Annals of Nuclear Medicine (v.29, #1)
68Gallium- and 90Yttrium-/177Lutetium: “theranostic twins” for diagnosis and treatment of NETs by Rudolf A. Werner; Christina Bluemel; Martin S. Allen-Auerbach; Takahiro Higuchi; Ken Herrmann (1-7).
Abundant expression of somatostatin receptors (SSTR) is frequently identified in differentiated neuroendocrine tumors and may serve as potential target for diagnostic imaging and treatment. This article discusses the “theranostic approach” of SSTR-targeting compounds including an overview of its role for diagnosis, staging and restaging, discussing its way to being established in clinical routine, and giving an outlook about further potentially relevant developments.
Keywords: Neuroendocrine tumor; Theranostic; SPECT/CT; PET/CT; PRRT; Radionuclide therapy
Time efficient 124I-PET volumetry in benign thyroid disorders by automatic isocontour procedures: mathematic adjustment using manual contoured measurements in low-dose CT by Martin Freesmeyer; Christian Kühnel; Julian G. Westphal (8-14).
Benign thyroid diseases are widely common in western societies. However, the volumetry of the thyroid gland, especially when enlarged or abnormally formed, proves to be a challenge in clinical routine. The aim of this study was to develop a simple and rapid threshold-based isocontour extraction method for thyroid volumetry from 124I-PET/CT data in patients scheduled for radioactive iodine therapy.PET/CT data from 45 patients were analysed 30 h after 1 MBq 124I administration. Anatomical reference volume was calculated using manually contoured data from low-dose CT images of the neck (MC). In addition, we applied an automatic isocontour extraction method (IC0.2/1.0), with two different threshold values (0.2 and 1.0 kBq/ml), for volumetry of the PET data-set. IC0.2/1.0 shape data that showed significant variation from MC data were excluded. Subsequently, a mathematical correlation using a model of linear regression with multiple variables and step-wise elimination (mIC0.2/1.0), between IC0.2/1.0 and MC, was established.Data from 41 patients (IC0.2), and 32 patients (IC1.0) were analysed. The mathematically calculated volume, mIC, showed a median deviation from the reference (MC), of ±9 % (1–54 %) for mIC0.2 and of ±8.2 % (1–50 %) for mIC1.0 Contour extraction with both, mIC1.0 and mIC0.2 gave rapid and reliable results. However, mIC0.2 can be applied to significantly more patients (>90 %) and is, therefore, deemed to be more suitable for clinical routine, keeping in mind the potential advantages of using 124I-PET/CT for the preparation of patients scheduled for radioactive iodine therapy.
Keywords: 124I-PET; Benign thyroid disorders; Isocontour; Thyroid volumetry; Threshold
Improved spillover correction model to quantify myocardial blood flow by 11C-acetate PET: comparison with 15O-H2O PET by Yuki Mori; Osamu Manabe; Masanao Naya; Yuuki Tomiyama; Keiichiro Yoshinaga; Keiichi Magota; Noriko Oyama-Manabe; Kenji Hirata; Hiroyuki Tsutsui; Nagara Tamaki; Chietsugu Katoh (15-20).
11C-acetate has been applied for evaluation of myocardial oxidative metabolism and can simultaneously estimate myocardial blood flow (MBF). We developed a new method using two-parameter spillover correction to estimate regional MBF (rMBF) with 11C-acetate PET in reference to MBF derived from 15O-H2O PET. The usefulness of our new approach was evaluated compared to the conventional method using one-parameter spillover correction.Sixty-three subjects were examined with 11C-acetate and 15O-H2O dynamic PET at rest. Inflow rate of 11C-acetate (K1) was compared with MBF derived from 15O-H2O PET. For the derivation, the relationship between K1 and MBF from 15O-H2O was linked by the Renkin-Crone model in 20 subjects as a pilot group. One-parameter and two-parameter corrections were applied to suppress the spillover between left ventricular (LV) wall and LV cavity. Validation was set using the other 43 subjects’ data. Finally, rMBFs were calculated using relational expression derived from the pilot-group data.The relationship between K1 and MBF derived from 15O-H2O PET was approximated as K1 = [1–0.764 × exp(−1.001/MBF)] MBF from the pilot data using the two-parameter method. In the validation set, the correlation coefficient between rMBF from 11C-acetate and 15O-H2O demonstrated a significantly higher relationship with the two-parameter spillover correction method than the one-parameter spillover correction method (r = 0.730, 0.592, respectively, p < 0.05).In 11C-acetate PET study, the new two-parameter spillover correction method dedicated more accurate and robust myocardial blood flow than the conventional one-parameter method.
