Effects of CT-based attenuation correction on quantitative SPECT/CT of jawbone.

OBJECTIVE: With single photon emission computed tomography (SPECT)/computed tomography (CT) quantitative examinations, CT-based attenuation correction (CTAC) is considered necessary, though its effect on the quantitative values of an examined area close to the body surface, such as the jawbone, has not been elucidated. We performed an investigation to determine whether quantitative evaluation using a bone SPECT standalone device without CT is possible. SUBJECTS AND METHODS: The calculated indices were maximum standardized uptake value (SUVmax) and SUVpeak. Grouping was performed based on the presence or absence of CTAC. The CTAC group underwent CTAC, while the noAC group did not.Validation was performed using clinical data of patients who underwent a jawbone SPECT/CT examination. Becquerel calibration factor (BCF) is required for calculation of SUV, and was determined with values obtained with both phantom and syringe methods. The index for the uptake areas in each group was assessed using a paired t-test. RESULTS: Using BCF obtained with the phantom method, both SUVmax and SUVpeak were higher in the noAC group. In contrast, BCF obtained with the syringe method showed no significant difference between the CTAC and noAC groups in regard to SUVmax and SUVpeak. This tendency was found regardless of the device used. Also, a high correlation was observed between the groups for both devices (r=0.95 and 0.93). CONCLUSION: Our findings show that BCF obtained with a syringe method should be used when performing quantitative evaluation without CTAC. They also indicate that quantitative evaluation using a SPECT standalone device may be possible for jawbone SPECT/CT examinations.

Clinical value of the threshold derived from bone single-photon emission computed tomography/computed tomography in differentiating sternoclavicular arthritis.

OBJECTIVE: With the recent improvements in the quantitative accuracy of single-photon emission computed tomography (SPECT)/ computed tomography (CT), the value of using standardized uptake value (SUV) in bone SPECT/CT for quantitative assessment has been reported.We established a threshold for inflamed and normal areas of the sternoclavicular joint and examined the clinical value of bone SPECT/CT. SUBJECTS AND METHODS: The threshold between the inflamed and normal areas of the sternoclavicular joint was initially calculated. The diagnostic performance of the calculated threshold was subsequently compared with the visual assessment of the whole-body image. The clinical value of the threshold was examined in cases of ambiguous visual assessment and a sub-analysis with pustuloticarthro-osteitis (PAO) patients was done. RESULTS: The threshold between the inflamed and the normal area in the 93 sternoclavicular joints of 51 patients was 4.46. The area under the ROC curve (AUC), accuracy, sensitivity, and specificity of SUVmax for differentiating sternoclavicular arthritis were 0.92, 0.86, 0.88, and 0.85, respectively. Similarly, the AUC of visual assessment were 0.87, and the difference was not significant (P=0.11). In 25 patients with PAO, the AUC, accuracy, sensitivity, and specificity of SUVmax were 0.94, 0.90, 0.96, and 0.84, respectively with a significant higher AUC of visual assessment (0.82, P=0.032). Furthermore, for cases where there was ambiguous uptake upon visual assessment, the accuracy, sensitivity, and specificity of SUVmax were 0.84, 1.00, and 0.71, respectively, which was useful to judge regarding the initiation of treatment. CONCLUSION: Quantitative assessment using SUVmax and the threshold found using bone SPECT/CT for the presence of sternoclavicular arthritis is clinically useful and can be a useful tool for the initiation of treatment, especially in PAO patients.

Effectiveness of quantitative bone SPECT/CT for bone metastasis diagnosis.

