Page 77 - ARNM-3-2

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

Table 1. (Continued)
Kinetic parameters Right kidney Left kidney
Automatic data Manual data Automatic data Manual data
Case 11
T (min) 4.15 4.05 4.71 4.32
max
T (min) 5.75 6.60 7.00 7.14
1/2
30-min min/max ratio 0.22 0.28 0.30 0.31
Case 12
T (min) 4.15 4.35 9.00 9.22
max
T (min) 6.20 6.45 35.00 36.20
1/2
30-min min/max ratio 0.26 0.27 0.45 0.48

Table 2. Comparison of the kinetic parameters between the two region-of-interest selection methods

Case Kidney ROI selection method T (min) T (min) 30-min min/max ratio
max 1/2
P1 Left Rectangular 4.2 8.5 0.32
Free-hand 4.0 7.9 0.28
P2 Right Rectangular 3.8 9.2 0.35
Free-hand 3.5 8.7 0.30
P3 Left Rectangular 4.5 7.8 0.29
Free-hand 4.3 7.4 0.26
P4 Right Rectangular 5.1 10.1 0.38
Free-hand 4.8 9.6 0.33
P5 Left Rectangular 4.0 8.9 0.31
Free-hand 3.8 8.2 0.27
P6 Right Rectangular 3.7 9.5 0.34
Free-hand 3.4 9.1 0.29

Table 3. Statistical analysis of the comparison between the Table 4. Fitting function and mathematical model
two ROI selection methods parameters of Case 1

Statistical parameters ROI selection method Fitting function parameters Left kidney Right kidney
Rectangular Free-hand A0 5,687 200,181
Mean and standard deviation Ce 0.98 3.35
T (min) 4.22±0.52 4.00±0.49 αe 1.90 1.45
max
T (min) 8.99±0.83 8.32±0.74 Cs 4.91 0.0011
1/2
30-min min/max ratio 0.33±0.03 0.29±0.02 αs 0.48 0.88
Paired t-test results (rectangular vs. Reduced χ 2 4.77 13.95
free-hand)
R 2 0.98 0.97
T p=0.035*
2
max R adjusted 0.98 0.96
T p=0.041*
1/2 Notes: A indicates the activity concentration of the tracer that is
0
30-min min/max ratio p=0.029* injected and metabolized by the kidney; Ce indicates the perfusion time
2
Correlation analysis (R values R =0.94 constant; αe indicates a weighting factor of the perfusion phase;
2
between the TACs of both methods) Cs indicates a time constant in the secretion-drainage phase
Note: *p<0.05. (urination); αs indicates a weighting factor related to the secretion-
Abbreviations: TAC: Time-activity curve; ROI: Region-of-interest. drainage phase, and t is the time variable.

Volume 3 Issue 2 (2025) 69 doi: 10.36922/ARNM025070008