Annals of Nuclear Medicine (v.24, #4)

Minimally invasive radioguided parathyroidectomy for hyperparathyroidism by Yoshifumi Ikeda; Junichi Takayama; Hiroshi Takami (233-240).
Clinical or subclinical hyperparathyroidism (HPT) is one of the most common endocrine disorders. In patients with HPT who meet the indications for parathyroidectomy, complete surgical resection of all hyperfunctioning parathyroid tissue is essential for the curative treatment. The conventional surgical approach is bilateral neck exploration, whereas minimally invasive parathyroidectomy has been made possible by the introduction of 99mTc-sestamibi scintigraphy for preoperative localization of parathyroid adenomas. In minimally invasive surgery, the surgeon expects some modalities that predict complete resection of all hyperfunctioning parathyroid glands. The prevalence rate of 99mTc-sestamibi scanning for single parathyroid adenoma was widely accepted as 85–95%. Moreover, the recent developing technology of semiconductor electronics has produced useful portable γ-probes. Intraoperative navigation using these devices provides the possibility of easy and definitive identification of parathyroid nodules during the operation. In minimally invasive radioguided parathyroidectomy using γ-probe, different protocols are based on different timing and doses of tracer injected. Each procedure is technically easy, safe, with a low morbidity rate, and has better cosmetic results and lower overall cost than conventional bilateral neck exploration. We have applied this technique in selected patients and achieved success comparable to that achieved with contemporaneously performed standard neck exploration. In the hands of a competent surgeon, the use of sestamibi scanning and radioguided parathyroidectomy in appropriately selected patients is a useful technique.
Keywords: Hyperparathyroidism; Radioguided surgery; Parathyroidectomy; Minimally invasive surgery

18F-fluoride uptake in bone metastasis: morphologic and metabolic analysis on integrated PET/CT by Masashi Kawaguchi; Ukihide Tateishi; Kazuya Shizukuishi; Akiko Suzuki; Tomio Inoue (241-247).
The aim of our study was to evaluate detectability of bone metastatic lesions and evaluate the correlation between 18F-fluoride uptake patterns on positron emission tomography (PET) and morphologic changes on CT using integrated PET/CT.We performed whole-body 18F-fluoride PET/CT staging for 27 patients with known cancer. Tumor types comprised breast (n = 7), prostate (n = 7), and others (n = 13). A total of 154 uptake lesions were evaluated. Both tracer uptake patterns determined by 18F-fluoride PET and morphologic patterns based on CT findings such as morphologic changes, involved locations, and grades scored using five-point scale were compared with histologic tumor subtypes and clinical laboratory data.CT patterns of metastatic lesion were lytic or unclassified in 26 lesions, sclerotic in 53 lesions, and mixed in 75 lesions. Multiple linear regression analysis revealed that metastatic bone lesions with high maximum standardized uptake value (SUVmax) tended to show sclerotic or mixed changes on CT (P < 0.0001), and were also distributed in bone cortex alone or both bone cortex and medulla (P < 0.0001).In patients with bone metastasis, the lesions with sclerotic or mixed changes or located in bone cortex alone or both bone cortex and medulla tend to show high SUVmax on 18F-fluoride PET/CT.
Keywords: 18F-fluoride; PET; PET/CT; Bone metastasis; Skeletal imaging

