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Annals of Nuclear Medicine (v.23, #2)

Detection of ectopic gastric mucosa using ^99mTc pertechnetate: review of the literature by Pinar O. Kiratli; Tamer Aksoy; Murat F. Bozkurt; Diclehan Orhan (pp. 97-105).

Technetium-99m (^99mTc) pertechnetate scintigraphy in a child with acute gastrointestinal bleeding of unknown origin suggests ectopic gastric mucosa caused by Meckel’s diverticulum or gastrointestinal duplication cysts. Our objective was to define the patterns of scintigraphic findings likely to be encountered in patients with ectopic gastric mucosa with illustrative cases and to review the literature. Fifty children (age 1 year to 14 years) were evaluated for ectopic gastric mucosa using ^99mTc pertechnetate scintigraphy. Functioning ectopic gastric mucosa was detected in eight patients with Meckel’s diverticula and three patients with bowel duplication. Three patients showed atypical findings on scintigraphy which were perforated appendix, calyceal stasis, and regional enteritis. Ectopic functioning gastric mucosa in Meckel’s diverticulum is visualized simultaneously with the stomach, whereas in intestinal duplications tracer activity can be visualized in the dynamic sequence or before gastric tracer visualization in an irregular pattern. A variety of scintigraphic patterns can be found in patients with ectopic gastric mucosa undergoing ^99mTc pertechnetate scintigraphy depending on the location and size of the ectopic tissue. Also, acquisition of delayed images is useful when the initial images are equivocal in children.

Keywords: Ectopic gastric mucosa; Radionuclide imaging; Meckel’s diverticulum; Pediatrics; Intestinal duplication

Benign ovarian and endometrial uptake on FDG PET-CT: patterns and pitfalls by Yiyan Liu (pp. 107-112).

Increased ovarian or endometrial uptake may cause a dilemma in the interpretation of whole body F18-fluorodeoxyglucose-positron emission tomography (FDG-PET) imaging or even misdiagnosis of malignant disease. Knowledge of benign FDG uptake of the ovaries and uterus is important for daily practice of nuclear medicine radiologists. Increased uptake in the ovaries or uterus indicates a pathologic or neoplastic process in postmenopausal patients. In premenopausal women, increased ovarian or endometrial uptake can be functional or malignant. Benign functional uptake of premenopausal ovaries or uterus is related to the menstrual cycle; therefore, information about the patient’s menstrual status is crucial for interpretation. In addition, correlation with computed tomography (CT), especially diagnostic CT acquired at the same time of PET/CT is very useful in clarifying the location of the uptake and the existence or disappearance of the discrete lesion. Increased ovarian uptake may also be identified in histologically different benign tumor entities. Nonmenstrual-related endometrial uptake may be present in many benign diseases as well.

Keywords: FDG-PET; Ovaries; Endometrium; Menstrual cycle

An experimental study on the antitumor effect of ¹³¹I-17-AAG in vitro and in vivo by Tu Wenyong; Liu Lu; Chen Daozhen; Yin Weidong; Huang Ying (pp. 113-122).

