Imaging of regional lymph node metastases with 99mTc-depreotide in patients with lung cancer

Purpose The aim of this study was to evaluate the clinical usefulness of scintigraphy with ^99mTc-depreotide in the assessment of loco-regional nodal spread in patients with suspected lung cancer in comparison with computed tomography (CT).Methods Eighty-six patients were investigated with single-photon emission computed tomography (SPECT) of the thorax after i.v. injection of 740 MBq ^99mTc-depreotide. The results were evaluated in conjunction with a thoracic CT scan in all 86 patients with 204 lymph node stations. The scintigraphic results were correlated with cytological (38), histological (20) or clinical–radiological (146) findings and compared with CT. The quantitative evaluation of depreotide uptake was performed on 48 cytologically or histologically verified nodal stations from 28 patients by SPECT using region of interest analysis with four different reference regions.Results ^99mTc-depreotide scintigraphy for all 204 investigated lymph node stations had a sensitivity of 99% and a negative predictive value of 98% in determining lymph node involvement. Scintigraphy and CT showed the same level of accuracy, 76.4%. CT findings had a higher positive predictive value but a lower negative predictive value compared to ^99mTc-depreotide scintigraphy. The quantitative evaluation of depreotide uptake in lymph nodes using vertebra as a reference region showed that a cut-off level of 0.56 excludes malignant involvement of lymph nodes, while a cut-off level of 1.66 excludes benign disease in lymph nodes. About 73% of all investigated lymph node stations showed uptake values between these cut-off levels.Conclusion Absence of ^99mTc-depreotide uptake on scintigraphic imaging can exclude regional lymph node involvement with a high degree of probability and may be useful in clinical practice. The quantitative evaluation of depreotide uptake in regional lymph nodes did not increase the diagnostic accuracy of the method in general but did elucidate the lymph node status in some patients.     

Diagnosis and staging of children’s lymphoma using the technetium-labelled somatostatin analogue, <Superscript>99m</Superscript>Tc-depreotide

Somatostatin receptor scintigraphy (SRS) is useful in diagnosing tumours with increased expression of somatostatin receptors. Lymphoma cells are known to express somatostatin receptors; however, the application of indium-labelled analogues in children is limited. The aim of this study was to investigate whether the technetium-labelled somatostatin analogue, depreotide, may be useful in diagnosing and staging malignant lymphoma in children. Fifteen children (mean age 13.8 years) with malignant lymphoma were studied (eight with Hodgkins lymphoma and seven with non-Hodgkins lymphoma). All children were investigated for verification of staging established by other modalities. Imaging was performed 3–5 h after administration of 300–550 MBq ^99mTc-depreotide. All patients underwent whole-body scan and single-photon emission tomography of the chest and/or abdomen. Images were assessed visually. In all patients, foci of increased tracer uptake were found. The neck and thorax were the most frequent lesion localisations. Abdominal lesions were found in four patients, and bone lesions in three. In two patients, diffusely increased uptake was observed throughout the skeleton (verified as representing bone marrow involvement). In 11 patients, the number of abnormal sites detected by SRS was greater than that detected by CT. Based on radionuclide examination, three children were upstaged and none were downstaged. It is concluded that ^99mTc-depreotide shows increased accumulation in pathological sites in malignant lymphoma in children. SRS with ^99mTc-depreotide provides a single-day imaging method with high sensitivity in lymphoma and with all the advantages of a technetium-labelled compound. Further studies are required on the specificity and the possible value of ^99mTc-depreotide in the follow-up of these patients.     

The usefulness of bone-marrow scintigraphy in the detection of bone metastasis from prostatic cancer

We used a combination of bone and bone-marrow scintigraphy to study 25 patients with prostatic cancer. Of the 18 cases whose ^99mTc-methylene diphosphonate (MDP) bone scans showed hot spots in the lower lumbar region of the spine and/or the pelvic bone, 8 had normal bone-marrow scintigrams. These 8 patients were subsequently shown to have senile, degenerative changes of the spine. On the other hand, in 9 of the 10 patients whose bone-marrow scintigrams showed accumulation defects, follow-up study and characteristic X-ray findings confirmed the presence of metastases. In all 6 cases with extensive bone metastases shown by ^99mTc-MDP bone scintigraphy, ^99mTc-sulphur-colloid bone-marrow scintigraphy showed multiple accumulation defects. In conclusion, bone-marrow scintigraphy was found to be useful in distinguishing metastatic lesions from benign degenerative changes in the cases with suspected bone involvement, as well as in evaluating equivocal lesions in the pelvis.     

