Efficacy Evaluation of Combination Treatment Using Gemcitabine and Radioimmunotherapy with 90Y-Labeled Fully Human Anti-CD147 Monoclonal Antibody 059-053 in a BxPC-3 Xenograft Mouse Model of Refractory Pancreatic Cancer.

The poor prognosis of pancreatic cancer requires the development of more effective therapy. CD147 expresses in pancreatic cancer with high incidence and has a crucial role in invasion and metastasis. We developed a fully human monoclonal antibody (059-053) with high affinity for CD147. Here we evaluated the efficacy of combined treatment using radioimmunotherapy (RIT) with 90Y-labeled 059-053 and gemcitabine in a BxPC-3 xenograft mouse model. Expression of CD147 and matrix metalloproteinase-2 (MMP2) in BxPC-3 tumors was evaluated. In vitro and in vivo properties of 059-053 were evaluated using 111In-labeled 059-053 and a pancreatic cancer model BxPC-3. Tumor volume and body weight were periodically measured in mice receiving gemcitabine, RIT, and both RIT and gemcitabine (one cycle and two cycles). High expression of CD147 and MMP2 was observed in BxPC-3 tumors and suppressed by 059-053 injection. Radiolabeled 059-053 bound specifically to BxPC-3 cells and accumulated highly in BxPC-3 tumors but low in major organs. Combined treatment using RIT with gemcitabine (one cycle) significantly suppressed tumor growth and prolonged survival with tolerable toxicity. The two-cycle regimen had the highest anti-tumor effect, but was not tolerable. Combined treatment with 90Y-labeled 059-053 and gemcitabine is a promising therapeutic option for pancreatic cancer.

[Administration Accuracy of Automated Infusion Device for PET Using Improved Disposable Kit].

PURPOSE: The AI-300 automated infusion device (Sumitomo Heavy Industries, Ltd., Tokyo, Japan) is subject to administration error as a function of smaller volumes of 18F-FDG dispensed via a three-way cock supplied with a disposable kit. The present study aimed to validate the administration accuracy of the AI-300 using an improved disposable kit for quantitative positron emission tomography (PET) assessment. METHODS: We determined administration accuracy between the improved and previous disposable kits by measuring variations in dispensed volumes and radioactive concentrations of 18F-FDG according to the criteria of the Japanese Society of Nuclear Medicine. A reference value was generated by measuring radioactivity using a standard dose calibrator. RESULTS: The values obtained using the previous kit deviated from the reference values by a maximum of -10.6%, and the deviation depended on dispensed volumes of 18F-FDG<0.25 mL. In contrast, the values were relatively stable when using the improved kit with dispensed 18F-FDG volumes < 0.25 mL. Variations in radioactive concentrations were relatively stable using the improved kit, whereas that of the previous kit was slightly unstable at high radioactive concentrations. CONCLUSION: The administration accuracy of the AI-300 using the previous kit varied considerably according to smaller dispensed volumes, but the improved kit might alleviate this problem. The present results indicated that the improved disposal kit should be immediately implemented to eliminate uncertainty surrounding quantitative PET findings.

Validation of Cross-calibration Schemes for Quantitative Bone SPECT/CT Using Different Sources under Various Geometric Conditions.

PURPOSE: Several cross-calibration schemes have been proposed to produce quantitative values in bone SPECT imaging. Differences in the radionuclide sources and geometric conditions can decrease the accuracy of cross-calibration factor (CCF). The present study aimed to validate the effects of calibration schemes using different sources under various geometric conditions. METHODS: Temporal variations as well as variations in acquisition counts and the shapes of 57Co standard and 99mTc point sources and a 99mTc disk source were determined. The effects of the geometric conditions of the source-to-camera distance (SCD) and lateral distance on the CCF were investigated by moving the camera or source away from the origin. The system planar sensitivity of NEMA incorporated into a Symbia Intevo SPECT/CT device (Siemens®) was defined as reference values. RESULTS: The temporal variation in CCF using the 57Co source was relatively stable within the range of 0.7% to 2.3%, whereas the 99mTc source ranged from 2.7% to 7.3%. In terms of source shape, the 57Co standard point source was the most stable. Both SCD and lateral distance decreased as a function of distance from the origin. Errors in the geometric condition were higher for the 57Co standard point source than the 99mTc disk source. CONCLUSIONS: Different calibration schemes influenced the reliability of quantitative values. The 57Co standard point source was stable over a long period, and this helped to maintain the quality of quantitative SPECT/CT imaging data. The CCF accuracy of the 99mTc source decreased depending on the preparative method. The method of calibration for quantitative SPECT should be immediately standardized to eliminate uncertainty.