Quantitative analysis of dopamine transporters in human brain using [11C]PE2I and positron emission tomography: evaluation of reference tissue models by Chie Seki; Hiroshi Ito; Tetsuya Ichimiya; Ryosuke Arakawa; Yoko Ikoma; Miho Shidahara; Jun Maeda; Akihiro Takano; Hidehiko Takahashi; Yuichi Kimura; Kazutoshi Suzuki; Iwao Kanno; Tetsuya Suhara (249-260).
Dopamine transporter (DAT) is a reuptake carrier of dopamine at presynapse that regulates dopaminergic neural transmission. [11C]PE2I is a cocaine analog developed as a potent positron emission tomography (PET) ligand for DAT with high selectivity. The aim of this study was to evaluate the applicability of quantification methods using reference tissue models for [11C]PE2I.Dynamic PET scans were performed in 6 young healthy male volunteers after an intravenous bolus injection of [11C]PE2I. Metabolite-corrected arterial plasma-input functions were obtained. Compartment model analysis and plasma-input Logan analysis were performed to determine the kinetic parameters and distribution volume (V T). The distribution volume ratio (DVR) was calculated as the ratio of V T in the cerebral region to that in the cerebellum. DVRs were also determined by the original multilinear reference tissue model method (MRTMo) and the simplified reference tissue model method (SRTM), comparing the results with those obtained from graphical analysis using arterial input function. To estimate errors in DVR calculated using the reference tissue model, a simulation study that focused on cerebellar kinetics and scan duration was performed.The highest [11C]PE2I binding was observed in the striatum, followed by the midbrain and thalamus. The 2-tissue model was preferable to the 1-tissue model for describing the [11C]PE2I kinetics in the cerebellum. Both the measured and 90-min simulated data showed that reference tissue models caused an underestimation of DVR in the striatum. The simulation showed that 90-min scan duration was insufficient when cerebellar kinetics was described as a 1-tissue model. Nevertheless, DVR values determined by MRTMo and SRTM were in good agreement with those by the graphical approach in other lower binding regions.Due to the [11C]PE2I kinetics in the cerebellum and limited scan duration for 11C, MRTMo and SRTM underestimated the striatal DVR. Despite this limitation, the present study demonstrated the applicability of reference tissue models. Since DAT in the midbrain and thalamus is of interest in the pathophysiology of neuropsychiatric disease, this noninvasive quantitative analysis will be useful for clinical investigations.
Keywords: [11C]PE2I; Human; Kinetic modeling; Positron emission tomography (PET); Reference tissue model

Evaluation of the risk of radiation exposure from new 18FDG PET/CT plans versus conventional X-ray plans in patients with pediatric cancers by Takeshi Murano; Ukihide Tateishi; Takeshi Iinuma; Naoki Shimada; Hiromitsu Daisaki; Takashi Terauchi; Noriyuki Moriyama; Tomio Inoue (261-267).
Unnecessary radiological examination should be avoided, particularly for children, who are more vulnerable to radiation than adults. Replacement of X-ray examination with 18F-fluoro-2-deoxy-d-glucose (18FDG) positron emission tomography/computed tomography (PET/CT) is a potential option for reduction of radiation exposure, and thus improvement in the quality of life (QOL) of patients. Therefore, this study aimed to evaluate new plans integrating 18FDG PET/CT versus current conventional imaging (CI) plans for patients with pediatric cancers. The effects of radiation exposure from the two kinds of plans were compared using shortening of the average life expectancy as an index, and the related findings and effects of radiation exposure are discussed.Effective radiation doses from CT scanning were calculated using the ImPACT CT Patient Dosimetry Calculator software. Radiation doses in different organs and tissues from radiopharmaceuticals were obtained from the International Commission on Radiological Protection (ICRP) publication 80. Shortening of average life expectancy was calculated using software in which the linear non-threshold model (LNT) by the ICRP was adopted.In current CI plans, the mean effective dose was 168.8 mSv (range 50.5–513.4 mSv) for males and 127 mSv (range 54–239.7 mSv) for females. The mean shortening of average life expectancy was 177 days (range 53.3–542 days) for males and 185 days (range 80.4–371 days) for females. In new plans, the mean effective dose was 64.1 mSv (range 54.1–84.5 mSv) for males and 68.2 mSv (range 58.1–88.0 mSv) for females. The mean shortening of life expectancy was 67.6 days (range 57.1–89.2 days) for males and 102.5 days (range 86.8–132.6 days) for females.New 18FDG PET/CT plans may relieve the patient’s physical burden and contribute to improvement of the patient’s QOL. These plans may also reduce medical costs because the number of examinations to be performed is reduced. Although deterministic effects are not observed in the CI plan, careful attention should be paid to other potential effects. Because the effective dose resulting from this plan is over 100 mSv, at which stochastic effects are known to occur, radiation-induced cancers may be expected.
Keywords: FDG; PET/CT; Radiation exposure; Risk; Shortening of life expectancy

