The Role of Whole Body DWI in the Evaluation of Bone Disease in Multiple Myeloma / 中国实验血液学杂志

OBJECTIVE@#To explore the characteristics of ADC value changes in DWI of newly diagnosed symptomatic MM patients and its correlation with R-ISS stage.@*METHODS@#The data of 148 newly diagnosed symptomatic MM patients treated by whole-body DWI scan at The First Affiliated Hospital of Soochow University from June 2016 to June 2019 were selected and retrospectively analyzed and 30 cases of age-matched healthy people were selected as controls. The differences of ADC values between the patients in normal control group, DWI- group and DWI+ group were compared, and the relationship between ADC values and R-ISS stage in MM patients was compared.@*RESULTS@#The plasma cell percentage of the patients in DWI+ group was higher than those in DWI- group. ADC values of vertebra, sternum, rib, pectoral girdle, pelvic girdle of the patients in DWI+ group were significantly higher than those in DWI- group and normal control group. The ADC values of each part of the patients in DWI- group were higher than those in normal control group. ADC values of sternum, rib and pectoral girdle in the patients at R-ISS stage III were higher than those at R-ISS stage I and II, while, there was no statistical difference between R-ISS stage I and II groups. And there was no significant difference in ADC values of other bone parts such as vertebra and pelvic girdle in patients at R-ISS stage Ⅰ-Ⅲ.@*CONCLUSION@#DWI+ in MM patients is related to higher tumor invasion. The ADC values of the DWI+ group are higher than those of the DWI- group; the bone ADC values of the DWI- patients are still higher than the normal ones. And there is a certain relationship between ADC value and R-ISS stage.

(99m)Tc-Pertechnetate Scintigraphy Predicts Successful Postoperative Ablation in Differentiated Thyroid Carcinoma Patients Treated with Low Radioiodine Activities

BACKGROUND: Postoperative routine radioiodine (RAI) treatment is currently debated for patients with low-risk differentiated thyroid carcinoma (DTC) patients. If performed, a low 131I activity (i.e., 1 to 2 GBq) is recommended with the aim to ablate thyroid remnant and facilitate subsequent follow-up by thyroglobulin measurement. The purpose of this study was to evaluate the relationship between postsurgical technetium-99m (99mTc)-pertechnetate scintigraphy and the rate of successful remnant ablation after low activity radioiodine ablation in patients with DTC. METHODS: Enrolled were 193 patients with low risk DTC who underwent total thyroidectomy and RAI ablation with a fixed 1.1 GBq activity of 131I. 99mTc-pertechnetate scans were done and thyrotropin stimulated thyroglobulin (sTg) levels measured just before ablation. Ablation effectiveness was assessed 6 to 12 months later by sTg measurement, neck ultrasound and diagnostic whole body scan. RESULTS: A negative 99mTc-perthecnetate scans was the best predictor of successful ablation (P<0.001) followed by preablative sTg levels <0.8 ng/mL (P=0.008) and 99mTc-pertechnetate uptake rate values <0.9% (P=0.065). Neither sex nor age of the patient at the time of ablation or tumor histology and size showed a significant association with the rate of successful ablation. CONCLUSION: The 99mTc-pertechnetate scintigraphy is a simple and feasible tool to predict effectiveness of low activity 131I thyroid to ablate thyroid remnants in patients with DTC.

The Predictive Values of Lesion Size, F-18 FDG Avidity and I-131 Avidity for the Clinical Outcome of I-131 Treatment in Patients with Metastatic Differentiated Thyroid Carcinoma Only in the Lung / 대한핵의학회잡지

