Annals of Nuclear Medicine (v.25, #8)

Radionuclides of rare earth elements are gaining importance as emerging therapeutic agents in nuclear medicine. β -particle emitter 142Pr [T 1/2 = 19.12 h, E β  = 2.162 MeV (96.3%), Eγ = 1575 keV (3.7%)] is one of the praseodymium-141 (100% abundant) radioisotopes. Production routes and therapy aspects of 142Pr will be reviewed in this paper. However, 142Pr produces via 141Pr(n, γ)142Pr reaction by irradiation in a low-fluence reactor; 142Pr cyclotron produced, could be achievable. 142Pr due to its high β -emission and low specific gamma γ-emission could not only be a therapeutic radionuclide, but also a suitable radionuclide in order for biodistribution studies. Internal radiotherapy using 142Pr can be classified into two sub-categories: (1) unsealed source therapy (UST), (2) brachytherapy. UST via 142Pr-HA and 142Pr-DTPA in order for radiosynovectomy have been proposed. In addition, 142Pr Glass seeds and 142Pr microspheres have been utilized for interstitial brachytherapy of prostate cancer and intraarterial brachytherapy of arteriovenous malformation, respectively.
Keywords: Brachytherapy; Internal radiotherapy; Praseodymium-142; Radionuclide production; Unsealed source therapy

HIV infection results in profound alterations of immunologic function that render the patient severely immunocompromised, and susceptible to malignancies and opportunistic infections. Three AIDS-defining malignancies include Kaposi’s sarcoma (KS), non-Hodgkin’s lymphoma (NHL) and invasive cervical cancer. In AIDS patients, KS is often aggressive and multifocal, with visceral involvement and widespread cutaneous and nodal spread; NHL is always high grade and often widely disseminated at the time of diagnosis with frequent involvement of extranodal sites; cervical cancer is invasive and has greater likelihood of progression and metastasis. Although there are very sparse systemic data available in the literature, limited studies has shown that FDG PET-CT is a valuable imaging technique in the diagnosis, staging, restaging and monitoring therapeutic response in these malignancies. In addition, a unique application of FDG PET/CT is the differentiation of cerebral lesions between lymphoma and toxoplasmosis in AIDS patients, which cannot be reliably achieved with either CT or MRI. HIV-associated opportunistic infections may involve different pathogens and multiple tissues, organs or systems. Some preliminary observations have revealed a promising role of FDG PET-CT in the diagnosis and identification of these infections such as tuberculosis, fever of unknown origin, pneumocystis pneumonia and candidiasis. However, it should be stressed that FDG PET-CT alone has no role in identifying the pathology of abnormalities. FDG PET-CT, at best, can localize the sites of abnormalities and impact on patient’s management in clinical decision making.
Keywords: Human immunodeficiency virus (HIV); Acquired immunodeficiency syndrome (AIDS); Positron emission tomography/computed tomography (PET-CT); Kaposi’s sarcoma (KS); Non-Hodgkin’s lymphoma (NHL); Opportunistic infection

18F-FDG uptake in primary lung cancer as a predictor of intratumoral vessel invasion by Tetsuya Ishibashi; Mitsuhito Kaji; Tatsuya Kato; Keidai Ishikawa; Masatoshi Kadoya; Nagara Tamaki (547-553).
This study investigated how fluorodeoxyglucose (FDG) uptake on PET in the primary tumor may predict intratumoral vessel invasion (IVI) in it.A total of 512 patients with lung neoplasms determined by a surgical procedure and histopathological diagnosis had undergone FDG-PET scanning.Among the 440 cases confirmed to be malignant, the maximum standardized uptake value (SUVmax) was significantly lower in IVI-negative cases than IVI-positive cases (P < 0.001). In the substudy on adenocarcinoma (AC), SUVmax was significantly lower in IVI-negative cases too (P < 0.001), but SUVmax in squamous cell carcinoma was without significant difference. In addition, IVI was associated with a significantly higher probability of lymph node metastasis (P < 0.001).This study indicates that a malignant lung tumor with higher SUVmax has a significantly higher probability of IVI and lymph node metastasis, particularly if the malignancy is an AC.
Keywords: PET; Fluorodeoxyglucose (FDG); Lung cancer; Intratumoral vessel invasion

