Search

The melanoma targeting peptides (Ala-triazol)Ac-Re(Arg(11))CCMSH and N4-CO-Re(Arg(11))CCMSH were radiolabeled with [(99m)Tc(CO)3](+) and [(99m)TcO2](+), respectively, and examined for in vitro cell binding, in vivo biodistribution and imaging properties. The (Ala-triazol)Ac-Re(Arg(11))CCMSH and N4-CO-Re(Arg(11))CCMSH were synthesized as protected peptides on resin followed by rhenium cyclization with [(C6H5)3P]2ReOCl3 in DMF. The peptides were labeled with (99m)Tc and examined for radiochemical stability and melanoma cell binding. In vivo biodistribution and SPECT/CT imaging studies were performed in B16/F1 melanoma tumor bearing C57 mice. (99m)Tc(CO)3-(Ala-Triazol)Ac- Re(Arg(11))CCMSH and (99m)TcO2-N4-CO-Re(Arg(11))CCMSH were stable and internalized in B16/F1 melanoma cells upon binding. In vivo biodistribution studies revealed that tumor uptake of (99m)Tc(CO)3-(Ala-Triazol)Ac-Re(Arg(11))CCMSH was 6.08±1.06% ID/g and 7.05±1.48% ID/g at 2 h and 4 h post injection, respectively. Tumor uptake of (99m)TcO2-N4-CORe(Arg(11))CCMSH was 7.54±1.82% ID/g and 2.28±0.22% ID/g at 1 h and 2 h post injection, respectively. SPECT/CT imaging studies showed that tumor selective uptake of the radiolabeled peptides, which was confirmed by competitive blocking studies.

We describe the design and synthesis of a new Tc-99m labeled bioconjugate for imaging activated complement, based on Short Consensus Repeats 1 and 2 of Complement Receptor 2 (CR2), the binding domain for C3d. To avoid non specific modification of CR2 and the potential for modifying lysine residues critical to the CR2/C3d contact surface, we engineered a new protein, recombinant CR2 (rCR2), to include the C-terminal sequence VFPLECHHHHHH, a hexahistidine tag (for site-specific radiolabeling with [(99m)Tc(CO)(3)(OH(2))(3)](+)). The protein was characterized by N-terminal sequencing, SDS-PAGE and size exclusion chromatography. To test the function of the recombinant CR2, binding to C3d was confirmed by enzyme-linked immunosorbent assay (ELISA). The function was further confirmed by binding of rCR2 to C3d(+) red blood cells (RBC) which were generated by deposition of human or rat C3d and analyzed by fluorescence microscopy and flow cytometry. The affinity of rCR2 for C3d(+), in presence of 150 mM NaCl, was measured using surface plasma resonance giving rise to a K(D)≈500 nM. Radiolabeling of rCR2 or an inactive mutant of rCR2 (K41E CR2) or an unrelated protein of a similar size (C2A) with [(99m)Tc(CO)(3)(OH(2))(3)](+) at gave radiochemical yields >95%. Site-specifically radiolabeled rCR2 bound to C3d to C3d(+) RBC. Binding of radiolabeled rCR2 to C3d was inhibited by anti-C3d and the radiolabeled inactive mutant K41E CR2 and C2A did not bind to C3d(+) RBCs. We conclude that rCR2-Tc(99m) has excellent radiolabeling, stability and C3d binding characteristics and warrants in vivo evaluation as an activated complement imaging agent.

Wandering spleen is the term commonly applied to splenic hypermobility that results from laxity or maldevelopment of its suspensory ligaments. It comes to medical attention usually as an abdominal mass, or when the spleen undergoes torsion. Diagnosis on clinical grounds alone is rarely made, and ultrasonography, CT and MRI findings have no specific characteristics for this condition. 99mTc-labeled colloid taken up by the spleen may provide a specific diagnosis. We report a case of wandering spleen, in which the preoperative diagnosis was made on the basis of sequential liver-spleen scintigraphy with 99mTc-Sn-colloid and blood-pool scintigraphy with 99mTc-RBC. This is a rare case, in which hypermobility was assessed by sequential 99mTc-Sn-colloid scintigraphy, and to our knowledge, is the first case in which 99mTc-RBC scintigraphy provided useful information on splenic blood volume and its location.