[A Comparison of Planar Sensitivity and Spatial Resolution among Different Collimators and Energy Windows on 223Ra Imaging].

OBJECTIVE: The present study aimed to reveal the influence of combination of different collimators and energy windows on the planar sensitivity and the spatial resolution during experimental 223Ra imaging, and to determine optimal imaging parameters. METHODS: A vial type source containing 223Ra solution (4.55 MBq / 5.6 ml) was placed in the air at 100 mm away from the collimator surface. Planar images were acquired with LEHR, LMEGP, ELEGP and MEGP collimators on two dual-head gamma cameras (Symbia intevo (Siemens) and Infinia 3 (GE)). We compared three energy window combinations: 1) single window at 82 keV, 2) double window at 82+154 keV, 3) triple window at 82+154+270 keV. The energy spectrum, the sensitivity and the spatial resolution, such as full-width at half-maximum (FWHM) and full-width at tenth-maximum (FWTM), of each collimator were assessed. RESULTS: Five energy spectra (at around 82, 154, 270, 351 and 405 keV) were essentially observed among four collimators. The sensitivity was high for LEHR collimator, then ELEGP and LMEGP collimator was 3-4 fold, which is greater than MEGP collimator. The 82 keV energy window of four collimators has best spatial resolution. Moreover, the spatial resolution of the 82 keV energy window with LMEGP and ELEGP collimator was almost equal to that of the triple window with MEGP collimator. CONCLUSIONS: Optimal imaging parameters were single energy window using LMEGP or ELEGP, and then triple energy window using MEGP collimator.

Calculation Accuracy of Gross Tumor Volume at the Diaphragm Boundary Evaluated Using Respiratory-gated PET/CT.

OBJECTIVE: The present study aimed to clarify gross tumor volume (GTV) contouring accuracy at the diaphragm boundary using respiratory-gated PET/CT. METHODS: The lung/diaphragm boundary was simulated using a phantom containing 18F solution (10.6 kBq/mL). Tumors were simulated using spheres (diameter, 11-38 mm) containing 18F and located at the positions of the lungs and liver. The tumor background ratios (TBR) were 2, 4, and 8. The phantom was moved from the superior to inferior direction with a 20-mm motion displacement at 3.6 s intervals. The recovery coefficient (RC), volume RC (VRC), and standardized uptake value (SUV) threshold were calculated using stationary, non-gated (3D), and gated (4D) PET/CT. RESULTS: In lung cancer simulation, RC and VRC in 3D PET images were, respectively, underestimated and overestimated in smaller tumors, whereas both improved in 4D PET images regardless of tumor size and TBR. The optimal SUV threshold was about 30% in 4D PET images. In liver cancer simulation, RC and VRC were, respectively, underestimated and overestimated in smaller tumors, and when the TBR was lower, but both improved in 4D PET images when tumors were >17 mm and the TBR was >4. The optimal SUV threshold tended to depend on the TBR. CONCLUSIONS: The contouring accuracy of GTV was improved by considering TBR and using an optimal SUV threshold acquired from 4D PET images.

Clinical Value of 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in Upper Tract Urothelial Carcinoma: Impact on Detection of Metastases and Patient Management.

OBJECTIVE: To determine the diagnostic accuracy of 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) for detecting metastasis and its impact on patient management with upper tract urothelial carcinoma (UTUC). PATIENTS AND METHODS: Consecutive patients with UTUC underwent 18F-FDG PET/CT after CT for initial staging (n = 47) and for restaging at recurrence (n = 9). Diagnostic accuracy for detecting metastases with PET/CT and CT was compared statistically. The impact of PET/CT on patient management was assessed by comparing questionnaires that were completed by the attending physicians before and after PET/CT. RESULTS: In the lesion-based analysis, 142 lesions were diagnosed as metastases. The sensitivity of PET/CT was significantly better than that of CT (85 vs. 50%, p = 0.0001). In the patient-based analysis, 22 patients were diagnosed as having metastases. The sensitivity/specificity/accuracy of PET/CT tended to be superior to those of CT, but these values were not significantly different (95, 91, and 93% vs. 82, 85, and 84%; p = 0.25, 0.50, and 0.063, respectively). The clinicians changed their assessments of disease extent and management plans in 18 (32%) and 11 (20%) patients, respectively, based on the PET/CT results. CONCLUSIONS: The diagnostic accuracy of PET/CT for detecting metastasis was superior to that of CT. PET/CT provided additional information to the CT-based staging, which had an impact on patient management.

