Diagnostic value and therapeutic impact of (18)F-FDG-PET/CT in differentiated thyroid cancer. Results of a German multicentre study.

UNLABELLED: The clinical significance of (18)F-FDG-PET/CT in the follow-up of patients with differentiated thyroid carcinoma was evaluated and the results were compared with those of (18)F-FDG-PET, (131)I-whole-body scintigraphy including SPECT/CT (WBS) and ultrasound. In addition, it was the aim to investigate the impact of (18)F-FDG-PET/CT on the therapeutic management. PATIENTS, METHODS: 327 patients (209 women, 118 men; mean age 53 ± 18 years) with differentiated thyroid cancer (242 papillary, 75 follicular, 6 mixed, 1 Hürthle cell and 3 poorly differentiated tumours) were analyzed retrospectively at four tertiary referral centres. 289 (18)F-FDG-PET/CT and 118 (18)F-FDG-PET studies were performed in these patients between 2007 and 2010. In addition, an overall clinical evaluation was performed, including cytology, histology, thyroglobulin level, ultrasound, WBS, and subsequent clinical course in order to compare the molecular imaging results. Finally, the change in therapeutic management due to findings of (18)F-FDG-PET/CT was investigated. RESULTS: The sensitivity of (18)F-FDG-PET/CT was 92%, the specificity was 95%. Sensitivity and specificity of (18)F-FDG-PET alone were 67% and 93%, respectively. WBS showed a sensitivity of 65% and a specificity of 94%. The corresponding values of ultrasound were 37% and 94%, respectively. The sensitivity of (18)F-FDG-PET/CT in the group of patients with a negative WBS (n=194) amounted to 96%. When (18)F-FDG-PET/CT and WBS were considered in combination, tumour tissue was missed in only 2 out of 133 patients; when (18)F-FDG-PET and WBS were combined, tumour tissue was missed in 1 out of 24 patients. (18)F-FDG-PET/CT resulted in management change in 43% (n=57/133) with a decision on surgical approach in 20% (n=27/133). CONCLUSIONS: (18)F-FDG-PET/CT is superior to (18)F-FDG-PET alone in patients with differentiated thyroid cancer and has a direct impact on the therapeutic management of patients with suspected local recurrence or metastases, particularly in those with negative WBS.

[Endovascular brachytherapy (EVBT) with Rhenium-188 for restenosis prophylaxis after angioplasty of infrainguinal lesions: early experience]. / Endovaskuläre Brachytherapie (EVBT) mit Rhenium-188 zur Restenoseprophylaxe nach Angioplastie infrainguinaler Läsionen: Erste Erfahrungen.

PURPOSE: Restenosis remains a major problem in percutaneous transluminal angioplasty (PTA) of peripheral arteries. The aim of this feasibility study was to evaluate the technical feasibility and safety of a new endovascular brachytherapy (EVBT) device with Rhenium-188 in restenosis prophylaxis of infrainguinal arteries. MATERIALS AND METHODS: From March 2006 to April 2009, 52 patients with 71 infrainguinal arterial lesions were treated with Re-188 to prevent restenosis after PTA. 40 patients with 53 lesions (24 de-novo lesions and 29 restenoses) were reexamined (clinic, color-coded duplex ultrasound) after a mean follow-up period of 12.7 months (2.6 to 25.1 months). The liquid beta-emitter Re-188 was introduced to the target lesion via an EVBT certified PTA balloon and a tungsten applicator. After the calculated irradiation time, Re-188 was aspirated back into the tungsten applicator. A dose of 13 Gy was applied at a depth of 2 mm into the vessel wall. RESULTS: After a mean follow-up of 12.7 months, the overall restenosis rate after Re-PTA was 15.1 % (8 / 53 lesions). The restenosis rate for de-novo lesions was 20.8 % (5 / 24) and 10.3 % for restenoses (3 / 29). In 4 patients reintervention was necessary (3 PTAs and 2 major amputations). No periprocedural complications were observed. No elevated radiation dose for the patient or the interventionalist was measured. CONCLUSION: EVBT with a Re-188 filled balloon catheter was technically feasible and safe after PTA of infrainguinal arterial lesions with restenosis rates lower than expected compared to published results. Treatment of restenoses seems to be more effective than de-novo lesions.

Neoadjuvant chemotherapy affects staging of colorectal liver metastasis--a comparison of PET, CT and intraoperative ultrasound.