OBJECTIVE: This study was conducted to investigate the utility of standardized uptake value (SUV) derived from bone single photon emission tomography/computed tomography (SPECT/CT) for diagnosing bone metastasis. SUBJECTS AND METHODS: One hundred forty-seven patients with malignant cancer (breast or prostate cancer), joint disorders, primary skeletal disease, or cartilaginous bone neoplasms who underwent skeletal quantitative SPECT/CT were retrospectively investigated. Acquired data were classified as normal fourth lumbar vertebra, skeletal degenerative changes, or bone metastasis. Receiver operating characteristic (ROC) curves were used to determine the optimum cut-off value for SUVmax to distinguish among these diagnoses. RESULTS: Mean SUVmax values for the normal L4 bone (n=101), skeletal degenerative changes (n=47) and bone metastasis (n=64) groups were 4.47±1.66 (range 1.01-11.25), 6.99±2.58 (2.21-14.6), and 25.4±15.7 (3.88-98.87), respectively. Compared to the other two groups, SUVmax for the bone metastasis group was significantly higher (P<0.001). In the normal bone group, sensitivity, specificity and accuracy for discriminating bone metastasis were 96.3%, 95.1%, and 95.7% respectively, with a best SUVmax cut-off value of 7.40. For the skeletal degenerative changes group sensitivity, specificity and accuracy were 87.5%, 93.6%, and 90.4% respectively, with a best SUVmax cut-off value of 11.26. CONCLUSION: Quantitative bone SPECT/CT may be useful for bone metastasis diagnosis.

Quantitative bone SPECT/CT applications for primary bone neoplasms.

OBJECTIVE: To evaluate the clinical utility of quantitative values obtained with bone single photon emission computed tomography/computed tomography (SPECT/CT) for primary bone neoplasms. SUBJECTS AND METHODS: Bone SPECT/CT scans of 23 patients with 19 benign bone neoplasms (5 osteoid osteomas, 4 bone giant cell tumor, 4 osteofibrous dysplasia, 3 intraosseous ganglion, 2 aneurysmal bone cyst, 1 intraosseous hemangioma) and 5 malignant bone neoplasms (2 osteosarcoma, 1 periosteal osteosarcoma, 1 malignancy in bone giant cell tumor, 1 Ewing sarcoma) were retrospectively analyzed with maximum standardized uptake value (SUVmax), peak SUV (SUVpeak), mean SUV (SUVmean), metabolic bone volume (MBV), and total bone uptake (TBU) of primary lesions. RESULTS: Mean SUVmax of 19 benign and 5 malignant primary bone neoplasms were 6.89±3.26 (range 3.9-15.13) and 10.31±3.19 (5.0-13.45) respectively, with statistically significant difference (P=0.048). Mean SUVpeak of those were 5.87±2.83 (range 3.5-13.63) and 9.18±3.05 (4.09-12.03) respectively, with statistically significant difference (P=0.032). Mean SUVmean of those were 4.43±2.11 (range 2.59-9.37) and 7.13±2.90 (3.3-10.42) respectively, with statistically significant difference (P=0.027). Mean MBV of those were 22.0±30.0 (range 2.47-110.61) and 27.8±39.94 (8.59-99.24) respectively, with no statistically significant difference (P=0.72). Mean TBU of those were 80.64±94.57 (range 10.50-373.57) and 166.60±203.97 (28.68-528.13) respectively, with no statistically significant difference (P=0.17). CONCLUSION: Quantitative values obtained with bone SPECT/CT may serve as osteoblastic biomarkers for primary bone neoplasm.

Quantitative 67Ga-citrate SPECT/CT for evaluating disease activity in patients with interstitial lung disease.