To observe the antitumor effect of ¹³¹I-17-allylamino-17-demethoxygeldanamycin (¹³¹I-17-AAG) in vitro/in vivo and explore its antitumor mechanism with a view to its potential therapeutic application. ¹³¹I-17-AAG was prepared by the reaction of 17-AAG with Na [¹³¹I] in the presence of hydrogen peroxide. The effects of ¹³¹17-AAG on cell growth inhibition and cell cycle distribution in vitro were studied in BEL-7402 cells lines. Following BEL-7402 tumor implantation by subcutaneous xenografts into nude mice, the reagents were injected through the tail vein, and the tumor volume was measured and analyzed. At the end of the experiment, tumor specimens were processed for histopathological analysis. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) was used to investigate apoptosis. The expression change of Akt2 was tested by Western-blot analysis.Methyl-thiazolyl-tetrazolium assay showed inhibition rates of 27.7 ± 5.3%, 57.3 ± 4.3%, and 63.7 ± 3.1%, in Na¹³¹I group, 17-AAG group, and ¹³¹I-17-AAG group, respectively. The inhibition rate in the ¹³¹I-17-AAG group differed significantly between N^a131I group and 17-AAG group (F = 229.49, P < 0.001). Following 48 h of treatment with the drug in each group, flow cytometry analysis indicated that detected sub-G peaks (black) were 1.54 ± 0.13%, 5.72 ± 1.05%, 12.97 ± 1.44%, and 20.65 ± 1.36%, in dimethyl sulfoxide (DMSO) group, Na¹³¹I group, 17-AAG group, and ¹³¹I-17-AAG group, respectively. Following infusion for 32 days, the tumor volumes in the ¹³¹I-17-AAG group were significantly smaller than those in the DMSO group (F = 24.18, P < 0.001) or the ¹³¹I group (F = 20.68, P < 0.001). Histopathological and TUNEL analyses showed that ¹³¹I-17-AAG inhibited the proliferation of tumor cells and induced apoptosis. The expression of Akt2 in ¹³¹I-17-AAG was significantly lower than that in the DMSO group or ¹³¹I group. ¹³¹I-17-AAG can effectively inhibit the growth of BEL-7402 tumor cells in vitro and in vivo. ¹³¹I-17-AAG is a promising agent for the treatment of BEL-7402 cell tumor.

Keywords: 17-Allylamino-17-demethoxygeldanamycin; ¹³¹I; BEL-7402 cell lines; Akt2; Cell apoptosis

Technetium-99m-GSA clearance in mice under long-term dietary restriction by Katsuyasu Kouda; Hirao Kohno; Harunobu Nakamura; Sang K. Ha-Kawa; Yoshiaki Sonoda; Masayuki Iki (pp. 123-129).

Dietary restriction (DR) without malnutrition is widely acknowledged to prolong lifespan in laboratory animals. Evidence suggests that DR retards age-related decline in protein turnover of most organs. However, there has been no report about hepatic serum glycoprotein catabolism under DR. In the current study, we evaluate the hepatic uptake of asialoglycoprotein in ICR mice with DR by measuring the plasma clearance of technetium-99m galactosyl human serum albumin (Tc-GSA).The amount of food supplied to the restricted mice was 70% of that consumed by the mice fed ad libitum (AL). The regimen was initiated at the age of 7 weeks and terminated after the age of 44 weeks. The plasma clearance of Tc-GSA was measured at the age of 7 weeks, 14 weeks, 28 weeks, and 42 weeks.The restricted animals showed a marked decrease in their body and liver weight, and hepatic uptake of Tc-GSA per liver weight in the restricted mice was greater than that in the mice fed AL. On the other hand, the Tc-GSA plasma clearance in the mice fed AL was stable during the study period, and that in the restricted mice showed no change with age either, and those in the two groups were similar. In addition to the receptor function, there was no difference in the expression of mRNAs of the asialoglycoprotein receptor between the two groups. Serum concentrations of cholinesterase and hepatic mRNAs of glutamine synthetase in the restricted mice were higher than those in the mice fed AL. Serum levels of amino acids in the restricted mice were lower than those in the mice fed AL.The data presented here show that the DR did not affect the capacity of hepatic serum glycoprotein catabolism, whereas several protein metabolic pathways were affected.

Keywords: Diet; Liver function test; Blood proteins

Influence of thyroid-stimulating hormone on ¹⁸F-fluorodeoxyglucose and ^99mTc-methoxyisobutylisonitrile uptake in human poorly differentiated thyroid cancer cells in vitro by Chung Ho Kim; Ie Ryung Yoo; Yong An Chung; Young Ha Park; Sung Hoon Kim; Hyung Sun Sohn; Soo Kyo Chung (pp. 131-136).