The therapeutic effects on pneumatic dilatation were evaluated quantitatively by radionuclide transit study using 99mTc-Sn colloid in an achalasia patient. After dilatation, transit time (T3/4) with distilled water has improved from 13.5 seconds to 5.5 seconds. Radionuclide transit study using 99mTc-Sn colloid was a preferable method to evaluate the efficacy of the treatment quantitatively in an achalasia.

The bone scan is sensitive in detection of active bone/joint lesions. A normal bone scan virtually excludes the presence of an inflammatory process with high precision, but the poor specificity of bone scans is well known. In recent years, various new agents including 99Tcm-hexamethylpropylene amine oxime (HMPAO)-labelled white blood cells, nanocolloid, polyclonal IgG, anti-granulocyte antibody, 111In-labelled IgG, leucocytes, chemotactic peptides etc. have been widely evaluated in inflammatory imaging, especially in the orthopaedic context. This study was undertaken to compare the usefulness of 99Tcm-nanocolloid and 99Tcm-polyclonal IgG in the detection of focal bone/joint inflammation. Twenty-seven patients with a common presentation of bone/joint pain resulting from various pathologies were included in the study. A total of 47 lesions were imaged. The overall sensitivity and specificity of both nanocolloid scan and IgG scan were identical with 95% sensitivity and 100% specificity, in detecting inflammatory foci. However, specificity dropped to 18% with nanocolloid scans and 16% with IgG scans when an attempt was made to distinguish noninfective from infective inflammatory processes; thus neither type of scan permits differentiation between septic and nonseptic inflammatory processes with sufficient accuracy. As both nanocolloid and IgG scans are equally sensitive and specific in detecting inflammation, the choice of type of scan will depend on cost, imaging time and availability of the radiopharmaceutical.

Indium-111 oxine labelled leucocyte (111In oxine leucocyte) scintigraphy is the test of choice in detecting occult infection and localising focal inflammation. 111In oxine labelling is technically difficult and expensive and leucocyte labelling with technetium-99m stannous colloid (99mTc Sn colloid) has been considered to be an alternative. Leucocytes from 40 cases referred for investigation of occult infection or localisation of inflammation were simultaneously labelled with 111In oxine and 99mTc Sn colloid with dual isotope acquisition performed at 1, 3 and 24 h. Twenty-four hour 99mTc Sn colloid scans were corrected for 111In downscatter. Each case was independently interpreted by two experienced observers. Twenty-one patients demonstrated positive 111In oxine leucocyte scans. Using 111In oxine leucocyte scans as the gold standard, 99mTc Sn colloid leucocyte scanning had an overall sensitivity of 86% and a specificity of 95%. Clinical follow-up verified that three patients had false negative 99mTc Sn colloid leucocyte scans and one patient had a false positive. Further clinical evaluation of 99mTc Sn colloid labelled leucocytes is required before they can become a reliable replacement for 111In oxine leucocytes.

The splenic uptake rate of Tc-sulphur colloid or Tc-tin colloid was measured and found to correlate well with splenic function. The normal tracer uptake rate was 0.0002/s-0.0006/s (measured uptake rate divided by measured injected activity). Lower values indicated hyposplenism (sensitivity = 0.97, specificity = 0.95), and values over 0.0006/s indicated hypersplenism (sensitivity = 0.96, specificity = 0.97). Higher values of splenic uptake were associated with proportional reductions in the white blood cell and platelet counts, and to a lesser extent the haemoglobin concentration in peripheral blood. Patients with rheumatoid arthritis had increased tracer uptake, but still below the criteria for hypersplenism, whereas patients with Felty's syndrome had tracer uptake rates in the 'hypersplenic' range.