Chronic inhalant use is associated with significant toxic effects, including neurological, renal, hepatic, and pulmonary damage. However, there is a paucity of reports regarding respiratory complications in inhalant abusers. The aim of this study was to evaluate pulmonary epithelial permeability in the volatile substance abuse (VSA) using Tc-99m DTPA aerosol scintigraphy.This study included 18 patients with volatile substance abuse and 18 volunteer controls. All of patients and controls were smokers. Tc-99m DTPA aerosol scintigraphy was performed in all cases. Time-activity curves from each lung were generated and clearance half-time (T 1/2) of Tc-99m DTPA were calculated. T 1/2 of whole lung was calculated as a mean of the T 1/2 of left and right lung.The T 1/2 values of Tc-99m DTPA clearance in the substance abusers were significantly decreased as compared to the control group with respective mean values of 28.86 ± 8.44, and 62.14 ± 26.12 min (p = 0.001). It was seen Tc-99m DTPA clearance from lung was faster as the duration of substance abuse was increased.Tc-99m DTPA pulmonary clearance is markedly accelerated in the volatile substance abuse. This suggests that inhalant abuse of substance may produce abnormalities in pulmonary alveolo-capillary membrane function.
Keywords: Volatile substance abuse; Inhalant abuse; Tc-99m DTPA; Pulmonary epithelial permeability; Clearance half-time (T 1/2)

Accelerated BMIPP uptake immediately after reperfused ischemia in the isolated rat heart model by Kenji Fukushima; Mitsuru Momose; Chisato Kondo; Nobuhisa Hagiwara; Shuji Sakai (560-565).
123I-beta-methyl iodophenyl pentadecanoic acid (BMIPP) can visualize myocardial fatty acid metabolism and has extensive potential for diagnosing cardiac diseases such as acute coronary syndrome in the clinical setting. Increased BMIPP uptake with decreased perfusion occasionally occurs under acute reperfusion ischemia and the kinetics of BMIPP remain unclear. The present study uses the isolated rat heart model to measure kinetic changes in BMIPP under acute reperfusion ischemia.Male Wistar rats were allotted to normal control (NG), mild (MG) and severe (SG) ischemia groups. The hearts were perfused according to the Langendorff method at a constant flow rate, and BMIPP wash-in and wash-out were studied. No-flow ischemia was applied for 15 and 30 min to the MG and SG groups, followed immediately by the wash-in and wash-out study. Whole heart radioactivity was determined using an external gamma detector throughout the experiment. Rates of myocardial uptake (K 1, mL/min) and clearance (k 2, min−1) were generated using a compartmental model analysis. The same procedures and protocols were performed using 99mTc-sestamibi (MIBI) as a perfusion study.Perfusion pressure significantly increased and mean heart rate significantly decreased in the severe ischemia group (heart rate: 244 ± 76, 304 ± 105 and 94 ± 140 bpm; perfusion pressure: 67 ± 13, 101 ± 31 and 160 ± 84 mmHg for NG, MG and SG, respectively). MIBI-K 1 significantly decreased, whereas BMIPP-K 1 increased in the MG and SG groups (MIBI-K 1: 3.45 ± 1.10, 1.95 ± 0.82, and 1.05 ± 0.13 mL/min; BMIPP-K 1: 3.06 ± 0.88, 3.91 ± 0.87, and 4.94 ± 1.51 mL/min for NG, MG and SG, respectively) with an inverse relationship to the severity of ischemia. MIBI-k 2 increased markedly in severe ischemia (NG vs. MG: p < 0.05), whereas BMIPP-k 2 did not change in the ischemic groups (MIBI-k 2: 0.00072 ± 0.0011, 0.00038 ± 0.00076 and 0.043 ± 0.033; BMIPP-k 2: 0.0056 ± 0.0028, 0.0029 ± 0.0010 and 0.0037 ± 0.0022 min−1 for NG, MG and SG, respectively).Myocardial BMIPP uptake increased immediately upon reperfusion after no-flow ischemia, and was inversely related to the severity of ischemia. The increased uptake was not due to reduced clearance, but to accelerated extraction.
Keywords: Fatty acid metabolism; I-123 BMIPP; Isolated rat heart; Myocardial ischemia; SPECT

Transient ischemic dilatation (TID) of LV cavity during stress gated myocardial perfusion imaging (GMPI) is known as a predictor of severe CAD and signifies worse prognosis.To assess predictive and prognostic value of TID of LV cavity using GMPI and clinical outcome in patients treated conservatively or with revascularization.189 patients out of 2689 were recruited (M:F 127/62, mean age 56 ± 9 years) whose same-day stress GMPI revealed TID ratio (>1.22) with no (sum stress score, SSS < 2) or reversible perfusion defects (sum difference score, SDS > 2). Coronary angiography (CA) was performed within 3 months in 125/189 cases who were followed for mean period of 18 ± 4 months for fatal or non-fatal MI.CA was positive in 121/125 patients with TID for significant CAD (LAD = 11, multi vessel disease = 110 patients, positive predictive value 95%) and negative for obstructive disease in 4/125 (false-positive cases). 41/121 underwent revascularization within 2 months of CA (Intervention group), and remaining 80/121 were managed conservatively (Non-Intervention group). Overall event rate was 20% (4/16%: fatal/non-fatal MIs). Kaplan–Meier survival curves revealed event-free survival in Intervention and Non-Intervention groups for fatal MI 98/96% (P = 0.758), and for non-fatal MI, it was 97/58%, respectively (P = 0.042).We conclude that TID is a reliable predictor of multi vessel CAD and is associated with high incidence of non-fatal MIs than fatal MIs. Revascularization (PCI/CABG) rather than medical treatment should be considered in patients with TID for better clinical outcome.
Keywords: TID; Positive predictive value; Gated SPECT; Clinical outcome

