Measurement of Musele Blood Flow in the
Human Forearm with Radioactive
Krypton and Xenon
By GERALD B. HOLZMAN, M.D., HENRY N. WAGNER, JR., M.D.,
MASAHIRO IO, M.D., DAVID RABINOWITZ, M.D., AND KENNETH L. ZIERLER, M.D.
Downloaded from http://circ.ahajournals.org/ by guest on June 16, 2017
Carrier-free Kr 85 and Xe 133 were obtained in
state from Oak Ridge National Laboratory, and were transferred to a 40-ml. stainlesssteel container by attaching the gas cylinder to
an evacuated container, the temperature of which
had been reduced by means of liquid nitrogen.
Phosphate buffer at pH 7.0 was then introduced
into the evacuated container to return the pressure to atmospheric. The final volume of one
curie of radioactive gas was appiroximately 3 to 5
ml. in equilibrium with about 35 ml. of buffer
solution. In this way a highly concentrated aqueous solution of Kr 85 and Xe 133 was obtained
despite the slight water solubility of these gases.
The aqueous solution was sterilized by passage
through a membrane Millipore filter, with care
to avoid contact with air. Terminal calibration of
the dose was made by comparison with a sealed
National Bureau of Standards Kr 85 standard.
Xe 133 was calibrated with ftiulium-170, which
has a gamma emission of 0.084 mev and a
half-life of 127 days. Final concentration of both
gases was usually 500 to 1,000 ,uc. per ml.
To measure forearm muscle blood flow, the
aqueous solution of the radioactive substance was
injected into the volar surface of the forearm
through a 25-gage needle to a depth of % inch.
The injection was made slowly toi minimize tissue
trauma. Immediaitely following injection, a collimated Nal (Ti activated) crystal scintillation
detector was placed directly over the injection site
and radioactivity was recorded by means of a
IN 1949 Kety proposed that if the rate of
removal from the site of injection of an
intramuscularly injected radioactive isotope
was limited principally by flow, then the
clearance of the tracer from the injection site
could be used to measure local blood flow.'
In the past, sodium-24 or iodine-131 has
been used for this purpose, but with considerable variability in the results obtained in serial
studies of the same persons.2
The chemically inert gases krypton-85 and
xenon-133 have certain advantages
over
a gaseous
Na24
and I 131. They are chemically and physiologically inert; they are not normally present in
the body; and they are rapidly excreted from
the body via the lungs.3 The long physical
half-life of Kr 85 ( 10.3 years) and the half-life
of Xe'33 (5.27 days) make the use of these
nuclides more convenient than Na 24 (15
hours). Finally, the lower gamma ray energies
of Kr85 (0.513 mev) and Xe'33 (0.081 mev)
are more suitable for external radiation detection than the high energy of Na24 (1.368
mev), which is difficult to localize accurately
in the body.
Accordingly, blood flow to forearm muscle
was estimated by external monitoring of the
rate of disappearance of radioactivity following intramuscular injection of an aqueous solution of Kr85 or Xe 33
gamma ray spectrometer, count rate meter, and
linear chart recorder. An Armac scintillation detector was used in certain studies.
In five healthy adult men, forearm muscle
blood flow was estimated simultaneously by two
methods, the Kr 85 or Xe 133 method and the
constant injection dye-dilution method.4
Materials and Methods
There were 119 determinations in 52 subjects
who were hospital employees or convalescent patients from the medical wards of the Johns Hopkins Hospital. All were free from known peripheral vascular disease.
Calculation of Results
1
is
a typical linear chart recording of
Figure
the time course of Kr85 radioactivity in the human forearm following an intramuscular injection
of
From The Johns Hopkins University School of
Medicine, Baltimore, Maryland.
Circulation, Volume XXX, July 1964
an
rate
aqueous solution of the gas.
of
function
27
of
Although
the
not
a
single exponential
time (fig. 2),
a
determination
clearance
was
was
HOLZOANA ET AL.
8)
C. P.M.
4,000
C. P.M.
Background 30 )OC.P
M
4,00°r
2,000-
2,000F
T 152= 17 min.
30
40
20
10
TIME AFTER INJECTION(min.)
