99Tcm-HMPAO labelled leucocytes: comparison with 111In-tropolonate labelled granulocytes

The lipophilic complex, 99Tcm-hexamethylpropyleneamine oxime (HMPAO) is an efficient leucocyte label, and labels granulocytes with more stability than mononuclear leucocytes. The recovery of 99Tcm-HMPAO granulocytes, expressed as the percentage of injected granulocyte-associated activity circulating as granulocyte-associated activity 40-45 min after injection, was 37% (S.E. 3%), similar to the recovery of 111In-labelled granulocytes isolated and labelled in plasma using tropolone. The T1/2 of 99Tcm-HMPAO labelled granulocytes in blood was 4.4 h (S.E. 0.4 h), less than that of 111In-labelled granulocytes, although when a correction was made for 99Tcm elution, it was 6.4 h. The initial biodistribution of 99Tcm-labelled leucocytes was similar to 111In-labelled granulocytes, with a rapid initial lung transit, prominent splenic activity, bone marrow activity and minimal hepatic activity, although, unlike 111In, 99Tcm activity was also seen in urine, occasionally in the gallbladder, and, from about 4 h, consistently in the colon. Bone marrow activity was particularly prominent with 99Tcm. About 6% of 99Tcm was excreted in the faeces up to 48 h after injection, and about 17% in urine up to 24 h. The time-activity curves of reticuloendothelial activity up to 24 h were broadly similar for the two labelled cell preparations, and the differences that were observed can be explained on the basis of a higher rate of 99Tcm elution. Clinical information given by the two agents was similar in 27 of 30 patients who received both. Of the three who gave different information, one received 111In-labelled granulocytes which were considered to be functionally suboptimal and two, with inflammatory bowel disease, showed different distributions of abnormal bowel activity. We conclude that with respect to granulocyte kinetics and clinical data, 99Tcm-HMPAO labelled leucocytes are comparable with 111In-tropolonate labelled granulocytes.     

Clinical comparison of 99Tcm-HMPAO labelled leucocytes and 99Tcm-nanocolloid in the detection of inflammation

Forty-five patients with various inflammatory diseases were imaged with 99Tcm-HMPAO labelled leucocytes and 99Tcm-nanocolloid within 7 days. The overall sensitivity of 99Tcm-leucocytes was 97% and that of 99Tcm-nanocolloid 59% and both agents had a 100% specificity. The 99Tcm-leucocyte method showed reliable results in various inflammatory and infectious conditions, and seems suitable as a primary imaging method. On the contrary, 99Tcm-nanocolloid cannot be recommended for use in inflammatory bowel diseases, soft tissue abscesses or prosthetic vascular graft infections. However, 99Tcm-nanocolloid gave reliable information in inflammatory and infectious bone and joint diseases in which it had a 90% sensitivity and 100% specificity. In those lesions the 99Tcm-nanocolloid method may be useful, because it is simple, fast and cheap. Yet, further evaluation is needed.     

Comparison of indium-111 oxinate labelled autologous granulocytes with indium-111 oxinate and indium-111 chloride as abscess scanning agents

Bacterial abscesses were evoked in goats. Imaging of these abscesses was obtained by means of labelling autologous granulocytes with ¹¹¹In oxinate, reinjection of the cells into the animal, and scintigraphy by gamma camera one day later. Comparable imaging results, however, were obtained after intravenous injection of ¹¹¹In oxinate or of ¹¹¹In chloride.The gamma camera images were supported by tissue distribution studies. In the case of administration of ¹¹¹In oxinate to the goats, the radioactivity accumulated in the cell fraction of the blood to a significant extent. This did not occur in the case of plain ¹¹¹In chloride. It remained unexplained why such different accumulation in cells did not result in differences in the scintigraphic studies.Blood clearance studies supplied conclusive evidence that the granulocytes stayed in the circulation for several days following labelling with ¹¹¹In oxinate and reinjection of the cells into the animals.     

