Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “TECHNETIUM”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,027 records · Page 57Linked to original sources
PubMed1991

Technetium-99m carboxymethylcellulose: a newly developed fibre marker for gastric emptying studies.

We report a study of technetium-99m-labelled carboxymethyl-cellulose (99mTc-CMC) as a newly developed non-digestible marker of the solid phase of gastric contents. The radiosynthesis is simple and shows a high labelling efficiency. In vitro and in vivo experiments demonstrated stability of the marker in the gastrointestinal tract during the process of gastric emptying. The gastric half-emptying time in ten healthy volunteers of both sexes was 105 +/- 17 min (mean +/- SD). This rate of gastric emptying is similar to that of non-digestible solid-phase markers such as in vivo labelled 99mTc-chicken liver or radio-iodinated cellulose. In comparison with digestible solid-phase markers such as 99mTc-labelled pancake or 99mTc-cooked egg, gastric emptying of 99mTc-CMC occurred more slowly, confirming the expected behaviour of a non-digestible solid-phase marker. We conclude that 99mTc-CMC has the advantage of a simple and rapid labelling procedure and may be useful for clinical studies of gastric emptying.

Adult↗
PubMed1991

Comparison of radionuclide estimation of glomerular filtration rate using technetium 99m diethylenetriaminepentaacetic acid and chromium 51 ethylenediaminetetraacetic acid.

Simultaneous measurements of the clearance rates of technetium 99m diethylenetriaminepentaacetic acid (99mTc-DTPA) and chronium 51 ethylenediaminetetraacetic acid (51Cr-EDTA) were performed in 30 patients with a range of renal function (glomerular filtration rates between 9 and 120 ml/min). Using multiple blood samples, the two clearance values correlated well (r = 0.991, standard error 3.9 ml/min), but DTPA clearance was systematically higher by 7.6%. For each radiopharmaceutical, an equation was derived to correct clearance values obtained using only plasma samples taken at 2 and 4 h for the systematic error inherent in this technique compared with analysis of the complete plasma concentration-time curve. The root mean square error remaining after application of these equations was 1.9 ml/min for both the EDTA and DTPA data. The corresponding errors obtained using the equation derived by Brochner-Mortensen for EDTA plasma clearance were 2.2 ml/min and 1.9 ml/min, respectively, these values were not significantly different from those obtained using the equations derived in this study.

Adult↗
PubMed1993

Quantification of technetium-99m lung radioactivity from planar images.

Six methods of quantifying technetium-99m lung uptake from planar gamma camera images were evaluated. Camera sensitivities, the broad beam attenuation coefficient and build-up factors were derived from suitable phantom measurements. The accuracy of the methods was evaluated by quantifying the lung uptake of 99mTc macroaggregated albumin (MAA) in ten patients and assuming complete trapping by the lung of the known activity of injected MAA particles. Three methods based on published techniques which related the count rate from an image of a lung to that from a lung phantom were the least accurate, producing lung activities which were typically about 70% of the injected activity. Of the other three techniques, the depth-dependent build-up factor method was slightly more accurate than the geometric mean and the depth-independent build-up factor methods, producing average values (+/- SD) of lung activity which were 100% +/- 3%, 106% +/- 3% and 101% +/- 5%, respectively, of the injected activity. To measure lung uptake, all of these latter three methods required an attenuation correction with a flood source transmission scan, and therefore their accuracy was affected by the variation in the activity distribution and attenuation across an image of the thorax.

Aerosols↗
PubMed1993

Effect of mitochondrial viability and metabolism on technetium-99m-sestamibi myocardial retention.

This study investigated the mechanism of myocardial retention of technetium-99m-sestamibi. 99mTc-sestamibi was injected intravenously into guinea pigs, and the myocardium was homogenized and fractionated by differential centrifugation. More than 90% of myocardial 99mTc-sestamibi was localized within the mitochondrial fraction. Calcium was found to release 99mTc-sestamibi from the mitochondrial fraction, with an IC50 of 2.54 +/- 0.98 mM. This effect was potentiated by NaCl, and inhibited by the mitochondrial calcium channel blocker ruthenium red. In vitro uptake of 99mTc-sestamibi was found to increase from 10.5% +/- 3.0% to 61.2% +/- 0.2% with the addition of 10 mM succinate, indicating that respiration is involved. Since irreversible ischemia results in cellular and mitochondrial calcium "overload" and loss of mitochondrial metabolic function, 99mTc-sestamibi should not be retained in necrotic or irreversibly ischemic myocardium, and could potentially act as a sensitive indicator of myocardial cell viability.