Comparison of whole-body <Superscript>18</Superscript>F-FDG PET, <Superscript>99m</Superscript>Tc-MIBI SPET,and post-therapeutic <Superscript>131</Superscript>I-Na scintigraphy in the detection of metastatic thyroid cancer

The usefulness of fluorine-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) in differentiated thyroid cancer (DTC) has been demonstrated by many investigators, but in only a small number of studies have FDG-PET images been compared with those obtained using other non-iodine tumour-seeking radiopharmaceuticals. In most of the studies, planar imaging was performed for comparison using thallium-201 chloride or technetium-99m 2-methoxyisobutylisonitrile (^99mTc-MIBI). Furthermore, FDG-PET studies were not always performed in the hypothyroid state with increased levels of thyroid stimulating hormone (TSH), which are known to increase FDG uptake by DTC. The aim of this study was to compare the ability of FDG-PET to detect metastatic DTC with that of ^99mTc-MIBI whole-body single-photon emission tomography (SPET) and post-therapeutic iodine-131 scintigraphy, evaluated under TSH stimulation. Nineteen patients (8 men, 11 women; age range, 38–72 years, mean 60 years; 17 thyroidectomised and 2 inoperable patients following ¹³¹I ablation of the remaining thyroid tissue; 16 papillary and 3 follicular carcinomas) with metastatic DTC underwent FDG-PET whole-body scan (WBS) and ^99mTc-MIBI SPET WBS at an interval of less than 1 week, followed by ¹³¹I therapy. The SPET images were reconstructed using the maximum likelihood expectation maximisation (ML-EM) method. All patients were hypothyroid at the time of each scan. ¹³¹I WBS was performed 3–5 days after oral administration of the therapeutic dose. A total of 32 lesions [10 lymph node (LN), 15 lung, 6 bone, 1 muscle] were diagnosed as metastases, as confirmed by histopathology and/or other imaging modalities (X-ray, US, CT, MRI, bone, ²⁰¹Tl and ¹³¹I scans). FDG-PET, ^99mTc-MIBI SPET and post-therapeutic ¹³¹I scintigraphy respectively revealed a total of 26 (81.3%), 20 (62.5%) and 22 (68.8%) lesions. These techniques respectively demonstrated nine (90.0%), eight (80.0%) and six (60.0%) LN metastases, and eleven (73.3%), seven (46.7%) and ten (66.7%) lung metastases. They each demonstrated five of the six bone metastases (83.3%). FDG-PET and ^99mTc-MIBI SPET were positive in 17 (78.3%) and 14 (63.6%) of the 22 ¹³¹I-positive lesions, respectively, and also in nine (90.0%) and six (60.0%) of the ten ¹³¹I-negative lesions, respectively. Three of the five ¹³¹I-positive and FDG-PET-negative lesions were miliary type lung metastases with a maximal nodular diameter of less than 10 mm. Comparison of FDG-PET with ^99mTc-MIBI SPET revealed concordant results in 24 lesions, and discordant results in eight lesions (seven with positive FDG-PET alone and one with positive ^99mTc-MIBI SPET alone). In conclusion: (a) even using whole-body SPET, FDG PET is superior to ^99mTc-MIBI in terms of ability to detect metastases of DTC; (b) the higher sensitivity of FDG-PET compared with the previous studies could partly be due to increased serum TSH.     

<Superscript>99m</Superscript>Tc-HYNIC octreotide in neuroblastoma

Disease status assessment of neuroblastoma patients requires computed tomography (or magnetic resonance imaging), bone scan, metaiodobenzylguanidine (MIBG) scan, bone marrow tests, and urine catecholamine measurements. There is no clinical experience concerning the evaluation of these patients by means of technetium-99m (^99mTc)-somatostatin analog scintigraphy. Furthermore, these radiopharmaceuticals are promising imaging agents owing to their lower cost, availability, dosimetry, and ease of preparation. An 8-year-old boy already diagnosed with stage-IV neuroblastoma received chemotherapy. In the follow-up, after obtaining the parents’ informed consent, iodin 131 (¹³¹I)-MIBG and ^99mTc-6-hydrazinopyridine-3-carboxylic acid (HYNIC)-octreotide scans were done on separate days to evaluate tumor extension. Even as the ¹³¹I-IBG scan showed mild diffuse uptake in the projection of both lung hili, the ^99mTc-HYNIC-octreotide scan showed multiple axial and appendicular bone uptakes and paravertebral, abdominal, mediastinal, and supraclavicular ganglionar uptakes. The ^99mTc-HYNIC-octreotide showed much more lesion extension than the ¹³¹I-MIBG. Therefore, ^99mTc-HYNIC-octreotide may be a promising radiopharmaceutical for the evaluation of neuroblastoma patients. This finding justifies the pre liminary evaluation of this tracer in the context of a clinical trial.     