In poorly differentiated thyroid cancer originating from thyroid follicular cells, the ability to concentrate iodine is lost. This makes recurrence undetectable by ¹³¹I whole-body scan. In this situation, other radiopharmaceuticals, such as ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) and technetium-99m-methoxyisobutylisonitrile (^99mTc-MIBI), are used to evaluate recurrence or metastasis. Some reports suggest that ¹⁸F-FDG uptake is increased by thyroid-stimulating hormone (TSH) stimulation. This study aimed to determine the influence of TSH on ¹⁸F-FDG and ^99mTc-MIBI uptake in human poorly differentiated thyroid cancer cells in vitro.The cells were stimulated with 1000 μU/ml of recombinant human thyroid-stimulating hormone (rhTSH) for 1 day, 3 days, and 5 days. Each cell was incubated with 0.5 MBq/ml-1 MBq/ml of ¹⁸F-FDG or 0.5 MBq/ml-1 MBq/ml of ^99mTc-MIBI for 1 h at 37°C. The uptake of each radiopharmaceutical in the cells was quantified as a percent of whole radioactivity per total viable cell number. The quantification of glucose transporter 1, 2, 3 and 4 mRNA expression was measured using RT-PCR.TSH stimulation increased ¹⁸F-FDG uptake in a time-dependent manner. Following 5 days of rhTSH stimulation, ¹⁸F-FDG uptake was approximately 2.2 times that of the control. The increase in ¹⁸F-FDG uptake following rhTSH stimulation was correlated to the increase in GLUT4 mRNA level. The GLUT1 mRNA level was unchanged. An increased uptake of ^99mTc-MIBI was observed with a pattern similar to that of ¹⁸F-FDG. The ^99mTc-MIBI uptake was approximately 1.5 times that of the control 5 days later.These results suggest that TSH stimulates ¹⁸F-FDG and ^99mTc-MIBI uptake in poorly differentiated papillary thyroid cancer, and therefore ¹⁸F-FDG-PET or ^99mTc-MIBI scans under TSH stimulation may be more accurate than under suppression.

Keywords: Poorly differentiated thyroid cancer; TSH; ¹⁸F-FDG; ^99mTc-MIBI

Usefulness of fatty meal-stimulated cholescintigraphy in the diagnosis and treatment of chronic acalculous cholecystitis by Kusai Al-Muqbel; Mohammed Bani Hani; Mohammad Daradkeh; Abdullah Rashdan (pp. 137-142).

Fatty meal cholescintigraphy (fatty meal CS) is a potential physiologic alternative for cholecystokinin (CCK) CS in the diagnosis and treatment of chronic acalculous cholecystitis (CAC). However, there are limited data in the literature to support this assumption. Our objective was to determine the usefulness of fatty meal CS in the diagnosis and treatment of CAC.We retrospectively reviewed the medical records of 198 patients who had undergone fatty meal CS for presumed CAC. Data retrieved focused on symptom improvement following management. Gallbladder ejection fraction (GBEF) of 50% or less was considered abnormal. Patients were divided into groups on the basis of test results and management.In group 1a, patients with low GBEF and cholecystectomy, 88% (54 of 61) reported symptom improvement, whereas the remaining 12% (7 of 61) retained their symptoms. Group 1b consisted of patients with low GBEF and who were managed medically. Persistence of symptoms was noted in 76% (32 of 42) of patients, whereas the remaining 24% (10 of 42) had symptom improvement. Group 2 consisted of patients with normal GBEF. Follow-up showed that 60% (47 of 78) of patients had symptom improvement either spontaneously or on medical treatment, whereas the remaining 40% (31 of 78) retained their symptoms.Fatty meal CS is a very useful technique in the diagnosis of CAC. It predicts a good surgical outcome once GBEF is low in patients with high pre-test probability for CAC. Moreover, fatty meal CS may be a good alternative to CCK CS.

Keywords: Fatty meal; Cholescintigraphy; CCK; Chronic acalculous cholecystitis; Gallbladder ejection fraction

Role of NMDA receptor upon [¹⁴C]acetate uptake into intact rat brain by Shinichiro Hirose; Sotaro Momosaki; Rie Hosoi; Kohji Abe; Antony Gee; Osamu Inoue (pp. 143-147).

