[Use of the Renodinamika-81 automated system of acquisition, storage and processing of radionuclide renography data in mass screening studies]

An automated Renodinamika-81 system was used for examination of 212 students to detect latent pathology of the urinary system. Renography by a common method with simultaneous data recording on a punched tape was performed. The software was based on the FORTRAN language for SM-4 computers. Changes were detected in 20.7% of the students. The Renodinamika-81 system was recommended for early examination of patients identified as a risk group during mass screening of the population.

A trial of automatic kidney detection in a dynamic renal study

We developed an automatic kidney detection procedure designed to do away with extraneous margins such as the liver or spleen while leaving the kidney margins intact using Laplacian operations and concurrence calculations. We evaluated the detectability of kidneys using our procedures and found that the renal margins were successfully detected in 84 cases of 100 subjects (84%) including 176 kidneys out of a total of 198 kidneys (89%). It was shown that as the renal function decreased the detectability of the renal margin decreased. In eight cases (16 kidneys) out of 9 patients who later resultantly received hemodialysis even manual settings of the renal ROI were very difficult. After excluding these 8 cases the detectability was 92% for all the cases and 95% for the kidneys. It was our conclusion that this method is sufficient for clinical application.

Micturition detection switch

Micturating renograms often need to be carried out on children, with whom difficulty may be experienced in synchronizing onset of micturition with camera and computer acquisition. A flow detection system has been developed which will automate these acquisitions, resulting in far fewer false starts or lost studies. The unit was developed specifically for the camera/computer system in our department (IGE 400T and DEC 11/34) but with only minor modifications would be suitable for interfacing to other equipment. It is a free standing unit which requires no modifications of the camera or computer circuitry apart from access to the remote start buttons.

[Automation of renographic studies using a microcomputer]

The paper is concerned with the results of the automation of renogram storage and processing. The computer system 15 VUMS-28 (on the basis of the ELEKTRONIKA-60 computer) fitted out with storage on the magnetic tape (KML) AZII-4, two 3-channel renographs (NP-356 and NP-307), manufactured in Hungary, and a plotter N-306 were interfaced by means of the KAMAK apparatus. The REN-1 program in the QUASIC language ensuring simultaneous storage and processing of renograms from two renographs was developed. The maximum time (Tmax) and semiexcretion time (T 1/2) as well as a system of indicators based on a linear chamber model of hippuran transport were used for analysis of renograms.

[Radionuclide evaluation of the function of the operated kidneys]

Altogether 68 patients were examined in early and late periods after operations on the kidneys. Function of the operated kidney was checked up by the results of two-indicator renal scintigraphy with 99mTc-DTPA and 131I-hippuran. When the kidney preserved its secretory capability and the suppression of organ function was caused by inhibited urine passage via the upper urinary tract, therapy aimed at the restoration of the kidney integrity and the elimination of the urine discharge obstruction, resulted in a rapid and complete recovery of all renal functions. Operative treatment of prolonged urological diseases complicated by chronic pyelonephritis, helped to accelerate secretory-excretory processes and slightly improved function of unchanged nephrons. A progressive decrease in the actively functioning parenchyma was recorded on scintigrams in 28% of the cases of the formation of the arteriosclerotic kidney. The authors found radionuclide investigations appropriate in the postoperative period not only in the development of complications and recurrences of urological diseases. Two-indicator renal scintigraphy with glomerulotropic and tubulotropic radiopharmaceuticals made it possible to give an objective assessment of the efficacy of surgical intervention.

The individual kidney function. A comparison between frame summation and deconvolution

A variety of methods have been developed to estimate the individual kidney function. Many methods use a scintillation camera the data from which are processed in a computer system. To compare two of these methods, the principles of which are completely different, such as the 'Oberhausen' method of frame summation and background subtraction and a method that uses deconvolution, the scintillation camera data of 121 patients have been collected. A computer program was written to calculate the individual kidney function by which both methods were used. It is often asserted that specific techniques of frame summation and background subtraction are not suitable to define the individual kidney function. To see if this assertion is true, two different methods have been compared using the contribution of the left kidney to the individual kidney function. An excellent correlation between the two methods was found (R = 0.9808, n = 121) which proves the ability of both the 'Oberhausen' method and the method that uses deconvolution. However, it is also seen that the 'Oberhausen' method may give false results, caused by an increasing background count outside the kidneys in patients with a large difference in function between the two kidneys.

Estimating the effective renal plasma flow from the hippurate renogram

A method for estimating the effective renal plasma flow (ERPF) from renograms is presented. Renograms obtained in 91 patients were used to test the method. The clearance values derived from renography were compared with those obtained with infusion clearance. It was shown that the ERPF was able to be estimated from the renogram with a standard error of +/- 94 ml min-1.

A comprehensive analysis of renal DTPA studies. I. Theory and normal values

Gamma camera renograms, using DTPA, were analysed to obtain flow rates and transit times during the initial arterial phase (0-36 s) and the later glomerular phase (37 s onwards). This paper outlines the underlying theory, and the effect of age on all the variables, calculated from patients with normal renal function.

A microprogrammed data acquisition system for renography

The purpose of this project was to design an efficient, low cost, and portable system for renography suitable for clinical use. The principles involved in the renographic test, and the procedures and calculations which act on the design of our system, are given. The system consists of an Apple II Plus computer equipped with 48K memory, two disk drives with diskettes of 143K each, a thermal printer with graphic capability, the Microsoft Z80 card, and an interface which is specifically designed for renographic data acquisition.