OBJECTIVE: To determine whether results of a standardized uptake value (SUV)-based semi-quantitative analytic method for gallium-67 (67Ga)-citrate single photon emission tomography/computed tomography (SPECT/CT) reflects disease activity in patients with interstitial lung disease. SUBJECTS AND METHODS: Gallium-67-citrate SPECT/CT was used to evaluate disease activity in 24 patients with interstitial pneumoniaon clinical grounds at a single institution from June 2018 to August 2020. SUV in a given volume of interest over the bilateral pulmonary parenchyma was calculated using a dosimetry software package. Correlations of maximum SUV (SUVmax) and mean SUV (SUVmean) with clinical factors, including KL-6, lactate dehydrogenase (LDH), and C-reactive protein (CRP), were evaluated in all 24, as well as in 15 patients with spirometry results using Pearson's rank correlation test. RESULTS: The mean bilateral pulmonary SUVmax value showed a moderately significant correlation with KL-6 (Pearson's correlation coefficient r=0.51, P=0.012) and LDH (r=0.51, P=0.010), a weak non-significant correlation with DLCO% (r=-0.26, P=0.34), and no correlation with CRP (r=-0.01, P=0.94), FVC% (r=0.11, P=0.71), or FEV1.0% (r=0.14, P=0.62). Eleven patients with high KL-6 (≥1000U/mL) were defined as having disease activity. Maximum SUV sensitivity, specificity, and accuracy for predicting interstitial lung disease activity were 72.7%, 76.9%, and 75.0%, respectively, with a best cut-off value of 3.78. CONCLUSION: Semi-quantitative values obtained with 67Ga-citrate SPECT/CT showed a moderate correlation with KL-6 and moderate diagnostic performance for predicting disease activity of interstitial lung disease. It is rather unlikely that quantitative 67Ga-citrate SPECT/CT will have a role into the algorithm of interstitial lung disease.

Quantitative bone SPECT/CT applications for cartilaginous bone neoplasms.

OBJECTIVE: To evaluate the ability of quantitative values obtained with bone single photon emission computed tomography/computed tomography (SPECT/CT) to differentiate benign from malignant cartilaginous bone neoplasms. SUBJECTS AND METHODS: Bone SPECT/CT scans of 10 patients with 8 benign cartilaginous bone neoplasms (4 enchondromas, 1 periosteal chondroma, 1 osteochondroma, 1 bizarre parosteal osteochondromatous proliferation, 1 chondroblastoma) and 2 malignant cartilaginous bone neoplasms (1 periosteal chondrosarcoma, 1 chondrosarcoma) were retrospectively analyzed with maximum standardized uptake value (SUVmax), mean SUV (SUVmean), metabolic bone volume (MBV), and total bone uptake (TBU) of primary lesions. RESULTS: Mean SUVmax of 8 benign and 2 malignant cartilaginous bone neoplasms were 1.93±1.02 (range 0.59-3.41) and 6.07±0.86 (5.46-6.67), respectively with no overlap (P=0.028). Mean SUVmean of those were 1.24±0.71 (range 0.36-2.36) and 4.05±0.30 (3.84-4.26), respectively with no overlap (P=0.00036). Mean MBV of those were 7.17±4.19 (range 3.17-13.77) and 10.29±10.05 (3.19-17.4), respectively with no significant difference (P=0.74). Mean TBU of those were 9.22±8.31 (range 1.15-23.61) and 43.19±43.7 (12.26-74.13), respectively with no significant difference (P=0.47). CONCLUSION: Standardized uptake value obtained with bone SPECT/CT may be useful to differentiate benign from malignant cartilaginous bone neoplasms, thus helping the orthopedic surgeon towards the most appropriate treatment procedure.

Investigation of appropriate semi-quantitative index for assessment of esophageal and breast cancer treatment response in Japanese patients using 18F-FDG PET/CT findings.

OBJECTIVE: To examine the correlation of the quantitative indexes standardized uptake value (SUV), SUV corrected for lean body mass (SUL) and SUV corrected for Japanese lean body mass (SULj) with body weight to develop an appropriate quantitative index independent of body weight fluctuation for assessment of response to cancer treatment in Japanese patients. SUBJECTS AND METHODS: Fifty-six males with esophageal cancer and 30 females with breast cancer underwent fluorine-18-fluoro-2-deoxy-D-glucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) scans, once before and once after, receiving neoadjuvant chemotherapy prior to planned surgical resection. The maximum value, peak value, and average value of SUV, SUL and SULj were calculated by setting a spherical volume of interest (3cm diameter) in a normal area of the liver. The correlation between each index and body weight was obtained from the correlation coefficient (r) and the significance of the correlation was tested. RESULTS: Analyses were conducted with all patients (P<0.01), as well as after dividing into those with only esophageal (P<0.05) or breast (P<0.01) cancer. Regarding the correlation coefficient between each index and body weight, a significant difference was seen for SUVmax, SUVpeak and SUVmean. In contrast, there was no correlation with body weight for SULmax, SULpeak, SULmean, SULjmax, SULjpeak, or SULjmean in any of the 3 groups. CONCLUSION: Based on the correlation with body weight, we concluded that both SUL and SULj (SUL corrected for Japanese lean body mass) is useful for assessment of cancer treatment response in Japanese patients.