Comparison of 111In-oxine and 111In-Acetylacetone for the labeling of cells: in vivo and in vitro biological testing

We have compared several complexes of indium as cell labels: indium-111-acetylacetone, indium-111-oxine, and indium-111-chloride complexed with 8-hydroxyquinoline (oxine) immediately prior to use. In labelling with acetylacetone, it was shown that the labeling efficiency is directly proportional to the amount of acetylacetone present, but the cell viability (as measured by in vitro aggregation studies), is inversely proportional to the amount of acetylacetone present. Biological studies were carried out in dogs using indium-111-labeled platelets; survival times and recovery values obtained with platelets labeled using all three techniques were similar. The same solutions were also used to label white blood cells; labeling efficiencies of greater than 80% were obtained in all cases, and the viability (as measured by trypan blue exclusion) was high in all cases. Chemotactic ability of the white cells labeled with indium-111-oxine is higher than that of unlabeled control cells; however, cells labeled with indium-111-acetylacetone were the same as the unlabeled control cells.     

Technetium-99m and indium-111 double labelling of granulocytes for kinetic and clinical studies

A new technique of labelling granulocytes with both technetium-99m hexamethylpropylene amine oxime (HMPAO) and indium-111 in a single protocol was developed in order to exploit the advantages of each radiolabel in clinical and investigative studies. Fourteen patients were included in this prospective study. Granulocytes were labelled with both¹¹¹In-tropolonate and^99mTc-HMPAO. In vitro shape change assay and in vivo distribution and recovery studies were performed to assess the activation of and damage to these cells due to the labelling procedure. The comparative kinetics of¹¹¹In and^99mTc in the blood, liver, spleen, and bone marrow were studied by blood sampling and dual radionuclide imaging early (1 h) and late (24 h) after injection. The functional integrity of the double-labelled granulocytes and the feasibility of the technique were investigated in 14 patients with a painful prosthetic hip due to causes other than infection. The efficiency of double labelling was 63% (SD 14%) for¹¹¹In and 39% (SD 12%) for^99mTc-HMPAO. In vitro granulocyte activation and ex vivo recovery values were comparable to those from single radionuclide labelling. No artefactual granulocyte sequestration was seen in the lungs or liver. The radioactivity was distributed between the liver, spleen and bone marrow and, to a lesser extent, the lung. Early^99mTc counts in the liver, spleen and bone marrow, in relation to background, were significantly higher than¹¹¹In counts while the reverse was seen in late images. Furthermore, circulating free^99mTc was significantly higher than free¹¹¹In at 24 h. Organ^99mTc counts, expressed in relation to the activity in early images, decreased in the spleen, increased in the liver and remained unchanged in bone marrow, whereas¹¹¹In counts increased in the bone marrow and liver, and decreased in the spleen. Granulocytes can be labelled with both¹¹¹In and^99mTc-HMPAO in a single protocol without crosschelation, cellular activation or damage. By favourably exploiting their kinetics for early and late imaging, double-labelled granulocytes may be useful in several clinical and investigative situations.     

Quantification of pulmonary uptake of indium-111 labelled granulocytes in inflammatory bowel disease