Lung ventilation–perfusion imbalance in pulmonary emphysema: assessment with automated V/Q quotient SPECT by Kazuyoshi Suga; Yasuhiko Kawakami; Hiroaki Koike; Hideyuki Iwanaga; Osamu Tokuda; Munemasa Okada; Naofumi Matsunaga (269-277).
Tc-99m-Technegas–MAA single photon emission computed tomography (SPECT)-derived ventilation (V)/perfusion (Q) quotient SPECT was used to assess lung V–Q imbalance in patients with pulmonary emphysema.V/Q quotient SPECT and V/Q profile were automatically built in 38 patients with pulmonary emphysema and 12 controls, and V/Q distribution and V/Q profile parameters were compared. V/Q distribution on V/Q quotient SPECT was correlated with low attenuation areas (LAA) on density-mask computed tomography (CT). Parameters of V/Q profile such as the median, standard deviation (SD), kurtosis and skewness were proposed to objectively evaluate the severity of lung V–Q imbalance.In contrast to uniform V/Q distribution on V/Q quotient SPECT and a sharp peak with symmetrical V/Q distribution on V/Q profile in controls, lung areas showing heterogeneously high or low V/Q and flattened peaks with broadened V/Q distribution were frequently seen in patients with emphysema, including lung areas with only slight LAA. V/Q distribution was also often asymmetric regardless of symmetric LAA. All the proposed parameters of V/Q profile in entire lungs of patients with emphysema showed large variations compared with controls; SD and kurtosis were significantly different from controls (P < 0.0001 and P < 0.001, respectively), and a significant correlation was found between SD and A-aDO2 (P < 0.0001).V/Q quotient SPECT appears to be more sensitive to detect emphysematous lungs compared with morphologic CT in patients with emphysema. SD and kurtosis of V/Q profile can be adequate parameters to assess the severity of lung V–Q imbalance causing gas-exchange impairment in patients with emphysema.
Keywords: Single photon emission computed tomography (SPECT); Pulmonary perfusion; Pulmonary ventilation; Ventilation–perfusion imbalance; Pulmonary emphysema

Tumor grade-related thallium-201 uptake in chondrosarcomas by G. Capa Kaya; Y. Demir; S. Ozkal; T. Sengoz; M. Manisalı; O. Baran; M. Koc; B. Tuna; D. Ozaksoy; H. Havıtcıoglu (279-286).
Diagnosis of low-grade chondrosarcoma, especially discrimination between enchondroma and low-grade chondrosarcoma, may be difficult pathologically. The aim of this study was to evaluate the value of thallium-201 (Tl-201) scintigraphy in the diagnosis of chondrosarcoma and to investigate whether there was a correlation between Tl-201 uptake and tumor grade.We retrospectively evaluated 121 patients with pathologically proven bone and soft tissue tumors diagnosed between the years 1999 and 2007. All patients were followed by the Bone and Soft Tissue Tumor Working Group in our hospital. Twenty-three patients, mean age 44 ± 15 (range 17–72) years, with a diagnosis of cartilaginous tumors were included. Increased Tl-201 uptake at the lesion sites greater than background was evaluated as malignant tumor. For the pathologic classification, a grading system (grade 1–3) based on the histopathologic findings was used. Pearson correlation coefficient was used to determine whether there was any correlation between Tl-201 uptake and tumor grade in chondrosarcoma.There were 7 enchondromas and 16 chondrosarcomas. Four of 16 patients with chondrosarcoma had lesions pathologically classified as grade 3, 5 as grade 2, and 7 had grade 1 chondrosarcoma. Increased Tl-201 uptake was observed in all patients with grade 3 chondrosarcoma and 2 patients with grade 2 chondrosarcoma. Of 10 patients with chondrosarcoma, 3 grade 2 chondrosarcomas and 7 grade 1 chondrosarcomas, there was no Tl-201 uptake in the tumor region. A significant correlation was found between Tl-201 uptake and tumor grade in chondrosarcoma (p = 0.002, r = 0.71). Only a few reports in literature have demonstrated false negative results in low-grade chondrosarcoma.Tl-201 uptake was related to tumor grade in chondrosarcoma. If there is a possibility of chondrosarcoma, Tl-201 scintigraphy should be reported with caution.
Keywords: Tl-201; Chondrosarcoma; Tumor grade