[Simulation at Incomplete Acquisition on Stress-rest Cerebral Blood Flow Quantitative Values One Day Method].

The QSPECT dual table autoradiography (DTARG) method can be used for quantitative determination of cerebral blood flow. We verified the influence on quantitative values obtained for cerebral blood flow in the case when usual acquisition was impossible and evaluated those values. Results obtained with an acquisition time of 30 min were considered to be true values, and the correlation and consistency with results of other times were evaluated. Values obtained with a shortened acquisition time showed a high correlation with the true value. As for consistency, there were differences among the various data collection intervals. Nevertheless, regardless of the use of a shortened acquisition time and the data acquisition interval, values obtained with the QSPECT program showed a high correlation with the true value. Based on our findings showing a high correlation, a quantitative evaluation of cerebral blood flow can be performed with the QSPECT DTARG method, even with complications, such as examination interruption, thus, it is considered to be a flexible method.

Usefulness of quantitative bone SPECT/CT for evaluating medication-related osteonecrosis of the jaw treatment response.

OBJECTIVE: For assessment of therapeutic response in medication-related osteonecrosis of the jaw (MRONJ) cases, the clinical usefulness of quantitative bone single-photon computed tomography-computed tomography (SPECT/CT) results was investigated. MATERIALS AND METHODS: Sixteen patients (18 lesions) with a clinical diagnosis of MRONJ underwent bone SPECT/CT scanning before and during/after anti-inflammatory therapy given for 3 or more months. The GI-BONE software package was used to determine standard uptake values (SUVs), including maximum (SUVmax), peak (SUVpeak), and mean (SUVmean), and metabolic bone volume (MBV) and also total bone uptake (TBU). In both responders (downstage) and non-responders (upstage or no change), differences in quantitative values between the first and second SPECT/CT examinations were analyzed using a Wilcoxon test. RESULTS: Following therapy, significant reductions in SUVmax, SUVpeak, SUVmean, MBV and TBU values for 11 lesions were noted in the responders after therapy (p = 0.003, p = 0.006, p = 0.004, p = 0.003, and p = 0.002, respectively). On the other hand, those for the seven lesions in the non-responder group were not significantly different (p = 0.17, p = 0.16, p = 0.26, p = 0.96, and p = 0.12, respectively). Results for SUVmax change showed sensitivity and specificity values of 45.5% and 85.7%, respectively, for differentiating responders from non-responders, with - 37.3% the optimal cutoff value. Those for MBV change were 72.7 and 85.7%, respectively, with - 29.4% the optimal cutoff value. Those for TBU change were 81.8% and 85.7%, respectively, with - 36.3% the optimal cutoff value. CONCLUSION: The present findings showed that therapeutic response in MRONJ cases could be determined by use of quantitative SUV, MBV, and TBU values based on bone SPECT/CT findings.

Usefulness of quantitative bone SPECT/CT for medication-related osteonecrosis of the jaw in clinical settings.