Whole-body iodine-131 metaiodobenzylguanidine imaging for detection of bone metastases in patients with paraganglioma: comparison with bone scintigraphy

Iodine-131 metaiodobenzylguanidine (¹³¹I-MIBG) therapy is an effective treatment for patients with malignant paraganglioma for which surgical resection is not indicated. We performed high-dose ¹³¹I-MIBG therapy on two patients with malignant paraganglioma and multiple bone metastases. The bone metastases were diagnosed by magnetic resonance imaging (MRI). Metastatic bone lesions were evaluated by whole-body ¹³¹I-MIBG imaging and bone scintigraphy. Whole-body ¹³¹I-MIBG imaging showed extensive metastatic bone lesions, whereas conventional bone scintigraphy did not. There was a remarkable discrepancy between ¹³¹I-MIBG imaging and bone scintigraphy in the diagnosis of metastatic bone lesions of malignant paraganglioma in our two patients. High-dose ¹³¹I-MIBG imaging may detect early stages of bone metastases, compared with bone scintigraphy, in patients with malignant paraganglioma.     

<Superscript>99m</Superscript>Tc-bombesin detects prostate cancer and invasion of pelvic lymph nodes

Biopsy is the standard method for the diagnosis of prostate cancer; however, it is inadequate for the assessment of lymph node invasion. Radionuclide imaging might be useful for both diagnosis and N staging, but it requires high uptake of radiotracers in order to overcome difficulties arising from the anatomy of the region. The aim of this study was to assess whether or not technetium-99m labelled bombesin (^99mTc-BN) scan is able to detect prostate cancer and invasion of pelvic lymph nodes. Ten patients were studied with ^99mTc-BN, transrectal ultrasonography, biopsy, computed tomography and magnetic resonance imaging. All the patients with cancer were operated on. Planar dynamic scintigraphy and single-photon emission tomography (SPET) were performed after administration of 185 MBq ^99mTc-BN. Two patients showed benign adenoma and eight showed cancer at biopsy. The average Gleason's score was 7.5±1.3. ^99mTc-BN dynamic planar scan showed hot spots in the prostatic fossa in two of the eight patients with cancer, both of whom had a prostate-specific antigen level higher than 20 ng/ml. In these patients, high uptake inside the prostatic fossa was detected as early as 1 min after injection, before the arrival of radioactivity in the bladder. True positive SPET scans were obtained in all eight patients with cancer. Invasion of the obturator nodes was detected by SPET in three patients, and in all three was confirmed at surgery. Our preliminary data encourage further studies on the prostate with ^99mTc-BN. If the high sensitivity of ^99mTc-BN SPET is confirmed, this method may play an important role in diagnosing and staging prostate cancer.     

Comparison of whole-body STIR-MRI and <Superscript>99m</Superscript>Tc-methylene-diphosphonate scintigraphy in children with suspected multifocal bone lesions