Animals↗
PubMed1991

The APE nebuliser--a new delivery system for the alveolar targeting of particulate technetium 99m diethylene triamine penta-acetic acid.

We report the validation of a new delivery system--aerosol production equipment (known by the acronym APE), which generates a particulate aerosol of technetium 99m diethylene triamine penta-acetic acid (DTPA) with a mass-median aerodynamic diameter of 0.35 microns and a geometric standard deviation of 1.8 Twenty subjects were studied; in group 1 were 12 healthy men with normal spirometry; in group 2 were 8 men with AIDS who had mildly abnormal lung function following an episode of pneumocystis pneumonia-spirometry FEV1 3.08 (0.73) L, FVC 4.83 (0.82) L [mean (SD)]. The APE nebulizer was used to form a particulate aerosol with 200 MBq of 99mTc DTPA, which was collected in a 35 1 reservoir of air, which was subsequently inhaled. The mean (SD) inhalation time was 4.7 (0.44) min. The output of the nebulizer (% of activity inhaled) was 82%. Using planar imaging, the penetration index (right lung) in group 1 was 0.93 (0.18), mean (SD), and in group 2 it was 0.91 (0.12). There was virtually no tracheal deposition and extrapulmonary deposition (oropharynx and stomach) was less than 5% of the aerosol delivered. Single-photon emission tomography (SPET) studies carried out in five patients from group 1 confirmed homogeneous intrapulmonary deposition of 99mTc-DTPA. In view of the excellent intrapulmonary deposition of 99mTc-DTPA produced by the APE nebulizer, it may provide an alternative to conventional ventilation studies using radioactive gases.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Bone marrow transplantation: effects of conditioning and cyclosporin prophylaxis on microvascular permeability to a small solute (technetium 99m diethylene triamine penta-acetic acid).

Microvascular permeability to small diffusible solutes has rarely been measured at a clinical level. We have developed a simple non-invasive technique for measuring the permeability surface area (PS) product, which is suitable for clinical use. We illustrate its potential value in six subjects who underwent bone marrow transplantation for chronic myeloid leukaemia. These patients received high-dose cyclosporin A (CyA) for prevention of graft versus host disease (GVHD) and sustained an easily measurable increase in microvascular permeability to technetium 99m diethyltriamine penta-acetic acid (99mTc-DTPA). This was measured as the PS product, which increased from 1.1 (SD 0.3) to 2.2 (0.4) ml/min per 100 ml tissue between baseline and treatment with CyA for prevention of GVHD (P less than 0.01). The increase broadly correlated with nephrotoxicity which was measured, from the plasma DTPA clearance, as global glomerular filtration rate (GFR). This decreased from 106 (11.1) to 49 (6.7) ml/min (P less than 0.001). These abnormalities, both in PS product and GFR, were sustained for several months, after which they tended to return towards baseline levels. We conclude firstly that this technique has a potential clinical role and secondly that endothelial abnormalities due to CyA deserve further study.

Adult↗
PubMed1991

Excretion of technetium 99m hexakismethoxyisobutylisonitrile in milk.

The amount of radioactivity excreted in breast milk following the administration of technetium 99m hexakismethoxyisobutylisonitrile (99mTc-MIBI) to a patient referred for cold spot myocardial scintigraphy was determined. During the first 24 h after administration, only 41.2 kBq 99mTc (0.0084% of the injected dose) was excreted in 448 ml milk with the highest concentration of 0.49 kBq/ml in the first sample. The images obtained show a high concentration of 99mTc-MIBI in the lactating breasts contrary to the very small percentage excreted in the milk. Comparison with various recommendations regarding nursing after administration of radiopharmaceuticals seems to indicate that the administration of 99mTc-MIBI does not necessitate an interruption of breast-feeding.

Adult↗
PubMed1996

Rates of flow of technetium 99m--labeled human serum albumin from peripheral injection sites to sentinel lymph nodes.