OBJECTIVE: This study was conducted to investigate the clinical utility of quantitative bone single-photon computed tomography-computed tomography (SPECT/CT) for detection and classification for medication-related osteonecrosis of the jaw (MRONJ). MATERIALS AND METHODS: Fifty-nine patients (69 lesions) clinically diagnosed as MRONJ by four specialists of Japanese Society of Oral Surgery according to the AAOMS diagnostic criteria and who underwent bone SPECT/CT were enrolled. One reader determined standard uptake values (SUVs), including maximum (SUVmax), peak (SUVpeak), and mean (SUVmean), as well as metabolic bone volume (MBV), representing total volume above threshold, and total bone uptake (TBU), calculated as MBV × SUVmean, using the GI-BONE software package. One-way repeated-measures analysis of variance and subsequent post hoc analysis were employed to compare quantitative values between clinical stages. To check reproducibility of values, another reader calculated these quantitative values. RESULTS: Mean SUVmax values for stage 0 (n = 21), 1 (n = 13), 2 (n = 25), and 3 (n = 10) were 5.82 ± 3.20, 5.46 ± 3.79, 8.16 ± 3.93, and 10.57 ± 8.43, respectively, while values for MBV were 9.52 ± 6.33, 11.36 ± 7.32, 12.4 ± 8.21, and 17.84 ± 16.94, respectively, and for TBU were 40.60 ± 46.97, 53.70 ± 77.26, 62.37 ± 42.91, and 102.01 ± 74.52, respectively. There were significant differences for SUVmax, SUVpeak, and SUVmean between clinical stages (p = 0.024, p = 0.027, p = 0.039, respectively). Subsequent post hoc analysis showed that SUVmax and SUVpeak of stage 3 were significantly higher than those of stage 0 (p = 0.046, 0.045, respectively). MBV and TBU showed a tendency to increase with increased stage, though differences between stages were not significant (p = 0.15, p = 0.053, respectively). Little differences of mean SUVmax, SUVpeak, SUVmean, MBV, and TBU between two readers were observed (- 3.10%, - 0.26%, - 4.24%%, 0.69%, and - 3.42%, respectively). The intraclass correlation coefficients (ICCs) of SUVmax, SUVpeak, SUVmean, MBV, and TBU were 0.985, 0.990, 0.980, 0.994, and 0.994, respectively (almost perfect for all values). CONCLUSION: As objective and reliable indicators, SUVmax and SUVpeak derived from quantitative bone SPECT/CT results are useful for detection of early status disease, as well as staging in MRONJ patients.

Quantitative bone SPECT/CT for evaluating treatment response in patient with sternoclavicular arthritis.

We report here a case of sternoclavicular arthritis due to SAPHO syndrome in a 60-year-old female in which quantitative values determined using bone SPECT/CT were useful to evaluate response. After celecoxib and alendronate sodium hydrate therapy, the chief complaints were well relieved and post-treatment Tc-99m HMDP bone SPECT/CT examination showed decreased uptake. The maximum standardized uptake value (SUV), peak SUV, mean SUV, metabolic bone volume, and total bone uptake of the untreated lesion were 18, 16, 10, 17 mL, and 180, respectively, which were decreased to 8, 7, 5, 15 mL, and 75, respectively, after the treatment. In comparison with pre-treatment situation, those parameters were decreased by -56%, -56%, -50%, -12%, and -58%, respectively, following celecoxib and alendronate sodium hydrate therapy, likely reflecting treatment response. Quantitative bone SPECT/CT may be useful to evaluate joint inflammatory activity and treatment response in a patient with osteoartritis.

Automatic detection of primary and metastatic lesions on cervicothoracic region and whole-body bone using a uniform machine-learnable approach for [18F]-FDG-PET/CT image analysis.