PURPOSE: We aimed to evaluate the prognostic values of radiography, F-18 FDG PET, and I-131 whole body scans in patients with lung-only metastasis from differentiated thyroid carcinoma (DTC).METHODS: Between 1998 and 2013, we included 31 patients (F: 26, M: 5) with lung-only metastasis from DTC who had been treated with I-131 and underwent PET. Lung metastasis was categorized according to the size (macronodular ≥1.0 cm vs. micronodular <1.0 cm), FDG avidity (avid vs. non-avid), and I-131 avidity (avid vs. non-avid). Progression-free survival (PFS) was evaluated for each patient.RESULTS: Among 31 patients, seven (23%) had macronodular lung metastasis, 26 (84%) had FDG avid lung metastasis, and 16 (52%) had I-131 avid lung metastasis. During the median follow-up period of 9.4 y, median PFS was 6.1 y. Based on Kaplan-Meier analysis, macronodular lung metastasis (p = 0.017) and I-131 non-avid lung metastasis (p = 0.059) were significantly associated with worse outcomes, but FDG avid lung metastasis was not (p = 0.135). Patients with FDG non-avid lung metastasis did not experience disease progression during follow-up, while 11 of 26 patients (42%) experienced disease progression. Based on univariate analysis, the hazard ratio for a poor prognosis was 3.78 (p = 0.029) for macronodular lung metastasis and 3.29 (p = 0.079) for I-131 non-avid lung metastasis.CONCLUSIONS: Macronodular and I-131 non-avid lung metastasis were associated with a poor prognosis in lung-only metastasis from DTC. Although FDG avid lung metastasis may be associated with a poor prognosis, a larger-scale study is needed.

Reliability of the EOS Imaging System for Assessment of the Spinal and Pelvic Alignment in the Sagittal Plane

BACKGROUND: The sagittal alignment of the spine and pelvis is not only closely related to the overall posture of the body but also to the evaluation and treatment of spine disease. In the last few years, the EOS imaging system, a new low-dose radiation X-ray device, became available for sagittal alignment assessment. However, there has been little research on the reliability of EOS. The purpose of this study was to evaluate the intrarater and interrater reliability of EOS for the sagittal alignment assessment of the spine and pelvis. METHODS: Records of 46 patients were selected from the EOS recording system between November 2016 and April 2017. The exclusion criteria were congenital spinal anomaly and deformity, and previous history of spine and pelvis operation. Sagittal parameters of the spine and pelvis were measured by three examiners three times each using both manual and EOS methods. Means comparison t-test, Pearson bivariate correlation analysis, and reliability analysis by intraclass correlation coefficients (ICCs) for intrarater and interrater reliability were performed using R package “irr.” RESULTS: We found excellent intrarater and interrater reliability of EOS measurements. For intrarater reliability, the ICC ranged from 0.898 to 0.982. For interrater reliability, the ICC ranged from 0.794 to 0.837. We used a paired t-test to compare the values measured by manual and EOS methods: there was no statistically significant difference between the two methods. Correlation analysis also showed a statistically significant positive correlation. CONCLUSIONS: EOS showed excellent reliability for assessment of the sagittal alignment of the spine and pelvis.

Development of dual reporter imaging system for Francisella tularensis to monitor the spatio-temporal pathogenesis and vaccine efficacy

PURPOSE: Study on the pathogen and the pathogen-related disease require the information at both cellular and organism level. However, lack of appropriate high-quality antibodies and the difference between the experimental animal models make it difficult to analyze in vivo mechanism of pathogen-related diseases. For more reliable research on the infection and immune-response of pathogen-related diseases, accurate analysis is essential to provide spatiotemporal information of pathogens and immune activity to avoid false-positive or mis-interpretations. In this regards, we have developed a method for tracking Francisella tularensis in the animal model without using the specific antibodies for the F. tularensis. MATERIALS AND METHODS: A dual reporter plasmid using GFP-Lux with putative bacterioferritin promoter (pBfr) was constructed and transformed to F. tularensis live vaccine strain to generate F. tularensis LVS (FtLVS)-GFP-Lux for both fluorescence and bioluminescence imaging. For vaccination to F. tularensis infection, FtLVS and lipopolysaccharide (LPS) from FtLVS were used. RESULTS: We visualized the bacterial replication of F. tularensis in the cells using fluorescence and bioluminescence imaging, and traced the spatio-temporal process of F. tularensis pathogenesis in mice. Vaccination with LPS purified from FtLVS greatly reduced the bacterial replication of FtLVS in animal model, and the effect of vaccination was also successfully monitored with in vivo imaging. CONCLUSION: We successfully established dual reporter labeled F. tularensis for cellular and whole body imaging. Our simple and integrated imaging analysis system would provide useful information for in vivo analysis of F. tularensis infection as well as in vitro experiments, which have not been fully explained yet with various technical problems.