0
Figure 1
Linear chart recording followinsg the injection of
0.5 ml. of Kr85.
Downloaded from http://circ.ahajournals.org/ by guest on June 16, 2017
made of the time required for the counting rate
to fall to one half the value obtained 2JS minutes
after injection. This is referred to hereafter as the
half-time. To obtain forearm muscle blood flow in
units of ml./min./100 Gm. of forearm muscle, it
was assumed that the radioactivity remaining in
the injected region was described by the equation
Q -Q e-kt* The clearance constant k can be
expressed by k - F/VX,t and we multiplied V by
the specific gravity of tissue (approximately 1
Gm./ml.).
The method of calculating the data was based
on the proposals of Kety, xvho assumed that the
rate of disappearance of intramuscularly injected
* Q -quantity present; Q. = initial quantity present; e - base natural log; k - clearance constant
(fraction/min.); t - time (min.).
f F - blood flow in ml./min.; V - volume (ml.)
of tissue being cleared of the inert gas; X - partition
coefficient between tissue and blood, assumed to be
1.00 in the Kr85 studies and 0.73 in the Xe'33
studies.5 6
,000
800
20
30
40
10
TIME AFTER INJECTION(min.)
0
Figure 2
Se?nilogarithmic plot of figure 1.
radioactive sodium is proportional to the remainiing
quantity of the radioisotope, and the constant of
proportionality is the ratio of blood flow to the
volume of distribution of the radioisotope.' An
alternate formulation has been made by Zierler.
Its particular advantage is that it is unnecessary
to make any assumptions about the shape of the
time-concentration curve. To obtain flow per unit
volume, the area under the time-concentration
curve is integrated by planimetry and divided
into QO, the amount of radioactivity injected as
measured by the external detector immediately
after injection, i.e., F/V - QO
Qo
where t equals the mean transit time.
To compare the clearance method with the
dye-dilution method, which measures total forearm flow, it was assumed that 60 per cent of the
Table 1
Paired Kr85 Clearance Half-Times in the Same Subject
Experiment
1 irst observation
Second obiservation
30 T
30 K
14.5()
10.8()
27.00
9.80
24.00
26.50
16.00
9.00
8.50
13.80
9.80
24.00
8.00
19.00
20.25
22
6 an1( 7
55
10 and 49
15 and 19
29 T
29 K
51
23
11 and 17
54
35.00
16.00
19.00
14.50
Per cent differenlce
1.2.00
13.00
12.30
23.75
10.00
10.00
6.75
Mean per cent difference: 32
irculZation,
4.9
9.7
11.8
20.2
23.3
26.7
28.6
36.4
36.5
38.3
46.2
62.0
72.9
Volume
XXx,
July
1964
MUSCLE BLOOD FLOW IN FOREARM
29h
Table 2
The Effect of Volume of Injectate
Experimnent
Downloaded from http://circ.ahajournals.org/ by guest on June 16, 2017
17
19
23 B
15 R
18
16 R
16 L
15 L
12 L
11
21
14 R
22 B
9R
20
10
14 L
22 A
24
12 R
8
9L
Mean
on
the Half-Time Clearance of Kr85
0.2 ml.
T
1
2
min.
10.0
11.0
12.5
16.0
16.0
18.3
18.5
18.8
18.8
19.0
19.5
21.5
24.0
24.0
25.1
26.5
27.0
27.0
27.3
33.5
34.0
34.5
21.9
0.5 ml.
Experiment
54
53
39
53
23
40
53
54
32
23
50
49
22
C
A
A
C
B
A
B
B
A
A
A
A
51 C
6.8
7.0
7.0
7.8
10.0
10.3
11.3
14.5
15.5
35.0
43.0
Mean
17.4
elsewhere.7' 8
Results
The half-time of disappearance of Kr 85
from the injection site based on 65 determinations in 28 subjects in the supine position
averaged 17.8 8.2 min. (mean + 1 S.D.)..
The average Xe 133 clearance half-time based
on five determinations in four subjects was
16.0± 7.1 min.
To evaluate reproducibility, we carried out
paired injections in the same arm but not in
the same spot in 13 subjects. A minimum of
1 hour elapsed between injections. Table 1
lists the results. The difference between two
determinations ranged between 5 and 73 per
cent of the mean; the mean difference was
32 per cent. In one patient who had three
injections, the mean difference was 31 per
cent.