Keywords: 11C-acetate; 15O-H2O; PET; Regional myocardial blood flow; Spillover correction
Comparison of brain perfusion SPECT parameters accuracy for seizure localization in extratemporal lobe epilepsy with discordant pre-surgical data by Supatporn Tepmongkol; Kanokporn Tangtrairattanakul; Sukalaya Lerdlum; Tayard Desudchit (21-28).
Extratemporal lobe epilepsy is difficult to localize. We aimed to define the best parameter(s) of SPECT for confirmation of seizure origin among the region of maximum cerebral perfusion in ictal phase (MP), maximum change of cerebral perfusion from interictal to ictal phase (MC), and maximum extent of hyperperfusion in ictal phase (ME) of 99mTc ECD brain perfusion SPECT as well as combined SPECT parameters, and combined SPECT and MRI for seizure localization in extratemporal lobe epilepsy.Twenty intractable extratemporal lobe epilepsy patients who had 99mTc-ECD brain SPECT were reviewed. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy of single SPECT parameter, combined SPECT parameters, and combined SPECT and MRI parameters for localization of seizure origin were calculated using pathology and surgical outcomes (Engel class I and II) as gold standards.Combined SPECT parameters provided more specificity, PPV and accuracy than single SPECT parameters. The best combined SPECT parameters was MP+MC with 80.6 % accuracy, 92.4 % specificity and 43.8 % PPV. Combination of SPECT parameter with MRI (ME+MRI) was the most sensitive (41.7 %), specific (97.5 %), accurate (88.2 %) parameter and had highest PPV (76.9 %) and NPV (89.3 %) for seizure localization. It improved specificity and PPV when compared to MRI alone.Combined SPECT parameters improved the specificity and accuracy in seizure localization. The most specific and accurate SPECT combination is MP+MC. The combined SPECT parameter with MRI further improved sensitivity, specificity, accuracy, PPV and NPV. The authors recommend using SPECT combination, MP+MC, when MRI is negative and ME+MRI when there is MRI lesion.
Keywords: Seizure origin; Ictal onset zone; Epileptogenic zone; 99mTc-ECD; Neocortical
The preliminary study of 18F-FLT micro-PET/CT in predicting radiosensitivity of human nasopharyngeal carcinoma xenografts by Yujia Zheng; Zhongyi Yang; Yongping Zhang; Qi Shi; Xiao Bao; Jianping Zhang; Huiyu Yuan; Zhifeng Yao; Chaosu Hu; Yingjian Zhang (29-36).
The purpose of the preliminary study was to investigate the value of 18F-FLT micro-PET/CT in predicting radiosensitivity of human nasopharyngeal carcinoma (NPC) xenografts in nude mice models.Twelve BALB/c-nu nude mice were randomly divided into two groups. They were subcutaneously injected with either CNE1 or CNE2 cell suspension. Xenograft volumes were measured after tumor formation. When the tumors reached nearly 10 mm in diameter, they received 15-Gy irradiation. Before and 24 h after irradiation, mice were performed with 18F-FLT micro-PET/CT. The region of interest (ROI) was manually drawn, and the percent of injected dose per gram of the tumor and muscle in the ROIs was recorded. Tumor-to-muscle ratio (T/M) was calculated and compared with volume changes. Additionally, we also used ten untreated mice as control group.After irradiation, CNE2 tumors decreased significantly while CNE1 tumors continuously grew and became stable after 1 week. However, in control group, CNE1 and CNE2 tumors continuously enlarged in the observed time. Therefore, we could regard CNE2 group as irradiation responder while CNE1 group as non-responder. In irradiation group, the value of T/M before irradiation (T/M 0) of CNE1 mice was statistically lower than CNE2 mice (1.62 ± 0.38 versus 5.57 ± 1.30; P = 0.004). Besides, T/M decreased significantly in CNE2 group after irradiation (5.57 ± 1.30 versus 3.59 ± 1.06; P < 0.001). By means of a receiver operating characteristic curve, the optimal cut value of T/M 0 and ∆T/M to predict responder was 2.38 and −0.15, respectively (both sensitivity and specificity = 100.0 %). 18F-FLT PET/CT has the potential to predict radiosensitivity in NPC xenografts nude mice models.