BACKGROUND: The new technique of sentinel lymphadenectomy for cutaneous melanoma provided us with a unique opportunity to quantitate the rates of lymphatic flow in afferent lymphatics. METHODS: Seventeen melanoma patients underwent preoperative lymphoscintigraphy with technetium 99m-human serum albumin (HSA). The time and distance between the injection site and the sentinel lymph node (LN) were recorded. By comparison, lymphatic flow rates between footpad, popliteal LN, femoral LN, and systemic blood were measured in 60 female mice (C57BL/6) after footpad injection of 99mTc-HSA. RESULTS: The rate of lymphatic flow to 14 axillary, four inguinal, one popliteal, and one parotid sentinel LNs averaged 10.4 +/- 7.3 cm/min. In contrast, the lymphatic flow rate between the footpad and the popliteal LN in mice (analogous to the sentinel LN in human beings) averaged 1.33 +/- 0.52 cm/min. There was a marked delay in the passage of radionuclide through the popliteal LN with consequent slowing of the rate of flow between the popliteal and femoral LNs to 0.22 cm/min. CONCLUSION: Lymphatic flow to the sentinel LN occurs rapidly from both human skin and murine footpads. This information might be helpful in planning the timing of the incision after vital blue dye injection for identifying the sentinel LN.

Animals↗
PubMed1994

Technetium-99m sestamibi scintigraphy for the assessment of lower extremity ischaemia in peripheral arterial disease.

Technetium-99m sestamibi was used for functional investigation of the muscle perfusion of lower extremities in 35 patients with peripheral vascular disease. The aim was to test what useful information could be obtained by additional imaging of the legs in patients referred for risk stratification with dipyridamole myocardial scanning. Posterior images were acquired over the thighs and calves after postocclusive reactive hyperaemia and at rest. Inter- and intraextremity ratios and differences between the stress and rest data were used for the assessment of abnormal circulation. Arteriography was performed in every case, and surgical procedures or transluminal angioplasty in 31 patients. To estimate diagnostic accuracy, the results of 99mTc-sestamibi scintigraphy were compared with those of angiography and the functional consequences of revascularization procedures. The sensitivity and specificity of 99mTc-sestamibi scintigraphy were 55% and 25%, respectively, with an overall accuracy of 50%. Apparently methodological error was not responsible for these poor results. Instead, a paradoxically high uptake of the radiopharmaceutical in muscles supplied by significantly stenosed vessels was identified as the main source of both false-negative and false-positive results. The phenomenon resembles the findings of a previous study involving delayed administration of thallium-201 after exercise. In conclusion, 99mTc-sestamibi scintigraphy has not proved sufficiently reliable to help in the management strategy for patients with peripheral vascular disease.

Dipyridamole↗
PubMed1994

Effect of renal maturation on the clearance of technetium-99m mercaptoacetyltriglycine.

To investigate the effect of growth and maturation on the global kidney clearance of technetium-99m mercaptoacetyltriglycine (99mTc-MAG3), we investigated 509 children who attended for 99mTc-MAG3 renography in our department. In order to estimate the normal maturation of the kidney, only children who were classified as "normal" using diagnostic criteria were included in this study (n = 109). Kidney clearance was calculated using a gamma camera technique and a 20-min blood sample. There was a progressive increase in the clearance of 99mTc-MAG3 throughout childhood and into adolescence (mean clearance value below 2 month was 31.4 ml/min, mean clearance value above 12 years was 287 ml/min). When clearance was normalised to body surface area (BSA) a different pattern was seen, with a progressive increase from 3 weeks of age (mean value < 0.2 years: 208 ml/min/1.73 m2) to a plateau at the end of the first year of life (mean value > 2 years: 303 ml/min/1.73 m2). Maturation of the kidney as defined by the normalised clearance of 99mTc-MAG3 is therefore complete by the end of the 1st year of life, after which any change in non-corrected clearance values may be attributed to growth. To investigate the appropriate normalisation factor for 99mTc-MAG3 clearance in children, clearance values were compared to height, weight and BSA. The relationships were described using a linear model; the correlation coefficients demonstrated that BSA has the highest strength of relationship with 99mTc-MAG3 clearance. Body surface area may be used over 1 year of age to normalise the clearance values of 99mTc-MAG3.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1997

Detection of acute inhalation injury in fire victims by means of technetium-99m DTPA radioaerosol inhalation lung scintigraphy.