[Radionuclide studies with a dynamic kidney phantom]

Altogether 120 studies with a dynamic kidney phantom (DKP) were conducted permitting one to imitate the normal functioning of the kidneys or different pathological states of the organ. The studies were conducted with the help of a gamma-chamber of MV-9100 type using a computer system SEGAMS (Hungary) and a chronoscope RIKh-5M-01. On completion of the experiment the activity-time curves were plotted characterizing the time course of the passage of a radioactive tracer through phantom cylinders that imitate the kidneys. The results obtained have demonstrated DKP potentialities for the imitation of various renal functional states. Studies with a DKP make it possible to select an optimum regimen for research and to assess the quality of performance of nuclear medical diagnostic equipment.

[Determination of the amount of functioning renal parenchyma based on multipositional scintigraphy data]

The paper is concerned with mathematical calculations of two methods to determine the amount of the functioning renal parenchyma using the polyposition statistic scintigraphy data. These methods are used to determine the depth of kidney location from the body surface in the lumbar region. An analysis of polyposition scintigraphy of 122 patients without tumor lesion has shown that in 41.7% of the cases the difference in the depth of location was over 1 cm. in 13.1% over 2 cm and in 5.7% over 3 cm. If one of the kidneys is shifted forward by 3 cm, in scintigraphy gamma-irradiation from this kidney for 99mTc will be weakened more than 1.5 times, and for 197Hg more than 1.75 times. It is only in renal insufficiency and in obese patients that the method of estimated RPD accumulation in the kidneys with regard to lateral projections is the best as compared to that using the results of scintigraphy of front and back projections.

Scintillation camera renography with 99mTc-DTPA and 131I-Hippuran

Two different indicators for scintillation camera renography, 99mTc-DTPA and 131I-Hippuran, were compared directly in 37 patients. Quantitative data were obtained by means of a small digital computer. 99mTc-DTPA gave better kidney image quality, but also higher background than 131I-Hippuran. The two indicators gave renographic curves of slightly different shape, those after DPTA being flatter, but estimations of separate kidney function were not significantly different. Early kidney uptake of indicators was roughly proportional to glomerular filtration rate, but with a wide scatter.

Background correction factors in renography with single probe detectors

The background correction factor was determined with [131I]albumin, FA, in eighty-six patients with various nephro-urological diseases, with [131I]hippuran in eighty unilaterally nephrectomized patients (FH), and in twenty-five patients in whom the renogram showed background configuration, FH, B. FH was approximately the same on the left and the right side, the mean values being 1.39 and 1.35, respectively. FA showed a significant side difference, the mean values being 1.30 and 1.19 on the right side, respectively. FH, B was higher than FH, which shows that some uptake of hippuran can take place in apparently non functioning kidneys.

A simple method of background subtraction in two-detector renography

To increase the accuracy in the routine measurement of the side distribution of kidney function from 131I-Hippuran renograms, a simple method of background subtraction has been developed. Principally a background curve was adapted to the renogram on each side, assuming an initial amplitude corresponding to the amplitude of phase I of the renogram. The amplitudes of the renogram over background after 2 min is recognized as a measured of kidney function and a background quotient was calculated by dividing the background curve amplitude at 2 min with its initial amplitude. Mean values of the background quotient recorder over thorax was 0.62 and over an empty kidney region 0.73. It was found that a quotient of 0.70 could be used generally, thus omitting the need for a background curve registration at each renographic examination.

Methodological aspects of renography in children

Kidney function in children by renography has been evaluated. For reproducible results a high degree of standardization with respect to position, hydration and dosage was necessary. The wide range of kidney size and depth in children requires age-adapted collimators. For practical use for different size have been constructed for the age-groups: less 1 year, 1-5 years, 6-9 years and 10-15 years. A reduction in the surrounding activity of the kidneys is thereby obtained and disturbing influence from the bladder or contralateral kidney is prevented. Kidney function variables from the renogram are presented in terms of uptake and excretion ratios. The correlation between sum of uptake ratios and clearance measurements is good in cases with slight or moderate difference in kidney size. The standardized renographic technique has many advantages for kidney function measurements in children. The method is applicable in all ages, it is simple and reliable without extensive preparations and requires a low radiation dose. Also in children we can confirm the previous opinion obtained in adults that renography is a clinical valuable method of measuring kidney function.

A method for subtraction of the extrarenal "background" in dynamic 131I-hippurate renoscintigraphy

Using a Toshiba GC-401 gamma camera with MDS computer Trinary a new method was developed for subtracting the extrarenal (extracanalicular) "background" from the count rate recorded over the kidneys after intravenous administration of 131I-hippurate. Mean subtraction factors of the "blood" activity curve were calculated from a study of 27 patients who were given 51Cr-HSA for purposes of conventional renography with "background" subtraction. The values of the mean subtraction factors FR,L for the right and left kidney, by which a blood count rate should be multiplied amounted to 0.86 +/- 0.12 and 0.79 +/- 0.13, respectively. A comparison of the coefficients of variation of the pure renal signal when mean vs. individually determined subtraction factors were used, and the verification of the method in unilaterally nephrectomized patients have demonstrated that determination of the factors, FR,L, for each patient individually is not required and sufficient precision can be obtained by using the method and factors reported in this study.

Renography in the foetal and newborn lamb

Hippuran renography indicates kidney function as reflected in a substance handled mainly by the tubules. The working conditions of the kidneys undergo a fundamental change at birth with the cessation of placenta circulation, and these organs become responsible for waste elimination. 131I-hippuran renography was performed on foetal and newborn lambs using a gamma camera and a computer. The intervals of the maximum- and half-time renal activity were determined. These decreased by a half from mean foetal value of Tm=7 mi and T12=19 min in 1 to 1.5 days and reached the full-grown level in 2 to 5 weeks. No sudden change occurred as a result of the first breath.