This pilot study was undertaken to correlate the patterns of lymphatic drainage demonstrated by vulvar lymphoscintigraphy with the clinical and pathologic findings of the inguino-femoral lymph nodes in patients with vulvar cancer. Ten patients were studied with the radionuclide Technetium-antimony trisulfide colloid (Tc 99m ASC) using a perilesional technique. Images were obtained at 2-4 hr postinjection. Four of the six patients with central lesions or lesions that crossed the midline had bilateral groin uptake, and two had unilateral uptake to the side on which the lesion was predominantly located. Three of these patients, each with suspicious groin nodes bilaterally, had metastatic nodal disease, two unilateral and one bilateral, in whom the uptake was bilateral and unilateral, respectively. Three of the four patients with unilateral lesions had ipsilateral groin drainage only and one had no drainage. Three underwent a bilateral lymphadenectomy and none had metastasis. The pattern of Tc 99m ASC uptake was not predictive of metastatic nodal disease. In two of the three patients with unilateral groin recurrence the side of recurrence was the same as that demonstrated on lymphoscintigraphy, and in the third case there was bilateral drainage. Further data are needed to determine the role of lymphoscintigraphy in the management of vulvar cancer.

The impact of naproxen treatment on juxta-articular hemodynamics and bone metabolism in experimental juvenile arthritis was studied in the articular carrageenan injection model. Unilateral gonarthritis was induced for 12 weeks in eight dogs receiving naproxen (dosage, 2 mg/kg) and eight controls. Regional blood flow was assessed by the microsphere method, plasma volume by the distribution space of [125I]fibrinogen, and bone metabolism by the 2-h uptake of [99mTc]diphosphonate ([99mTc]DPD). Synovial effusion was less prominent with naproxen treatment as judged by joint fluid volume and pressure. Naproxen reduced the arthritic capsular hyperemia, almost normalized a severe blood flow increase in patella and both juxta-articular epiphyses, ameliorated an expansion of plasma volume in the patella and the distal femoral epiphysis, and normalized an increased [99mTc]DPD uptake in subchondral femoral bone and the tibial cortex. Significantly increased arteriovenous shunting in the arthritic extremity was unaffected by naproxen. The study suggests that long-term cyclooxygenase inhibition offers protection against hemodynamic and metabolic changes in juxta-articular bone secondary to synovial inflammation.

A multicenter study was carried out on 191 patients (196 examinations) with lymphatic system disorders to evaluate the efficacy and safety of 99mTc-rhenium Colloid, a tracer for lymphoscintigraphy (TCK-17). Local pain and swelling occurred at the site of injection in 79.6% and 5.1% of patients, respectively, and 2 patients experienced mild fever. The accuracy was calculated on the basis of the results obtained by other diagnostic methods. Lymphoscintigraphy using TCK-17 was sensitive diagnostic procedures, but low specificity. The efficacy was classified into five grades: "Excellent", "Good", "Moderate", "Equivocal", and "Poor". 67.3% of all examination were evaluated as "Excellent" or "Good". This study revealed TCK-17 was a useful radiopharmaceutical for lymphoscintigraphy because of its safety and effectiveness.

A comparative study of the parts played by technetium-99m diphosphonate and gallium-67 citrate bone scanning in the early diagnosis of infectious spondylodiscitis is presented. Nineteen patients were included in the study. All patients (11 men aged 19-70 years and eight women aged 18-72 years) had a history of back pain varying in duration from one to 15 weeks. A 99mTc diphosphonate bone scan was positive in 17 patients. The two patients with negative results had less than two weeks of back pain. The 67Ga citrate bone scan showed uptake in all patients.

Using data from 17 patients with liver cirrhosis and 3 patients with fatty liver, we have compared the utility of 3 hepatic imaging agents in the evaluation of hepatic functional reserve. Evaluated here were 99mTc-galactosyl human serum albumin (GSA) which is a new ligand for hepatic binding protein, 99mTc-N-pyridoxyl-5-methyl tryptophan (PMT) of a hepatobiliary agent, and 99mTc-Sn colloid. In each patient, we performed these 3 imaging studies within a week and also examined hepatic function tests (indocyanine green test, hepaplastin test, choline-esterase, etc). In each imaging study, serial images and dynamic data were obtained after the injection of 99mTc-GSA (185 MBq/3 mg), 99mTc-PMT (185 MBq), or 99mTc-Sn colloid (185 MBq). Using the obtained dynamic data, we analyzed the liver kinetics of the 3 agents based on 1 compartment model with 3 parameters (hepatic clearance, hepatic excretion rate, non-specific volume of distribution). From fitting the liver and heart data to this model, three unknown parameters were determined. Patlak plot was also applied in order to estimate liver uptake rate. Both curve fitting and Patlak plot could determine appropriate parameters in every study. In 99mTc-GSA, a nonlinear 3 compartment model was also applied in order to estimate hepatic blood flow, liver receptor density, and affinity of receptor-GSA binding separately. Using the obtained parameters, we analyzed the correlations between the parameters and the results of hepatic function tests. In all of the parameters, those obtained from 99mTc-GSA imaging showed the most significant statistical correlation with the results of hepatic function tests. From the present results, 99mTc-GSA imaging was concluded to be the best for evaluation of hepatic functional reserve.