Keywords: Nasopharyngeal carcinoma; Nude mouse; 18F-FLT; Micro-PET/CT; Radiosensitivity
Definitive chemo-radiotherapy for squamous cell carcinoma of the pharynx: impact of baseline low hemoglobin level (<12 g/dL) and post-radiation therapy F-18 FDG-PET/CT by Ryoko Katahira-Suzuki; Masaharu Hata; Ukihide Tateishi; Takahide Taguchi; Shoko Takano; Motoko Omura-Minamisawa; Tomio Inoue (37-45).
To identify reliable predictors of overall survival (OS), locoregional control (LC), and metastasis-free survival (MFS) after definitive concurrent chemo-radiotherapy (CCRT) for squamous cell carcinoma (SCC) of the pharynx (nasopharynx, oropharynx and hypopharynx), we examined 16 potential prognostic factors, including pre-treatment hemoglobin level and pre- and post-treatment [18F]fluorodeoxyglucose positron emission tomography CT (F-18 FDG-PET/CT) maximum standardized up-take values (SUVmax) of primary sites and lymph node (LN) regions.We retrospectively reviewed records of 70 patients treated with definitive CCRT for pharyngeal cancer in our institution during July 2006–April 2012, with particular regard to 16 prognostic factors: age, sex, T stage, N stage, retropharyngeal LN (RPLN) involvement, existence of multiple primary cancer, treatment interruptions, overall treatment time, chemotherapy type, pre-treatment hemoglobin level, pre-treatment body mass index, enteral feeding period, and pre- and post-treatment F-18 FDG-PET/CT SUVmax of primary site and LN region. All patients in our cohort underwent pre- and post-treatment F-18 FDG-PET/CT.Multivariate analysis associated improved OS with pre-treatment hemoglobin level (≥12 g/dL; hazard ratio [HR] 3.902; 95 % confidence interval [CI] 1.244–12.236; P = 0.020) and post-treatment SUVmax (primary site) (SUVmax <5.00; HR 4.237; 95 % CI 1.072–16.747; P = 0.039). Improved LC was associated with pre-treatment hemoglobin level (≥12 g/dL; HR 2.983; 95 % CI 1.123–7.920; P = 0.028), and post treatment SUVmax (primary site) (SUVmax <5.00; HR 5.233; 95 % CI 1.582–17.309; P = 0.007). No variable was found to be significant for improved MFS.Significant predictors for outcome in pharyngeal SCC treated with definitive CCRT were pre-treatment baseline hemoglobin level and post-treatment F-18 FDG-PET/CT SUVmax for primary site. Patients who have hemoglobin level lower than 12 g/dL may tend to have dismal prognosis. Additional treatment should be considered in those who have higher SUVmax at primary site in post-treatment F-18 FDG-PET/CT finding.
Keywords: Pharynx; Chemo-radiotherapy; FDG-PET; SUVmax ; Hemoglobin level
Evaluation of normality and reproducibility parameters of scintigraphy with 99mTc-MAA in the diagnosis of intrapulmonary vascular dilatations by Andréa Simone Siqueira de Queirós; Simone Cristina Soares Brandão; Liana Gonçalves Macedo; Maira Souto Ourem; Vitor Gomes Mota; Luiz Arthur Calheiros Leite; Edmundo Pessoa Almeida Lopes; Ana Lúcia Coutinho Domingues (46-51).
