, R. L.

Lasser, E. C.

English

NASA Technical Reports Server

A FLUO2OF3..hNiGRAPHY SYSTEM FOR RAPIr /  PRESEI\ITATlON OF 
SINGLE PLANE BODY SECTIOi\IS* 
b Elliott C .  Lasser, I L Z . D . ~ ,  N o r ~ a n  A. Bctiiy, P h . D ,  , and Ronald t .  Crcpeau, hS.5, c 
Depctrttnent of Radiology, Univ~rs i ty  of Caf lfornicl, San Diego 
La Jolla, California 92037 
P,BSTRACT 
--- 
A single-scan TV radiograpl-iy unit has been covpfed to the moving f i l m  hulclcr OF- a 
conven~ional  o v e r h e ~ d  tube fluo;oscop> unit so i hat i t  can be used in a torncjyrapl;fc r;radz. Tila 
method produces a true tornographic section which is presented immediately on the TV mai;iior, 
Field size arid section thickness have been found to be satisfactor)!. The system ulioivs rapid 
locu!Ic;n of the plane and area of interest. Patient dose per exposure, vqhel-r eompc~red FO fast 
fi lm, for thick body parts was fovnd to be reduced by appro>:imately 7 to 55 t i m e s .  
KEY WORDS 
Fluoroplanigraphy, tomography, planigraphy, body section. 
* This work partially supported by NASA Grunt No. NGL 05-009-033. 
a Chair~ncin and Professor, Department of Radiology, UCSD. 
Professor of Radiology, UCSD. 
c Developmental Engineer, UCSD. - 
https://ntrs.nasa.gov/search.jsp?R=19710024887 2020-03-11T22:01:18+00:00Z
A FLUGR0PL.A.N IGRAPi-IY SYSTEM FOX RAPlD PRESENTAT! ON OF 
SINGLE PLANE BODY SECTIONS 
INTRODUCTION 
--
The clinical usefulness of body section radiography is wel l  established. These seciior~s 
are usucrtly produced by syrtchronized movements of both tube and f i l m  during the p-risd o: >;-;.ciy 
exposure. The use of f i l m  iniposes certain rest:-icti01-i~ on the rne~hod's uti lizcatioi-~. Firs!, a pilo: 
study a t  the projected depth of interest must be done. Only after inspection of this piloi ~ i i i d y  
and only after suitable modifications for :echniclue and position have been accomp8isi?ed can an 
adequate definitive body section radiogram be obfained. This is time consuming and fhc desc 
to  the patient is often excessive. If one attempts to overcome this by mu!tiple body pion- 
radiograpkis produced by existing techniques, a certain degree of unshcrrpness is imposed by 
virtue of scai-ter occurrir~g along mi~liiple screen and f i l m  interfcrccs. Furfher, fhe darini::ve 
plane of interest is often compromised because of patient movement during the interval of i fma  
necessary to make additional corrections and to view i-he resulting radiograms. 
T h e  use of a fluoroscopic presentation overcomes to u very large extent the difficuiiies 
outlined above by providing the radiologist with the capability of making adjustments i n  icchniqve  
ar;d posiiion of the patient rapidly and accurately with a very reduced pafien'r dose. Thre)ugl-i the 
use of a single-scan TV system1 with video disk recorder as a substitute for the usuai f i lm  =cording, 
we have been able to uccomplish recording of true tomogrurns fluoroscopicn\ ly . 
 he method presented produces a true tomographic image identical to that seen on F i l m .  
2 Unlike the method presented by Frimann-Dcthl and Ghl continuous motion and x-ray inpvl 
over a period of time sufficient to produce a stationary image is not required. Seco~-d, sincc the 
monitor is displaying a true tomographic sectioli, i t  can be photographed and utilized as that 
portion of the completed study. 
The method appears to have the potentia / for extension to studies of organs having 
,A, FLUOROPLANIGRL,? SYSTEM FOR RAPiD FZESENTATION OF 
SING!-E PLANE BODY SECTIOP4S 
associated motion. The image can be digitized and processcd by coinpuier For citi?rr c l ida i l i i t ~ i i ve  
analysis or representation on video after edge enhancement, contrast enhancemenf, si~biraction. e tc ,  
The basic roentgenographic equipment consists of a G .  E. Model 73 horizoni-ai table 
which was modified to accommodate a 9 "  - 6" image intensifier undertable installation, 