The study was performed to compare whole-body short time inversion recovery (STIR) MR imaging and ^99mTc-methylene diphosphonate planar scintigraphy in the examination of children with suspected multifocal skeletal malignant lesions. Sixteen patients with known or suspected malignant skeletal disease underwent both whole-body STIR MR imaging and bone scintigraphy. The lesions were described and numbered according to scintigraphic evaluation criteria. Thus, 16 regions were analyzed in each patient for the comparison between the two modalities. Histology was proven in the primary malignant regions. Follow-up MRIs were registered. Scintigraphy and MRI follow-up were evaluated as gold standard. A total of 139 different lesions was observed by both modalities. Baseline whole-body MRI revealed 119 bone lesions in 256 possible sites (46.5%); scintigraphy revealed only 58 lesions (22.6%). Congruence was observed in only four patients (25%). According to the location of the lesion, correlation was observed in 39/139 lesions (28%). In all, 57.5% of the lesions were detected only by MRI and 14.5% of the lesions were detected only by scintigraphy. Whole-body MRI was more sensitive (P<0.001). Of all lesions numbered which could be separated in the initial MRI, whole-body MRI detected 178 lesions in the patients. The results suggest that whole-body MRI using a STIR sequence is an effective radiation free method for examination of children with suspected multifocal bone lesions. MRI showed more lesions than conventional ^99mTc-methylene diphosphonate scintigraphy. Therefore, whole-body MRI may be feasible as a screening modality for metastatic and skip lesions in osteosarcoma, PNET, Ewing sarcoma and Langerhans cell histiocytosis in children.     

Somatostatin receptor scintigraphy using <Superscript>99m</Superscript>Tc-EDDA/HYNIC-TOC in patients with medullary thyroid carcinoma

Purpose Several new somatostatin analogues have been developed for the diagnosis and therapy of different tumours. Since somatostatin receptors are often over-expressed in medullary thyroid carcinoma (MTC), the aim of our study was to evaluate the utility of scintigraphy with the somatostatin analogue ^99mTc-EDDA/HYNIC-TOC in MTC in comparison with other diagnostic techniques. Methods Forty-five patients with MTC, aged 14–83 years, were investigated. Scintigraphy using ^99mTc-EDDA/HYNIC-TOC (Tektrotyd) was performed 2 and 4 h post injection of 740 MBq (20 mCi) of the tracer. Other imaging techniques were also applied and analysed in individual cases (ultrasonography, computed tomography, ^99mTc(V)-DMSA, ¹³¹I-MIBG, ^99mTc-MDP, ¹¹¹In-DTPA-octreotide and ¹⁸F-FDG-PET) and compared with ^99mTc-EDDA/HYNIC-TOC. Results In group 1 (eight patients before thyroidectomy), uptake of the tracer was found in the primary tumours. In group 2 (six patients with remission), a false positive result was found in one patient; in the remaining five patients, no pathological foci were visualised. In group 3 (31 patients with post-surgical hypercalcitoninaemia), scintigraphy was true positive in 23 patients (74.2%): uptake in the thyroid bed was found in five patients, in the lymph nodes in 18 and in bone metastases in four. Using ^99mTc-EDDA/HYNIC-TOC scintigraphy, the overall sensitivity was 79.5%, specificity 83.3%, accuracy 80.0%, positive predictive value 96.9% and negative predictive value 38.5%. Conclusion ^99mTc-EDDA/HYNIC-TOC is clinically useful for scintigraphy in the follow-up of patients with MTC. It can be used in clinical practice for preoperative evaluation, for localisation of local recurrence or distant metastases and particularly for therapy decision making.     

First experiences with technetium-99m furifosmin as tumour-seeking agent in breast cancer and recurrent ovarian cancer

Recent in vitro studies suggest that technetium-99m furifosmin may have tumour-seeking properties. We analysed the diagnostic value of^99mTc-furifosmin scintigraphy in nine patients with documented carcinoma of the breast and in eight patients with continued recurrent ovarian cancer. In the breast,^99mTc-furifosmin failed to visualize the primary malignant tumour and the associated malignant lymph nodes in all patients. In contrast, multiple sites of increased tracer uptake were demonstrated in one patient with acute benign inflammatory breast disease. In four of eight patients with recurrent ovarian cancer,^99mTc-furifosmin scintigraphy demonstrated early (5 min p.i.) localized increased uptake corresponding to adhesions to the bowel as diagnosed by computed tomography, but failed to reveal further abnormalities in all patients. The present study demonstrates that furifosmin is of no value in the imaging of breast cancer and recurrent ovarian cancer. These results do not continue the pattern observed in cell culture studies and are quite in contrast to the findings of mammoscintigraphy using^99mTc-methoxyisobutylisonitrile and^99mTc-tetrofosmin.     