The formation of intrapulmonary vascular dilations (IPVD) is the key event for the onset of hepatopulmonary syndrome, vascular changes secondary to portal hypertension that leads to hypoxemia. The diagnosis of IPVD can be made by contrasted transthoracic echocardiography or scintigraphy with technetium-macroaggregated albumin—(99mTc-MAA)—that is a sensitive and specific diagnostic method and quantifies the IPVD magnitude. However, its procedure and diagnostic indices are not yet standardized and well defined in health services. The aims of this study were to define normality values and evaluate the inter- and intra-observer reproducibility degree of diagnostic indexes of IPVD through 99mTc-MAA scintigraphy.Cross-sectional study was conducted at the Clinical Hospital, Federal University of Pernambuco (HC-UFPE) between July and December 2012. Fifteen patients with hepatosplenic schistosomiasis and nine patients without liver or heart disease (control group) were assessed. After clinical assessment, ultrasound and echocardiography, patients underwent 99mTc-MAA scintigraphy, and a relative brain uptake value exceeding 6 % or systemic uptake value exceeding 11 % was considered diagnostic of IPVD. Each assessment was performed by two independent observers. To analyze the results of the normal group, the nonparametric Bootsptrap method simulation model combined with the Monte Carlo method was used and to analyze inter- and intra-observer reproducibility indexes, the kappa and intra-class correlation coefficient were used.In normal subjects, the average brain uptake of 99mTc-MAA was 7.9 ± 0.01 % and systemic uptake was 12.4 ± 0.03 %, with low dispersal rates for both measures. The intra-observer agreement was 100 %, with kappa index of 1.0 (p < 0.0001), suggesting a perfect agreement. The inter-observer agreement was also 100 % (kappa = 1.0, p < 0.0001) for brain uptake; however, systemic uptake showed kappa = 0.25 (p = 0.07), which features tolerable concordance. The intra-class correlation was excellent for both uptake indexes.The normality values were slightly higher than those reported in studies from other countries. The demographic characteristics of the Brazilian population, the small number of patients or different methodologies can be the causes of such differences. 99mTc-MAA scintigraphy showed excellent reproducibility.
Keywords: 99mTc-MAA scintigraphy; Intrapulmonary vascular dilatation; Normality parameters; Reproducibility
188Re-HYNIC-trastuzumab enhances the effect of apoptosis induced by trastuzumab in HER2-overexpressing breast cancer cells by Tsai-Yueh Luo; Po-Ching Cheng; Ping-Fang Chiang; Ting-Wu Chuang; Chung-Hsin Yeh; Wuu-Jyh Lin (52-62).
The development of radioimmunotherapy has provided an impressive alternative approach in improving trastuzumab therapy. However, the mechanisms of trastuzumab and radiation treatment combined to increase therapeutic efficacy are poorly understood. Here, we try to examine the efficacy of cytotoxicity and apoptosis induction for 188Re-HYNIC-trastuzumab in cancer cell lines with various levels of Her2.Fluorescence flow cytometry was used to detect the alterations of apoptosis induction after 188Re-HYNIC-trastuzumab treatment in two breast cancer cell lines with different levels of HER2 (BT-474 and MCF-7) and a colorectal carcinoma cell line (HT-29) for control.Our results indicated that 188Re-HYNIC-trastuzumab led to cell death of breast cancer cells specifically in HER2 level-dependent and radioactivity dose-dependent fashions. In BT-474 cells, 370 kBq/ml of 188Re-HYNIC-trastuzumab enhanced the cytotoxicity to a level nearly 100-fold that of trastuzumab-alone treatment. The results also revealed that the mitochondria-dependent pathway attenuated irradiation-induced apoptosis in HER2-expressing breast cancer cells after 188Re-HYNIC-trastuzumab treatment. In contrast, only after 48 h of 188Re-HYNIC-trastuzumab treatment, BT-474 cells exhibited typical apoptotic changes, including exposure of phospholipid phosphatidylserine on the cell surface, or fragmented DNA formation, in a radioactivity dose-dependent manner.Briefly, our study demonstrates that 188Re-labeled HYNIC-trastuzumab not only enhances cell death in a radioactivity dose-dependent fashion, but may also prolong the effects of apoptosis involved with the mitochondria-dependent pathway in HER2-overexpressing breast cancer cells. It is possible that the 188Re-HYNIC-trastuzumab treatment induced a second round of apoptosis to prolong the effects of cell kill in these cancer cells. These data revealed that 188Re-HYNIC-trastuzumab has the potential for use as a therapeutic radiopharmaceutical agent in HER2-overexpressing breast cancer cell treatment.