To clarify the role of N-methyl-d-aspartate (NMDA) receptors upon [¹⁴C]acetate uptake in the rodent central nervous system (CNS), ibotenic acid (IBO) was infused into the right striatum of the rat brain.Autoradiograms of [¹⁴C]acetate uptake in the brain for 2 h following the infusion of IBO (10 μg/μl) were obtained in both non-treated and MK-801 (1 mg/kg, i.v.) pretreated rats. The effect of MK-801 on [¹⁴C]acetate uptake in the normal rat brain was also studied.Infusion of IBO significantly decreased [¹⁴C]acetate uptake in the infused side of the striatum. The expression of monocarboxylate transporter-1 was not altered, suggesting that the activity of tricarboxylic acid (TCA) cycle in glial cells might be depressed. Pretreatment with MK-801 completely blocked the decreasing effect of IBO on [¹⁴C]acetate uptake. MK-801 also increased [¹⁴C]acetate uptake in the whole brain of normal rats.These results indicate the important roles of NMDA receptors on [¹⁴C]acetate uptake in the intact rat brain.

Keywords: Glia; [¹⁴C]acetate; MK-801; Ibotenic acid; Rat

Biodistribution of immunoliposome labeled with Tc-99m in tumor xenografted mice by Naoto Kitamura; Naoyuki Shigematsu; Tadaki Nakahara; Momoe Kanoh; Jun Hashimoto; Etsuo Kunieda; Atsushi Kubo (pp. 149-153).

Immunoliposome (PEG, GAH, liposome; PGL), consisting of F(ab′)₂ fragment of monoclonal antibody, GAH and polyethyleneglycol-coated (PEGylated) liposome was provided. Immunoliposome, PGL was labeled with technetium-99m (Tc-99m) by two methods: labeling F(ab′)₂ fragment with Tc-99m; Tc-99m-PGL, and entrapping Tc-99m into liposome; PGL[Tc-99m]. The objective of this study was to compare the biodistribution of Tc-99m-PGL and PGL[Tc-99m] in human gastric cancer xenografted mice.Tc-99m-PGL, PGL[Tc-99m], and Tc-99m-entrapped liposome; Lipo[Tc-99m] were prepared. They were injected into human gastric cancer, MKN45, xenografted mice via the tail vein, and their biodistribution was studied.No marked accumulation of either PGL[Tc-99m] or Lipo[Tc-99m] was observed in the stomach. The uptake of Tc-99m-PGL by the liver, spleen, and lung was higher than that by the tumor. On the other hand, the uptake of PGL[Tc-99m] by the lung and spleen was markedly lower as compared with that of Tc-99m-PGL; the accumulation of PGL[Tc-99m] was lower in the lung and higher in the spleen as compared with that of the tumor. Although the liver uptake of PGL[Tc-99m] was markedly decreased as compared with that of Tc-99m-PGL, it was higher than the uptake of the tumor. The Tc-99m-PGL was strongly taken up by the tumor, with a high level of incorporation also seen in the stomach. These findings suggest the need for further study of the labeling stability.PGL[Tc-99m] appears to show promise for high tumor uptake and retention. This is an important implication for the potential application of immunoliposomes entrapped with Re-186, instead of Tc-99m, in internal radiotherapy.

Keywords: Biodistribution; Immunoliposome; Tc-99m

Comparative study of FDG PET/CT and conventional imaging in the staging of rhabdomyosarcoma by Ukihide Tateishi; Ako Hosono; Atsushi Makimoto; Yuki Nakamoto; Tomohiro Kaneta; Hiroshi Fukuda; Koji Murakami; Takashi Terauchi; Tsuyoshi Suga; Tomio Inoue; Edmund E. Kim (pp. 155-161).