Efficiency of 18F-FDG and 99mTc-depreotide SPECT in the diagnosis of malignancy of solitary pulmonary nodules

Purpose The purpose of the study was to compare ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET) and ^99mTc-depreotide single-photon emission computed tomography (SPECT) in the diagnosis of malignancy of solitary pulmonary nodules (SPNs).Methods Twenty-eight patients without any history of cancer and presenting an SPN (0.8–3 cm in size) underwent FDG PET and depreotide SPECT. Depreotide SPECT and FDG PET were performed on a double-head gamma camera and a dedicated PET scanner respectively. Twenty-five out of 28 lesions were removed by thoracotomy or assessed by biopsy (n=1) and histologically examined. A strategy of serial CT scanning was adopted in the three remaining patients.Results Histological findings revealed 18 malignant nodules and seven benign lesions. Stability over a 2-year period indicated a benign process in the remaining three cases. Both techniques yielded true positive results in 15 of the 18 cancers. FDG PET identified two additional adenocarcinomas not detected by depreotide SPECT. A carcinoid tumour not visualised on FDG PET was identified by depreotide SPECT. Seven of the ten benign lesions did not reveal tracer uptake on either depreotide SPECT or FDG PET. Both techniques showed false positive results for the same two lesions. One more false positive was seen on FDG PET. FDG PET and depreotide SPECT had a sensitivity of 94.4% and 88.9% respectively; this difference was not significant. In our experience, depreotide SPECT and FDG PET are equally sensitive (92.3%) for large (>1.5 cm) and equally specific (85.7%) for small (up to 1.5 cm) SPNs suspicious for malignancy.Conclusion This study showed ¹⁸F-FDG PET to be more sensitive than ^99mTc-depreotide SPECT in the diagnosis of malignancy of SPNs. However, the combination of both techniques may provide additional accuracy.     

Differentiation of malignant and degenerative bone lesions using dexamethasone interventional 3- and 24-hour bone scintigraphy

Seventy-seven adult patients with suspected skeletal metastases were divided into two groups. In group A (n=30), following intravenous administration of 20 mCi (740 MBq) of technetium-99m methylene diphosphonate (^99mTc-MDP), 3- and 24-h scintigraphy of bone lesions was performed. The 24/3 h lesion to bone background radiouptake ratio (RUR) was calculated for each lesion. In group B (n=47), the same procedure was followed with dexamethasone intervention (10 mg in 24 h) following the 3-h acquisition. In group A, after determination of the critical point, malignant and degenerative bone lesions could be separated with a sensitivity, specificity and accuracy of 0.76, 0.72 and 0.73, respectively. The mean RUR of the malignant lesions was 1.20± 0.23, and that of the benign lesions, 0.95± 0.15. In group B cases, significantly increased sensitivity, specificity and accuracy of 0.87, 0.94 and 0.92, respectively, were found (P<0.001). The mean RUR of the malignant lesions was 1.48± 0.34, and that of degenerative lesions, 0.88± 0.19. Dexamethasone interventional bone scintigraphy seems to be a new cost-effective method for differentiating malignant from degenerative bone lesions using the RUR. Correspondence to: A. Bhatnagar     

Unusual bone scintigraphy in chronic myelogenous leukemia — report of a case showing extensive uptake defect

An extensive ^99mTc-methylene diphosphonate uptake defect was observed on bone scintigraphy in a 35-year-old male with chronic myelogenous leukemia. This type of bone scintigraphy pattern is quite unusual in leukemic patients and we speculate that acute disturbance of blood supply to the bone marrow was probably the cause.     

Pre-operative localisation of hyperfunctional parathyroid tissue with <Superscript>11</Superscript>C-methionine PET