A non-invasive radioisotope technique for the measurement of total liver blood flow (TBF) is described. The method requires the use of two intravenously administered tracers, 99mTc (technetium 99m) human serum albumin (HSA) and 99mTc colloid. Computer analysis of first-pass time activity curves for HSA for liver and lung tissues yields values for the arterial and portal contributions to liver blood flow, from which TBF can be determined. These values are then corrected for attenuation using the images of the colloid distribution. The use of the method is illustrated in 17 subjects. Assumptions, limitations and possible applications of the technique are discussed.

Intra-arterial infusion liver scintigraphy was performed in 11 patients with primary or metastatic liver tumor, and intraportal infusion liver scintigraphy was performed in 6 patients for prophylaxis of liver metastasis from colorectal cancer. 99mTc-Sn colloid or 99mTc-phytate was administered through the catheter of which tip was placed in the portal vein or the hepatic artery, and then liver image was obtained. When 99mTc-phytate was infused intra-arterially, significant amount of the infused tracer passed through the liver and we could not get sufficient information to assess the distribution of drug administered through the catheter. On the other hand, intraportal infusion liver scintigraphy using 99mTc-Sn colloid or 99mTc-phytate and intra-arterial infusion liver scintigraphy using 99mTc-Sn colloid revealed heterogeneity of liver uptake, tracer uptake in spleen, low uptake area corresponding to the liver tumor and high uptake area around it. The findings will be clinically useful, and these methods are thought to be helpful to confirm the satisfactory drug distribution.

A computer-assisted quantitative analysis was undertaken of normal radiophosphate bone uptake adjacent to the porous-coated acetabular component in asymptomatic patients. Implants ranged from 1.6 to 49 months of age. In 62 hips, it was found that implants newer than 12 months of age had uptakes that were significantly greater than those 12 months or older. Between 12 and 49 months, there was no correlation with age, indicating a stabilization of the remodeling process.

Thirty-seven cases of portal hypertension with endoscopically proven oesophageal varices underwent liver biopsy to determine the etiology of portal hypertension. Of the total, 19 had cirrhosis and 18 idiopathic portal hypertension (IPH). Later all these patients underwent Tc99mSn colloid, static and dynamic scintigraphy of the liver and spleen. Ratios of the area and of the integral and slope of the integral for liver and spleen were calculated to see if any of these ratios can differentiate cirrhotics from IPH. Significant difference (P less than 0.001) was noted in the ratio of the area (L/S) in both patients and controls, but the ratios of the integral and the slope of the integral were not only significantly different (P less than 0.001) in the patients and controls but also in the two groups of patients (cirrhosis and IPH). The sensitivity of this test when compared with the histology was 58% for both cirrhosis and IPH but when compared with clinical diagnosis it was 76% for cirrhosis and 62% for idiopathic group. Therefore by adding the above mentioned test in the routine study of liver scintigraphy in patients with portal hypertension, further differentiation of cirrhotic group can be done from the idiopathic group.

Colloids used for bone marrow scintigraphy are also taken up in the liver and spleen. The liver activity in particular hampers interpretation of the study. In this study, four small-sized commercial colloids labelled with 99Tcm were compared for bone marrow uptake relative to the liver, spleen and background activity. Three human albumin colloids (Microlite, E.I. du Pont de Nemours & Co; Solco Nanocoll, Solco Nuclear; TCK-9, International CIS) and one antimony sulphide colloid (TechneScan Sb2S3, Mallinckrodt Diagnostics) were compared. The study was performed in patients routinely referred for liver/spleen scintigraphy who had a normal result. Each examination was carried out using single photon emission computed tomography. After correction for attenuation and scattering of photons, the activity of the bone marrow of the lumbar spine was related to the liver, spleen and background activity. The bone marrow/liver activity quotient of Solco Nanocoll and TCK-9 was almost twice the value for Microlite and TechneScan Sb2S3. The bone marrow/spleen quotient was almost four times higher and the bone marrow/background quotient almost twice as high for Solco Nanocoll as for the other three colloids, between which there were no significant differences.