In most patients the clearance during the
Experiment
29
26
26
29
27
25
28
27
T
'2
min.
A
B
A
B
B
A
A
A
9.0
10.7
12.7
19.5
22.5
23.5
24.0
Mean
16.3
8.8
16.0
20.0
20.3
22.5
23.8
25.0
54 A
51 B
24 B
forearm consists of muscle, the latter being perfused by 80 per cent of the total forearm blood
flow. Evidence that these two assumptions are
valid when the arm is at rest has been presented
Circulation, Volume XXX, July 1964
0.8 ml.
T %2 min.
second observation was faster than during the
first. This may have been due to a physiologic
increase in forearm muscle blood flow in response to the experimental procedure.
Table 2 shows the effect of variation in the
volume of injectate on the clearance rate of
Kr 85. The average half-times for 0.5 ml. (17.4
min.) and 0.8 ml. (16.3 min.) were not significantly different. The mean half-time for a
0.2-ml. injectate was 21.9 7.0 min. (mean
+ 1 S.D.); the mean half-time for 0.5 ml. was
17.4 10.3 min. The difference between the
0.2- and 0.5-ml. volume was not significant
(p = 0.12). The smaller volume was selected
as less likely to alter blood flow by producing
local tissue reaction.
To determine whether the size of the area
of the forearm being monitored had an effect
on the clearance half-time of Kr 85, two different detection systems were used simultaneously in 10 experiments (table 3). One detector consisted of a right cylindrical collimator
with a 134-inch diameter field; the other was a
flat-field collimator with a 6-inch diameter
HOLZMAN ET AL.
30
C. P. M.
C.P.M.
80,000
60X0000
XE 133
50,000
Tl
17- =10.7min.
40,000
XE133
20,000-
2 0,000
0
0
20
40
10
30
50
TIME AFTER INJECTION (min.)
0
8,OOOE
C.P.M.
5 ,oooF
4,000r
Background
KR85
Downloaded from http://circ.ahajournals.org/ by guest on June 16, 2017
e
J
_
I
0
1
KR 85
2,000
Tl12 =Igmin.
_1
30
40
20
50
10
TIME AFTER INJECTION (min.)
Figure 3
800EL-
Linear chart recording following the injection of
0.5 ml. of a mixture of Krs5 and Xe133.
field. In the case of the latter, the half-time
was 18.8 + 12.8 min. (mean
1 S.D.) while
that with a 134-inch field was 14.1 6.4 min.
The mean difference of 4.7 min. was not significant (p>O.l).
To determine the simultaneous clearances
of Kr85 and Xe 133, and Kr85 and Na 24, the
clearance of each was measured by means of
gamma-ray spectrometry. Figure 3 is a linear
chart recording following the injection of a
__1
----L-
-1
10
20
30
40
TIME A FTER INJECTION (min.)
0
Figure 4
Semilogarithmic plot of figure 3.
mixture of Kr 8e5 and Xe133 in a 0.5-mI. volume. The data are plotted on semilogarithmic
paper in figure 4. The Kr85 contribution to
the Xe 133 measurement was subtracted prior
to plotting the Xe 133 clearance. The results of
10 paired Kr85 and Xe 133 clearances are listed in table 4. The ratio of the Kr 85 half-time
to the Xe 133 half-time was 1.48 for the forearm
Table 3
Effect of Detector Size an the Clearance Half-Time of Kr85 from the Human Forearm
Experiment
27 A
26 B
29 A
29 B
31 A
27 B
30 A
30 B
26 A
25 A
Mean
1 S.D.
6 inch field
T
2
mlin.
22.5
9.0
9.0
13.0
19.0
20.5
14.5
13.8
14.0
53.0
18.8
12.8
1 2 inch field
T
>2
min.
25.5
9.0
8.5
12.3
17.0
18.5
10.8
9.8
7.3
22.5
14.1
6.4
Difference
3.0
0.0
0.5
0.7
2.0
2.0
3.7
4.0
6.7
30.5
4.7
9.4
Circulation, Volume
XXX,
July 1964
MUSCLE BLOOD FLOW IN FOREARM
31
Table 4
Simultaneous Measurements of the Kr85 and Xe"33 Clearance
Experiment
Xe T 1/2 (mtin.)