The current study was conducted to compare the diagnostic accuracy between ¹⁸F-fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET)/computed tomography (CT), and conventional imaging (CI) for the staging and re-staging of patients with rhabdomyosarcomas.Thirty-five patients who underwent FDG PET/CT prior to treatment were evaluated retrospectively. CI methods consisted of ^99mTc-hydroxymethylene diphosphonate bone scintigraphy, chest radiograph, whole body CT, and magnetic resonance imaging of the primary site. The images were reviewed and two boardcertified radiologists reached a diagnostic consensus. Tumor stage was confirmed by histological examination and/or follow-up examinations.Interpretation on the basis of FDG PET/CT, and CI, diagnostic accuracies of the T and N stages were similar. Using FDG PET/CT, the M stage was correctly assigned in 31 patients (89%), whereas the accuracy of CI in M stage was 63%. TNM stage was correctly assessed with FDG PET/CT in 30 of 35 patients (86%) and with CI in 19 of 35 patients (54%). The overall TNM staging and M staging accuracies of FDG PET/CT were significantly higher than that of CI (P < 0.01).FDG PET/CT is more accurate than CI regarding clinical staging and re-staging of patients with rhabdomyosarcomas.

Keywords: FDG PET/CT; Rhabdomyosarcoma; Stage

Improvement of likelihood estimation in Logan graphical analysis using maximum a posteriori for neuroreceptor PET imaging by Miho Shidahara; Chie Seki; Mika Naganawa; Muneyuki Sakata; Masatomo Ishikawa; Hiroshi Ito; Iwao Kanno; Kiichi Ishiwata; Yuichi Kimura (pp. 163-171).

To reduce variance of the total volume of distribution (V _T) image, we improved likelihood estimation in graphical analysis (LEGA) for dynamic positron emission tomography (PET) images using maximum a posteriori (MAP).In our proposed MAP estimation in graphical analysis (MEGA), a set of time-activity curves (TACs) was formed with V _T varying in physiological range as a template, and then the most similar TAC was sought out for a given measured TAC in a feature space. In simulation, MEGA was compared with other three methods, Logan graphical analysis (GA), multilinear analysis (MA1), and LEGA using 500 noisy TACs, under each of seven physiological conditions (from 9.9 to 61.5 of V _T). PET studies of [¹¹C]SA4503 were performed in three healthy volunteers. In clinical studies, the V _T images estimated from MEGA were compared with region of interest (ROI) estimates from a nonlinear least square (NLS) fitting over four brain regions.In the simulation study, the estimated V _T by GA had a large underestimation (y = 0.27x + 8.72, r ² = 0.87). Applying the other methods (MA1, LEGA, and MEGA), these noise-induced biases were improved (y = 0.80x + 4.04, r ² = 0.98; y = 0.85x + 3.05, r ² = 0.99; y = 0.96x + 1.21, r ² = 0.99, respectively). MA1 and LEGA produced increased variance of the estimated V _T in clinical studies. However, MEGA improved signal-to-noise ratio (SNR) in V _T images with linear correlations between ROI estimates with NLS (y = 0.87x + 5.1, r ² = 0.96).MEGA was validated as an alternative strategy of LEGA to improve estimates of V _T in clinical PET imaging.

Keywords: Positron emission tomography; MAP-based estimation algorithm in graphical analysis; Logan graphical analysis; Kinetic analysis

Gated myocardial perfusion SPECT for preoperative risk stratification in patients with noncardiac vascular disease by Daiki Kayano; Kenichi Nakajima; Hiroshi Ohtake; Seigo Kinuya (pp. 173-181).