What can be identified by three-phase bone scintigraphy in patients with chronic osteomyelitis of the mandible? by Nobuyoshi Fukumitsu; Kiyoto Ujigawa; Yutaka Mori; Kenkichi Auchi; Kazuo Miida; Satoshi Tatsuno; Morio Tonogi; Yutaka Aoyagi; Gen-yuki Yamane (287-293).
Three-phase bone scintigraphy has been used for the diagnosis of osteomyelitis in some regions of the body. However, its utility in patients with chronic osteomyelitis of the mandible (COM) has been reported only occasionally and the significance has not been fully examined. The aim of this study was to investigate what can be identified from each phase of the three-phase bone scintigraphy in patients with COM.Three-phase bone scintigraphy using 99mTc-labeled phosphonates was performed [96 s (phase 1), 5 min (phase 2) and 3 h (phase 3)] in 15 patients with COM. An increase in accumulation was regarded as a positive result in visual analysis. We investigated the positive ratio of each phase, including in the classification of the disease type, serum white blood cell count, C-reactive protein value and morbidity period. We also calculated the uptake ratio relative to the contralateral side using mean and maximum counts of the region of interest in semiquantitative analysis and investigated the correlation between the uptake ratios of each phase.The positive ratio of phases 2 and 3 was 100% and higher than that of phase 1 (33.3%, p = 0.0001). Almost all patients with a positive result in phase 1 had the osteolytic type (5/6). The extent of increased uptake on phase 3 images was similar to that of phase 2 images. The uptake ratio of phase 2 correlated with that of phase 3 (mean: r = 0.88, p < 0.0001, max: r = 0.78, p = 0.0006), but was not as high as that of phase 3.The phase 1 results reflect hyperemia and have a strong potential to diagnose the disease type. Phase 3 alone is sufficient to diagnose the disease and the extent of lesion in patients with highly suspected COM.
Keywords: Three-phase bone scintigraphy; Chronic osteomyelitis; Mandible; Uptake ratio