Kr T 1/2 (min.)
Ratio Kr T 1/2:Xe T 1/2
Forearm
51
51
55
50
55
49
C
B
A
A
B
A
20.00
26.50
16.25
12.30
10.70
10.00
23.75
35.00
24.00
20.00
19.00
20.25
1.19
1.32
1.48
1.63
1.78
2.03
5
5
5
5
D
B
A
C
6.40
7.50
7.60
3.50
7.70
9.20
1.20
1.23
1.28
1.66
1.4
Legs
9.75
5.80
Mean
Downloaded from http://circ.ahajournals.org/ by guest on June 16, 2017
and 1.30 when the injections were made in the
leg. The over-all ratio was 1.44 and the correlation coefficient 0.95. A typical Kr85 and
CPM
70,000r
50,000O
30,000[
0,000k
7.5
12.5
7.5
2.5
TIME AFTER INJECTION (min.)
Na24 study is shown in figures 5 and 6. The
data are presented in table 5. The ratio of the
Kr 85 half-time to the Na 24 half-time was 2.03.
The importance of local blood flow in
determining the rate of Kr85 clearance was
demonstrated by the effect that major alterations in blood flow had on the clearance rates.
In studies of seven subjects an Armac.5 scintillation detector was used. The left side of figure 7 is a linear chart record of a normal
clearance after an injection of 0.5 ml. Kr 85. As
seen in the graph on the right, a slower clearance was observed when a blood pressure cuff
on the arm above the site of injection was
CPM
30,000~
213,0 0 0
Na 24
12
2__
Kr 85t
=18 min.
9,000
10,000
3,000
8,000
17.5
12.5
7.5
2.5
TIME AFTER INJECTION (min.)
Figure 5
Linear chart recording following the injection of
0.5 ml. of a mixture of Kr85 and Na24.
Circulation, Volume XXX, July 1964
NA24
6,000
t1'2=1 1.75 min.
2
5
15
TIME AFTER INJECTION
Figure 6
Semilogarithmic plot of figure 5.
HOLZMAN ET AL.
32
Pm
I
90,000r
50, 00(
70,000 F
30,0(iO1-,.
i0t00
i
o
l
20
lME
30
o1
27(I
1(
30
50,000 F
AFTER INJECTION [min.)
Figure 7
Left, a normal linear chart recording following the,
injection of 0.5 ml. of Krs;;. Right, a linear chart
recording demonstrating the effect of venous occluisioni.
Downloaded from http://circ.ahajournals.org/ by guest on June 16, 2017
inflated to 20 mm. Hg below diastolic pressure. This same patient 1 hour later had a
blood pressure cuff inflated to 30 mm. Hg
above systolic pressure. The cuff was kept
inflated for 15 minutes during which time 0.5
ml. of Kr 85 was injected into the forearm below the level of the cuff. Upon release of the
cuff reactive hyperemia produced a rapid
wash-out of the radioactivity (fig. 8). In all
cases arterial occlusion prevented the clearance of the radioactivity and venous occlusion
markedly diminished it.
Forearm muscle blood flow was estimated
eight times in five healthy adult men by the
isotope clearance method simultaneous with
the indicator dye-dilution method. The results
of the comparison are shown in table 6. The
flow in ml./100 GmJ/mi. determined by the
Kr 85 clearance was from 0.95 to 1.65 times the
value obtained by the dye-dilution technic.
The mean difference between the two methods was 23 per cent, the range of difference
being 6 to 49 per cent. The correlation coefficient was 0.75. Kr > estimations averaged
1.28 times faster and Xe estimations 1.34
`
30,000 h
3ackground
10,000
0
20
10
TIME AFTER INJECTION (min.)
Figure 8
A linear chart recording illustrating the effect of arterial occlusion and reactire lhyperernia.
times faster than the dye-dilution determinations.