Star-Shaped Intense Uptake of ¹³¹I on Whole Body Scans Can Reflect Good Therapeutic Effects of Low-Dose Radioactive Iodine Treatment of 1.1 GBq

BACKGROUND: After initial radioactive iodine (RAI) treatment in differentiated thyroid cancer patients, we sometimes observe a star-shaped region of intense uptake of 131I on whole body scans (WBSs), called a ‘star artifact.’ We evaluated the clinical implications of star artifacts on the success rate of remnant ablation and long-term prognosis. METHODS: Total 636 patients who received 131I dose of 1.1 GBq for the initial RAI therapy and who did not show distant metastasis at the time of diagnosis were retrospectively evaluated. A negative second WBS was used for evaluating the ablation efficacy of the RAI therapy. Among them, 235 patients (36.9%) showed a star artifact on their first WBS. RESULTS: In patients with first stimulated thyroglobulin (sTg) levels ≤2 ng/mL, patients with star artifacts had a higher rate of negative second WBS compared with those without star artifacts (77.8% vs. 63.9%, P=0.044), and showed significantly higher recurrence-free survival (P=0.043) during the median 8.0 years (range, 1.0 to 10.0) of follow-up. The 5- and 10-year recurrence rates (5YRR, 10YRR) were also significantly lower in patients with star artifacts compared with those without (0% vs. 4.9%, respectively, P=0.006 for 5YRR; 0% vs. 6.4%, respectively, P=0.005 for 10YRR). However, ablation success rate or recurrence-free survival was not different among patients whose first sTg levels >2 ng/mL regardless of star artifacts. CONCLUSION: Therefore, star artifacts at initial RAI therapy imply a good ablation efficacy or a favorable long-term prognosis in patients with sTg levels ≤2 ng/mL.

Clinical utility of 18F-FDG PET/CT in the follow-up of a large cohort of patients with high-risk differentiated thyroid carcinoma

ABSTRACT Objective To evaluate the clinical utility of 18F-FDG PET/CT in patients with high-risk DTC. Subjects and methods Single-center retrospective study with 74 patients with high-risk differentiated thyroid cancer (DTC), classified in 4 groups. Group 1: patients with positive sTg or TgAb, subdivided in Group 1A: negative RxWBS and no foci of metastases identified at conventional image (n = 9); Group 1B: RxWBS not compatible with suspicious foci at conventional image or not proportional to sTg level (n = 13); Group 2: patients with histological findings of aggressive DTC variants (n = 21) and Group 3: patients with positive RxWBS (n = 31). Results 18F-FDG PET/CT identified undifferentiated lesions and helped restage the disease in groups 1B and 2. The scan helped guide clinical judgment in 9/13 (69%) patients of group 1B, 10/21 (48%) patients of group 2 and 2/31 (6%) patients of group 3. There was no clinical benefit associated with group 1A. 18F-FDG PET/CT was associated with progressive disease. Conclusion 18F-FDG PET/CT is a useful tool in the follow-up of patients with high-risk DTC, mainly in the group of RxWBS not compatible with suspicious foci at conventional image or not proportional to sTg level and in those with aggressive DTC variants. Additionally, this study showed that 18F-FDG PET/CT was associated with progression and helped display undifferentiated lesions guiding clinical assessments regarding surgeries or expectant treatments.