Quantification of myocardial perfusion SPECT using freeware package (cardioBull) by Koichi Okuda; Kenichi Nakajima; Tetsuo Hosoya; Takehiro Ishikawa; Shinro Matsuo; Masaya Kawano; Junichi Taki; Seigo Kinuya (571-579).
We have developed freeware package for automatically quantifying myocardial perfusion and 123I-labeled radiopharmaceutical single-photon emission computed tomography (SPECT), which is called “cardioBull”. We aim to evaluate diagnostic performance of the detection of coronary artery disease (CAD) on the developed software in comparison with commercially available software package [Quantitative Perfusion SPECT (QPS)].Stress-rest 99mTc-sestamibi myocardial perfusion SPECT was performed in 36 patients with CAD and 35 control patients. A ≥75% stenosis in the coronary artery was identified by coronary angiography in the CAD group. Segmental perfusion defect score was automatically calculated by both cardioBull and QPS software. Summed stress score (SSS) was obtained to detect CAD by the receiver operator characteristic (ROC) analysis. Areas under the ROC curves (AUC) were calculated in patient-based and coronary-based analyses.Mean SSSs showed no significant difference between cardioBull and QPS (6.0 ± 7.1 vs. 5.6 ± 7.0). The AUC for cardioBull was equivalent to that for QPS (0.91 ± 0.04 vs. 0.87 ± 0.04, p = n.s.). Sensitivity, specificity, and accuracy for cardioBull were 89, 74, and 82%, respectively. For the regional detection of CAD, the AUC showed largest value in left anterior descending coronary artery (LAD) territory (0.86 ± 0.06 for cardioBull, 0.87 ± 0.06 for QPS, p = n.s.). Sensitivity, specificity and accuracy of cardioBull were 70, 88, and 83% for the LAD; 91, 62, and 66% for the left circumflex coronary artery (LCx); and 78, 69, and 70% for the right coronary artery (RCA), respectively.The AUC, sensitivity, specificity and accuracy for the detection of CAD showed high diagnostic performance on the developed software. In addition, the developed software provided comparable diagnostic performance to the commercially available software package.
Keywords: Myocardial perfusion SPECT; Automatic quantification; Coronary artery disease; Image processing

Coronary spasm after completion of adenosine pharmacologic stress test by Ping-Ping Han; Yue-Qin Tian; Hong-Xing Wei; Qi Wang; Zuo-Xiang He (580-585).
Adenosine is a frequently used pharmacologic stress agent in myocardial perfusion imaging. Its safety profile is well established, and most of its side effects are mild and transient. Coronary vasospasm occurs occasionally during or after adenosine stress test in rare cases, which may lead to seriously adverse outcomes. This study reported 3 such cases after completion of adenosine pharmacologic stress test.
Keywords: Coronary spasm; Adenosine; Pharmacologic stress; SPECT

Quantification of [18F]-FDG uptake in atherosclerotic plaque: impact of renal function by Thorsten Derlin; Christian R. Habermann; Jasmin D. Hahne; Ivayla Apostolova; Susanne Klutmann; Janos Mester; Ralph Buchert (586-591).
Impaired renal function causes both increased and prolonged tracer availability in the blood-pool which might result in increased tracer accumulation in atherosclerotic lesions. Therefore, the aim of this study was to investigate a possible correlation between the intensity of tracer uptake in atherosclerotic lesions and renal function.Data from 50 [18F]-FDG scans were visually evaluated for tracer uptake in vessel wall alterations. Lesions were analyzed semiquantitatively by determining the blood-pool standardized uptake values (SUVblood-pools), maximum SUVs (SUVmaxs), and the target-to-background ratio (TBR). These parameters were tested for correlation with estimated glomerular filtration rate (eGFR), and cardiovascular risk factors.Both SUVblood-pools (r s = −0.32, p = 0.03) and SUVmaxs for [18F]-FDG (r s = −0.50, p < 0.0001) showed a significant negative correlation with eGFR. TBRs for [18F]-FDG demonstrated a significant positive correlation with eGFRs (r s = 0.21, p = 0.02).This study found that both intravascular tracer availability (SUVblood-pool) and intralesional tracer uptake (SUVmax) are influenced by renal function. Calculation of TBR to account for that effect may result in overcorrection in case of [18F]-FDG. Renal insufficiency or subclinical changes in renal function have to be considered as a confounding factor in PET of atherosclerotic lesions.
Keywords: SUV; Plaque; Atherosclerosis; Renal function; [18F]-FDG; PET