Mortality and morbidity in fire victims are largely a function of injury due to heat and smoke. While the degree and area of burn together constitute a reliable numerical measure of cutaneous injury due to heat, as yet no satisfactory measure of inhalation injury has been developed. In this study, we employed technetium-99m diethylene triamine penta-acetic acid (DTPA) radioaerosol lung scintigraphy (inhalation scan) to evaluate acute inhalation injury in fire victims. Ten normal controls and 17 survivors from a fire accident were enrolled in the study. All patients suffered from respiratory symptoms (dyspnoea and/or cough with sputum). 99mTc-DTPA aerosol inhalation lung scintigraphy was performed in all subjects, using a commercial lung aerosol delivery unit. The degree of lung damage was presented as the clearance rate (k; %/min) calculated from the time-activity curve over the right lungs. In addition, the distribution pattern of the radioactivity in the lungs was evaluated and classified into two groups: homogeneous distribution and inhomogeneous distribution. A plain chest radiograph (CxR) and pulmonary function test (PFT) were performed in the same group of patients. The results showed that 6/17 (35.3%) patients had inhomogeneous distribution of radioactivity in their inhalation scans, and 11/17 (64.7%) had homogeneous scans. Five of the six patients with inhomogeneous scans were admitted for further management, and all patients with homogeneous scans were discharged from the emergency department and needed no further intensive care. The clearance rates of the right lung were 0.73%+/-0.13%/min for normal controls and 1.54%+/-0.58%/min for fire victims. The difference was significant, with a P value of less than 0.01. Using a cut-off value of 0.9%/min (all normal subjects were below 0. 9%/min), 14 (82.4%) patients had abnormal clearance rates of 99mTc-DTPA from the lung. In contrast, only three (17.6%) patients had abnormal CxR and three (17.6%) had abnormal PFTs. We conclude that (1) conventional CxR and PFT are not good modalities for evaluating inhalation injury in fire victims because of their low sensitivity, and (2) 99mTc-DTPA radioaerosol inhalation scintigraphy can provide an objective evaluation of inhalation injury during a fire accident and may be useful in therapeutic decision-making and disease monitoring.

Administration, Inhalation↗
PubMed1997

In vivo detection of multidrug-resistant (MDR1) phenotype by technetium-99m sestamibi scan in untreated breast cancer patients.

Technetium-99m sestamibi is a transport substrate recognised by the multidrug-resistant P-glycoprotein (Pgp). To test whether 99mTc-sestamibi efflux is enhanced in breast carcinomas overexpressing Pgp, we determined the efflux rates of 99mTc-sestamibi and Pgp levels in tumours from 30 patients with untreated breast carcinoma. Patients were intravenously injected with 740 MBq of 99mTc-sestamibi and underwent a 15-min dynamic study followed by the acquisition of static planar images at 0.5, 1, 2 and 4 h. Tumour specimens were obtained from each patient 24 h after 99mTc-sestamibi scan and Pgp levels were determined using 125I-MRK16 monoclonal antibody and in vitro quantitative autoradiography. All breast carcinomas showed high uptake of 99mTc-sestamibi and data from region of interest analysis on sequential images were fitted with a monoexponential function. The efflux rates of 99mTc-sestamibi, calculated from decay-corrected time-activity curves, ranged between 0.00121 and 0.01690 min-1 and were directly correlated with Pgp levels measured in the same tumours (r=0.62; P<0.001). Ten out of 30 breast carcinomas (33%) contained 5 times more Pgp than benign breast lesions and showed a mean concentration of 5.73+/- 1.63 pmol/g of tumour (group A). The remaining 20 breast carcinomas had a mean Pgp concentration of 1.29+/-0.64 pmol/g (group B), equivalent to that found in benign breast lesions. 99mTc-sestamibi efflux from tumours of group A was 2.7 times higher than that observed in tumours of group B (0.00686+/-0.00390 min-1 vs 0.00250+/-0.00090 min-1, P<0.001). The in vivo functional test with 99mTc-sestamibi showed a sensitivity and a specificity of 80% and 95%, respectively. In conclusion, the efflux rate of 99mTc-sestamibi may be used for the in vivo identification of the multidrug resistant (MDR1) phenotype in untreated breast cancer patients.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1997

ECG-manifest and ECG-silent dipyridamole technetium-99m sestamibi SPET perfusion defects in patients with ischaemic heart disease.