Prognostic value of (18) F-fluoroazomycin arabinoside PET/CT in patients with advanced non-small-cell lung cancer.

This study evaluated the prognostic value of positron emission tomography/computed tomography (PET/CT) using (18) F-fluoroazomycin arabinoside (FAZA) in patients with advanced non-small-cell lung cancer (NSCLC) compared with (18) F-fluorodeoxyglucose (FDG). Thirty-eight patients with advanced NSCLC (stage III, 23 patients; stage IV, 15 patients) underwent FAZA and FDG PET/CT before treatment. The PET parameters (tumor-to-muscle ratio [T/M] at 1 and 2 h for FAZA, maximum standardized uptake value for FDG) in the primary lesion and lymph node (LN) metastasis and clinical parameters were compared concerning their effects on progression-free survival (PFS) and overall survival (OS). In our univariate analysis of all patients, clinical stage and FAZA T/M in LNs at 1 and 2 h were predictive of PFS (P = 0.021, 0.028, and 0.002, respectively). Multivariate analysis also indicated that clinical stage and FAZA T/M in LNs at 1 and 2 h were independent predictors of PFS. Subgroup analysis of chemoradiotherapy-treated stage III patients revealed that only FAZA T/M in LNs at 2 h was predictive of PFS (P = 0.025). The FDG PET/CT parameters were not predictive of PFS. No parameter was a significant predictor of OS. In patients with advanced NSCLC, FAZA uptake in LNs, but not in primary lesions, was predictive of treatment outcome. These results suggest the importance of characterization of LN metastases in advanced NSCLC patients.

[Comparison of (18)F-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography image quality between commercial and in-house supply of FDG radiopharmaceuticals].

OBJECTIVE: PET images are affected by scanner model, reconstruction conditions, injected dose, scan duration, patient health status and FDG radiopharmaceutical supply systems. The present study compares images of 40 patients using commercial and in-house FDG systems with one PET scanner (Aquiduo). METHODS: The PET images were evaluated using the physical indexes of NECpatient, NECdensity and SNRliver proposed by the Japanese guidelines for oncological FDG-PET/CT, and by visual assessment. RESULTS: There were no significant differences in the physical indexes between PET images generated using commercial and in-house FDG. The physical indexes were also acceptable according to the recommended Japanese guidelines. NECdensity was higher when a higher dose/body weight of commercial FDG was injected (correlation coefficient: r=0.576, p<0.001) and lower when BMI was lower and in-house FDG was injected (r=-0.786, p<0.0001). These results suggest that scan duration should be increased if the injected dose of commercial FDG/body weight is <5.5 MBq/kg, and if individuals with BMI >21.4 kg/m(2) are injected with in-house FDG. CONCLUSIONS: Scan duration should be varied depending on FDG supply systems to ensure more accurate image quality and quantitative values during evaluations of response to therapy and prognostic prediction.

[Improvement of quantitative accuracy using phase-based respiratory-gated PET/CT in phantom and clinical studies].

OBJECTIVE: The present study aimed at determining the quantitative accuracy of phase-based respiratory-gated PET/CT imaging using phantom and clinical studies. METHODS: The effects of target size, target-to-background ratio (TBR), and respiratory motion on PET images were estimated using a NEMA body phantom comprising six spheres (diameter 10-37mm) in a solution of F-18 of three different TBRs (4, 6, 8). The phantom was moved in a superior-inferior direction at motion displacements of 0, 10, 20 and 30 mm. Stationary images of the phantom as well as non-gated (3D) and gated (4D) images of the phantom while moving were reconstructed and the recovery coefficient (RC) of individual spheres was calculated from each image. We then determined the RC improvement rate to evaluate improvements conferred by 4D-PET/CT. We retrospectively analyzed data from 14 patients with lung cancer who were examined by 3D- and 4D-PET/CT. Each lesion on the 3D-PET/CT and each of the five phases of the 4D-PET/CT were analyzed. RESULTS: Larger motion displacement and TBR resulted in increased RC degradation for small spheres. The RC improvement rate showed that 4D acquisition improved the RC of spheres with larger motion displacement exceeding 13 mm in diameter. 4D-PET/CT alone can reduce the effects of motion blurring, but partial volume effects may still be the dominant source of quantitative inaccuracy for small lesions. The trends of phantom and clinical studies for evaluating the improvement rate were similar. CONCLUSIONS: 4D-PET/CT significantly improved the quantitative accuracy of PET images particularly when larger motion displacement exceeded 17mm in diameter such as in lung cancer.