Keywords: 188Re-HYNIC-trastuzumab; Apoptosis; HER2-overexpression; Breast cancer cell line; Radioimmunotherapy
Feasibility and performance of lymphoscintigraphy in sentinel lymph node biopsy for early cervical cancer: results of the prospective multicenter SENTICOL study by Anne-Sophie Bats; Albane Frati; Marc Froissart; Isabelle Orliaguet; Denis Querleu; Slimane Zerdoud; Eric Leblanc; Hélène Gauthier; Catherine Uzan; Désirée Deandreis; Emile Darai; Khaldoun Kerrou; Henri Marret; Emilie Lenain; Patrice Mathevet; Fabrice Lecuru (63-70).
To evaluate feasibility, SLN detection rate, and SLN location of lymphoscintigraphy in sentinel lymph node (SLN) biopsy for early cervical cancer.Ancillary analysis of data from the multicenter prospective SENTICOL study (January 2005–June 2007) of patients with early cervical cancer (FIGO stage IA with emboli to IB1) was conducted. Preoperative lymphoscintigraphy was performed after intracervical administration of 60 or 120 MBq of 99mTc-labeled radiocolloid on the day before (long protocol) or morning of (short protocol) surgery. SLNs were identified intraoperatively using combined radioactivity/patent blue detection. SLNs were sampled electively and routine bilateral pelvic lymphadenectomy was performed by laparoscopy. A centralized review of lymphoscintigraphies was performed to assess feasibility, detection rates, and anatomic SLN location.Of 139 patients included in the SENTICOL study, 133 received radiocolloid injection, and 131 (98.5 %) underwent preoperative lymphoscintigraphy, with the long protocol in three-fourths of cases. The lymphoscintigraphic detection rate was 87.8 %, with a median of 2 (1–4) SLNs per patient. By multivariate analysis, factors independently associated with lymphoscintigraphic SLN detection were age [odds ratio (OR) 0.91, 95 % confidence interval (95 % CI) 0.87–0.96; P < 0.001], and protocol (long vs. short; OR 8.23, 95 % CI 1.87–36.25; P = 0.005). Bilateral SLN identification by lymphoscintigraphy occurred in 67 % of cases and was independently influenced by age (OR 0.95, 95 % CI 0.92–0.98, P < 0.001) and protocol (OR 5.42, 95 % CI 2.21–13.27; P < 0.001). Although 60.5 % of preoperative SLNs were in the external iliac territory, unusual drainage patterns included the common iliac (19.6 %), para-aortic (10.8 %), and parametrial (6 %) basins.Our study demonstrates the feasibility and good detection rate of preoperative lymphoscintigraphy, with better detection in younger patients and with the long protocol. The high proportion of SLN basins in unexpected territories is of interest to guide intraoperative detection. Further studies are needed to better evaluate preoperative detection and to assess the contribution of lymphoscintigraphy to intraoperative detection.
Keywords: Sentinel lymph node; Cervical cancer; Lymphoscintigraphy; Feasibility; Detection
Improvement in PET/CT image quality in overweight patients with PSF and TOF by Takafumi Taniguchi; Go Akamatsu; Yukiko Kasahara; Katsuhiko Mitsumoto; Shingo Baba; Yuji Tsutsui; Kazuhiko Himuro; Shohei Mikasa; Daisuke Kidera; Masayuki Sasaki (71-77).