At dipyridamole myocardial scintigraphy, perfusion defects are seldom backed up by significant ECG changes. This would suggest myocardial blood flow heterogeneity, rather than true ischaemia, as the cause of the scintigraphic abnormalities. Electrocardiographic surface mapping has been documented to be more accurate than standard 12-lead ECG in the detection of provoked ischaemia. Thus, to investigate the relationship between ECG changes and perfusion abnormalities, body surface maps were recorded during dipyridamole infusion in 55 subjects (11 normals and 44 patients with ischaemic heart disease) undergoing dipyridamole technetium-99m sestamibi single-photon emission tomography (SPET). All had a normal resting ECG. The extent and severity of the sestamibi defect were quantified. New negative areas in the isointegral maps and rest-dipyridamole map differences >2 SD from normal limits were considered abnormal. After dipyridamole in normals, neither perfusion defects nor >/=1 mm ST segment depression on 12-lead ECG nor new negative areas in isointegral maps occurred. In patients, dipyridamole induced new perfusion defects in 35 (80%) but ST segment depression in only 18 (41%, P<0.001). Of the 35 patients with perfusion defects, 17 (49%, group 1) showed ST segment depression, while the other 18 (51%, group 2) did not. Abnormal body surface maps were found in 100% of group 1 and 88% of group 2 patients (NS). In group 1, the provoked hypoperfusion was of greater extent (P=0.007) and severity (P=0.01) and the onset of map abnormalities was significantly earlier (P<0. 001) than in group 2; time to map abnormalities was also significantly shorter than time to ST segment depression (P=0.01). In the 35 patients with complete scintigraphic, body map and angiographic data, the severity of reversible perfusion defect proved to be the strongest correlate of ST segment depression upon logistic regression analysis. Thus, sestamibi SPET abnormalities after dipyridamole are almost always associated with electrical changes on body surface maps, suggesting myocardial ischaemia as their cause. The much less common 12-lead ECG changes are slower to appear and reflect a more severe hypoperfusion.

Body Surface Potential Mapping↗
PubMed1997

The occurrence of false-positive technetium-99m sestamibi bull's eye defects in different reference databases. A study of an age- and gender-stratified healthy population.

Myocardial perfusion single-photon emission tomographic (SPET) imaging has been shown to be sensitive in the detection of coronary artery disease (CAD), whereas its specificity has been suboptimal. The aim of the present study was to study the frequency of abnormal bull's eye perfusion defects in a large age-stratified group of healthy subjects undergoing myocardial SPET assessed by comparison with two existing commercially available reference databases. One hundred and twenty-eight healthy volunteers (76 males and 52 females) with a less than 5% likelihood of CAD underwent rest and exercise technetium-99m sestamibi SPET. The false-positive response rate, defined as a significant reversible defect, was 12% when compared to the CEqual database and 29% when compared to the Cedars-Sinai database. With the CEqual program, rest defects occurred in 12% of the subjects. Defects occurred more often in women than in men, but the difference did not attain statistical significance. Significant defects were most frequent in the inferior wall and in women in the anterior wall as well. The distribution of defects was independent of age. Our results suggest that the specificity of 99mTc-sestamibi myocardial SPET using commercially available reference files is suboptimal. The risk of obtaining a false-positive test result in subjects undergoing 99mTc-sestamibi myocardial SPET with a very low likelihood of CAD was higher than anticipated. With both reference files false-positive test results were most frequently observed in the inferior wall. Our data suggest that commercial reference files for myocardial SPET need to be optimised, and should be used with caution. The use of attenuation correction may prove to be a major step forward.

Adult↗
PubMed1997

Breast cancer staging using technetium-99m sestamibi and indium-111 pentetreotide single-photon emission tomography.

We evaluated the clinical usefulness of single-photon emission tomography (SPET) with technetium-99m sestamibi and indium-111 pentetreotide in breast cancer staging. Fifteen patients with clinical and/or mammographic findings suggesting T1-2N0-1 breast cancer were studied. SPET images were acquired 20 min after 99mTc-sestamibi injection and 4 and 24 h after 111In-pentetreotide injection. Patients underwent surgery the day after the later 111In-pentetreotide acquisition. Pathological examination showed 16 tumours in the 15 patients, with one bilateral carcinoma. The mean tumour diameter was 18.7 mm. Metastatic axillary involvement was found in 6/16 tumours, with a mean of five metastatic nodes per axilla. Both tracers correctly identified 15/16 primary tumours and five of the six cases of metastatic axillary node involvement. No difference between the tracers was observed in breast cancer staging. 99mTc-sestamibi seems to be the better tracer in terms of physical characteristics, execution time and cost-effectiveness. Our data suggest the future possibility of using nuclear medicine imaging to avoid axillary dissection in patients with T1 breast cancer.

Axilla↗
PubMed1997

Localization of ectopic parathyroid glands using technetium-99m sestamibi imaging: comparison with magnetic resonance and computed tomographic imaging.