To obtain data for calculation of the radiation dosage to the patient, the fate of Kr 85 in
the human forearm was determined in six individuals. Observations were made until the
amount of radioactivity present in the forearm was less than 0.1 per cent of the initial
value (95-per cent confidence limits). Results
are shown graphically in figure 9. In three
subjects less than 1 per cent of the initial
couint rate was present 632 hours after injection. In the three other subjects, 1.41 per cent
of the activity was present at 6 hours, 2.7 per
cent at 8 hours, and 1.35 per cent at 8 hours.
A final determination was carried out 2631
able 5
Simultaneous Measurements of the Kr85' and Na2" Clearance
Krypton-85
Experiment
156
57
57
58
58
T
l2 (nIliln.)
1 1.()
t13.25
B
A
B
A
18.00
Mean
30.0()0
63.5
27.15
Sodiunn-24 T 1/2 (min.)
Ratio Kr T 12: INa T 1/2
11.00
12.50
11.75
16.00
13.50
12.95
1.06
1.53
1.87
4.70
2.03
1.G()
Cirulation, Volum;e XXX, Julv 1964
MUSCLE BLOOD FLOW IN FOREARM33
33
Table 6
Simultaneous Measurements of Human Forearm Muscle Blood Flow by the Kr85 and
Dye-Dilution Method
Kr method
ml. /100 Gm./min.
Experiment
54
53
40
53
53
39
B
B
A
A
C
A
Dye-dilution method
mL / 100 Gm. min.
5.05
5.75
6.00
7.48
6.01
6.00
4.78
6.16
6.76
9.90
8.95
9.90
Per cent
difference
Kr/dye
5.5
6.9
11.9
27.8
39.3
49.1
0.95
1.07
1.13
1.32
1.49
1.65
Correlation coefficient: 0.75
Mean per cent difference: 23
Downloaded from http://circ.ahajournals.org/ by guest on June 16, 2017
to 30 hours after injection in four of the six
individuals. Less than 0.1 per cent of the
initial activity was present in all cases. Thus
the radiation to the forearm was well below
permissible amounts.
Foreorm
Radioactivity
Percent
of
Initial
Value
A
0.1
T
TIME
AFTER
INJECTION(hours)
Figure 9
Six studies demonstrating the amount of radioactivity
remaining in the injected forearm over a 10-hour
period.
Circulation, Volume XXX, July 1964
Summary and Conclusions
Blood flow to forearm muscle in man was
estimated by external monitoring of the rate
of disappearance of radioactivity from the
injection site following intramuscular injection of aqueous solutions of krypton-85 and
xenon-133. Krypton-85 clearance was markedly diminished by arterial occlusion and venous occlusion, while reactive hyperemia
transiently increased the rate of clearance.
The technic was atraumatic to the patient and
yielded flow data similar to those of the indicator dilution method without the necessity
of intra-arterial injections and multiple blood
sampling. When measured simultaneously,
Kr85 clearance was consistently slower than
both Xe 133 and Na 24, An important difference
between Na 24, Kr 85, and Xe 133 is their relative
solubility in fat, the last being the most soluble. The differences between the clearance
rates of Kr 85 and Xe'33 can be attributed to
the greater solubility of Xe 33 in blood relative to skeletal musele.9 Differences in clearance rates of both Kr 85 and Xe 133 result from
the relative proportions of lipid and water in
a given individual.10 The technic is of greatest
value in serial measurements in the same individual. Since the mean per cent difference
between our paired studies in the same individual was 32 per cent, one would be able to
detect changes in blood flow of this order of
magnitude.
References
1. KETY, S. S.: Measurement of regional circulation
by the local clearance of radioactive sodium.
Am. Heart J. 38: 321, 1949.
34HOLZMAN ET AL.
34
Downloaded from http://circ.ahajournals.org/ by guest on June 16, 2017
2. McGIRR, E. M.: Tissue clearance of inorganic
ions. Brit. M. Bull. 8: 192, 1952.
3. CHIDSEY, C. A., FRITTS, H. W., JR., HARDEWIC,
A., RICHARDS, D. WV., AND COURNAND, A.: Fate
of radioactive krypton (Kr-85); introduced
intravenously in man. J. Appl. Physiol. 14: 63,
1959.
4. BALTZAN, M. A., ANDRES, R., CADER, G., AND
ZIERLER, K. L.: Heterogeneity of forearm metabolism with special reference to free fatty
acids. J. Clin. Invest. 41: 116, 1962.