[Technical features and roles of cobalt-57 flood sources for daily quality control of gamma cameras].

Quality control (QC) detects changes in the performance of gamma cameras that could adversely affect interpretations of clinical studies. We used plate and sheet (57)Co flood sources to measure extrinsic uniformity during daily QC. Each source, when placed on the top of a collimated detector, allowed the acquisition of uniform images from both detectors, thus reducing the amount of time needed to perform daily QC. No serious problems with the gamma camera system were revealed by visual checks, and changes in detector sensitivity were rapidly determined by observing daily variations in the measured values of extrinsic uniformity. Furthermore, (57)Co flood sources confer advantages in that they shorten the time required for preparation of flood sources and reduce the consequent exposure of medical staff to radiation.

Evaluation of two-dimensional total bone uptake (2D-TBU) and bone scan index (BSI) extracted from active bone metastatic burden on the bone scintigraphy in patients with radium-223 treatment.

OBJECTIVE: Radium-223 is a first alpha-emitting radionuclide treatment for metastatic castration-resistant prostate cancer (mCRPC) patients with bone metastases. Although the spread-based bone scan index (BSI) and novel index of the intensity-based two-dimensional total bone uptake (2D-TBU) from bone scintigraphy may provide useful input in radium-223 treatment, they have not been evaluated in detail yet. This study aimed to fill this gap by evaluating BSI and 2D-TBU in patients treated with radium-223. METHODS: Twenty-seven Japanese patients with mCRPC treated with radium-223 were retrospectively analyzed. The patients were evaluated via blood tests and bone scans at baseline and 3 cycles intervals of treatment. BSI and 2D-TBU were analyzed via VSBONE BSI in terms of correlations, response to radium-223 treatment, association with treatment completion, and the Kaplan-Meier survival analysis was performed. RESULTS: Nineteen patients (70.4%) completed six cycles of radium-223 treatment, whereas eight patients (29.6%) did not complete the treatment regimen. A significant difference in baseline BSI and 2D-TBU was observed between these groups of patients. Both BSI and 2D-TBU were highly correlated (r = 0.96, p < 0.001). Univariate analysis showed an association between radium-223 completion in median BSI and 2D-TBU values (p = 0.015) and completion percentage differences (91.7% vs. 45.5%; p = 0.027). The Kaplan-Meier product limit estimator showed that the median overall survival was 25.2 months (95% CI 14.0-33.6 months) in the completion group and 7.5 months (95% CI 3.3-14.2 months) in the without completion group (p < 0.001). The overall survival based on median cutoff levels showed a significant difference in 2D-TBU (p = 0.007), but not in BSI (p = 0.15). CONCLUSIONS: The 2D-TBU may offer advantages over BSI in classifying patients towards radium-223 treatment based on the degree of progression of bone metastases. This study supports the importance of preliminary assessment of bone metastasis status using BSI and 2D-TBU extracted from VSBONE BSI for radium-223 treatment decisions.

[Quality control of dose calibrator using a traceable syringe-type (68)Ge/(68)Ga calibration source].

OBJECTIVES: Accurate calibration of dose calibrators (DC) is required for quantitative positron emission tomography (PET) studies to generate meaningful information. Values measured by DC depend not only on the radioactive nuclide but also the environment where measurements are taken. Therefore, DC must be calibrated at each location. The present study aimed to determine appropriate calibration values, and evaluate the performance of DC using a traceable (68)Ge/(68)Ga calibration source that is available as a surrogate (18)F source. METHODS: We used a (68)Ge/(68)Ga calibration source to determine the optimal DC value for measuring (18)F activity in the operating environment. Variations in sensitivity and geometry as well as measurement uncertainty were evaluated using the (68)Ge/(68)Ga source. We adopted the criteria of the Guide for the expression of uncertainty in measurement (GUM) to evaluate DC performance. RESULTS: Although the manufacturer's recommended (18)F calibration number for the CRC-25PET is 480, we found that the optimal number was 482. Over a period of one year, the sensitivity of the DC varied <0.1%, and the expanded uncertainty of DC measurements was 2.2%. CONCLUSION: Measurements of the certified activity of a traceable national standard were corrected, and the uncertainty of measurements as well as the accuracy of a DC were determined. Calibration numbers for DC should be regularly determined using (68)Ge/(68)Ga calibration sources at each location to ensure the most accurate results.