Purpose Previous studies have shown high sensitivity of positron emission tomography (PET) with ¹¹C-methionine in the pre-operative localisation of parathyroid adenoma and hyperplasia. Nonetheless, in secondary and tertiary hyperparathyroidism (HPT) and in patients with recurrent disease, pre-operative localisation of adenomatous (PTA) or hyperplastic tissue is still a problem with all available methods. The aim of this study was to define the optimal imaging protocol and to compare the diagnostic value of ¹¹C-methionine PET and ^99mTc-methoxyisobutylisonitrile (MIBI) single-photon emission computed tomography (SPECT): in particular, we wished to define the benefit of ¹¹C-methionine in those patients with inconclusive or negative conventional imaging.Methods Thirty highly pre-selected patients with HPT were enrolled. Sixteen patients had primary HPT, 12 patients had secondary HPT, and two patients had recurrences of parathyroid carcinomas. All patients had ultrasound of the neck, dual-phase scintigraphy with ^99mTc-MIBI and PET with ¹¹C-methionine. SUV_parathyroid/SUV_{cervical soft tissue} (target-to-background) and SUV_{parathyroid tissue}/SUV_{thyroid tissue} (target-to-non-target) ratios were calculated. After surgery, histology of specimens was obtained in all patients but one.Results In 12 patients with secondary or tertiary HPT, 36 hyperplastic parathyroid glands were histologically verified. Twenty-five of 36 lesions (69%) were detected with ¹¹C-methionine PET and 17 (47%) with ^99mTc-MIBI scintigraphy. PET studies were positive in 17/18 (94%) cases in which HPT was related to adenomas or carcinomas. ^99mTc-MIBI scintigraphy/SPECT yielded pathological lesions in 9/18 cases (50%). All eight atypical localisations of parathyroid glands were detected with PET but only six of the eight were detected with ^99mTc-MIBI scintigraphy/SPECT. In 10/11 patients with recurrent HPT and non-diagnostic scintigraphy/SPECT, hyperfunctional parathyroid tissue was identified with ¹¹C-methionine PET. The highest SUV_parathyroid/SUV_{cervical soft tissue} ratio was found 10 min, and the highest SUV_{parathyroid tissue}/SUV_{thyroid tissue} ratio 40 min post injection. In three patients clear delineation of hyperfunctional tissue was only achieved after 40 min post injection.Conclusion ¹¹C-methionine PET is a clinically useful method in highly pre-selected patients with recurrent primary HPT as well as in secondary and tertiary HPT if ultrasound and ^99mTc-MIBI SPECT are inconclusive or negative. PET imaging of atypical PTA localisations is more accurate than conventional scintigraphy. In order to achieve optimal contrast of parathyroid glands versus thyroid tissue and adjacent soft tissue, imaging at both 10 min and 40 min is recommended.     

Using <Superscript>99m</Superscript>Tc-DTPA radioaerosol inhalation lung scan as compared with computed tomography to detect lung injury in blunt chest trauma

Background

Detection of pulmonary contusion in patients with blunt chest trauma is very important so as to commence therapy immediately to avoid irreversible damage. The purpose of our study was to evaluate the efficacy of technetium-99m diethylene triamine pentaacetic acid (^99mTc-DTPA) aerosol inhalation lung scintigraphy in comparison with chest computed tomography (CT) in the diagnosis of pulmonary contusion at acute blunt chest trauma.

Methods

Twenty-nine patients with isolated blunt chest trauma were referred to the emergency department of our hospital, and nine healthy people participated in this study. Sixteen patients who had pulmonary contusion on CT scans were referred to as group 1, and 13 patients who had normal CT scans as group 2. Nine healthy people comprised a control group. ^99mTc-DTPA aerosol inhalation lung scintigraphy was performed on the first day in all patients.

Results

The mean half time (T_½) and penetration index values of ^99mTc-DTPA clearance were significantly lower in groups 1 and 2 compared with the control group. Among the three groups, there were no significant differences in arterial blood gas analysis except for PO₂. The mean T_½ value of ^99mTc-DTPA clearance did correlate with PO₂ values but not with pH, PCO₂, or HCO₃ values.

Conclusions

^99mTc-DTPA radioaerosol inhalation lung imaging may serve as a useful adjunct and supportive method to chest CT scanning for detecting mild pulmonary contusion.

     

Clinical usefulness of <Superscript>99m</Superscript>Tc-EDDA/HYNIC-TOC scintigraphy in oncological diagnostics: a preliminary communication