Fully automated 3D basal ganglia activity measurement in dopamine transporter scintigraphy (Spectalyzer) by Siroos Mirzaei; Rasoul Zakavi; Margarida Rodrigues; Thomas Schwarzgruber; Thomas Brücke; Jiri Bakala; Katalin Borbély; Norbert Leners; Peter Knoll; Rene Donner (295-300).
Semiquantitative evaluation of tracer uptake in basal ganglia is superior to visual assessment of images in dopamine transporter (DAT) scintigraphy especially in follow-up of the patients. Manual drawing of regions of interest (ROIs) in two-dimensional (2D) transaxial slices of the single photon emission computed tomography (SPECT) datasets leads to a large inter- and intra-reader variability, while being time consuming. Our aim was to investigate a technique that extracts 3D ROIs in a fully automated fashion and thus might provide reproducible user-independent results allowing better follow-up control and large-scale clinical studies.The highest activity of 123IFP-CIT is expected in the basal ganglia. The proposed method (Spectalyzer) uses the following steps to localize this maximum and extract the ROIs in 3D: (1) Dithers the SPECT volume to obtain a 3D volume with binary only. (2) Models the obtained point distributions as two multivariate Gaussian distributions and estimated their parameters using the expectation maximization algorithm. (3) Using the original SPECT activity values, thresholding is performed using a fixed percentage of maximum activity as a parameter to obtain the 3D ROIs. (4) A reference volume in the occipital region is automatically found based on the location of the two ROIs. (5) From the 3D ROIs, statistical information like mean and median activity and the volume is extracted, relative to the activity in the reference region. The resulting values are compared with values from manual 2D ROIs. Further validation is performed by means of an anthropomorphic striatal phantom.The method was evaluated on 12 SPECT volumes including anthropomorphic striatal phantoms. In all cases the two basal-ganglia were successfully localized and the 3D ROIs estimated, with perfect reproducibility. The obtained values for the mean activity showed the same trend with the values obtained manually and also with the results of the 2D semiautomatic software, but without the substantial inter- and intra-reader variations.The proposed method is successful in finding the 3D ROIs and performing the subsequent measurements automatically. It is proposed as an automatic reproducible approach for semiquantitative analysis of DAT scintigraphy.
Keywords: Dopamine transporter scintigraphy; Semiquantification; 3D ROI

Basic performance and stability of a CdTe solid-state detector panel by Katsutoshi Tsuchiya; Isao Takahashi; Tsuneaki Kawaguchi; Kazuma Yokoi; Yuuichi Morimoto; Takafumi Ishitsu; Atsurou Suzuki; Yuuichirou Ueno; Keiji Kobashi (301-311).
We have developed a prototype gamma camera system (R1-M) using a cadmium telluride (CdTe) detector panel and evaluated the basic performance and the spectral stability.The CdTe panel consists of 5-mm-thick crystals. The field of view is 134 × 268 mm comprising 18,432 pixels with a pixel pitch of 1.4 mm. Replaceable small CdTe modules are mounted on to the circuit board by dedicated zero insertion force connectors. To make the readout circuit compact, the matrix read out is processed by dedicated ASICs. The panel is equipped with a cold-air cooling system. The temperature and humidity in the panel were kept at 20°C and below 70% relative humidity. CdTe polarization was suppressed by the bias refresh technique to stabilize the detector. We also produced three dedicated square pixel-matched collimators: LEGP (20 mm-thick), LEHR (27 mm-thick), and LEUHR (35 mm-thick). We evaluated their basic performance (energy resolution, system resolution, and sensitivity) and the spectral stability in terms of short-term (several hours of continuous acquisition) and long-term (infrequent measurements over more than a year) activity.The intrinsic energy resolution (FWHM) acquired with Tc-99m (140.5 keV) was 6.6%. The spatial resolutions (FWHM at a distance of 100 mm) with LEGP, LEHR, and LEUHR collimators were 5.7, 4.9, and 4.2 mm, and the sensitivities were 71, 39, and 23 cps/MBq, respectively. The energy peak position and the intrinsic energy resolution after several hours of operation were nearly the same as the values a few minutes after the system was powered on; the variation of the peak position was <0.2%, and that of the resolution was about 0.3%. Infrequent measurements conducted over a year showed that the variations of the energy peak position and the intrinsic energy resolution of the system were at a similar level to those described above.The basic performance of the CdTe-gamma camera system was evaluated, and its stability was verified. It was shown that the camera could be operated daily for several months without calibration.
Keywords: Cadmium telluride; Gamma camera; Architecture; High resolution; Stability