Wnt1 induces osteoblastic changes in a well-established osteolytic skeletal metastatic model derived from breast cancer.

BACKGROUND: Osteoblastic skeletal metastasis is frequently observed in prostate cancer. An effective therapy has not been developed due to the unclear molecular mechanism. The Wnt family is involved in various biological phenomena including bone metabolism. There is no direct evidence that the family causes osteoblastic skeletal metastasis. AIMS: The present study aims to evaluate whether overexpressed Wnt induces osteoblastic bone metastasis in a well-established osteolytic bone metastatic model. METHODS AND RESULTS: The breast cancer-derived 5a-D-Luc-ZsGreen cells were transfected with Wnt1, Wnt3A, and Wnt5A expression vectors, producing stably highly expressing cells. These cells were intracardially transplanted in nude mice. Bone metastasis development was confirmed by fluorescence imaging. Hind-limb bones including metastasis were dissected and visualized through micro-CT imaging. After imaging, sections were stained with hematoxylin and eosin (H&E), and immunohistochemically stained with an anti-SATB2 antibody. Luminescent imaging confirmed mice with bone metastases in the hind limbs. Micro-CT imaging found an osteoblastic change only in bone metastasis of mice transplanted with Wnt1-expressing cells. This was confirmed on H&E-stained sections. SATB2 immunostaining showed differentiated osteoblasts were at the site of bone metastases in the diaphysis. SATB2 in the Wnt/ß-catenin pathway activated by overexpressed Wnt1 could induce osteoblastic change. CONCLUSION: Our findings provided direct evidence Wnt1 is involved in osteoblastic bone metastasis development. Our model would be a powerful tool for further elucidating molecular mechanisms underlying the disease and developing effective therapies.

Comparison of skeletal segmentation by deep learning-based and atlas-based segmentation in prostate cancer patients.

OBJECTIVE: We aimed to compare the deep learning-based (VSBONE BSI) and atlas-based (BONENAVI) segmentation accuracy that have been developed to measure the bone scan index based on skeletal segmentation. METHODS: We retrospectively conducted bone scans for 383 patients with prostate cancer. These patients were divided into two groups: 208 patients were injected with 99mTc-hydroxymethylene diphosphonate processed by VSBONE BSI, and 175 patients were injected with 99mTc-methylene diphosphonate processed by BONENAVI. Three observers classified the skeletal segmentations as either a "Match" or "Mismatch" in the following regions: the skull, cervical vertebrae, thoracic vertebrae, lumbar vertebrae, pelvis, sacrum, humerus, rib, sternum, clavicle, scapula, and femur. Segmentation error was defined if two or more observers selected "Mismatch" in the same region. We calculated the segmentation error rate according to each administration group and evaluated the presence of hot spots suspected bone metastases in "Mismatch" regions. Multivariate logistic regression analysis was used to determine the association between segmentation error and variables like age, uptake time, total counts, extent of disease, and gamma cameras. RESULTS: The regions of "Mismatch" were more common in the long tube bones for VSBONE BSI and in the pelvis and axial skeletons for BONENAVI. Segmentation error was observed in 49 cases (23.6%) with VSBONE BSI and 58 cases (33.1%) with BONENAVI. VSBONE BSI tended that "Mismatch" regions contained hot spots suspected of bone metastases in patients with multiple bone metastases and showed that patients with higher extent of disease (odds ratio = 8.34) were associated with segmentation error in multivariate logistic regression analysis. CONCLUSIONS: VSBONE BSI has a potential to be higher segmentation accuracy compared with BONENAVI. However, the segmentation error in VSBONE BSI occurred dependent on bone metastases burden. We need to be careful when evaluating multiple bone metastases using VSBONE BSI.

Gastrointestinal tract disorder in natriuretic peptide receptor B gene mutant mice.