The aim of this study was to evaluate the effect of the point spread function (PSF) and time of flight (TOF) on PET/CT images of overweight patients in relation to the iteration number and the acquisition time.This study consisted of a phantom study and a clinical study. The NEMA IEC body phantom and a 40 cm diameter large phantom (LG phantom) simulating an overweight patient were used in this study. Both phantoms were filled with 18F solution with a sphere to background ratio of 4:1. The PET data were reconstructed with the baseline ordered-subsets expectation maximization (OSEM) algorithm, with the OSEM + PSF model, with the OSEM + TOF model and with the OSEM + PSF + TOF model. The clinical study was a retrospective analysis of 66 patients who underwent 18F-FDG PET/CT. The image quality was evaluated using the background variability (coefficient of variance, CVphantom and CVliver) and the contrast (CONTHOT and SNR).In phantom study, the CVphantom of the LG phantom was higher than that of the NEMA phantom. The PSF decreased the CVphantom of the LG phantom to the NEMA phantom level. The TOF information accelerated the CVphantom plateau earlier. The best relationship between the CVphantom and the CONTHOT was observed for the OSEM + PSF + TOF. In clinical study, the combination of PSF and TOF decreased the CVliver for overweight patients to that for normal weight patients while it increased the SNR similarly between two patient groups.The combination of the PSF and TOF correction improved the image quality of the LG phantom and overweight patients.
Keywords: Point-spread-function; Time-of-flight; PET/CT; Image quality; Overweight
Regional glucose metabolic reduction in dementia with Lewy bodies is independent of amyloid deposition by Kazunari Ishii; Chisa Hosokawa; Tomoko Hyodo; Kenta Sakaguchi; Kimio Usami; Kenji Shimamoto; Makoto Hosono; Yuzuru Yamazoe; Takamichi Murakami (78-83).
There is evidence that some cases of patients with dementia with Lewy bodies (DLB) can demonstrate Alzheimer disease (AD) like reduced glucose metabolism without amyloid deposition. The aim of this study was to clarify whether regional hypometabolism is related to amyloid deposits in the DLB brain and measure the degree of regional hypometabolism.Ten consecutive subjects with DLB and 10 AD patients who underwent both Pittsburgh compound B (PiB)-PET and 18F-fluoro-2-deoxyglucose (FDG)-PET were included in this study. Regional standardized uptake value ratio (SUVR)s normalised to cerebellar cortices were calculated in the FDG- and PiB-PET images.All AD patients and five DLB patients showed amyloid deposits (PiB positive). In the DLB group the parietotemporal and occipital metabolism were significantly lower than those in the AD group but there was no difference between the posterior cingulate hypometabolism between DLB and AD groups. There were no differences in regional glucose metabolism between PiB positive and negative DLB patients.In the DLB brain, it is suggested that decreased regional glucose metabolism is unrelated to amyloid deposits, although the hypometabolic area overlaps with the AD hypometabolic area and the degree of parietotemporal and occipital hypometabolism in DLB brain is much larger than that in AD brain.
Keywords: Dementia with Lewy bodies; Glucose metabolism; Amyloid deposit; PET
Distribution of residual long-lived radioactivity in the inner concrete walls of a compact medical cyclotron vault room by Toshioh Fujibuchi; Akihiro Nohtomi; Shingo Baba; Masayuki Sasaki; Isao Komiya; Yoshiyuki Umedzu; Hiroshi Honda (84-90).
Compact medical cyclotrons have been set up to generate the nuclides necessary for positron emission tomography. In accelerator facilities, neutrons activate the concrete used to construct the vault room; this activation increases with the use of an accelerator. The activation causes a substantial radioactive waste management problem when facilities are decommissioned. In the present study, several concrete cores from the walls, ceiling and floor of a compact medical cyclotron vault room were samples 2 years after the termination of operations, and the radioactivity concentrations of radionuclides were estimated.Cylindrical concrete cores 5 cm in diameter and 10 cm in length were bored from the concrete wall, ceiling and floor. Core boring was performed at 18 points. The gamma-ray spectrum of each sample was measured using a high-purity germanium detector. The degree of activation of the concrete in the cyclotron vault room was analyzed, and the range and tendency toward activation in the vault room were examined. 60Co and 152Eu were identified by gamma-ray spectrometry of the concrete samples. 152Eu and 60Co are produced principally from the stable isotopes of europium and cobalt by neutron capture reactions. The radioactivity concentration did not vary much between the surface of the concrete and at a depth of 10 cm. Although the radioactivity concentration near the target was higher than the clearance level for radioactive waste indicated in IAEA RS-G-1.7, the mean radioactivity concentration in the walls and floor was lower than the clearance level.The radioactivity concentration of the inner concrete wall of the medical cyclotron vault room was not uniform. The areas exceeding the clearance level were in the vicinity of the target, but most of the building did not exceed the clearance levels.