This study assessed the clinical usefulness of a new technetium-99m labelled somatostatin analogue from the standpoint of oncological diagnostics. The study group comprised 40 patients in whom malignant neoplasms (32 primary and 8 metastatic) had been diagnosed. Among the primary tumours there were 21 cases of lung cancer (2 small cell and 19 non-small cell), seven pituitary adenomas (five hormonally active and two inactive), one liposarcoma, two carcinoids and one breast carcinoma. The metastatic tumours consisted of three malignant melanomas, one phaeochromocytoma, one prostatic cancer, one leiomyosarcoma, one pancreatic carcinoma ectopically secreting ACTH and one carcinoid of the thymus. The radiopharmaceutical ^99mTc-EDDA/HYNIC-Tyr³-octreotide was administered i.v. at an activity of 740–925 MBq. The imaging comprised a whole-body scan and a single-photon emission tomography acquisition. Positive scintigrams were obtained in all cases of small cell and non-small cell lung cancer, four out of five hormonally active pituitary adenomas, one out of two cases of carcinoid, the liposarcoma and the breast cancer. Neoplastic metastases were visualised in two out of three patients with melanoma and in patients with phaeochromocytoma, ACTH-secreting pancreatic carcinoma and thymic carcinoid. Scintigrams were negative in both hormonally inactive pituitary adenomas, in one case of metastatic malignant melanoma, in the leiomyosarcoma and in the case of metastasis from prostatic carcinoma. The results of this pilot study indicate that ^99mTc-EDDA/HYNIC-TOC is a potentially useful radiopharmaceutical for imaging of a wide range of primary and metastatic tumours. Special attention should be paid to the successful imaging of all cases of non-small cell lung cancer .     

99mTc-EDDA/HYNIC-TOC scintigraphy in the differential diagnosis of solitary pulmonary nodules

Forty-three consecutive patients with solitary pulmonary nodules (SPNs) on chest radiographs were studied scintigraphically after administration of the somatostatin analogue ^99mTc-EDDA/HYNIC-TOC. The objective of the study was to assess the usefulness of the procedure for differentiation of SPNs as malignant or benign. The administered activity was 740–925 MBq, and a single-photon emission computed tomography imaging technique was employed. Verification of the nodule aetiology was based on histology or cytology and bacteriology. A stable tumour size on chest radiography for at least 3 years was accepted as an additional criterion of benignity. In 29 patients, nodules were found to be malignant. The diagnoses included ten adenocarcinomas, five squamous cell carcinomas, two large cell carcinomas, six non-small cell lung cancers without specification of the more detailed morphology, two small cell lung cancers, two typical carcinoids and two metastatic tumours (leiomyosarcoma and malignant melanoma). In 14 patients the following benign tumours were diagnosed: four tuberculomas, one other granuloma, three hamartomas, one non-specific inflammatory infiltrate, one abscess, one peripheral carcinoid with the morphological characteristics of a benign tumour, one ectopic lesion of thyroid tissue and two benign tumours of unspecified aetiology with a stable size over 3 and 5 years respectively. Positive scintigraphic results were obtained in 26 of the 29 patients (90%) with malignant SPNs; among these, 24 of the 25 (96%) cases of primary pulmonary carcinoma yielded positive results. The remaining two false negative cases were the metastatic tumours, liposarcoma and melanoma. Of the 14 benign lesions, ten (71%) did not accumulate the radiopharmaceutical. The remaining four benign tumours that were visible on scintigrams comprised one tuberculoma, one hamartoma, one abscess and one case in which the diagnosis could not be established (the tumour had a stable size over 3 years). In conclusion, scintigraphy with ^99mTc-EDDA/HYNIC-TOC appears to be an effective procedure for differentiation between malignant and benign SPNs. A fully credible assessment of the clinical efficacy of this procedure requires further study in a larger number of patients.     

99mTc-EDDA/HYNIC-octreotate scintigraphy, an efficient method for the detection and staging of carcinoid tumours: results of 3 years’ experience

Purpose At all stages of the disease, serious difficulties are encountered in the imaging diagnosis of carcinoids. Somatostatin receptor scintigraphy (SRS) holds great promise for detecting primary tumours and metastases. ^99mTc-EDDA/HYNIC-octreotate should significantly improve the diagnosis of carcinoids in comparison with ¹¹¹In-Octreoscan owing to the better affinity for SSR2 and the higher count rate. The aim of this study was to assess the diagnostic efficiency of ^99mTc-EDDA/HYNIC-octreotate scintigraphy in the detection and staging of carcinoid tumours.Methods The study population comprised 75 patients (age 48.5±15.5 years): 46 with histological confirmation of carcinoid and 29 with suspected disease. ^99mTc-EDDA/HYNIC-octreotate (740 MBq) SRS and CT were performed in all patients. Fifteen patients were examined with ¹¹¹In-Octreoscan. Results High-quality ^99mTc-EDDA/HYNIC-octreotate images were obtained in all cases, with maximum tumour tracer accumulation 4 h p.i. The mean target/non-target ratios for whole body (WB) and SPECT scans were, respectively, as follows: primary lesions: 4.5 and 10.2; metastases: liver, 3.1 and 12.3; abdominal focal lesions, 2.7 and 5.8; lung, 2.7 and 8.3; mediastinum, 3.4 and 7.6; bones, 6.8 and 19.0. ^99mTc-EDDA/HYNIC-octreotate WB scans revealed more metastases than ¹¹¹In-Octreoscan, with better individual separation. ^99mTc-EDDA/HYNIC-octreotate SRS revealed new metastatic lesions in seven patients with confirmed carcinoid, and in four with dissemination the primary focus was found. Five patients qualified for radioguided surgery and 11 were referred to ⁹⁰Y-DOTA-TATE therapy. The sensitivity of SRS in comparison with CT was higher for primary lesions and liver and abdominal lymph node metastases. In the subgroup of patients with suspected neuroendocrine tumours, two duodenal carcinoids, one thymic carcinoid and one ileal carcinoid were found.Conclusion ^99mTc-EDDA/HYNIC-octreotate, with high imaging quality, is an excellent alternative to ¹¹¹In-Octreoscan for staging of carcinoids, and it seems to be the method of choice for detection of the primary focus in patients with metastases from an unknown primary tumour.     