PURPOSE: Surgery for colorectal liver metastasis facilitates long-term survival, and neoadjuvant chemotherapy improves resectability but may also alter staging accuracy. The aim of this study was to evaluate the effects of neoadjuvant chemotherapy on the efficacy of positron emission tomography (PET), PET-computed tomography (CT), CT and intraoperative ultrasound (IUS) in the detection of liver metastasis. METHODS: Between January 2007 and January 2010, 34 patients with resectable colorectal liver metastasis were included in this retrospective analysis. Seventeen patients had received neoadjuvant chemotherapy. PET or PET-CT, CT or magnetic resonance imaging (MRI) and IUS were performed in all patients. Sensitivity, specificity, positive predictive value and negative predictive value were analysed. Histopathological examination of the resected specimens served as standard reference. RESULTS: A total of 109 liver segments were resected, of which 50 showed no metastatic involvement (45.9%). For patients without systemic chemotherapy, sensitivities for PET, CT/MRI and IUS were 92%, 64% and 100% respectively as compared with 63%, 65% and 94% for patients after neoadjuvant chemotherapy in a segment-based analysis. For PET, standardised uptake values were decreased by 3.9 in 10 patients after chemotherapy whereas lesion diameters were similar (3.0 vs. 3.2 cm). Additional metastases were detected by IUS in seven patients resulting in a change of operative procedure in 20.6%. CONCLUSION: Staging accuracy of colorectal liver metastasis is influenced by neoadjuvant chemotherapy. For PET, decreased tumour metabolism rather than downsizing may account for a drop in sensitivity after neoadjuvant chemotherapy. IUS is critical to avoid incomplete resections.

[Procedure guideline for sentinel lymph node diagnosis]. / Verfahrensanweisung für die nuklearmedizinische Wächter-Lymphknoten-Diagnostik.

The authors present a procedure guideline for scintigraphic detection of sentinel lymph nodes in malignant melanoma and other skin tumours, in breast cancer, in head and neck cancer, and in prostate and penile carcinoma. Important goals of sentinel lymph node scintigraphy comprise reduction of the extent of surgery, lower postoperative morbidity and optimization of histopathological examination focussing on relevant lymph nodes. Sentinel lymph node scintigraphy itself does not diagnose tumorous lymph node involvement and is not indicated when lymph node metastases have been definitely diagnosed before sentinel lymph node scintigraphy. Procedures are compiled with the aim to reliably localise sentinel lymph nodes with a high detection rate typically in early tumour stages. Radiation exposure is low so that pregnancy is not a contraindication for sentinel lymph node scintigraphy. Even with high volumes of scintigraphic sentinel lymph node procedures surgeons, theatre staff and pathologists receive a radiation exposure <1 mSv/year so that they do not require occupational radiation surveillance.

Validation of sentinel lymph node dissection in prostate cancer: experience in more than 2,000 patients.

PURPOSE: Sentinel lymph node dissection (SLND) has replaced extended lymphadenectomy for nodal staging in several solid tumours. We present our results of SLND in prostate cancer in regard to detection and false-negative rate. METHODS: In a 2-day protocol about 300 MBq (99m)Tc-nanocolloid are injected into the prostate. Two hours later static scans of the pelvis are performed to get information about the number and location of radioactive lymph nodes. During surgery the radioactive nodes are excised with the help of a gamma probe and sent separately to the pathologist. The histological procedure includes haematoxylin and eosin staining, serial sections and immunohistochemistry. RESULTS: Since 1999, a total of 2,020 men underwent SLND alone or in combination with either standard or extended lymphadenectomy after radical retropubic prostatectomy. Lymph nodes positive for metastases were found in 16.7% of patients. The scintigraphic detection rate was 97.6% and the intraoperative detection rate 98%. For 187 lymph node-positive men who had either standard or extended lymphadenectomy in addition to SLND the false-negative rate could be calculated, resulting in false-negative findings in 11 of 187 patients (6%). CONCLUSION: Our results demonstrate that SLND in prostate cancer is a reliable procedure for nodal staging.

[Impact of nuclear medicine imaging techniques for lymph node surgery]. / Bedeutung der nuklearmedizinischen Bildgebung für die Lymphknotenchirurgie.