We propose a method to detect primary and metastatic lesions with Fluorine-18 fluorodeoxyglucose (FDG) accumulation in the lung field, neck, mediastinum, and bony regions on the FDG-PET/CT images. To search for systemic lesions, various anatomical structures must be considered. The proposed method is addressed by using an extraction process for anatomical regions and a uniform lesion detection approach. The uniform approach does not utilize processes that reflect any region-specific anatomical aspects but has a machine-learnable framework. Therefore, it can work as a lesion detection process for a specific anatomical region if it machine-learns the specific region data. In this study, three lesion detection processes for the whole-body bone region, lung field, or neck-mediastinum region are obtained. These detection processes include lesion candidate detection and false positive (FP) candidate elimination. The lesion candidate detection is based on a voxel anomaly detection with a one-class support vector machine. The FP candidate elimination is performed using an AdaBoost classifier ensemble. The image features used by the ensemble are selected sequentially during training and are optimal for candidate classification. Three-fold cross-validation was used to detect performance with the 54 diseased FDG-PET/CT images. The mean sensitivity for detecting primary and metastatic lesions at 3 FPs per case was 0.89 with a 0.10 standard deviation (SD) in the bone region, 0.80 with a 0.10 SD in the lung field, and 0.87 with a 0.10 SD in the neck region. The average areas under the ROC curve were 0.887 with a 0.125 SD for detecting bone metastases, 0.900 with a 0.063 SD for detecting pulmonary lesions, and 0.927 with a 0.035 SD for detecting the neck-mediastinum lesions. These detection performances indicate that the proposed method could be applied clinically. These results also show that the uniform approach has high versatility for providing various lesion detection processes.

Quantitative evaluation of single-photon emission computed tomography findings in lower extremity possible without computed tomography-based attenuation correction.

OBJECTIVE: For performing accurate quantitative analysis of single-photon emission computed tomography (SPECT)/computed tomography (CT) images, CT-based attenuation correction (CTAC) is considered to be necessary. However, the effect on quantitative values for an examined area close to the body surface, such as in the lower extremity, has yet to be elucidated. We performed the present investigation to determine the possibility of quantitative evaluation using a SPECT standalone device without CT. METHODS: Validation was performed using clinical data of patients who underwent a lower extremity SPECT/CT examination, with grouping based on presence or absence of CTAC, scatter correction and resolution recovery. Using a reference group in which all types of correction were applied, standardized uptake values (SUVs), including maximum (SUVmax) and peak (SUVpeak), were examined in each group and compared. RESULTS: As compared to the reference group, the difference in quantitative values became smaller in the order of the applied scatter correction and resolution recovery, applied resolution recovery, applied scatter correction, and neither scatter correction or resolution recovery applied groups, with no significant difference between the reference group and that with neither scatter correction or resolution recovery applied. A similar tendency was seen for both SUVmax and SUVpeak. CONCLUSIONS: In bone SPECT quantitative examinations of the lower extremity, quantitative evaluation without CTAC is possible without the use of scatter correction or resolution recovery. Thus, quantitative evaluation can be performed with use of a standalone SPECT device without CT.

Usefulness of Quantitative Bone Single-Photon Emission Computed Tomography/Computed Tomography for Evaluating the Treatment Response of Bone Metastasis in a Lung Cancer Patient.

We report a case of bone metastasis arising from lung cancer, including quantitative values obtained with bone single-photon emission computed tomography/computed tomography (SPECT/CT), which were useful to evaluate the treatment response. The first bone SPECT/CT during pembrolizumab therapy for lung cancer recurrence showed intense 99mTc-HMDP uptake of the right femur head and mild uptake of the left ribs. After the palliative radiotherapy for the right femur head metastasis and chemotherapy, the second bone SPECT/CT showed a decrease in focal uptake of the right femur hip and increasing uptake of the left ribs. There was also new uptake appearance in the sternum, right rib, spine (Th2, Th9, Th12, L4, S1), and bilateral pelvic bone (left ilium, acetabular cartridge, femur, right ilium and ischium). The change of maximum standardized uptake values (SUVmax) for the right femur head and left third and eighth rib bony metastases were -72.6% (from 22.96 to 6.28), +407.7% (from 2.97 to 15.08), and +229.2% (from 2.60 to 8.56), respectively. The change of whole-lesion metabolic bone volume and total bone uptake was +235.4% (from 22.75 to 76.3 cm3) and +219.1% (from 205.0 to 654.09), respectively. Two quantitative bone SPECT/CT images clearly showed the good response of femur head metastasis due to radiotherapy, and progression of other bone metastases regardless of chemotherapy.

