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Advances in Radiotherapy
& Nuclear Medicine Modeling renal TAC in dynamic scintigraphy

the construction of TACs by modeling the physiological that the entire kidney (for functional determination) and
processes in the kidneys. the renal pelvis (for pyelocaliceal drainage) are included
in the ROI. A larger ROI is preferred over a narrowly
2. Materials and methods surrounding region around the kidney.

2.1. Dynamic renal scintigraphy From the established TAC, the parameters characterizing
In this work, the GE Discovery NM630 Gamma camera the kinetics of renal function that can be assessed are the
(GE Hualun Medical Systems Co, China was used for following:
imaging data collection and clinical TAC construction. (i) Split function: It is particularly useful in identifying
This camera is used in nuclear medicine for many purposes, unilateral changes or differences in renal function
including dynamic renal scintigraphy. It is a specialized and is calculated by generating a TAC that plots the
gamma camera designed for high-resolution imaging amount of radioactive material in the kidney over
with enhanced sensitivity and speed. The camera detects time. The split function value is obtained by dividing
the gamma rays emitted by the radiopharmaceutical and the counts collected during the uptake phase for each
creates images that show the distribution and function of kidney by the sum of the counts from both kidneys.
the kidneys over time. During dynamic renal scintigraphy Normal range values of this index are between 42%
with the GE Discovery NM630 Gamma camera, multiple and 58%. 7-12
images are taken at different time points after the injection (ii) Relative uptake: The measurement of the
of the radiopharmaceutical. This allows for the assessment radiopharmaceutical’s relative uptake is crucial in
of renal blood flow, GFR, renal function, and the detection assessing the specific renal function, which varies
of any abnormalities such as obstruction or reflux. The depending on the radiopharmaceutical used. When
dynamic images produced by this technique provide using 99mTc-MAG3 and DTPA, a common approach
information to healthcare professionals for the diagnosis involves placing an ROI over each kidney and
and management of various kidney disorders, including calculating the integrated counts within the renal
renal artery stenosis, renal transplant evaluation, and ROI during specific time intervals (e.g., 1 – 2 min,
renovascular hypertension. In addition, it can help in the 1 – 2.5 min, or 2 – 3 mins) after injection. Another
7-12
evaluation of renal function before and after interventions method that can be used is the Rutland-Patlak plot.
such as surgery or renal artery angioplasty. (iii) Time to peak (TTP or T ): It refers to the time it
max
takes for the tracer concentration to reach its highest
The data used in this study were collected from patients point or the peak value (maximum concentration
who underwent dynamic renal scintigraphy over the past in the kidney) when the accumulation trend of the
2 years at the Babor Medical Clinic. In compliance with radiopharmaceutical is reversed. In general, for a
local regulations, data were anonymized by enabling healthy kidney, TTP values are about 5 min, and the
the anonymization option in the DICOM files before maximum activity at the peak decreases to half the
extraction. Dynamic renal scintigraphy began immediately value after 15 min from the injection. 13
after the intravenous injection of TC-99m diethylene (iv) Clearance time (T ): It is a quantitative parameter
1/2
triamine penta-acetic acid (DTPA), with the dose based on commonly used to describe the rate at which the
the patient’s weight and other factors, and by considering radiopharmaceutical is cleared from the kidney. It
12 healthy and pathogenic cases from the Setif region represents the time taken for the radiopharmaceutical
(Algeria) with different sexes and ages. The detectors activity to decrease by half in the ROI after reaching its
were positioned in an H-shaped configuration over the peak uptake. This parameter is important in diuretic
abdomen, and the patient was placed in the supine position. renography for detecting urinary tract obstruction. 13
Dynamic renal scintigraphy was performed according to (v) The 30-min min/max ratio: It reflects the time it
standard protocols. In the imaging protocols used in this takes for the radiopharmaceutical to pass through
6
work, 30 frames were captured during the 1 min, and the kidneys. It indicates the amount of residual
st
then 90 frames were captured at a sequence of three frames activity in the cortex. It is calculated by comparing
per minute. The image acquisition process continued for the radioactivity level in the kidneys at 30 min
a total duration of 30 min to monitor the tracer uptake, to the peak concentration. This ratio is helpful in
distribution, and clearance in the kidneys. “Xeleris GE diagnosing urinary tract blockages and renovascular
health care (USA),” was used to automatically generate hypertension. 13
the clinical TAC, allowing clinicians to select the ROI (vi) Upslope ratio: It refers to the ratio of the maximum
corresponding to the two kidneys and background on the slope of the TAC during the ascending limb to the
image sum of all captured frames. It is necessary to ensure average slope of the entire curve. This parameter

Volume 3 Issue 2 (2025) 63 doi: 10.36922/ARNM025070008