A new type of respirometer

International Journal of Ap lied Radiation and Isotopes, 1965, Vol. p. 341. Pergamon Press Lt $ Printed in Northern Ireland

.

A New

Type

16,

A 1.4-

of Respirometer

1964)

(Received 30 November

1.2-

A NEW type of respirometer was developed at the Institute J. Stefan, Ljubljana, Yugoslavia. The method of continuous ionization is used.(l12) The diameter of the tube is 2 cm and the isotope used is RaD (c(, ,k?). To improve the linearity over the extreme range of velocities, two sources were used instead of one: the first one of activity 18 PC and the second of activity 38 ,z, positioned at different places along the tube. The linearity attained is better than 5 per cent over the range from 2 l/min to 60 l/min. In the same way another tube was made for the measurements in the range from 8 l/min to

I.O-

Flow rate,

l/min

FIG. 2 300 l/min. The results, obtained with the smaller diameter tube’ are shown in Figs. 1 and 2. We intend to extend the measuring range to flows smaller than 1 l/min. So far the new instrument has produced very good results. It was possible to follow very accurately the dynamics of breathing and no additional strain of the patient was involved. It is believed that the new respirometer will be of great advantage in lung surgery. M. HRIBAR Institute J. Stefan Ljubljana, Yugoslavia I 20

I 40

I 60

I 80

Flow

rote,

FIG. 1

I

100

Chin

I

129

I 140

References *

1. &I&K B. and HRIBAR M. Internal Report J. Stefan Institute (1961). 2. CLAYTONC. G. and WEBBJ. W. ht. J. appl. Rad. Isotopes 15, 603 (1964).

341