Nuclear medicine imaging techniques allow the noninvasive in vivo visualization of cellular and subcellular molecular processes. In the context of lymph node surgery and patient management in uro-oncology, two molecular nuclear imaging techniques deserve special interest: positron emission tomography (PET) for staging, restaging, and follow-up, and preoperative identification and subsequent biopsy of the sentinel lymph node (the first lymph node in the lymphatic drainage system of the tumor). Both methods and their clinical potential are described in this review. Future trends in molecular imaging in uro-oncology are also discussed.

[Influence of the injection technique on the false negative rate of SLNE in multifocal breast cancer]. / Einfluss der Injektionstechnik auf die Falsch-negativ-Rate bei der SLNE des mehrherdigen Mammakarzinoms.

AIM: We investigated the influence of the injection technique on the false negative rate in identifying the sentinel lymph node in multifocal breast cancer. PATIENTS, METHODS: 958 consecutive patients were divided into unifocal and multifocal breast cancer patients. The scintigrafic and intraoperative detection rate as well as the false negatives were calculated in relation to peritumoral or subareolar injection. RESULTS: In all patients the scintigrafic and intraoperative detection rate exceeded 99%, except in patients with multifocal cancer, who were injected peritumorally. In this group the intraoperative detection rate declined to 96%. In patients with unifocal breast cancer the false negative rate was below 5%, independent of the injection technique. Multifocal breast cancer patients showed a significant dependence on the injection technique. The false negative rate was 26.3% in patients with peritumoral injection and 5.6% in those with subareolar injection. CONCLUSION: The results clearly demonstrate that in multifocal breast cancer a reliable detection of a SLN is impossible with the peritumoral injection technique. Subareolar injection seems to be a way to operate on multifocal breast cancer with SLNE, but the number of investigated patients is too low for statistic approval. So, prospective studies should be performed to validate these preliminary results before SLNE becomes routine in multifocal breast cancer.

[Radioiodine therapy for combined disseminated and nodular thyroid autonomy. Results after using a correction term for the disseminated part]. / Radioiodtherapie bei kombinierter Schilddrüsenautonomie: Ergebnisse nach Korrektur für disseminierte Anteile.

AIM: In combined focal and disseminated thyroid autonomy a variety of concepts in the treatment with radioiodine are used. The difference lies mainly in the calculation of the autonomous volume. This retrospective study shows a new method of calculating the autonomous volume. PATIENTS AND METHODS: In 398 patients with combined thyroid autonomy and good correlation of scintigraphically hot nodules and lesions defined by ultrasound the volume of the nodules is ascertained from scintigraphic and ultrasound parameters and the volume of the disseminated autonomous tissue is assessed with a weighting factor (VF). This factor is the ratio of impulse density in a ROI over the disseminated volume divided by the corresponding impulse density over the nodular volume of the thyroid scintigraphy. The sum of nodular volume and weighted perinodular volume gives the total autonomous volume. A standard radioiodine test gives the maximum iodine-131-uptake and effective half-life to calculate the activity to obtain a treatment dose of 400 Gy. RESULTS: The rate of success with and without thyrostatic medication was 97% with an 18.6% rate of hypothyroidism observed from 4 months post therapy onwards. CONCLUSION: The use of the weighting factor VF in the treatment of combined autonomy leads to an excellent rate of success in patients with good correlation of functional imaging and ultrasound findings.

Unilateral multicystic dysplastic kidney: experience in children.