This study describes a method for quantifying the pulmonary trapping of indium-111 labelled polymorphonuclear (PMN) cells in patients with inflammatory bowel disease (1131) in comparison to non-inflamed controls. Twenty patients with extensive IBD were studied by ¹¹¹In-PMN scintigraphy. Gamma-camera images were obtained at 2.5–4 h (early) and 20–25 h (late) after the injection of autologous PMNs labelled in plasma with ¹¹¹In-tropolonate. Local uptake in the chest, iliac bone marrow, spleen and liver was quantified as the counts per pixel per second per MBq of injected ¹¹¹In for both early and late scans. Fourteen subjects without inflammatory disease were studied as controls. IBD patients showed significantly greater loss of splenic activity between early and late scans compared with controls (mean ± SD: –35.7% ± 16.6% versus –4.5% ± 6.1%, P < 0.001). There was no significant difference between control and IBD groups with respect to liver and bone marrow uptake on both early and late scans. Chest uptake was significantly higher in patients with 11313 on both early (6.4 ± 1.6 cps/MBq/pix) and late (5.6 ± 1.5cps/MBq/pix) scans, compared with the controls (4.8 ± 1.3 cps/MBq/pix, P < 0.005 and 3.4 ± 1.0 cps/MBq/pix, P < 0.001 respectively). The chest uptake in the control group on the late scans demonstrated a significant linear correlation with iliac uptake (y=0.23x + 0.41, r=0.87, n=14). Assuming in controls that there is no parenchymal uptake of ¹¹¹In, this regression enables an estimate to be made, based on iliac counts, of the count rate from bone marrow in the chest wall. After subtraction of this from the total chest count rate, the true parenchymal uptake was derived, which averaged (2.86 ± 0.91) cps/MBq/pix in the IBD group compared to zero assumed in the control group. The higher lung ¹¹¹In-PMN uptake on the early scans in IBD compared to controls is suggested to reflect a combination of increased margination, compared to controls, and early migration, whilst the excess ¹¹¹In-PMN retention on late scans represents extravascular migration only. The bone marrow correction technique for quantification of pulmonary migration of ¹¹¹In-PMNs should prove useful for the evaluation of PMN kinetics in disease. Correspondence to: A.M. Peters     

The preparation and in vivo behaviour of 111In-oxine labelled neutrophils separated from whole blood using mono-poly resolving medium

using a single step separation procedure, we have developed a method for labelling human neutrophils with 111In-oxine. This method allows a rapid separation of neutrophils from whole blood, with negligible mononuclear or red cell contamination. Preliminary studies using 111In-labelled neutrophils show minimal lung retention and early accumulation in the spleen consistent with viable cells. In addition, focal accumulation of 111In has been imaged in patients with localized inflammation or sepsis.     

99Tcm-HMPAO显像评价药物性肺损伤的临床价值

目的探讨药物所致肺损伤的99Tcm-HMPAO摄取程度及其异常摄取机理。方法胺碘酮药物组及平阳霉素药物组分别制作不同剂量兔肺损伤模型,给药前及给药后1周、2周、3周、4周均行99Tcm-HMPAOSPECT前后位静态显像,在右肺中叶(R)和右上肢(B)绘制大小为7×5像素的感兴趣区,计算R/B,结果以x-±s表示,同时经耳缘静脉采血2ml,用放射免疫分析法检测血中内皮素含量。不同药物、不同剂量组兔一定时间后处死,取肺组织做光、电镜检查。结果不同药物、不同剂量组兔肺摄取99Tcm-HMPAO的程度与给药前均差异有显著性意义(P<0.05),不同剂量组血浆内皮素均呈明显上升趋势。光镜下肺组织呈典型间质性肺炎改变,电镜下显示内皮细胞胞浆有水肿性改变,在胞浆内显示大量吞银小泡。结论肺毛细血管内皮细胞可能是99Tcm-HMPAO异常聚集的主要部位,可反映药物所致肺损伤早期。     

99mTc-EDDA/HYNIC-TOC: a new 99mTc-labelled radiopharmaceutical for imaging somatostatin receptor-positive tumours: first clinical results and intra-patient comparison with 111In-labelled octreotide derivatives