Usefulness of Quantitative Bone SPECT/CT for Evaluating Treatment Response in a Patient with Mandibular Osteomyelitis.

We report here a case of mandibular osteomyelitis in a 63-year-old female in which quantitative values determined using bone SPECT/CT were useful to evaluate response to antibiotic therapy, hyperbaric oxygen therapy, and sequestomy. After finishing therapy, the chief complaints were well relieved, and posttreatment Tc-99m HMDP bone SPECT/CT examination showed decreased uptake. The maximum standardized uptake value (SUV), peak SUV, mean SUV, metabolic bone volume, and total bone uptake of the untreated lesion were 6.26, 5.16, 3.97, and 11.86 mL and 42.21, respectively, which were decreased to 4.65, 3.90, 2.77, and 9.67 mL and 26.80, respectively, following hyperbaric oxygen therapy and antibiotic administration, and were moreover decreased to 4.28, 3.67, 2.75, and 6.24 mL and 17.19, respectively, after sequestomy. In comparison with pretreatment situation, those parameters were decreased by -25.7, -24.4, -30.2, -18.5, and -36.5%, respectively, following hyperbaric oxygen therapy and antibiotic administration, and moreover by -31.6, -28.9, -30.7, -47.4, and -59.3, respectively, after sequestomy, likely reflecting treatment response. Quantitative bone SPECT/CT may be useful to evaluate bone inflammatory activity and treatment response in a patient with mandibular osteomyelitis.

Quantitative Bone Single Photon Emission Computed Tomography/Computed Tomography for Evaluating Response to Bisphosphonate Treatment in Patients with Paget's Disease of Bone.

We here report on 2 cases of monostotic Paget's disease of bone, one in the ilium and the other in the skull, including quantitative values obtained with bone single photon emission computed tomography/computed tomography (SPECT/CT), which were useful to evaluate the response to bisphosphonate treatment. The quantitative parameters determined with those findings were decreased, with the maximum standardized uptake value (SUV), peak SUV, mean SUV, metabolic bone volume, and total bone uptake in case 1 and case 2 reduced by 48.8 and 60.3%, 46.6 and 58.8%, 24.3 and 60.5%, 87.0 and 11.8%, and 90.2 and 55.8%, respectively, while TRACP-5B and alkaline phosphatase (ALP) were also reduced by 39.5 and 88.6% and by 53.7 and 78.1%, respectively. Quantitative SPECT/CT parameter decreases were correlated with TRACP-5B and ALP, indicating the usefulness of this modality to examine treatment response.

Examination of cross-calibration and concentration linearity with quantitative gallium-67 single-photon emission computed tomography: phantom experiment.

We evaluated whether scattered radiation should be considered for cross-calibration and concentration linearity with quantitative gallium-67 (67Ga) single-photon emission computed tomography (SPECT). The scanned data from cylinder and spherical phantoms were used. They were reconstructed using ordered subset expectation maximization with resolution recovery, scatter, and computed tomography (CT)-based attenuation correction. The standardized uptake values (SUVs) of the cylinder phantom SPECT/CT images were calculated using system planar sensitivity with and without scatter correction, and the results were compared with the theoretical value. To determine concentration linearity, the relationship between the measured SUVs in three different spherical phantoms was evaluated. SUVs calculated by system planar sensitivity without scatter correction were closer to the theoretical values. Furthermore, the 37-mm sphere showed proper radioactive linearity. Our study suggests the utility of the SUV for 67Ga SEPCT/CT. Nevertheless, additional studies are required.

Influence of image noise and object size on segmentation accuracy of FDG-PET imaging: a phantom experiment.