Intrathoracic stomach mimicking bone metastasis from thyroid cancer in whole-body iodine-131 scan diagnosed by SPECT/CT

SUMMARY The whole-body iodine-131 scintigraphy is an imaging technique in monitoring patients with a history of thyroid cancer. Although the rate of false positives is negligible, it is not nonexistent. We report the case of an intervened and treated patient for thyroid cancer with good clinical and biochemical response. Scintigraphic findings were consistent with unsuspected bone metastasis. Fused SPECT/CT data allowed accurate diagnosis of giant diaphragmatic hernia associated with intrathoracic stomach, a very rare pathology that can lead to false positive results.

Bilateral Renal Metastasis of Hürthle Cell Thyroid Cancer with Discordant Uptake Between I-131 Sodium Iodide and F-18 FDG / 대한핵의학회잡지

Renal metastasis of thyroid cancer is extremely rare. We report the case of a 62-year-old woman with Hürthle cell thyroid cancer (HCTC) with lungs, bones, and bilateral kidneys metastases. The renal metastatic lesions were clearly demonstrated by ¹³¹I whole body scan (WBS) with SPECT/CT. However, they exhibited false-negative results in ¹⁸F-FDG PET/CT, kidney ultrasonography, and contrast-enhanced CT scan. The findings imply that tumors have low glucose metabolism and are able to accumulate radioiodine, which is not commonly found in the relatively aggressive nature of HCTC. The patient received two sessions of 200 mCi ¹³¹I therapy within 6 months duration. There was complete treatment response as evaluated by the second post-therapeutic ¹³¹I SPECT/CT and serum thyroglobulin. To our knowledge, renal metastasis from HCTC with positive ¹³¹I but negative ¹⁸F-FDGuptake has not been reported in the literature. This case suggests that ¹³¹I SPECT/CTis useful for lesion localization and prediction of ¹³¹I therapy response.

A Case of Breast Cancer Brain Metastasis with a 16-Year Time Interval without Evidence of Cancer Recurrence / 한국유방암학회지

The median time of brain metastasis from the diagnosis of breast cancer is approximately 3 years. In this case report, a 69-year-old woman demonstrated cerebellar ataxia. Brain magnetic resonance imaging revealed enhanced lesions in bilateral cerebellar hemispheres. She had undergone surgery, radiation, and chemotherapy for uterine and breast cancer 24 years prior and 16 years prior, respectively. Although she had not received any anticancer treatment for 10 years, no recurrences were identified using whole body scans. A partial tumor resection was performed and the histological diagnosis was an adenocarcinoma from breast cancer. As no extracranial lesions were found, gamma-knife irradiation was performed, without additional systemic chemotherapy. One month posttreatment, the tumors dramatically reduced in size and the patient completely recovered from cerebellar ataxia. Systemic chemotherapy is not always required for brain metastasis from breast cancer with a long interval period, as long as no evidence of extracranial recurrence is detected.

Risk factors associated with high thyroglobulin level following radioactive iodine ablation, measured 12 months after treatment for papillary thyroid carcinoma

PURPOSE: The measurement of serum thyroglobulin (Tg) of papillary thyroid carcinoma patients, 12 months after total thyroidectomy and radioactive iodine (RAI) ablation following thyroxine hormone withdrawal (T4-off Tg) or recombinant human thyroid-stimulating hormone stimulation (rhTSH-Tg), is standard method for monitoring disease status. The aim of this study was to find predictive factors for detectable T4-off Tg during follow-up. METHODS: A retrospective review was conducted of 329 patients who underwent total thyroidectomy and RAI ablation between October 2008 and August 2012. Subjects were assigned to high (>1 ng/mL, n = 53) and low (≤1 ng/mL, n = 276) groups, based on T4-off Tg measured 12 months postoperatively. Demographic and clinicopathological characteristics at diagnosis and follow-up were compared between the 2 groups. RESULTS: The low and high T4-off Tg groups differed with respect to tumor size, preoperative Tg, ablative Tg, cervical lymph node metastasis, thyroglobulinemia out of proportion to results of diagnostic whole body scan, and American Thyroid Association 3-level stratification and restratification. Multivariate analysis confirmed that ablative Tg > 1.0 ng/mL (odds ratio [OR], 10.801; P = 0.001), more than 5 cervical lymph node metastasis (OR, 6.491; P = 0.003), and thyroglobulinemia out of proportion (OR, 9.221; P = 0.000) were risk factors. CONCLUSION: Ablative Tg >1.0 ng/mL, more than 5 cervical lymph node metastasis, and thyroglobulinemia out of proportion were independent factors for T4-off Tg >1 ng/mL 12 months postoperative. In low-risk patients without these risk factors, the possible omission of Tg measurements could be considered during follow-up.