OBJECTIVES: To report a retrospective study of unilateral multicystic dysplastic kidneys (MCDK) in children, assessing the contralateral kidneys and urinary tract, the functional consequences, and the urological and nephrological management and outcome, as unilateral MCDK is the most common cause of renal cystic disease in children, and malformations of the contralateral urinary tract and kidney (pelvi-ureteric obstruction, megaureter, reflux, renal dysplasia) have been reported. PATIENTS AND METHODS: The study included 97 patients (60 boys, 37 girls) with MCDK seen between 1985 and 1998; 82 were diagnosed in utero by ultrasonography (US). After birth, the diagnosis was verified by US, renal scanning (in 93) or intravenous urography (in four), and 89 (92%) had voiding cysto-urethrography (VCUG). Of the 97 children, 87 (90% had a mean (range) follow-up of 44.3 (15-115) months. RESULTS: The MCDK was removed in 17 children; the follow-up of 75 children (five lost to follow-up) showed total involution of the MCDK in 25%, shrinkage in 60% and a stable size in 15%. None had any sign of malignancy. The contralateral kidney showed anomalies in 19 of 97 children (20%); 12 had a dilated renal pelvis (two with megaureter), six had a high echogenicity of the contralateral kidney (one had reflux, and two also pelvic dilatation). In only four of the 89 children was reflux found by VCUG; 16 of the 19 anomalies were detected by US. Five children needed surgery on the contralateral urinary tract (three a pyeloplasty, and one each a pyeloplasty plus ureteroneocystostomy, and an antireflux procedure). Of the contralateral kidneys 43% showed compensatory hypertrophy. There was mild renal insufficiency in three children; renal function seemed to be slightly impaired in many. Five infants had hypertension (four with spontaneous resolution) caused by renal scarring after pyelonephritis or inborn dysplasia of the contralateral kidney. There were symptomatic urinary tract infections in seven children. CONCLUSION: US can be used safely to diagnose unilateral MCDKs and malformations of the contralateral urinary tract and kidney. In cases where US of the dysplastic kidney remains uncertain renal scintigraphy is necessary to detect the lack of renal function. The low rate of reflux makes routine VCUG unnecessary if the contralateral upper urinary tract and kidney appear to be normal on US. Nephrectomy of the dysplastic kidney in typical cases is also unnecessary. A long-term nephro-urological follow-up of children with MCDK is recommended.

[Valence of F-18-FDG-PET in the diagnosis of malignant lymphoma]. / Wertigkeit der F-18-FDG-PET in der Diagnostik des malignen Lymphoms.

PET enables tomographic imaging and quantification of molecular metabolism with high temporal and spatial resolution. For routine clinical questions in oncology F-18-labeled fluorodeoxyglucose is the tracer of choice. In malignant lymphoma staging, response control and follow-up studies are valid indications. The initial glucose-uptake and especially the response of metabolism to therapy are in correlation with the outcome of the disease. Complementary to conventional staging PET is able to detect further lymphnode manifestation or extranodal involvement that can result in up-staging. Down-staging is less frequent. In follow-up studies PET is valuable, to assess therapy response, to differentiate viability of lymphoma from fibrous remnants at end of therapy and to detect relapse at an early stadium. In this context it proves to be superior to conventional tomographic imaging. In individual cases relevant therapeutic consequences arise from the metabolic PET-informations. Whether in future PET will be able to partially replace conventional imaging and whether it withstands to cost/effectiveness analysis requires additional prospective studies.

FDG-PET for detection of recurrences from malignant primary bone tumors: comparison with conventional imaging.

BACKGROUND: The aim of this study was to assess the diagnostic ability of positron emission tomography using 2-[fluorine-18]fluoro-2-deoxy-D-glucose (FDG-PET) in the detection of recurrences from malignant primary bone tumors compared with conventional imaging. PATIENTS AND METHODS: In 27 patients (6 osteosarcomas, 21 Ewing's sarcomas), 41 FDG-PET examinations performed for diagnosis or exclusion of recurrent disease were evaluated. Conventional imaging techniques consisted of magnetic resonance imaging of the primary tumor site, thoracic computed tomography, and Tc-99m methylene diphosphonate bone scintigraphy. The reference methods were the histopathological analysis and/or the clinical and imaging follow-up. RESULTS: In 25 examinations reference methods revealed 52 sites of recurrent disease (local n = 7; distant: osseous n = 22, pulmonary n = 13, soft tissue n = 10). On an examination-based analysis FDG-PET had a sensitivity of 0.96, a specificity of 0.81 and an accuracy of 0.90. Corresponding values for conventional imaging were 1.0, 0.56 and 0.82. CONCLUSIONS: The sensitivity, specificity and accuracy of FDG-PET in the detection of recurrences from osseous sarcomas are high. On an examination-based analysis, FDG-PET had a not significantly lower sensitivity in comparison with conventional imaging. However, FDG-PET showed a small advantage in the detection of osseous and soft-tissue recurrences compared with conventional imaging.

18F-Fluorodeoxyglucose PET in a patient with primary small bowel lymphoma: the only sensitive method of imaging.

This report describes the case of a patient with primary small bowel lymphoma. Well-established methods of imaging did not give a hint on diagnosis. Increased 18F-fluorodeoxyglucose uptake was visualized on performance of positron emission tomography, corresponding with the intraoperatively found tumorous process. The present case points to a potential superiority of positron emission tomography in visualizing primary small bowel lymphoma.