Keywords: Compact medical cyclotron; Radioactivity concentration; Concrete wall; Neutron activation; Clearance level
Grading obstructive lung disease using tomographic pulmonary scintigraphy in patients with chronic obstructive pulmonary disease (COPD) and long-term smokers by Marika Bajc; Hanna Markstad; Linnea Jarenbäck; Ellen Tufvesson; Leif Bjermer; Jonas Jögi (91-99).
The severity of chronic obstructive lung disease (COPD) is defined by the degree of flow limitation measured as forced expiratory volume in 1 s, which mainly reflects impairment of large and intermediate airways. However, COPD is primarily a small airways disease. Therefore, better diagnostic tools are needed. Ventilation-Perfusion (V/P) SPECT is a sensitive method to detect obstructive lung changes but criteria for staging airway obstruction are missing.To define and validate criteria to stage COPD using V/P SPECT.74 subjects (healthy non-smokers, healthy smokers or with stable COPD) were included. All were examined with V/P SPECT in a hybrid SPECT/CT system. Spirometry was performed and patients were evaluated with the clinical COPD questionnaire (CCQ). V/P SPECT was interpreted independently. Preserved lung function (%) was evaluated. The degree of airway obstruction on V/P SPECT was graded according to newly-developed grading criteria. The degree of airway obstruction was graded from normal (0) to severe (3). The airway obstructivity-grade and degree of preserved lung function were compared to GOLD, CCQ and LDCT emphysema extent.Obstructivity-grade (r = 0.66, P < 0.001) and the degree of preserved lung function (r = −0.70, P < 0.001) both correlated to GOLD. Total preserved lung function decreased in relation to higher GOLD stage. There was a significant difference between healthy controls and apparently healthy long time smokers both regarding obstructivity-grade (P = 0.001) and preserved lung function (P < 0.001). Long-time smokers did not differ significantly from GOLD 1 COPD patients (P = 0.14 and P = 0.55 for obstructivity-grade and preserved lung function, respectively). However, patients in GOLD 1 differed in obstructivity-grade from non-smoking controls (P = 0.02).Functional imaging with V/P SPECT enables standardized grading of airway obstruction as well as reduced lung function, both of which correlate with GOLD stage. V/P SPECT shows that long-term smokers in most cases have signs of ventilatory impairment and airway obstruction not shown by spirometry.
Keywords: Ventilation/Perfusion SPECT; Pulmonary scintigraphy; Chronic obstructive pulmonary disease (COPD); Imaging interpretation criteria; Technegas
Assessing margin expansions of internal target volumes in 3D and 4D PET: a phantom study by Shyam S. Jani; James M. Lamb; Benjamin M. White; Magnus Dahlbom; Clifford G. Robinson; Daniel A. Low (100-109).
To quantify tumor volume coverage and excess normal tissue coverage using margin expansions of mobile target internal target volumes (ITVs) in the lung.FDG-PET list-mode data were acquired for four spheres ranging from 1 to 4 cm as they underwent 1D motion based on four patient breathing trajectories. Both ungated PET images and PET maximum intensity projections (PET-MIPs) were examined. Amplitude-based gating was performed on sequential list-mode files of varying signal-to-background ratios to generate PET-MIPs. ITVs were first post-processed using either a Gaussian filter or a custom two-step module, and then segmented by applying a gradient-based watershed algorithm. Uniform and non-uniform 1 mm margins were added to segmented ITVs until complete target coverage was achieved.PET-MIPs required smaller uniform margins (4.7 vs. 11.3 mm) than ungated PET, with correspondingly smaller over-coverage volumes (OCVs). Non-uniform margins consistently resulted in smaller OCVs when compared to uniform margins. PET-MIPs and ungated PET had comparable OCVs with non-uniform margins, but PET-MIPs required smaller longitudinal margins (4.7 vs. 8.5 mm). Non-uniform margins were independent of sphere size.Gated PET-MIP images and non-uniform margins result in more accurate ITV delineation while reducing normal tissue coverage.
Keywords: 4D-PET; Lung cancer