Variabilidad en la determinación de fracción grasa muscular en resonancia magnética utilizando la técnica de Dixon / Variability in magnetic resonance quantification of muscle fat fraction using Dixon's technique

Abstract. Muscle MRI has emerged as a valuable tool in the diagnosis of neuromuscular-disorders. The Dixon fat-water separation technique allows objective intra-muscular fat quantification. There are few reports concerning measurement standardisation with Dixon technique. The objective of this study was to evaluate the variability in fat quantification using Dixon's technique in a cohort of patients with congenital myopathies, by analysing intra-segment, intra-muscle, and inter-muscle variability of 60 muscles in each patient. Whole body MRI was performed on 31 patients, 23 with congenital myopathies and 8 healthy controls, aged between 10 months and 35 years old, from January 2014 to June 2016. The mean fat-fraction in healthy patients was around 5%, with less than 2% intra-muscle variability. An intra-muscle variability between 3.1-7.8% was estimated in patients with congenital myopathies. It may be concluded that there is high intra- and inter-muscle fat-fraction variability among patients with congenital myopathies, and this is an observation that should be incorporated in the analysis of fat replacement.

Resumen. La resonancia magnética muscular ha emergido como una valiosa herramienta de apoyo diagnóstico en enfermedades neuromusculares. La técnica de Dixon permite objetivar la fracción grasa muscular, pero no existe consenso sobre la estandarización de estas mediciones. El objetivo de este estudio fue evaluar la variabilidad en la determinación de fracción grasa utilizando la técnica de Dixon, estudiando la variabilidad intrasegmentaria, intramuscular e intermuscular en 60 músculos por paciente. Se realizó RM de cuerpo completo a 31 pacientes: 23 con miopatía congénita y 8 controles, entre 10 meses y 35 años de edad, desde enero del 2014 a junio del 2016. En pacientes sanos se estimó una fracción grasa promedio cercana al 5%, con una variabilidad intramuscular inferior al 2%. En pacientes con miopatías congénitas existe una variabilidad entre el 3,1-7,8%. El estudio permite concluir que existe una alta variabilidad intra e intermuscular en pacientes miopáticos, que no se observa en pacientes sanos.

Value of dedicated head and neck [18]F-FDG PET/CT protocol in detecting recurrent and metastatic lesions in post-surgical differentiated thyroid carcinoma patients with high serum thyroglobulin level and negative [131]I whole-body scan

Objective[s]: In clinical practice, approximately 10-25% of post-surgical differentiated thyroid carcinoma [DTC] patients with high serum thyroglobulin [Tg] and negative [131]I whole-body scan [WBS] have poor prognosis due to recurrent or metastatic lesions after radioactive iodine treatment. The purpose of this study was to evaluate the value of [18]F-FDG PET/CT scan in DTC patients with high serum Tg level and negative [131]I WBS

Methods: 69 post-surgical DTC patients with high serum Tg level and negative post ablation [131]I WBS were enrolled in this study. All DTC patients underwent head and neck ultrasound, CT scan and whole-body [18]F-FDG PET/CT, based on the dedicated head and neck protocol