hydraulically driven in conjunction with the x-ray tube (G.E. - B8130, 0rdogrupi-y 8ocdy- 
Section attachment). The Image amplifier - TV chain was modified as described by Eakcr and 
1 Miller with the exception thct ai the scme time as the readout beam is blanlted, the torget 
voi tage is dropped to  a negative 2 volts. This results in' a greater signal -to-noise i e v ~ I  and 
higher contrast imcges. The perf01 mance of a sirni lar system (resolution and grcy sccle cc~pckpiIitie.s> 
3 has been described by Baily and Crepcau . There are four travel an~pl i tvdcs  and ~wca iraaieE 
speeds avcri!abfe. These are: 6.25"; 12.5"; 18.75"; 2.5') and 6.25 'ysec. ,  12.5"/scc,, respectively, 
The  focal spot 10 screen distance is 43 ". 
RESCE LTS 
Since a fundamental difference between the use of film as a recording medium cad iiae 
image amplifier TV chain is the curvature of the input phosphor, it is important to knew {-he 
useable field size of the system. This was deterrnincd by establishing the in-focus p l a x  at rhc 
center or" the x-ray Field and then moving the test object outward from the center u n t i l  the 
in-focus layer was no loriger sharp. The size O F  the central area in which the ceratrca0 plane cf 
the in-focus layer appeared to remain constant was approximately circular and 3" i n  d i ame te r .  
The section thickness was determined though the use of a 1 cm. thick luci te block 
7 I i i i i v l r i 9  lcird rrbnkeis ~ p u ~ d c f  G: 1 rtr~ii. iriiati.;!a cr'zp;!; ;hiouyhobi- its ~ o f u i n ~ .  I I ~ C  ~ L L  biuig 
thickness war; then determined by visual examination of photographs taken OF the TV monitor, T h e  
A FL.UOROPL-,4,NiGRAPlia/ SYSTEM FCIR RkPiS PRESENTATION 01"' 
5IiqGL.E PLANE BODY SECitONS 
-3- 3 
1 # 
section ti~icknesses listed in Table f represent vcr lv~s  ai- which image bli~rrlng has b c c o l i ~ ~  v i s c ~ k ~ e  
to the eye.  For comparison, the section ihicknzss obiained using conventioncrl f i  ii-n t~rC~r i :c juec 
ore also given, 
A most important aspect of the mc-ihod is the large reduction in patieni- dos2 which c i ~ ~ ,  be 
achieved by ihe use of  his system. Table I I  gives a comparison between exposure r a t c s  ri-iscsrited 
a t  20 cm. above the table top for both f i l m  cnd fluoro techniquzs utilized in our in~,~esiigctiiot3 o" 
the system. 
In addition to thz test pattern, we have used a pelvic phantom and a pcrtie~i TO L U S ~ ~ S Z  
the dicagnostic capabilifies of ihe method. Thesc are illustrated in the following i'ovi Figii~es.  
Figure 1 illustrates a plclnigram recorded on Film of the hip joint in a pelvic pllclntai;i, This f i l m  
was recorded a t  65 kVp and 100 mP,s using a '12.5" stroke. Figure 2 is a pIm!ogrc,:>/r or ti32 T\f- 
rnoni'ior sl>owing the same section rcc oi-c'ed by the f !~ loropl~ni~raphiC system. The fc  ctoi-s t i s r c '  
were a 6.25" stroke, 70 kVp, and 3.5 mAs. In addiiion to the 6:l built in  grid, a 12.1 KIOV~~ICJ  
grid was used. Figure 3 shows a planigram of the right thorax of a patient wiih rnciasiices 
originating from a primary carcinoma of the cervix. This f i l m  was recorded using a 6,2PU dsi.roi:e, 
70 kVp, and 25 mAs. Figure 4 shows the same section recorded by Fl~oroplanigrap1-i~ The 
factors used were 6.25'\troke, 70 kVp, and 1.5 mAs. 
The use of the above described system which we have called fluoroplanigrcrphy rrmkes 
it possible to obtain stai-ic single-plane larninograms with far greater expediency tha,? conventional 
laminograms. Second, these can be obtained with significant reduction in  pai-ient dose. Third,  
a large savings in operational time is effected. Trial and error projections can be accomplished 
in seconds rather than minutes and, therefore, it is possible to quickly optimize the aE ignrncni- 
of + L ~  1 6 1 b  ,=,Lbl=u c .~a-L~ Ft - t lG .  I - * . -  S i i i ~ e  there I s  ci c~ri j ia i l i  diFSererlce beiween ihe TPu;cru~n scrring fur  ri le 
A FLUORi'lPI AtdJGRAPE-IY SYSTEM FOR RAP! D PRESENTATION OF 