Natriuretic peptide receptor B (NPR-B), which has high affinity for C-type natriuretic peptide (CNP) and synthesizes intracellular cGMP, may be involved in gastrointestinal tract (GIT) regulation. A mutant allele of the NPR-B-encoding gene (Npr2) is responsible for the phenotype of the short-limb dwarfism (SLW) mouse. Homozygosity for this autosomal-recessive gene (slw/slw) leads to dwarfism and death before weaning because of milk retention in the stomach and intestinal distention. To elucidate the relationship between CNP/NPR-B signaling and GIT function, we investigated the association between Npr2 mutation and the GIT phenotype in slw/slw mice. The pylorus and large intestine of the mutants did not respond to CNP stimulation; further, they showed pyloric lumen narrowing with randomly aligned circular muscle cells. Comparison of the cGMP and neuronal marker distribution in GIT tissues confirmed cGMP expression in neuronal tissues. An Auerbach's plexus and submucosal tissues of the mutants didn't express cGMP and expressed Ca(2+). In contrast, those of normal mice (controls) expressed both cGMP and Ca(2+). Sequencing revealed that the causative Npr2 mutation was a 7-base deletion in exon 8, resulting in a frameshift and premature termination codon appearance. Therefore, the GIT phenotype of slw/slw mice is because of a CNP/NPR-B-signaling defect caused by an Npr2 mutation. These results facilitate better understanding of the role of CNP/NPR-B signaling in GIT motility.

Atmospheric scanning electron microscope observes cells and tissues in open medium through silicon nitride film.

Direct observation of subcellular structures and their characterization is essential for understanding their physiological functions. To observe them in open environment, we have developed an inverted scanning electron microscope with a detachable, open-culture dish, capable of 8 nm resolution, and combined with a fluorescence microscope quasi-simultaneously observing the same area from the top. For scanning electron microscopy from the bottom, a silicon nitride film window in the base of the dish maintains a vacuum between electron gun and open sample dish while allowing electrons to pass through. Electrons are backscattered from the sample and captured by a detector under the dish. Cells cultured on the open dish can be externally manipulated under optical microscopy, fixed, and observed using scanning electron microscopy. Once fine structures have been revealed by scanning electron microscopy, their component proteins may be identified by comparison with separately prepared fluorescence-labeled optical microscopic images of the candidate proteins, with their heavy-metal-labeled or stained ASEM images. Furthermore, cell nuclei in a tissue block stained with platinum-blue were successfully observed without thin-sectioning, which suggests the applicability of this inverted scanning electron microscope to cancer diagnosis. This microscope visualizes mesoscopic-scale structures, and is also applicable to non-bioscience fields including polymer chemistry.

Reprint of: Atmospheric scanning electron microscope observes cells and tissues in open medium through silicon nitride film.

Direct observation of subcellular structures and their characterization is essential for understanding their physiological functions. To observe them in open environment, we have developed an inverted scanning electron microscope with a detachable, open-culture dish, capable of 8 nm resolution, and combined with a fluorescence microscope quasi-simultaneously observing the same area from the top. For scanning electron microscopy from the bottom, a silicon nitride film window in the base of the dish maintains a vacuum between electron gun and open sample dish while allowing electrons to pass through. Electrons are backscattered from the sample and captured by a detector under the dish. Cells cultured on the open dish can be externally manipulated under optical microscopy, fixed, and observed using scanning electron microscopy. Once fine structures have been revealed by scanning electron microscopy, their component proteins may be identified by comparison with separately prepared fluorescence-labeled optical microscopic images of the candidate proteins, with their heavy-metal-labeled or stained ASEM images. Furthermore, cell nuclei in a tissue block stained with platinum-blue were successfully observed without thin-sectioning, which suggests the applicability of this inverted scanning electron microscope to cancer diagnosis. This microscope visualizes mesoscopic-scale structures, and is also applicable to non-bioscience fields including polymer chemistry.

An open cohort study of bone metastasis incidence following surgery in breast cancer patients.