Results: Overall, 92 lesions were detected in 43 [62.3%] out of 69 patients with positive [18]F-FDG PET/CT scan, compared to only 39 lesions detected on CT scan in 26 [37.7%] out of 69 patients. The sensitivity, accuracy and negative predictive value of [18]F-FDG PET/CT were 88%,87% and 76%, respectively, which were significantly higher than those of CT scan [67.2%, 54.3% and 48.8%, respectively] [P<0.01]. Specificity and positive predictive value of [18]F-FDG PET/CT [90.5% and 95.2%, respectively] were similar to those of CT scan [95.2% and 96.2%, respectively] [P>0.05]. The maximum standardized uptake value [SUV[max]] threshold was 4.5 with a good diagnostic value [sensitivity of 92.3% and specificity of 100%]. The dedicated head and neck [18]F-FDG PET/CT protocol altered the treatment plan in 33 [47.8%] out of 69 DTC patients with high serum Tg level and negative [131]I WBS

Conclusion: Dedicated head and neck [18]F-FDG PET/CT protocol showed a higher diagnostic value, compared to CT scan and played an important role in detecting recurrent or metastatic lesions in post-surgical DTC patients with high serum Tg level and negative [131]I WBS

Incidental Detection of Struma Ovarii on the Whole Body Scan in a Differentiated Thyroid Cancer Patient

Post-therapeutic whole body scan (RxWBS) after radioactive iodine (RAI) remnant ablation (RRA) is useful for detect recurrent or metastatic foci of differentiated thyroid carcinoma (DTC) after total thyroidectomy. However, there is rare possibility of false positive iodine uptake in WBS. Here, we report a case of a 72-year-old woman, who underwent RRA after total thyroidectomy due to follicular variant papillary thyroid carcinoma. There is an abnormal iodine uptake in RxWBS in pelvic cavity. Additional single photon emission computed tomography (SPECT)-computed tomography (CT) imaging showed an intensive I-131 avid mass in left ovary. There was a multiple calcified mass in left ovary and enhancing wall thickening in left ureter with hydronephrosis in contrast enhanced CT. She underwent hysterectomy, oophorectomy, left ureterectomy and nephrectomy and diagnosed as mature cystic teratoma with thyroid tissues and ureter cancer. Struma ovarii should be considered if there was abnormal RAI uptake in pelvic cavity. I-131 SPECT-CT is useful for differential diagnosis of abnormal iodine uptakes in WBS.

Incidental Detection of Struma Ovarii on the Whole Body Scan in a Differentiated Thyroid Cancer Patient

Post-therapeutic whole body scan (RxWBS) after radioactive iodine (RAI) remnant ablation (RRA) is useful for detect recurrent or metastatic foci of differentiated thyroid carcinoma (DTC) after total thyroidectomy. However, there is rare possibility of false positive iodine uptake in WBS. Here, we report a case of a 72-year-old woman, who underwent RRA after total thyroidectomy due to follicular variant papillary thyroid carcinoma. There is an abnormal iodine uptake in RxWBS in pelvic cavity. Additional single photon emission computed tomography (SPECT)-computed tomography (CT) imaging showed an intensive I-131 avid mass in left ovary. There was a multiple calcified mass in left ovary and enhancing wall thickening in left ureter with hydronephrosis in contrast enhanced CT. She underwent hysterectomy, oophorectomy, left ureterectomy and nephrectomy and diagnosed as mature cystic teratoma with thyroid tissues and ureter cancer. Struma ovarii should be considered if there was abnormal RAI uptake in pelvic cavity. I-131 SPECT-CT is useful for differential diagnosis of abnormal iodine uptakes in WBS.

Comparison of Thyroglobulin Measurements Using Three Different Immunoassay Kits: A BRAMHS Tg-Plus RIA Kit, a BRAMHS hTg Sensitive Kryptor Kit, and a Beckman Coulter ACCESS Immunoassay Kit