S~NGLE P L A N E  eouv sEcrior\rs 
-4 - 
fluoroptanigr-cxro and co~~vt\nt ional  f i l m  plcir~igrorn, the lattcr ccr;n be imn?cdicr:ely o5ra;i -cl d i e r  
ihe prccise pfone of interest has been selected From the ~ I U O ~ O ~ C O P ~ C   presentation^. This s ~ c u ! ~ ,  
therefore, increase the total u~i l iza t ion  of the pianlgraphic procedure. 
The system wii h some minor changes also offers the possibility for achieving c ' ) / ,~c~rnic  
f i ~ o r o p l a n i ~ r a p h i c  studies. This can be accomplished by pulsing x-ray and recordin2 i;nyts ai 
fixed intervals of the planigrcaphic procedure. Raies up to  19 frames/sec. are possikle; fh;i 
limitation in the present system i s  a mechanical one, the rate a t  which the disk I~ead con  be 
moved. This upparutus will enable the examiner for the First time to assess pulsaiioris or otl-tcr 
Forn-is of motion in a selected plane in She body. Immediate applications to the h3f~i i - ,  V O C ~ ~  
cords, and soft palcate (in conjunction with speech disturbance studies) are suggesbcd. i t  woi:lcl 
also be csnticiperied that air  studies of the subarachnoid spaces in the vertebral cwnc t ~ ~ ~ 7 . 1  O F  r he 
ventricles in  the brain could be accomplished expeditiously and with new potentiirl 60; r h ~  
assessment of air bubble movement. 
The limitation on usable field size is due to the curvlsiure of the image ini-ensfi'fcrBs 
input screen. T h e  use of a unit with a flat screen \vould overcome this difficulty. liowcven-, i t  
should be pointed out that the curvature has rect benefit in thcrt ihin seci-ions can be obi-aiilad 
with short trave!s (Table I ) .  
The system described provides a true fluoroscopic presentation of a selected bcdy secrian . 
It provides a rapid method for localizction ancl selection of the plane of interest accorrplisl-iing 
this with significant savings in patient dose as compared to standard procedures using TFirn. 
Further developments will enable the radiologist to assess pulsating or other forms of n-ioiion i n  
a selected plane in the body. 
A FLUOROFtl-\NiGRiiI?I~'./ SYSTEM FOR RAF'iD ?RE5EN7;,47iOf~ OF 
SINGLE PLANE BODY SECTIONS 
REFERENCES 
1. Baker, V.D. and Miiier, W. B. : P, TV System for Electronic R~diography. Proz. of t i le 
20th Arinuctl Conf. on Eng . in Med . 6; Eiol . 10.1 (1 367). 
-
2 .  Frirnnnn-Dahl, J .  and KZhf ,  H. B. : lrnmcdiate Cenicring a i d  Tomographic Cu t  
Local izai-ion By Means of Roentgen Yeievision, Acta RadioIo~ica, 10, 235-21!0 ( 7  $70). 
- 
3 .  Buily, N .A. and Crepeau, R . L . :  Capabilities of a Single-Scai-r TV Radiography S>/zter;i 
for Digital Data Acquisition, Investi~u:ive Rw1'lology (In Pres3). 
A FLUOkC3iFl.4i\iiGZk\PHH~' SYSTEM FOR RAPID PRESCNPATION OF 
S f N G t E  PLANE BODY SECTIONS 
FIGUIX CAPTIONS 
Fig. 1:  PIcanigrclm of the hip joint in  cr pelvic phantom. Recorded on f i l m  using cr 
7 2.5 ' '  stroke n i  6.5 kVp and 700 m h .  
Fig. 2: Fluoropfanigi-am of the same section as shown in Fig. 1 photographed I'roni fcce 
of TV monitor. Recorded using cr 6-25" stroke a t  70 kVp, 3.5 mAs wi i l -  12:1 
moving grid. 
Fig. 3: Planigwm of the right thorax of a patient with rnetastices originating From a 
primary carcinoma of the cewix. Fi lm tvas recorded using a 6-25'' strcjite, 
70 kVp, and 25 mAs. 
Fig. 4: 
-- 
Fiuoroplcxnigrarn of same section as shown i n  Fig. 3 photographed from fc;~:: 
of T V  n?oi~i tor, Rew rded using a 6.25 " stroke at 70 kVp and '1 .5 ml?i,s. 
TABLE I 
SECTION THICI<NESS AS A FUNCTlOb! OF TUBE TRAVEL DlSTANCE 
----" - --- 
I 
------- 
FLUOROFLANE GRAPH'\( (mm. I 
------ 
FILM PLANiGR4Pi iV ( i . 1 1 ~  .) 1 
--".- ----- --" -- - - 
.1" 2 i I 
< 5 
I 
5 
8 1 
I 
--------_I/ 
TABLE I!  
EXPOSURE RATES AT 20 CM. ABOVE T A B L E  T O P  FOR 
VARIOUS PLANIGRAPH-Er"C T E C H N I Q U E S  
1 
i I 1 E X P O S U R E  
1 


A fluoroplanigraphy system for rapid presentation of single plane body sections

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