[¹¹¹In-diethylene triamine penta-acetic acid-d-Phe¹]-octreotide (DTPA-octreotide) scintigraphy has gained widespread acceptance as a diagnostic clinical procedure in oncology for imaging somatostatin receptor-positive tumours. However, indium-111 as a radiolabel has several drawbacks, including limited availability, suboptimal gamma energy and high radiation burden to the patient. We have recently reported on the preclinical development of ^99mTc-EDDA/HYNIC-TOC, a new octreotide derivative which showed promising results both in vitro and in vivo. We now report our initial clinical experiences with this new radiopharmaceutical in ten oncological patients. The clinical diagnoses were: carcinoid syndrome (n=5), thyroid cancer (n=3), pancreatic cancer (n=1) and pituitary tumour (n=1). The biodistribution and kinetics of ^99mTc-EDDA/HYNIC-TOC were compared with those of ¹¹¹In-DTPA-octreotide in six cases, and with those of ¹¹¹In-DOTA-TOC in five cases. With the new tracer tumours were imaged within 15 min after injection and showed the highest target/non-target ratios 4 h after injection. Tumour uptake persisted up to 20 h p.i. The rate of blood clearance was similar to that of ¹¹¹In-DTPA-octreotide but faster than that of ¹¹¹In-DOTA-TOC, while urinary excretion was lower compared with the ¹¹¹In derivatives. Semi-quantitative region of interest analysis showed that ^99mTc-EDDA/HYNIC-TOC produced higher tumour/organ (target/non-target) ratios than the ¹¹¹In derivatives, especially in relation to heart and muscle. Significantly more lesions could be detected in ^99mTc images. We conclude that ^99mTc-EDDA/HYNIC-TOC shows better imaging properties for the identification of somatostatin receptor-positive tumour sites than currently available ¹¹¹In-labelled octreotide derivatives.     

Radioimmunoscintigraphy of ovarian tumours with technetium-99m labelled monoclonal antibody-170: first clinical experiences

The recently developed technetium-99m-labelled monoclonal antibody-170 (MAb-170) was designed for diagnostic use in patients suffering from gynaecological adenocarcinoma. Following in vitro studies which showed immunoreactivity of this antibody to more than 90% of human adenocarcinomas, the present investigation was initiated to verify its usefulness for radioimmunoscintigraphy of ovarian tumours. Most of the 30 patients participating in this study underwent immunoscintigraphy prior to first-look surgery. Biokinetic evaluation in two patients showed a plasma half-time of 18.9 h (mean value,n = 2,r = 0.98) and a biexponential total body curve with values of 7.7 h and 17 days (r = 0.98). The mean 24-h urinary excretion was 12% of the injected dose. Radioimmunoscintigraphy using the MAb-170 recognised 12 of 13 cases of adenocarcinoma of the ovaries, corresponding to an overall sensitivity of 92.3% . Specificity was 94.1% (16/17). The calculation of accuracy yielded a figure of 93.3% (28/30). Of 33 known lesions, 26 were visualised successfully; thus the locoregional sensitivity was 78.8%. Of 29 benign tumour sites, 28 showed no evidence of tracer accumulation, corresponding to a locoregional specificity of 96.6%. The smallest lesion visualised was an adenocarcinoma of the corpus uteri with a diameter of 1.5 cm. Technetium-99m labelled MAb-170 is a promising new radiopharmaceutical for immunoscintigraphy of ovarian adenocarcinoma.     

99Tcm-labelled anti-CEA monoclonal antibody for tumour immunoscintigraphy: first clinical results

Twenty patients with malignant carcinoembryonic antigen (CEA)-producing tumour recurrences (colorectal n = 14; breast, lung, medullary thyroid carcinoma n = 2, each) were studied by immunoscintigraphy using an intact monoclonal anti-CEA antibody (BW 431/26) labelled with 99Tcm by a new labelling technique (Schwarz Method). This novel approach allows an almost quantitative labelling of the antibody, which is first reduced using a thiol, lyophilized in purified form, and then reacted with a stannous salt component before 99Tcm-pertechnetate binding. The labelling efficiency (as controlled by TLC) was greater than 95%, the in vitro stability at least 6 h. The imaging results (planar and SPECT) yielded a sensitivity of 91%, a specificity of 87% and a diagnostic accuracy of 90%. These first promising clinical results trigger the hope that the successful labelling of monoclonal antibodies with 99Tcm is a decisive step towards the more practically orientated use of tumour immunoscintigraphy.     