To assess the presence of primary biliary cirrhosis, 15 patients at various histopathologic stages were studied by Tc-99m IDA hepatobiliary and/or Tc-99m colloid hepatic imaging. In the earlier stages (I and II), seven of eight patients (88%) showed uniform hepatic retention of Tc-99m IDA. Of seven patients in the same stage, however, four (57%) showed no abnormality on Tc-99m colliod imaging. In three of these four negative patients (75%), uniform hepatic retention of Tc-99m IDA was noted. In the later stages (III and IV), all seven patients showed decreased clearance with or without delayed tracer appearance in the intestine and prominent hepatic retention on Tc-99m IDA imaging; with Tc-99m colloid imaging there was enlargement of the spleen and increased activity in the spleen and bone marrow. Thus, Tc-99m IDA imaging is considered to be more useful in revealing this functional disorder at the earlier stage of primary biliary cirrhosis and in evaluating progression from an earlier to a later stage of disease. Tc-99m colloid imaging also effectively evaluated progression.

A method is presented which combines gastro-oesophageal reflux quantification and oesophageal transit measurement so as to differentiate true reflux from residual oesophageal activity. A group of 33 subjects with gastro-oesophagitis reflux symptoms and endoscopically confirmed reflux oesophagitis and a group of 21 asymptomatic subjects with normal oesophageal, gastric and duodenal endoscopic findings were examined. The subjects were given 37 MBq 99mTc-Sn-colloid in saline orally and then scintiscanned dynamically. The gastro-oesophageal quantification was done after transit measurement and after the oesophageal time activity (to detect residual oesophageal activity) reached its minimum. The difference in the reflux indices between the two groups was highly significant. In low-grade oesophagitis measured reflux was lower than in higher grades of disease. Only 4.7% false-positive results were observed with a specificity of 95%, indicating that this method may be superior to methods published earlier.

Laterality of prostatic lymphatic drainage was successfully assessed in nine patients with prostatic carcinoma after direct unilateral transrectal injections of 99Tcm-antimony sulphide colloid by Franzen needle. Pelvic lymphatic drainage was equally divided between ipsilateral, contralateral and bilateral patterns. The frequent observation of radiocolloid migration to contralateral lymph node groups in patients with prostate carcinoma, including those with primary disease localized clinically to a single lobe of the prostate, indicates the potential for contralateral pelvic lymph node metastases in this population. This finding may be important in determining the appropriate surgical staging and treatment of patients with prostate carcinoma. The clinical applicability of lymphoscintigraphy in the evaluation of metastatic spread and in lymph node biopsy planning requires further study.

The usefulness of isotope lymphography was evaluated in patients with chronic lower leg swelling. Forty patients (15 male, 25 female, age range 5 months-67 years) were assigned one of six clinical diagnoses based on clinical assessments, venography and lymphography. All the patients and seven normal controls were examined with bilateral isotope lymphography involving subcutaneous injection of 0.15 ml 99mTc-antimony sulphide colloid into the first web space of each foot. The percentage uptake of isotope-colloid in the inguinal lymph nodes at 1 and 2 h was equated with lymphatic function. Highly significant (P = 0.0001) differences existed between the different clinical groups and isotope lymphography discriminated well between oedema of lymphatic and non-lymphatic origin. Isotope lymphography appears to be a safe and useful test of lymphatic function.

We have developed Tc-99m labeled activated carbon microspheres (99mTc-CH44) for use in mammary lymphoscintigraphy and detailed analysis of mammary lymph flow. 99mTc-CH44 was prepared according to the EDTA complex method. The labeling rate immediately after preparation was 97.7 +/- 2.6% at 37 degrees C and was 94.9 +/- 2.6% after 24-hour continuous shaking. The release of 99mTcO4- from 99mTc-CH44 was determined in vitro, using a simulation model. In this assay, the 99mTcO4- release rate in one hour was 6.6% and that in 6 hours was 38%. When 2ml (2mCi, 74MBq) of 99mTc-CH44 was injected into the mammary glands of 12 patients with breast tumors, the axillary, subclavian and parasternal lymph nodes of 10 patients were visualized 60 minutes later. In analysis of lymph flow in 25 rats using 99mTc-CH44 the lymph flow from the foot pad through the popliteal to the intraperitoneal lymph nodes was known to have only one route when examined by gross finding and histology. However, the examination using RI-technique indicated two routes. The examination in 9 patients with breast cancer indicated that the use of 99mTc-CH44 allowed detailed analysis of lymph flow. These results suggest that 99mTc-CH44 is useful for the preoperative mammary lymphoscintigraphy and detailed analysis of mammary lymph flow.