Myocardial perfusion single photon emission computed tomography (SPECT) is useful for preoperative cardiac risk stratification. We investigated the value of preoperative pharmacologic stress electrocardiographic (ECG)-gated myocardial perfusion SPECT for noncardiac vascular surgery.To assess the perioperative cardiac risk for noncardiac vascular surgery, preoperative pharmacologic stress ECG-gated myocardial perfusion SPECT was performed in 211 consecutive patients who underwent noncardiac aortic surgery. We examined myocardial perfusion and left ventricular function by the quantitative gated SPECT (QGS), and the correlation with perioperative cardiac events was investigated.Perioperative cardiac events occurred in 9 of 211 patients (4.3%). On the basis of univariate analysis, significant predictors for preoperative cardiac risk stratification included history of heart failure (P < 0.05), history of coronary artery revascularization (P < 0.05), summed stress score (SSS) (P < 0.0001), summed rest score (SRS) (P < 0.005), SSS ≥ 7 (P < 0.005), end-diastolic volume (EDV) ≥ mean + 2 standard deviation (SD) (134 ml for men and 93 ml for women) (P < 0.005), end-systolic volume (ESV) ≥ mean + 2 SD (60 ml for men and 37 ml for women) (p < 0.0001), left ventricular ejection fraction (EF) ≤ mean − 2 SD (48% for men and 55% for women) (P < 0.005) and wall motion abnormality (P < 0.05). On the basis of multivariate analysis, ESV ≥ mean + 2 SD was the only independent predictor for perioperative cardiac events (P < 0.005).Pharmacologic stress ECG-gated myocardial perfusion SPECT, which permits assessment of both myocardial perfusion and cardiac function, is useful for preoperative risk stratification of noncardiac vascular surgery.

Keywords: Gated myocardial perfusion SPECT; Noncardiac vascular surgery; Preoperative risk stratification; Cardiac event

Preliminary study on potential of the jPET-D4 human brain scanner for small animal imaging by Taiga Yamaya; Eiji Yoshida; Chie Toramatsu; Mayumi Nishimura; Yoshiya Shimada; Naoko Inadama; Kengo Shibuya; Fumihiko Nishikido; Hideo Murayama (pp. 183-190).

One trend in positron emission tomography (PET) instrumentation over the last decade has been the development of scanners dedicated to small animals such as rats and mice. Thicker crystals, which are necessary to obtain higher sensitivity, result in degraded spatial resolution in the peripheral field-of-view (FOV) owing to the parallax error. On the other hand, we are developing the jPET-D4, which is a dedicated human brain PET scanner that has a capability for depth-of-interaction (DOI) measurement. Although its crystal width is about twice that of commercially available small animal PET scanners, we expect the jPET-D4 to have a potential for small animal imaging by making full use of the DOI information. In this article, we investigate the jPET-D4’s potential for small animal imaging by comparing it with the microPET Focus220, a state-of-the-art PET scanner dedicated to small animals.The jPET-D4 uses four-layered GSO crystals measuring 2.9 mm × 2.9 mm × 7.5 mm, whereas the microPET Focus220 uses a single layer of LSO crystals measuring 1.5 mm × 1.5 mm × 10.0 mm. First, the absolute sensitivity, counting rate performance and spatial resolution of both scanners were measured. Next a small hot-rod phantom was used to compare their imaging performance. Finally, a rat model with breast tumors was imaged using the jPET-D4.Thanks to the thicker crystals and the longer axial FOV, the jPET-D4 had more than four times higher sensitivity than the microPET Focus220. The noise equivalent counting-rate performance of the jPETD4 reached 1,024 kcps for a rat-size phantom, whereas that of the microPET Focus220 reached only 165 kcps. At the center of the FOV, the resolution was 1.7 mm for the microPET Focus220, whereas it was 3.2 mm for the jPET-D4. On the other hand, the difference of resolution became smaller at the off-center position because the radial resolution degraded faster for the microPET Focus220. The results of phantom imaging showed that the jPET-D4 was comparable to the microPET Focus220 at the off-center position even as the microPET Focus220 outperformed the jPET-D4 except for the peripheral FOV.The jPET-D4 human brain PET scanner, which was designed to achieve not only high resolution but also high sensitivity by measuring DOI information, was proven to have a potential for small animal imaging.

Keywords: PET; Image reconstruction; Depth-of-interaction; DOI; Small animal

The effect of ¹⁸F-FDG-PET/CT respiratory gating on detected metabolic activity in lung lesions by Andrea Lupi; Marta Zaroccolo; Matteo Salgarello; Veronica Malfatti; Pierluigi Zanco (pp. 191-196).