99mTc-EDDA/HYNIC-TOC: a new 99mTc-labelled radiopharmaceutical for imaging somatostatin receptor-positive tumours; first clinical results and intra-patient comparison with 111In-labelled octreotide derivatives

[111In-diethylene triamine penta-acetic acid-D-Phe1]-octreotide (DTPA-octreotide) scintigraphy has gained widespread acceptance as a diagnostic clinical procedure in oncology for imaging somatostatin receptor-positive tumours. However, indium-111 as a radiolabel has several drawbacks, including limited availability, suboptimal gamma energy and high radiation burden to the patient. We have recently reported on the preclinical development of 99mTc-EDDA/HYNIC-TOC, a new octreotide derivative which showed promising results both in vitro and in vivo. We now report our initial clinical experiences with this new radiopharmaceutical in ten oncological patients. The clinical diagnoses were: carcinoid syndrome (n=5), thyroid cancer (n=3), pancreatic cancer (n=1) and pituitary tumour (n=1). The biodistribution and kinetics of 99mTc-EDDA/HYNIC-TOC were compared with those of 111In-DTPA-octreotide in six cases, and with those of 111In-DOTA-TOC in five cases. With the new tracer tumours were imaged within 15 min after injection and showed the highest target/non-target ratios 4 h after injection. Tumour uptake persisted up to 20 h p.i. The rate of blood clearance was similar to that of 111In-DTPA-octreotide but faster than that of 111In-DOTA-TOC, while urinary excretion was lower compared with the 111In derivatives. Semi-quantitative region of interest analysis showed that 99mTc-EDDA/HYNIC-TOC produced higher tumour/organ (target/non-target) ratios than the 111In derivatives, especially in relation to heart and muscle. Significantly more lesions could be detected in 99mTc images. We conclude that 99mTcEDDA/HYNIC-TOC shows better imaging properties for the identification of somatostatin receptor-positive tumour sites than currently available 111In-labelled octreotide derivatives.     

Tc-99m-HMPAO labelled human platelets: in vitro and in vivo results

The lipophilic 99mTc-HMPAO complex can be used for labelling platelets as well as granulocytes. Platelets were isolated according to standard isolation procedures for the evaluation of the optimal labelling parameters. The labelling efficiency (%) depends on incubation temperature (22 degrees C: 40%: 37 degrees C: 50%), incubation time (3 min: 20%, 25 min: 55%) and the incubation medium (plasma: 40%; saline 50%). The 60 min 99mTc elution out of the platelets ranged around 8%. The platelet recovery used as a quality control parameter is around 25% +/- 4% and is stable for at least 240 min. The high elution rate out of the platelets leads to renal excretion of the label and hence to significant kidney and bladder activity. Intestinal excretion of the label can also be frequently demonstrated. Fresh thrombotic lesions can normally be detected 4 h after reinjection of the labelled platelets, and in some patients as early as 1 h after reinjection. In conclusion, 99mTc-HMPAO seems to be a promising platelet label for imaging thrombotic lesions but not for platelet survival studies, because of the short physical half life of 99mTc.     

Tc-99m-HMPAO labelled human platelets: in vitro and in vivo results

The lipophilic ^99mTc-HMPAO complex can be used for labelling platelets as well as granulocytes. Platelets were isolated according to standard isolation procedures for the evaluation of the optimal labelling parameters. The labelling efficiency (%) depends on incubation temperature (22° C: 40%; 37° C: 50%), incubation time (3 min: 20%, 25 min: 55%) and the incubation medium (plasma: 40%; saline 50%). The 60 min ^99mTc elution, out of the platelets ranged around 8%. The platelet recovery used as a quality control parameter is around 25%±4% and is stable for at least 240 min. The high elution rate out of the platelets leads to renal excretion of the label and hence to significant kidney and bladder activity. Intestinal excretion of the label can also be frequently demonstrated. Fresh thrombotic lesions can normally be detected 4 h after reinjection of the labelled platelets, and in some patients as early as 1 h after reinjection. In conclusion, ^99mTc-HMPAO seems to be a promising platelet label for imaging thrombotic lesions but not for platelet survival studies, because of the short physical half life of ^99mTc.Supported by the Deutsche Forschungsgemeinschaft (BE 1054/1–2)     