BACKGROUND: To help design clinical trials of adjuvant bisphosphonate therapy for breast cancer, the temporal incidence of bone metastasis was investigated in a cohort of patients. We have tried to draw the criteria to use adjuvant bisphosphonate. METHODS: Consecutive breast cancer patients undergoing surgery between 1988 and 1998 (5459 patients) were followed up regarding bone metastasis until December 2006. Patients' characteristics at the time of surgery were analyzed by Cox's method, with bone metastasis as events. Patient groups were assigned according to Cox's analysis, and were judged either to require the adjuvant bisphosphonate or not, using the tentative criteria: high risk (>3% person-year), medium risk (1-3%), and low risk (<1%). RESULTS: Bone metastasis incidence was constant between 1.0 and 2.8% per person-year more than 10 years. Non-invasive cancer was associated with a very low incidence of bone metastasis (1/436). Multivariate Cox's analysis indicated important factors for bone metastasis were tumor grade (T), nodal grade (pN), and histology. Because T and pN were important factors for bone metastasis prediction, subgroups were made by pTNM stage. Patients at stages IIIA, IIIB and IV had an incidence of >3% per person-year, patients with stage I <1% per person-year, and those with stages II were between 1 and 3%. Further analysis with histology in stage II patients showed that stage IIB with high risk histology also had a high incidence (3% person year), whereas stage IIA with medium risk histology were <1%. CONCLUSIONS: Bone metastasis incidence remained constant for many years. Using pN, T, and histopathology, patients could be classified into high, medium, and low risk groups.

Post-operative breast cancer patients diagnosed with skeletal metastasis without bone pain had fewer skeletal-related events and deaths than those with bone pain.

BACKGROUND: Skeletal metastases are often accompanied by bone pain. To investigate the clinical meaning of bone pain associated with skeletal metastasis in breast cancer patients after surgery, we explored whether the presence of bone pain was due to skeletal-related events (SREs) or survival (cause specific death, CSD), retrospectively. METHODS: Consecutive breast cancer patients undergoing surgery between 1988 and 1998 were examined for signs of skeletal metastasis until December 2006. Patients who were diagnosed as having skeletal metastasis were the subjects of this study. Bone scans were performed annually for 5, 7 or 10 years; they were also conducted if skeletal metastasis was suspected. Data concerning bone pain and tumor markers at the time of skeletal metastasis diagnosis, and data relating to various factors including tumors, lymph nodes and hormone receptors at the time of surgery, were investigated. The relationships between factors such as bone pain, SRE and CSD were analyzed using the Kaplan-Meier method and Cox's analysis. RESULTS: Skeletal metastasis occurred in 668 patients but the pain status of two patients was unknown, therefore 666 patients were included in the study. At the time of skeletal metastasis diagnosis 270 patients complained of pain; however, 396 patients did not. Analysis of data using Cox's and Kaplan-Meier methods demonstrated that patients without pain had fewer SREs and better survival rates than those with pain. Hazard ratios regarding SRE (base = patients without pain) were 2.331 in univariate analysis and 2.243 in multivariate analysis. Hazard ratios regarding CSD (base = patients without pain) were 1.441 in univariate analysis and 1.535 in multivariate analysis. Similar results were obtained when analyses were carried out using the date of surgery as the starting point. CONCLUSION: Bone pain at diagnosis of skeletal metastasis was an indicator of increased SRE and CSD. However, these data did not support recommendations of follow-up bone surveys in breast cancer patients.

Evaluation of bone metastasis burden as an imaging biomarker by quantitative single-photon emission computed tomography/computed tomography for assessing prostate cancer with bone metastasis: a phantom and clinical study.

Metabolic bone volume (MBV), standardized uptake value (SUV), and total bone uptake (TBU) are new imaging biomarkers for quantitative bone single-photon emission computed tomography/computed tomography. The purpose of this study was to validate the quantitative accuracy and utility of MBV, SUVmean, and TBU for the assessment of bone metastases in prostate cancer. We used a bone-specific phantom with four hot spheres (φ = 13, 17, 22, 28 mm) filled with different Tc-99 m activities to simulate uptake ratios of 3 and 7, corresponding to normal and metastatic values. We calculated the error ratio (%Error) by comparing MBV, SUVmean, and TBU with true values for various parameters, including bone lesion size, uptake ratio, and SUV cut-off level. Differences for MBV, SUVmean, TBU, and bone scan index (BSI) were calculated to verify their utility in assessing bone metastases. Receiver-operating characteristic curve (ROC) analysis was performed to calculate the area under the curve (AUC) for each biomarker. MBV, SUVmean, and TBU were affected by lesion size, uptake ratio, and SUV cut-off level; however, TBU demonstrated the most stable %Error. The TBU %Error was within 15% in spheres 17 mm or larger when the SUV cut-off level was 7, regardless of the uptake ratio. The ROC analyses revealed the AUCs of BSI (0.977) and TBU (0.968). Additionally, TBU was able to assess bone metastasis when BSI provided false-negative results, but TBU also provided false-positive results by degenerative changes. The synergy between TBU and BSI could potentially improve diagnostic accuracy.