Respiratory gated PET/CT (positron emission tomography/computed tomography) of the lung is expected to increase the accuracy of quantitative determinations in lesional activities, regardless of the gating method used; reasonably, respiratory gating should increase standard uptake value (SUV; and possibly decrease lesional size), on the basis of the reduction of the “smearing effect.” However, literature data are very limited, particularly for in vivo studies. The objective of this article is to test the SUV variations in a large group of lung lesion studies.A group of 26 consecutive positive studies (21 men, 5 women, age 36-84, mean 68), performed on patients referred to our institution for known or suspected lung cancer, are examined. All studies were performed both with conventional PET/CT total body scan and with Real-Time Position Management (RPM) triggered selective gated study of the thorax. Four studies were considered technically unsatisfactory and were discarded; the remaining 22 studies are the object of this work. Max lesional SUVs were evaluated in both settings by semi-automated algorithms; for the gated studies, both values of the bin that showed more relevant variations from the clinical routinary study (“best bin”) and an average value that was calculated over all bins were determined. Results were compared on a one-to-one basis.In conventional, SUV showed a mean ± standard deviation (SD) value of 9.2 ± 6.9 (range 0.9–26). In the averaged gated studies, the mean ± SD value was 13.4 ± 11.7 (range 1.4–47); in the “best bin” dataset the mean ± SD was 14.9 ± 12.9, ranging from 1.6 to 53.1. In general, the use of respiratory trigger induced rather variable but overall consistent increases in SUV. If the percentage variations in the average trigger dataset are considered, there is an average increase of +60%, SD ± 97 (P < 0.05). Similar results are found in the “best bin” dataset, the average percentage increase in SUV values being +77.2% (SD ± 04.6).In lung cancer, triggering procedures increase the signal to noise ratio. The increase in SUV determined by gating is very variable, but generally relevant. This could lead to an SUV values cut-off revision, and may have an impact on smaller lesions detection.

Keywords: Lung cancer; ¹⁸F-FDG-PET; Respiratory trigger; Standard uptake value

Combined rest redistribution thallium-201 SPECT and low-dose dobutamine contractility assessment in a simple and practical new viability protocol by Sherif I. Heiba; Gennie Yee; Hussein M. Abdel-Dayem; Irini Youssef; John Coppola (pp. 197-203).

Rest-redistribution (RR) thallium-201 (Tl-201) imaging is commonly used for myocardial viability evaluation. Contractile reserve (CR) assessment with low-dose dobutamine (LDD) is another method that highly predicts functional recovery following revascularization. In this study, we investigate the feasibility of a new protocol that provides combined Tl-201 uptake, resting and CR functional regional myocardial information in a single examination.A total of 41 patients underwent RR-gated-SPECT Tl-201 myocardial perfusion imaging. The LDD infusion was maintained during delayed imaging. Segmental Tl-201 uptake was classified into normal, fixed decrease (mild to absent) and reversible, and sub-classified by wall motion (WM)/thickening (WT) changes between early resting and delayed LDD gated images into normal, fixed or improved dysfunctional (CR present) segments.Out of 820 examined segments, 33 showed no appreciable Tl-201 uptake to evaluate WM/WT. In a dysfunctional myocardium, CR was significantly higher (P < 0.001) in reversible and fixed than in normal Tl-201 segments. The CR in dysfunctional segments with fixed decrease Tl-201 uptake was significantly higher (P < 0.05) in mild and moderate than in severe fixed defects. Both fixed Tl-201 defects and lack of CR were observed more (P < 0.05) in akinetic/dyskinetic than in hypokinetic segments.Simultaneous assessment of myocardial viability by RR Tl-201 uptake, resting and CR functional regional information is feasible and can be easily attained using this new protocol. Moreover, this protocol requires no additional time or radioactivity when compared with the usual RR Tl-201 protocol. Validation of this protocol with patients’ revascularization data is needed.

