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Advances in Radiotherapy
& Nuclear Medicine Blood glucose and I-123 MIBG lung uptake

3. Results

3.1. Patients’ characteristics
A total of 199 patients had undergone I-123 MIBG
whole body scan from January 2014 to July 2022. A total
106 patients were excluded from this study, with 58 of
them being non-adult patients, 40 having metastasis
in chest area, and eight having no fasting glucose data.
Ninety-three patients were included in this study and
were divided into two groups based on their diabetic
status. Diabetic group consisted of 36 patients (21 males
and 15 females), while non-diabetic group consisted of
57 patients (28 males and 29 females), with mean age of
56 ± 14.1 years and 52 ± 14.6 years, respectively. Patients’
characteristics of both diabetic and non-diabetic groups
are summarized in Table 2. Figure 2. Semi-quantitative analysis. A 2 × 3 cm region of interest
2
was drawn manually and placed on the right-middle lung and on the
Fasting glucose showed a mean value of 136 ± 37.7 mg/dL mediastinum to calculate the lung-to-mediastinum ratio.
in diabetic group and 96 ± 8.2 mg/dL in non-diabetic
group. The time interval between the I-123 MIBG WBS Table 1. Pearson’s coefficient (r) between lung uptake of
and the fasting glucose determination was 17 ± 39.9 days I‑123 MIBG and fasting glucose level
and 21 ± 32.6 days, respectively, for diabetic and non-
diabetic groups. Strength of association Coefficient (r)
Positive Negative
3.2. Iodine-123 MIBG lung-to-mediastinum ratio
Small 0.1 – 0.3 −0.1 – −0.3
In this study, the 24-h LMRs for patients in diabetic group Medium 0.3 – 0.5 −0.3 – −0.5
and those in non-diabetic group were 1.38 ± 0.20 and Large 0.5 – 1.0 −0.5 – −1.0
1.17 ± 0.14, respectively (Figure 3).
Abbreviation: MIBG: Metaiodobenzylguanidine.
3.3. Correlation between fasting glucose and I-123
MIBG LMR Table 2. Patients’ characteristics
Pearson’s correlation analysis revealed a significant Diabetic Non‑diabetic P
positive, large association between fasting glucose and group (n=36) group (n=57)
24-h LMR, regardless of diabetic status, with Pearson’s Mean age (years) 56±14.1 52±14.6 0.21
r = 0.596 (P <0.001; Figure 4). Gender 0.343
The correlations between fasting glucose level and mean Male 21 (58%) 28 (49%)
24-h LMR of diabetic group and non-diabetic group were Female 15 (42%) 29 (51%)
also separately analyzed in this study. These two factors Fasting glucose (mg/dL) 136±37.7 96±8.2 <0.001
were correlated with a medium strength of association Time interval between 17±39.9 21±32,6 0.184
in the diabetic group (Pearson’s r = 0.397; P = 0.016) MIBG imaging and fasting
(Figure 5). A strong correlation between fasting glucose glucose determination (day)
level and mean 24-h LMR was detected in the non-diabetic Note: Data of quantitative variables are expressed as mean±SD, where
group, with Pearson’s r = 0.579 (P < 0.001) (Figure 5). data of categorical variables are expressed as count (percentage).
Abbreviation: MIBG: Metaiodobenzylguanidine.
4. Discussion
A neuroendocrine tumor (NET) is a rare tumor that can MIBG has been shown to be able to locate and treat
develop in many different organs of the body. It is formed NET. 17,18 It can be labeled with radioactive iodine nuclides,
from cells that release hormones into the blood in response such as I-131 and I-123. Figures 6-8 show I-123 MIBG
to a signal from the nervous system. Some examples of WBSs of three representative cases recruited in this
NET are carcinoid tumors, islet cell tumors, medullary study. All NETs share a set of similarities, in terms of the
thyroid cancer, pheochromocytomas, Merkel cell cancer, neuroendocrine secretory granules stored by the tumors,
and small-cell lung cancer. 15,16 amine precursor uptake mechanism, and biogenic amine

Volume 2 Issue 1 (2024) 3 https://doi.org/10.36922/arnm.2506