5. CONN, H. L., JR.: Equilibrium distribution of
radio-xenon in tissue: Xenon-hemoglobin association curve. J. Appl. Physiol. 16: 1065,
1961.
6. HARDEWIG, A., ROCHESTER, D. F., AND BRISCOE,
XV. A.: Measurement of solubility coefficients
of krypton in water, plasma and human
blood, using radioactive krypton-85. J. Appl.
Physiol. 15: 723, 1960.
7. COOPER, K. E., EDHOLM, 0. G., AND MOTTRAM,
R. F.: The blood flow in skin and muscle of
the human forearm. j. Physiol. 128: 258,
1955.
8. ANDRES, R., CADER, G., AND ZIERLER, K. L.: The
quantitatively minor role of carbohydrate in
oxidative metabolism by skeletal muscle in
intact man in the basal state. Measurements
of oxygen and glucose uptake and carbon
dioxide and lactate production in the forearm. J. Clin. Invest. 35: 671, 1956.
9. LAWRENCE, J. H., Loomis, W. F., TOBIAS, C. A.,
AND TURFPN, F. H.: Preliminary observations
on the narcotic effect of xenon with a review
of values for solubilities of gases in wxater
and oils. J. PhYsiol. 105: 197, 1946.
10. HYMIAN, C.: Peripheral blood flow measurements.: Tissue clearance. In Medical Research. Chicago, The Year Book Publishers,
Inc., vol. 8, p. 236, 1960.
William Withering
XVhat led to the publication of Withering's book on the foxglove, was what
he believed to be the misuse of the drug by the profession. He felt that this
would lead to its being discredited and thus a valuable medicinal agent would
be discarded. As he expressed it: "The use of the Foxglove is getting abroad and
it is better the world should derive some information, however imperfect, from
my experience, than that the lives of men should be hazarded by its unguarded
exhibition, or that a medicine of so much efficacy should be condemned and
rejected as dangerous and unmanageable." One of those who urged him to print
his experiences was Dr. Fowler at Stafford, who wrote him as follows:
"I understand you are going to publish on the Digitalis, which I am glad
to hear, for I have long wished to see your ideas in print abouit it.
The public
at this very instant stand in great need of your precept, guards, and cautions,
toward the safe and suceessful use of such a powerful sedative diuretic. I remember an officer in the Staffordshire militia who died here of dropsy four
years ago. The Digitalis relieved him a number of times in a wonderful manner,
so that in all probability he might have obtained a radical cure if he would have
refrained from hard drinking."-Louis H. RODDIS, M.D. William lVithering: The
Introduction of Digitalis Into Medical Practice. New York, Paul B. Hoeber, Inc..
1936, p. 59.
.
.
Circula/tion, Volume XXX, Juily 1 964
Measurement of Muscle Blood Flow in the Human Forearm with Radioactive
Krypton and Xenon
GERALD B. HOLZMAN, HENRY N. WAGNER, JR., MASAHIRO IIO, DAVID
RABINOWITZ and KENNETH L. ZIERLER
Downloaded from http://circ.ahajournals.org/ by guest on June 16, 2017
Circulation. 1964;30:27-34
doi: 10.1161/01.CIR.30.1.27
Circulation is published by the American Heart Association, 7272 Greenville Avenue, Dallas, TX 75231
Copyright © 1964 American Heart Association, Inc. All rights reserved.
Print ISSN: 0009-7322. Online ISSN: 1524-4539
The online version of this article, along with updated information and services, is
located on the World Wide Web at:
http://circ.ahajournals.org/content/30/1/27.citation
Permissions: Requests for permissions to reproduce figures, tables, or portions of articles
originally published in Circulation can be obtained via RightsLink, a service of the Copyright
Clearance Center, not the Editorial Office. Once the online version of the published article for
which permission is being requested is located, click Request Permissions in the middle column of
the Web page under Services. Further information about this process is available in the Permissions
and Rights Question and Answer document.
Reprints: Information about reprints can be found online at:
http://www.lww.com/reprints
Subscriptions: Information about subscribing to Circulation is online at:
http://circ.ahajournals.org//subscriptions/