Keywords: Rest redistribution myocardial perfusion; Thallium-201 SPECT; Low dose dobutamine

Tc-99m-MIBI scintigraphy in evaluating the effect of hepatocyte growth factor gene therapy for peripheral arteriosclerosis obliterans by Takuji Yamagami; Keiichi Kanda; Chio Okuyama; Tsunehiko Nishimura (pp. 205-208).

We report an 81-year-old man with arteriosclerosis obliterans with sharp rest pain of the left lower leg below the knee that was resistant to conventional drug therapy. Gene therapy using hepatocyte growth factor (HGF) was performed, following which the symptoms remarkably improved. Magnetic resonance (MR) angiography did not detect any development of collateral vessels following gene therapy; however, technetium-99m-methoxyisobutylisonitrile (Tc-99m)-MIBI scintigraphy revealed the development of micro-circulation in the lower leg following HGF gene therapy. This is the first report on the usefulness of Tc-99m-MIBI scintigraphy to evaluate the effectiveness of HGF gene therapy for peripheral arteriosclerosis obliterans.

Keywords: Angiogenesis; Gene therapy; Limb ischemia; Scintigraphy

Nuclear medicine practice in Japan: a report of the sixth nationwide survey in 2007 by Yasuo Kuwabara; Kiyoshi Koizumi; Yo Ushijima; Seigo Kinuya; Shigeo Kinomura; Kazuyoshi Suga; Hiroko Takeoka; Tohru Takeda; Hiroshi Toyama; Yasuo Arao; Yoshihiro Nishiyama; Kouji Murakami; Koichi Morita (pp. 209-215).

The Subcommittee on the Survey of Nuclear Medicine Practice in Japan has performed a nationwide survey of nuclear medicine practice every 5 years since 1982 to provide detailed information on its present status.Questionnaires were sent to all institutions known to the Japan Radioisotope Association to conduct nuclear medicine examinations. The questionnaires addressed the number and kind of nuclear medicine examinations performed as well as the kind and dose of the radiopharmaceuticals used during the month of June 2007. The annual number of total or specific examinations was then estimated.Of the institutions sent questionnaires, 1219 were for in vivo study, 49 for in vitro study, and 212 for positron emission tomography (PET) study. Of these, 92.2% provided answers. A total of 1569 gamma cameras were installed in 1119 institutions, of which 70% were dual-head cameras. The estimated total annual number of in vivo examinations expressed by the number of administered radiopharmaceuticals was 1.41 million, representing a decrease of 11.5% when compared with that of the previous survey (2002). The frequency of study with respect to single-photon emission computed tomography (SPECT) slightly increased to 42.3% from 39.9% in the previous survey. The most frequently performed scintigraphy was bone (38.3%), followed by myocardium (26.2%) and brain perfusion (14.1%). Brain perfusion scintigraphy slightly increased, whereas tumor scintigraphy decreased by one-half when compared with the previous survey. The most commonly used radiopharmaceutical for each scintigraphy was ^99mTc-HMDP for bone, thallium-201 (²⁰¹Tl)-chloride for myocardium, gallium-67 (⁶⁷Ga)-citrate for tumor, and technetium-99m-ethylcysteinate dimmer (^99mTc-ECD) for brain. The number of PET institutes increased from 36 to 212. ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG)-PET dramatically increased 14.8-fold during the past 5 years. Radionuclide therapy also increased. ¹³¹I therapy for thyroid cancer and hyperthyroidism was conducted yearly in 2373 and 4146 patients, respectively. A total of 13.1 million in vitro radioassays were carried out yearly, the number of which has been decreasing continuously since 1992.It was proved that the content of nuclear medicine practice in Japan has changed considerably in the past 5 years. Namely, ¹⁸F-FDG-PET and radionuclide therapy increased. This report might be useful for understanding the present trends of nuclear medicine practice in Japan.

Keywords: In vivo examination; In vitro examination; Radionuclide therapy; PET; Nuclear medicine practice

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Annals of Nuclear Medicine (v.23, #2)