BACKGROUND: Second-generation thyroglobulin immunometric assays (Tg-IMAs) have been developed with improved sensitivity. Our aim was to compare the diagnostic value of Tg-IMA measurements using a Kryptor (BRAHMS AG) kit (Tg-K) and an ACCESS (Beckman Coulter) kit (Tg-A) with that of the first-generation Tg measurement using a Tg-plus (BRAHMS AG) kit (Tg+). METHODS: We enrolled 82 differentiated thyroid cancer patients who underwent total thyroidectomy with radioactive iodine remnant ablation and who underwent diagnostic whole body scan using recombinant human thyroid stimulating hormone (rhTSH). The Tg+, Tg-K, and Tg-A were measured before rhTSH administration during levothyroxine treatment (suppressed Tg) from the same sample. Serum Tg+ was measured after rhTSH stimulation (stimulated Tg). RESULTS: Suppressed Tg+ was more significantly correlated with suppressed Tg-K (R²=0.919, P<0.001) than with suppressed Tg-A (R²=0.536, P<0.001). The optimal cut-off values of suppressed Tg+, Tg-K, and Tg-A for predicting stimulated Tg+ of 1 ng/mL were 0.3, 0.2, and 0.2 ng/mL, respectively. The sensitivity, specificity, and accuracy of suppressed Tg+ were 67%, 100%, and 90%, respectively; those of suppressed Tg-K were 83%, 90%, and 88%; those of suppressed Tg-A were 96%, 82%, and 87%, respectively. The positive predictive and negative predictive values of Tg+ were 100% and 87%, respectively; those of Tg-K were 79% and 92%; and those of Tg-A were 73% and 98%. CONCLUSION: We could not clearly demonstrate which kit had better diagnostic performance after comparison of first-generation Tg measurements with Tg-IMA measurements. Also, there were kit-to-kit variations between Tg-IMA kits. Suppressed Tg measured by Tg-IMA was insufficient to completely substitute for a stimulated Tg measurement.

F-18 Sodium Fluoride Positron Emission Tomography/Computed Tomography for Detection of Thyroid Cancer Bone Metastasis Compared with Bone Scintigraphy

OBJECTIVE: The aim of the study was to compare the diagnostic performances of F-18 sodium fluoride positron emission tomography/computed tomography (bone PET/CT) and bone scintigraphy (BS) for the detection of thyroid cancer bone metastasis. MATERIALS AND METHODS: We retrospectively enrolled 6 thyroid cancer patients (age = 44.7 ± 9.8 years, M:F = 1:5, papillary:follicular = 2:4) with suspected bone metastatic lesions in the whole body iodine scintigraphy or BS, who subsequently underwent bone PET/CT. Pathologic diagnosis was conducted for 4 lesions of 4 patients. RESULTS: Of the 17 suspected bone lesions, 10 were metastatic and 7 benign. Compared to BS, bone PET/CT exhibited superior sensitivity (10/10 = 100% vs. 2/10 = 20%, p = 0.008), and accuracy (14/17 = 82.4% vs. 7/17 = 41.2%, p 0.05). CONCLUSION: Bone PET/CT may be more sensitive and accurate than BS for the detection of thyroid cancer bone metastasis.

Radiation Dose from Whole-Body F-18 Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography: Nationwide Survey in Korea

The purpose of this study was to estimate average radiation exposure from 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) examinations and to analyze possible factors affecting the radiation dose. A nation-wide questionnaire survey was conducted involving all institutions that operate PET/CT scanners in Korea. From the response, radiation doses from injected FDG and CT examination were calculated. A total of 105 PET/CT scanners in 73 institutions were included in the analysis (response rate of 62.4%). The average FDG injected activity was 310 +/- 77 MBq and 5.11 +/- 1.19 MBq/kg. The average effective dose from FDG was estimated to be 5.89 +/- 1.46 mSv. The average CT dose index and dose-length product were 4.60 +/- 2.47 mGy and 429.2 +/- 227.6 mGycm, which corresponded to 6.26 +/- 3.06 mSv. The radiation doses from FDG and CT were significantly lower in case of newer scanners than older ones (P < 0.001). Advanced PET technologies such as time-of-flight acquisition and point-spread function recovery were also related to low radiation dose (P < 0.001). In conclusion, the average radiation dose from FDG PET/CT is estimated to be 12.2 mSv. The radiation dose from FDG PET/CT is reduced with more recent scanners equipped with image-enhancing algorithms.