We aimed to evaluate the influence of noise and object size on segmentation accuracy of fluorodeoxyglucose positron emission tomography (FDG-PET) imaging. The scanned data of spherical phantoms were used. For the gradient method, 40% maximum standardized uptake value (SUVmax) method, and SUV of 2.5 threshold method, we evaluated the correlation between segmentation accuracy and background variability and that between segmentation accuracy and sphere diameters. For the gradient method, background variability did not affect segmentation accuracy, but sphere diameters had a small effect. As for the 40% SUVmax threshold method, both sphere diameters and background variability affected the segmentation accuracy. In the SUV of 2.5 threshold method, segmentation accuracy was affected by sphere diameters but not by background variability. With regard to segmentation accuracy of FDG-PET imaging, the gradient method may be more accurate and reliable compared to threshold methods when applied to images with varying noise or object size.

Usefulness of Quantitative Bone Single Photon Emission Computed Tomography/Computed Tomography for Evaluating Response to Neoadjuvant Chemotherapy in a Patient with Periosteal Osteosarcoma.

We report here a case of periosteal sarcoma in a 10-year-old female, along with quantitative values obtained with bone single photon emission computed tomography/computed tomography (SPECT/CT), which were useful to evaluate treatment response to preoperative chemotherapy. Pretreatment radiograph images of the lower leg showed cortical thickening eroded by a broad-based soft-tissue mass without the involvement of the underlying cortex, while computed tomography (CT) revealed a small juxtacortical mass with thick calcification and periosteal reaction. In magnetic resonance imaging (MRI), the mass showed hypointensity in the inner part and isointensity in the outer part in T1-weighted images, while the inner part showed hypointensity and the outer part hyperintensity in T2-weighted images. Bone SPECT/CT results indicated the focal and intense uptake of the mass. Following neoadjuvant chemotherapy (NAC), radiograph and MRI results revealed a slight increase in size, with growing calcification. Although visual inspection of the bone SPECT/CT findings showed nearly the same amount of focal uptake, quantitative parameters determined with those findings were decreased, with maximum standardized uptake value (SUV), peak SUV, mean SUV, metabolic bone volume (MBV), and total bone uptake (TBU) reduced by -20.7%, -22.0%, -12.6%, -33.5%, and -41.9%, respectively. The excision biopsy at the surgery showed a pathological grade 1 (non-complete response) after NAC, including a more than 20% of cell necrosis part. The quantitative bone SPECT/CT was considered to reflect treatment response in this case.

Assessment of tumor response to chemoradiotherapy and predicting prognosis in patients with head and neck squamous cell carcinoma by PERCIST.

PURPOSE: To evaluate therapeutic response to chemoradiotherapy and prediction of recurrence and death in patients with head and neck squamous cell carcinoma (HNSCC) using Positron Emission Tomography Response Criteria in Solid Tumors (PERCIST). MATERIALS AND METHODS: Forty-two patients (mean 63.4, range 20-79 years) with nasopharyngeal (n = 10), oropharyngeal (n = 13), hypopharyngeal (n = 11), or laryngeal (n = 8) cancer underwent fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) before and approximately 3 months (mean 95.0, range 70-119 days) after undergoing concurrent chemoradiotherapy. The effect of PERCIST regarding progression-free survival (PFS) and overall survival (OS) was examined using log-rank and Cox methods. RESULTS: Complete metabolic response (CMR), partial metabolic response (PMR), stable metabolic disease (SMD), and progressive metabolic disease shown by PERCIST were seen in 30 (71.4%), 9 (21.4%), 3 (7.1%), and 0 patients, respectively. Fourteen (33.3%) developed recurrent disease (median follow-up 27.2, range 8.7-123.1 months) and 9 (21.4%) died (median follow-up 43.6, range 9.6-132.6 months). Furthermore, 4 (13.3%) of 30 patients with CMR developed recurrence, while 7 (77.8%) of 9 with PMR and all 3 (100%) with SMD developed recurrence. Two (6.7%) of 30 patients with CMR, 4 (44.4%) of 9 with PMR, and all 3 (100%) with SMD died. Patients who achieved CMR showed significantly longer PFS and OS as compared to those who did not (PMR and SMD) (both, p < 0.0001). CONCLUSION: PERCIST is useful for evaluating therapeutic response to chemoradiotherapy and predicting recurrence and death in HNSCC patients.