The aim of the study was to compare the accuracy of technetium-99m sestamibi imaging for localization of ectopic parathyroid glands in patients with hyperparathyroidism with that of magnetic resonance (MR) and computed tomographic (CT) imaging. Eleven patients with primary (n=3) or secondary (n=8) hyperparathyroidism were studied with 99mTc sestamibi parathyroid imaging CT and MR imaging. Images of the neck were acquired at 10 min and 2-3 after tracer injection. The three patients with primary hyperparathyroidism and five patients with secondary hyperparathyroidism underwent parathyroidectomy. The ectopic glands were confirmed by histopathological examination of the resected specimens. In respect of 20 parathyroid glands in the eight patients explored surgically, the sensitivity and specificity of sestamibi imaging were 70% (14/20) and 88%, respectively, those of CT, 40% (8/20) and 88%, and those of MR imaging, 60% (12/20) and 88%. Of these patients, three had parathyroid adenomas while five had hyperplasia (17 glands). Sestamibi imaging localized eight ectopic parathyroid glands, which were surgically confirmed (six were located in the thymus and two in the mediastinum). In one patient explored surgically, the ectopic gland was located outside the field of the MR coil. Although the remaining three cases of secondary hyperparathyroidism were not confirmed surgically, these patients demonstrated sestamibi uptake in five parathyroid glands, including three ectopic glands. MR images demonstrated abnormal parathyroid glands in the same regions as sestamibi imaging. Our data indicate that 99mTc-sestamibi imaging should be used initially to localize the ectopic parathyroid glands in patients with hyperparathyroidism for anatomical guidance prior to MR or CT imaging.

Choristoma↗
PubMed1976

Factors affecting uptake and retention of technetium-99m-diphosphonate and 99m-pertechnetate in osseous, connective and soft tissues.

The bone scanning complex, 99mTc-Sn-EHDP, consisting of the nuclide technetium-99m, stannous ion and ethane-1-hydroxy-1,1-diphosphonate, administered intravenously is retained in soft tissues in proportion to increasing calcium content of the tissues. Within bone tissue, the retention is proportional to vascularity and to surface area of calcium phosphate in bones and not necessarily to calcium and phosphate concentration. The nuclidic agent 99mTcO4-BUT NOT THE 99MTc-diphosphonate is selectively taken up by the thyroid and this uptake can be blocked by administering sodium perchlorate. Among the connective tissues studied, the tracheal cartilage seems to have the greatest potential to calcify with increasing age of the animal and man. Soft tissue does not retain the bone scanning complex 99mTc-Sn-EHDP but does retain 99mTcO4-.

Age Factors↗
PubMed1994

Use of technetium antigranulocyte monoclonal antibody Fab' fragments for the detection of osteomyelitis.

Accurate early diagnosis of osteomyelitis is critical for optimal clinical management. Conventional radiology (X-rays, CT) and nuclear medicine scans (bone, gallium, and technetium/indium white blood cell [WBC]) have limitations and drawbacks. The monoclonal antibody (MAb) ImmuRAID-MN3 (Immunomedics Inc., Morris Plains, NJ), a 99m-Tc Antigranulocyte Fab' fragment, recognizes a surface glycoprotein NCA-90/95 shared by granulocytes, carcino-embryonic antigen (CEA), and meconium antigen (MA). Intravenous injection of radiolabeled MAb enables in vivo labeling of human granulocytes and targets infected lesions in the bone and throughout the body. Technetium labeled Fab' fragments rapidly clear the blood pool and high-quality images can be obtained the same day, as early as 1 h postinjection. Results at our institution on 13 patients with clinically suspected osteomyelitis of infected long bones, prostheses, and diabetic foot ulcers were compared with the surgical/bacteriological verification of the presence or absence of infection. The MAb scan showed six true positives, six true negatives, and one false negative (very low grade infection). The procedure was safe, no clinical or laboratory adverse reactions were encountered. The MAb fragments are markedly less immunogenic than whole IgG, resulting in lower induction of human antimouse antibody (HAMA) titers. No HAMA to this MAb fragment has been detected in 24 patients (data from multiple institutions). Our preliminary results suggest that 99m-Tc ImmuRAID-MN3 is highly accurate for detection of osteomyelitis. This study is part of an ongoing multiinstitutional project sponsored by Immunomedics, Inc. to evaluate the efficacy and safety of this radiopharmaceutical.

Adult↗