The usefulness of In-111 labeled white cells in acute infection is well documented but the role of Tc-99m labeled white cell scintigraphy (WCS) has not been as clearly established. Using stannous fluoride colloid and a simple labelling procedure with 20 ml of autologous whole blood, three cases are presented in which Tc-99m WCS established unexpected diagnoses in patients who had remained undiagnosed despite extensive investigation.

Sixty-six percent of 54 patients with neuroblastoma demonstrated uptake of bone-seeking radioagents by the primary tumor. This is a higher incidence than previously reported. Uptake was slightly more common in abdominal than thoracic tumors. There was a significant correlation between the size of the tumor and tracer uptake. Calcification was demonstrated in the primary tumor in almost 90% of the 54 patients. This is a much higher incidence of calcification than previously reported. Microscopy shows that the calcification is not always due to tumor necrosis; it also occurs in areas of viable tumor cells. Tracer uptake is believed to be related to calcium metabolism. The rate of metabolic activity rather than the total amount of calcium present within the tumor may be the most important factor in determining the amount of uptake. No significant relationship was found between tracer uptake and tumor stage or homovanillic acid and vanillylmandelic acid metabolic activity.

The state of the skeleton was studied in 62 patients with otosclerosis to investigate diagnostic potentialities of 99mTc-phosphonium, of them in 34 patients the diagnosis was confirmed at operation. 38 patients suffered from acute and chronic otitis media, 18 from cochlear neuritis, 4 from Meniere's disease. Scintigraphic imaging was processed quantitatively. When comparing skeleton images of the patients and persons of the control group (25 persons) it was established that radionuclide investigation of the bones with 99mTc-phosphonium of patients with hypoacusis was a highly informative method for determination of a degree of disorder of the temporal bone. Systemic bone affection was observed in otosclerosis. Considerable RP fixation was found in patients with an active course of the otosclerotic process. A group of patients in whom hypoacusis was combined with disorder of the osseous capsule, was detected among the patients with acoustic neuritis. Scintigraphy with 99mTc-phosphonium was recommended as an obligatory diagnostic procedure for patients with hypoacusis.

The uptake of 99mTc-pertechnetate (TcO4), 99mTc-iron-ascorbic acid (Feasc), 99mTc-Solcocitran (Solcocitran), 99mTc-diphosphonate (HEDP) and 67Ga-citrate (Ga) in various brain lesions was compared. Influence of time from injection was also studied on the first three compounds. A rank correlation method was used to compare the scans which were judged visually by three independent observers. There was good agreement between the observers, as measured by Kendall's tau, but the concordance between rankings within the same type of lesion, as measured by Kendall's W, was rather poor. There was no significant difference in the uptake of TcO4, Feasc and Solcocitran. Ga showed generally poor uptake and its uptake in tumours and infarcts did not differ significantly. However, when HEDP and TcO4 were compared in two groups (I: Infarcts, haemorrhages and bone invading meningiomas, and II: Tumours not invaded into bone) a highly significant difference was obtained with much higher uptake of HEDP in Group I.

Myositis ossificans is primarily a disorder of young adults, whereby an area of muscle mass undergoes progressive ossification. The authors review a case in which the patient's presentation was somewhat atypical, and where the course of disease was unusually prolonged. Examination of the soft tissue lesion using Tc-99m diphosphonate bone scans was helpful in establishing the diagnosis and in determining the full extent of the process early in its evolution.

Bone uptake of 99 m Tc diphosphonate may allow early diagnosis of renal osteodystrophy. Our study deals with 53 patients treated by repeated hemodialysis and reveals scanning abnormalities in 75% of them. Bone scanning provides information which are not visualized radiologically, especially scattered or located pulmonary calcifications (15% in our series). It is valuable in the follow-up of bone changes and is part of the necessary investigations before carrying out parathyroidectomy.