FDG-PET for detection of pulmonary metastases from malignant primary bone tumors: comparison with spiral CT.

BACKGROUND: The purpose was the comparison of positron emission tomography using F-18-fluorodeoxy-glucose (FDG-PET) and spiral thoracic CT to detect pulmonary metastases from malignant primary osseous tumors. PATIENTS AND METHODS: In 71 patients with histologically confirmed malignant primary bone tumors (32 osteosarcomas, 39 Ewing's sarcomas) 111 FDG-PET examinations were evaluated with regard to pulmonary/pleural metastases in comparison with spiral thoracic CT. Reference methods were the clinical follow-ups for 6-64 months (median 20 months) or a histopathologic analysis. RESULTS: In 16 patients (23%) reference methods revealed a pulmonary/pleural metastatic disease. FDG-PET had a sensitivity of 0.50, a specificity of 0.98, and an accuracy of 0.87 on a patient based analysis. Comparable values for spiral CT were 0.75, 1.00, and 0.94. It was shown that no patient who had a true positive FDG-PET had a false negative CT scan, nor was a pulmonary metastases detected earlier by FDG-PET than by spiral CT. CONCLUSIONS: There seems to be a superiority of spiral CT in the detection of pulmonary metastases from malignant primary bone tumors as compared with FDG-PET. Therefore, at present a negative FDG-PET cannot be recommended to exclude lung metastases. However, as specificity of FDG-PET is high, a positive FDG-PET result can be used to confirm abnormalities seen on thoracic CT scans as metastatic.

Whole-body MR imaging for detection of bone metastases in children and young adults: comparison with skeletal scintigraphy and FDG PET.

OBJECTIVE: The purpose of this study was to compare the diagnostic accuracy of whole-body MR imaging, skeletal scintigraphy, and 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) for the detection of bone metastases in children. SUBJECTS AND METHODS: Thirty-nine children and young adults who were 2--19 years old and who had Ewing's sarcoma, osteosarcoma, lymphoma, rhabdomyosarcoma, melanoma, and Langerhans' cell histiocytosis underwent whole-body spin-echo MR imaging, skeletal scintigraphy, and FDG PET for the initial staging of bone marrow metastases. The number and location of bone and bone marrow lesions diagnosed with each imaging modality were correlated with biopsy and clinical follow-up as the standard of reference. RESULTS: Twenty-one patients exhibited 51 bone metastases. Sensitivities for the detection of bone metastases were 90% for FDG PET, 82% for whole-body MR imaging, and 71% for skeletal scintigraphy; these data were significantly different (p < 0.05). False-negative lesions were different for the three imaging modalities, mainly depending on lesion location. Most false-positive lesions were diagnosed using FDG PET. CONCLUSION: Whole-body MR imaging has a higher sensitivity than skeletal scintigraphy for the detection of bone marrow metastases but a lower sensitivity than FDG PET.

Characterization of 3-[123I]iodo-L-alpha-methyl tyrosine ([123I]IMT) transport into human Ewing's sarcoma cells in vitro.

3-[(123)I]Iodo-L-alpha-methyl tyrosine ([(123)I]IMT) scintigraphy of extracranial malignant tumors has been described, but little is known about the transport systems involved in [(123)I]IMT uptake into extracranial tumor cells. Here, the precise kinetics of [(123)I]IMT transport into human Ewing's sarcoma cells (VH-64) was determined. The apparent Michaelis constant was of high affinity value (K(m)=41.7+/-3.9 microM) and maximum transport velocitiy amounted to V(max)=20.7+/-0.6 nmol x mg protein(-1) x 10 min(-1). Inhibition experiments revealed the predominance of [(123)I]IMT uptake via sodium-independent system L.

High-activity samarium-153-EDTMP therapy followed by autologous peripheral blood stem cell support in unresectable osteosarcoma.