Comparison of simultaneous 99mTc-HMPAO and 111In oxine labelled white cell scans in the assessment of inflammatory bowel disease

Forty-seven patients, 29 with chronic inflammatory bowel disease (1131) and 18 with presumed irritable bowel syndrome, including one with uncomplicated diverticular disease, were studied with simultaneous technetium-99m hexamethylpropylene amine oxime and indium-111 oxine labelled leucocyte scans performed at 1, 3 and 24 h. Twenty-seven patients with IBD had active disease as judged by clinical and laboratory criteria and all of these had positive scans with both agents. No false positive studies were obtained. The 1-h ^99mTc-HMPAO WBC scans showed the same distribution to disease as the 3-h ¹¹¹-In WBC scans, with no difference in intensity (P < 0.92); they showed more extensive disease (P < 0.02) and more intense uptake (P < 0.001) than did the 1-h ¹¹¹-In scans. The 3-h ^99mTc-HMPAO WBC scans showed more extensive disease (P < 0.002), with greater intensity (P < 0.0005), than did the 3-h ¹¹¹In WBC scans. Physiological bowel activity on 3-h ^99mTc-HMPAO WBC scans was present in 12 patients but was faint and did not interfere with assessment of disease extent and activity. It is concluded that in terms of isotope availability, radiation dosimetry and image quality, ^99mTc-HMPAO is the agent of choice in detecting active IBD, with localization of disease possible at 1-h after re-injection and optimal resolution and definition of disease extent at 3 h. A negative scan reliably excludes active disease. Correspondence to: R.A. Allan     

Cognition and 99Tcm-HMPAO SPECT in Parkinson's disease.

99Tcm-hexamethylpropyleneamine oxime (HMPAO) single photon emission computed tomography (SPECT) of brain was performed in 43 unselected patients with Parkinson's disease to evaluate whether low cerebral perfusion on SPECT correlated with cognitive impairment in the patients. All patients received neurological, Mini-Mental State Examination and a neuropsychological assessment. Eighteen (41.9%) of the 43 patients were demented. Thirty patients (69.8%) had abnormal SPECT: 17 had perfusion defects in cortical regions, eight in basal ganglia and five in both regions. Of the 22 patients with abnormal cortical perfusion, 15 (68.2%) were demented; only three (14.3%) of the 21 patients without cortical defect were demented (P < 0.01). Twelve of the 15 demented patients had low perfusion in the parietal region alone or in parietal and occipital regions. The cortical perfusion defects, present in 22 (51.2%) Parkinson's patients, are highly correlated with cognitive impairment. The pattern of SPECT abnormality in most demented patients with Parkinson's disease is similar to that seen in Alzheimer's disease, suggesting that the underlying pathophysiology for dementia in patients with Parkinson's disease may be similar to that in Alzheimer's disease.     

99Tcm-labelled HSA-nanocolloid versus 111In oxine-labelled granulocytes in detecting skeletal septic process

Fifty-seven investigations of the skeletal system were performed on 54 patients, using a 99Tcm-labelled nanometer-sized HSA colloid in a crossover comparison with 111In oxine-labelled granulocytes for the detection of sites of infection. The findings were in agreement in 55 out of 57 investigations (96.5%). Based on 44 studies in which a final clinical diagnosis was obtained, both methods were found to display the same specificity (93%), whilst the sensitivity of 99Tcm nanocolloid scintigraphy (87%) was slightly higher than that obtained with 111In leucocyte scintigraphy (81%). In our opinion, 99Tcm nanocolloid is easier to use and the total duration of the investigation is considerably shorter. The use of 99Tcm is scintigraphically more advantageous and, with the dosage required, the absorbed radiation dose to the red bone marrow is three times lower than with 111In granulocytes. For the detection and therapy monitoring of osteomyelitis, as well as for the investigation of arthroplasties suspected of infective loosening, we consider scintigraphy with 99Tcm nanocolloid to be equivalent to leucocyte scintigraphy. Identical findings were obtained with both tracers in suspected spondylodiscitis.