• The Korean Journal of Nuclear Medicine
• /
• v.39 no.6
• /
• pp.481-488
• /
• 2005

Purpose: Functional imaging of dopamine transporter (DAT) defines integrity of the dopaminergic system, and DAT is the target site of drugs of abuse such as cocaine and methamphetamine. Functional imaging the DAT may be a sensitive and selective indicator of neurotoxic change by the drug. The aim of the present study is to evaluate the clinical implications of qualitative/quantitative analyses of dopamine transporter imaging in methamphetamine abusers. Materials and Methods: Six detoxified methamphetamine abusers (abuser group) and 4 volunteers (control group) were enrolled in this study. Brain MRI was performed in all of abuser group. Abuser group underwent psychiatric and depression assessment using brief psychiatric rating scale (BPRS) and Hamilton depression rating scale (HAMD), respectively. All of the subjects underwent I-123 IPT SPECT (IPT SPECT). IPT SPECT image was analysed with visual qualitative method and quantitative method using basal ganglia dopamine transporter (DAT) specific/non-specific binding ratio (SBR). Comparison of DAT SBR between abuser and control groups was performed. We also performed correlation tests between psychiatric and depression assessment results and DAT SBR in abuser group. Results: All of abuser group showed normal MRI finding, but had residual psychiatric and depressive symptoms, and psychiatric and depressive symptom scores were exactly correlated (r=1.0, p=0.005) each other. Five of them showed abnormal finding on qualitative visual I-123 IPT SPECT Abuser group had lower basal ganglia DAT SBR than that of control ($2.38{\pm}0.20\;vs\;3.04{\pm}0.27$, p=0.000). Psychiatric and depressive symptoms were negatively well correlated with basal ganglia DAT SBR (r=-0.908, p=0.012, r=-0.924, p=0.009). Conclusion: These results suggest that dopamine transporter imaging using I-123 IPT SPECT may be used to evaluate dopaminergic system of the basal ganglia and the clinical status in methamphetamine abusers.

• 대한핵의학회:학술대회논문집
• /
• 1996.05a
• /
• pp.212-212
• /
• 1996

• The Korean Journal of Nuclear Medicine
• /
• v.31 no.1
• /
• pp.19-29
• /
• 1997

Recently, [I-123]IPT SPECT has been used for early diagnosis of Parkinson's patients(PP) by imaging dopamine transporters. The dynamic time activity curves in basal ganglia(BG) and occipital cortex(OCC) without blood samples were obtained for 2 hours. These data were then used to measure dopamine transporters by operationally defined ratio methods of (BG-OCC)/OCC at 2 hrs, binding potential $R_v=k_3/k_4$ using graphic method or $R_A$= (ABBG-ABOCC)/ABOCC for 2 hrs, where ABBG represents accumulated binding activity in basal ganglia(${\int}^{120min}_0$ BG(t)dt) and ABOCC represents accumulated binding activity in occipital cortex(${\int}^{120min}_0$ OCC(t)dt). The purpose of this study was to examine the IPT pharmacokinetics and investigate the usefulness of simplified methods of (BG-OCC)/OCC, $R_A$, and $R_v$ which are often assumed that these values reflect the true values of $k_3/k_4$. The rate constants $K_1,\;k_2\;k_3$ and $k_4$ to be used for simulations were derived using [I-123]IPT SPECT and aterialized blood data with a standard three compartmental model. The sensitivities and time activity curves in BG and OCC were computed by changing $K_l$ and $k_3$(only BG) for every 5min over 2 hours. The values (BG-OCC)/OCC, $R_A$, and $R_v$ were then computed from the time activity curves and the linear regression analysis was used to measure the accuracies of these methods. The late constants $K_l,\;k_2\;k_3\;k_4$ at BG and OCC were $1.26{\pm}5.41%,\;0.044{\pm}19.58%,\;0.031{\pm}24.36%,\;0.008{\pm}22.78%$ and $1.36{\pm}4.76%,\;0.170{\pm}6.89%,\;0.007{\pm}23.89%,\;0.007{\pm}45.09%$, respectively. The Sensitivities for ((${\Delta}S/S$)/(${\Delta}k_3/k_3$)) and ((${\Delta}S/S$)/(${\Delta}K_l/K_l$)) at 30min and 120min were measured as (0.19, 0.50) and (0.61, 0,23), respectively. The correlation coefficients and slopes of ((BG-OCC)/OCC, $R_A$, and $R_v$) with $k_3/k_4$ were (0.98, 1.00, 0.99) and (1.76, 0.47, 1.25), respectively. These simulation results indicate that a late [I-123]IPT SPECT image may represent the distribution of the dopamine transporters. Good correlations were shown between (3G-OCC)/OCC, $R_A$ or $R_v$ and true $k_3/k_4$, although the slopes between them were not unity. Pharmacokinetic computer simulations may be a very useful technique in studying dopamine transporter systems.

• 대한핵의학회:학술대회논문집
• /
• 2002.11a
• /
• pp.24.2-24.2
• /
• 2002

• 대한핵의학회:학술대회논문집
• /
• 2003.11a
• /
• pp.25.2-25.2
• /
• 2003

• 대한핵의학회:학술대회논문집
• /
• 1995.05a
• /
• pp.222-222
• /
• 1995

• 대한핵의학회:학술대회논문집
• /
• 1996.05a
• /
• pp.179-179
• /
• 1996

• Proceedings of the KOSOMBE Conference
• /
• v.1996 no.05
• /
• pp.45-48
• /
• 1996

In the case of $^{123}I$ from the $^{124}Te$ (p,2n)reaction, the radionuclidic impurity is the high-energy gamma-emitting $^{124}I$, which interferes greatly with nuclear medicine images. The choice of a collimator can affect the quality of clinical SPECT images of [I-123]MIBG or [I-123]TPT. The tradeoffs that two different collimators make among spatial resolution, sensitivity, and scatter were studied by imaging a line source at 5cm, 10cm, 15cm distance using a number of plexiglass sheets between source and collimator, petri dist two-dimensional Hoffman brain phantom, and Jaszczak phantom after filling with $^{123}I$ (FWHM, FWTM, Sensitivity) for low energy ultra high resolution parallel hole(LEUHRP) collimator and medium energy general purpose (MEGP) collimator were measured as (9.27mm, 61.27mm $129CPM/[\mu}$ Ci) and (10.53m 23.17mm $105CPM/{\mu}$ Ci), respectively. The image quality of two-dimensional Hoffman brain Phantom with LEUHRP looked better than the one with MEGP. However, the image quality of Jasgczak phantom with LEUHRP looked much worse than the one with MEGP, The results suggest that the MEGP is preferable to LEUHRP for SPECT studies of [I-123]MIBG or [I-123]IPT.

• 대한핵의학회:학술대회논문집
• /
• 2003.11a
• /
• pp.26.1-26.1
• /
• 2003

• 대한핵의학회:학술대회논문집
• /
• 1997.05a
• /
• pp.146-146
• /
• 1997