PURPOSE: Despite highly efficacious chemotherapy, patients with osteosarcomas still have a poor prognosis if adequate surgical control cannot be obtained. These patients may benefit from therapy with radiolabeled phosphonates. PATIENTS AND METHODS: Six patients (three male, three female; seven to 41 years) with unresectable primary osteosarcoma (n = 3) or unresectable recurrent sites of osteosarcomas (n = 3) were treated with high-activity of Sm-153-EDTMP (150 MBq/kg BW). In all patients autologous peripheral blood stem cells had been collected before Sm-153-EDTMP therapy. RESULTS: No immediate adverse reactions were observed in the patients. In one patient bone pain increased during the first 48 hrs after therapy. Three patients received pain relief. Autologous peripheral blood stem cell reinfusion was performed on day +12 to +27 in all patients to overcome potentially irreversible damage to the hematopoietic stem cells. In three patient external radiotherapy of the primary tumor site was performed after Sm-153-EDTMP therapy and in two of them polychemotherapy was continued. Thirty-six months later one of these patients is still free of progression. Two further patients are still alive. However, they have developed new metastases. The three patients who had no accompanying external radiotherapy, all died of disease progression five to 20 months after therapy. CONCLUSION: These preliminary results show that high-dose Sm-153-EDTMP therapy is feasible and warrants further evaluation of efficacy. The combination with external radiation and polychemotherapy seems to be most promising. Although osteosarcoma is believed to be relatively radioresistant, the total focal dose achieved may delay local progression or even achieve permanent local tumor control in patients with surgically inaccessible primary or relapsing tumors.

Evaluation of chemotherapy response in primary bone tumors with F-18 FDG positron emission tomography compared with histologically assessed tumor necrosis.

PURPOSE: The purpose of this study was to evaluate the potential of positron emission tomography using F-18-fluoro-2-deoxy-D-glucose (FDG PET) to assess the chemotherapy response of primary osseous tumors compared with the degree of necrosis determined histologically. PATIENTS AND METHODS: Seventeen patients with primary bone tumors (11 osteosarcomas, 6 Ewing's sarcomas) were examined using FDG PET and planar bone scintigraphy before neoadjuvant chemotherapy and before surgery. Tumor response was classified histologically according to Salzer-Kuntschik (grades I-II: good response; grades IV-VI: poor response). In both imaging methods, quantification was performed using tumor to nontumor ratios (T:NT). RESULTS: Histologically, 15 patients were classified as having good responses (grade I, n = 1; grade II, n = 6; grade III, n = 8) and two as having poor responses (grades IV and V). FDG PET showed more than a 30% decrease in T:NT ratios in all patients who had good responses. However, three of these patients had increasing bone scintigraphy T:NT ratios, and another five had decreasing ratios of less than 30%. The patients with poor responses had increasing T:NT ratios and decreasing ratios of less than 30%, respectively, using both imaging methods. CONCLUSIONS: FDG PET seems to be a promising tool for evaluating the response of primary osseous tumors to chemotherapy. In this preliminary study, FDG PET was superior to planar bone scintigraphy.

FDG-PET for detection of osseous metastases from malignant primary bone tumours: comparison with bone scintigraphy.

The purpose of this study was to compare positron emission tomography using fluorine-18 fluorodeoxyglucose (FDG-PET) and technetium-99m methylene diphosphonate (MDP) bone scintigraphy in the detection of osseous metastases from malignant primary osseous tumours. In 70 patients with histologically proven malignant primary bone tumours (32 osteosarcomas, 38 Ewing's sarcomas), 118 FDG-PET examinations were evaluated. FDG-PET scans were analysed with regard to osseous metastases in comparison with bone scintigraphy. The reference methods for both imaging modalities were histopathological analysis, morphological imaging [additional conventional radiography, computed tomography (CT) or magnetic resonance imaging (MRI)] and/or clinical follow-up over 6-64 months (median 20 months). In 21 examinations (18%) reference methods revealed 54 osseous metastases (49 from Ewing's sarcomas, five from osteosarcomas). FDG-PET had a sensitivity of 0.90, a specificity of 0.96 and an accuracy of 0.95 on an examination-based analysis. Comparable values for bone scintigraphy were 0.71, 0.92 and 0.88. On a lesion-based analysis the sensitivity of FDG-PET and bone scintigraphy was 0.80 and 0.72, respectively. Analysing only Ewing's sarcoma patients, the sensitivity, specificity and accuracy of FDG-PET and bone scan were 1.00, 0.96 and 0.97 and 0.68, 0.87 and 0.82, respectively (examination-based analysis). None of the five osseous metastases from osteosarcoma were detected by FDG-PET, but all of them were true-positive using bone scintigraphy. In conclusion, the sensitivity, specificity and accuracy of FDG-PET in the detection of osseous metastases from Ewing's sarcomas are superior to those of bone scintigraphy. However, in the detection of osseous metastases from osteosarcoma, FDG-PET seems to be less sensitive than bone scintigraphy.