Hypertrophic osteoarthropathy manifested with isolated calcaneal periostitis in bone scintigraphy by Efstratios Moralidis; Georgios Gerasimou; Athina Theodoridou; Ilias Hilidis; Efrosyni Mylonaki; Anna Gotzamani-Psarrakou (313-317).
Hypertrophic osteoarthropathy (HOA) is an incompletely understood syndrome characterized by digital clubbing and periosteal proliferation of long bones and it is commonly associated with primary lung tumors. Bone scintigraphy is a sensitive method in detecting HOA and characteristic findings have been reported. We present the case of a man with newly diagnosed non-small cell lung cancer, unremarkable clinical examination and blood tests and no digital clubbing. During disease staging, however, bone scintigraphy showed intense calcaneal cortical proliferation bilaterally without involvement of other parts of the skeleton. Cortical reaction of both calcanei resolved significantly after chemotherapy. This case indicates that HOA may manifest with isolated calcaneal periostitis bilaterally, which is a new addition to the literature.
Keywords: Hypertrophic osteoarthropathy; Lung cancer; Calcaneal periostitis; Bone scintigraphy

Questionnaire survey of hospitals in Saitama Prefecture regarding the shortage of 99mTc-labeled radiopharmaceuticals and 99Mo/99mTc generators by Shigeru Kosuda; Hiroko Tomita; Katsumi Hayashi; Tamotsu Kita; Katsumi Koike; Takashi Arai (319-323).
A questionnaire survey was conducted at all 32 hospitals in Saitama Prefecture to investigate the current difficult situation in terms of nuclear medicine management in the face of the 99mTc shortage due to insufficient supply, and 29 hospitals (90.6%) replied.Of the 29, 15 (51.7%) reported a reduction in the number of nuclear medicine studies performed due to the shortage of supply, although the reduction was small. The decrease per month was less than 20 studies in 73% of the institutions. Of the nuclear medicine studies that involve the use of 99mTc, the studies whose reduction in number most seriously affected patient management were, in decreasing order: 99mTc-MAA lung perfusion scans, 99mTc-MAG3, 99mTc-DTPA, or 99mTc-DMSA renoscans, 99mTc-MDP bone scans, 99mTc-HMPAO or ECD brain SPECT studies, 99mTc-MIBI or tetrofosmin myocardial SPECT studies, 99mTc-radiocolloid sentinel lymphoscintigraphy, 99mTc-HSA-D or pyrophosphate bleeding scans, 99mTc-GSA hepatic function reserve scans, and 99mTc-MIBI parathyroid scans. The reduction is probably ascribable to factors such as cancellations of emergency studies, absence of substitute studies, sequential studies using the same radiopharmaceutical, and higher cost of the syringe-type products than the vial-type products. Substitutes for 99mTc studies were performed at 52% (15/29) of the institutions. Myocardial perfusion imaging with 201Tl chloride was the most common substitute study.The results of this survey suggested the several procedures to resolve the issues related to the shortage. The staffs at all institutions except one gave the impression that their nuclear medicine ordering systems had been greatly affected by the shortage of supply. This adverse circumstance, however, may provide a good opportunity to educate the public about nuclear medicine studies that use 99mTc and SPECT, with which citizen are now unfamiliar.
Keywords: Questionnaire survey; 99mTc-labeled radiopharmaceutical; 99Mo/99mTc generator; Reactor

Japanese guideline for the oncology FDG-PET/CT data acquisition protocol: synopsis of Version 1.0 by Hiroyoshi Fukukita; Michio Senda; Takashi Terauchi; Kazufumi Suzuki; Hiromitsu Daisaki; Keiichi Matsumoto; Yasuhiko Ikari; Masuo Hayashi (325-334).
This synopsis outlines the Japanese guideline Version 1.0 for the data acquisition protocol of oncology FDG-PET/CT scans that was created by a joint task force of the Japanese Society of Nuclear Medicine Technology (JSNMT) and the Japanese Council of PET Imaging, and published in Kakuigaku-Gijutsu 29(2):195–235, 2009, in Japanese. The guideline aims at standardizing the PET image quality among facilities and different PET/CT scanner models by determining and/or evaluating the data acquisition condition in experiments using an IEC body phantom, as well as by proposing the criteria for human image quality evaluation using patient noise equivalent count (NEC), NEC density, and liver signal-to-noise ratio.
Keywords: Guideline; FDG-PET; Oncology; NEC; QC