99mTc-methylene diphosphonate uptake by ossifications and calcifications of non-osseous metastatic tumors

Two cases of extra-osseous uptake of ^99mTc-methylene diphosphonate (MDP) by non-osseous metastatic tumors are reported. One was a metastasis with ossification in the abdominal wall from carcinoma of the sigmoid colon and the other was a metastasis with calcification from an ovarian carcinoma. The mechanism of extra-osseous uptake of ^99mTc-MDP is discussed. Bone scintigraphy can be a potential means to assess tumor spread with ossifications and calcifications.     

<Superscript>11</Superscript>C-acetate PET imaging of lung cancer: comparison with <Superscript>18</Superscript>F-FDG PET and <Superscript>99m</Superscript>Tc-MIBI SPET

Recently carbon-11 acetate (AC) positron emission tomography (PET) has been reported to be of clinical value for the diagnosis of cancer that is negative on fluorine-18 fluorodeoxyglucoce (FDG) PET. We investigated the uptake of AC in lung cancer to determine whether this tracer is of potential value for tumour detection and characterisation, and to compare AC PET imaging with FDG PET and technetium-99m sestamibi (MIBI) single-photon emission tomography (SPET). Twenty-three patients with 25 lung cancers underwent AC and FDG PET. Twenty of 23 patients were also investigated with MIBI SPET. Dynamic images were acquired for 26 min after the injection of 555 MBq of AC. Standardised uptake values (SUVs) and/or tumour to non-tumour activity ratios (T/N) for each tumour were investigated at 10–20 min after AC administration, 40–60 min after administration of 185 MBq FDG and 15–45 min after administration of 555 MBq MIBI. Twenty lung cancers were resected surgically, and the degree of tracer uptake in the primary lesion was correlated with histopathological features (cell dedifferentiation and aggressiveness) and prognosis. Rapid uptake of AC followed by extremely slow clearance was observed. For the purpose of tumour identification, AC PET was inferior to FDG PET in 8 of 25 (32%) lung cancers, and the T/N of AC was lower than that of FDG. However, AC PET was superior to FDG PET in the identification of a slow-growing tumour (bronchiolo-alveolar carcinoma). There was a positive correlation between AC uptake (T/N) and MIBI uptake (T/N) (r=0.799, P<0.0001). A positive correlation was not observed between either AC or MIBI uptake and the degree of cell dedifferentiation in lung adenocarcinomas, whereas FDG uptake did correlate with the degree of cell dedifferentiation. In lung adenocarcinoma, there was a weak correlation between aggressiveness and FDG uptake, but no correlation was evident for AC and MIBI. In addition, a positive correlation was not observed between AC or MIBI uptake and postoperative recurrence in lung adenocarcinoma, whereas FDG uptake did correlate with postoperative recurrence. Thus, the greater the FDG uptake, the higher the malignant grade. In conclusion, for the purpose of tumour identification, AC PET was inferior to FDG PET but superior to MIBI SPET. Neither AC nor MIBI uptake reflects the malignant grade in lung adenocarcinoma, whereas FDG uptake does. AC PET is less diagnostically informative than FDG PET in patients with lung cancer. However, AC PET may play a complementary role in the identification of low-grade malignancies that are not FDG avid.