Whole-body scintigraphy with both 99mTc-phosphonate and 67Ga was performed on 92 patients suspected of primary bone tumors. In 46 patients with primary malignant bone tumors, scintigraphy with 99mTc-phosphonate disclosed the primary tumor in 44 cases and skeletal metastases in 11, and 67Ga scintigraphy detected the primary tumor in 43 cases, skeletal metastases in 6 cases and soft-tissue metastases in 8 cases. In 25 patients with secondary malignant bone tumors, bone scintigraphy visualized a single lesion in 10 cases and several lesions in 15 cases, and 67Ga scintigraphy detected the primary tumor in 17 cases, skeletal metastases in 17 cases and soft-tissue metastases in 9 cases. In 21 patients with benign bone disease positive uptake of 99mTc-phosphonate was recognized in 19 cases and uptake of 67Ga in 17 cases. It is concluded that bone scintigraphy should be used in patients suspected of primary bone tumors. If malignancy is suspected, 67Ga scintigraphy should be performed in addition.

Bone scan imaging with the current bone-seeking radiopharmaceuticals, the technetium-99m labelled diphosphonates, provides a functional display of skeletal metabolism and has dramatically improved our ability to investigate skeletal pathology. While the role of bone scanning in metastatic disease was recognized early, and welcomed by oncologists and other specialists alike, in the field of metabolic bone disease the realization of its potential value has been slower, with perhaps more reluctant acceptance. Nevertheless, the skeleton remains an extremely difficult organ to investigate, and a familiarity with bone scanning should be an essential part of the investigational armamentarium for anyone with an interest in the metabolic bone disorders. The measurement of bone mineral by photon absorptiometry is a relatively new technique, which is rapidly gaining acceptance. The ability to accurately detect and quantify changes in bone mass is potentially of considerable value in the diagnosis and management of osteoporosis. The technique provides us with an extremely important and powerful research tool but, at the present time, its role in clinical practice has yet to be established.

A new method for simultaneously measuring radiochemical purity and estimated lung trapping of colloidal technetium-99m (99mTc) radiopharmaceuticals is described. The method employs a small filtration device comprised of two stacked membrane filters, differing in membrane composition and in pore size, situated over a filtrate collection vial. Specifically, an 8-microns pore polycarbonate membrane filter is situated above a 0.22-microns pore mixed-cellulose-esters membrane filter. For assay, a diluted aliquot of radiopharmaceutical is passed through the filtration device. Technetium-99m radioactivity on the membranes and in the vial is then measured. The polycarbonate filter traps and quantitates lung-capillary-occluding particles. The mixed-cellulose-esters filter traps and quantitates radiocolloid particles irrespective of relative size. The filtrate contains free pertechnetate. Within 4 min, this method yields results that compare well with those achieved by conventional techniques. The method works equally well for large colloidal particles [( 99mTc]stannous colloid), intermediate-size particles [( 99mTc]sulfur colloid), and small-size particles [( 99mTc] antimony trisulfide colloid).

The labeling of human serum albumin (HSA) with 99mTc using Sn(II) as the reductant has been reinvestigated in view of the possibility of formation of Sn-Tc colloids. Preparations of 99mTc-HSA and mixtures of 99mTc-TcO-4 with Sn(II)Cl2 have been analyzed by means of gel chromatography using various gel matrices and eluents. No Sn-Tc colloids could be eluded from samples of 99mTc-HSA preparations. The percentage of labeling was about 90%. A comparative investigation of a number of gel-chromatographic systems for the detailed analysis of 99mTc-HSA has been made. It is found that a long column with Sephadex G-200 gives the best results.

Distribution of osteotropic radiopharmaceuticals was studied in bone, different organs and tissues of rats. 99mTc-pyrophosphate (USSR and France) and 99mTc-diphosphonate (GDR and Hungary) were investigated. Differences in their behaviour were demonstrated. According to a degree of accumulation in the bone tissue, the preparations may be arranged as follows: 99mTc-diphosphonate (GDR), 99mTc-diphosphonate (Hungary), 99mTc-pyrophosphate (USSR and France).