Radioimmunoimaging for diagnosis of bone marrow involvement in breast cancer and malignant lymphoma

Radioimmunotherapy-based conditioning for hematopoietic cell transplantation in children with malignant and nonmalignant diseases

Targeted irradiation of the bone marrow with radiolabeled monoclonal antibodies (radioimmunotherapy) represents a novel therapeutic approach with both myeloablative and antileukemic potential. In an open-label, single-center pilot study, 30 pediatric and adolescent patients undergoing hematopoietic cell transplantation for malignant (n = 16) and nonmalignant (n = 14) disorders received treatment with a ⁹⁰Y-labeled anti-CD66 monoclonal antibody. Patients with a high risk of relapse (n = 7) received additional treatment with standard conditioning based on either total body irradiation or busulfan to intensify the antileukemic effect. In patients with comorbidities (n = 23), radioimmunotherapy was combined with a reduced-intensity conditioning regimen to reduce systemic toxicity. Preferential irradiation of the bone marrow was achieved in all patients. Nonrelapse mortality was 4 (13%) of 30 patients. In patients with malignant diseases, the probabilities of overall and disease-free survival at 2 years were 0.69 (95% confidence interval 0.37-0.87) and 0.46 (95% confidence interval 0.19-0.70), respectively. In patients with nonmalignant diseases, the probability of both overall and disease-free survival at 2 years was 0.94 (95% confidence interval 0.63-0.99). This pilot study demonstrates that radioimmunotherapy is effective in achieving myeloablation with low additional toxicity when used in combination with standard or reduced-intensity conditioning in young patients.

Radionuclide imaging of bone marrow disorders

Noninvasive imaging techniques have been used in the past for visualization the functional activity of the bone marrow compartment. Imaging with radiolabelled compounds may allow different bone marrow disorders to be distinguished. These imaging techniques, almost all of which use radionuclide-labelled tracers, such as ^99mTc-nanocolloid, ^99mTc-sulphur colloid, ¹¹¹In-chloride, and radiolabelled white blood cells, have been used in nuclear medicine for several decades. With these techniques three separate compartments can be recognized including the reticuloendothelial system, the erythroid compartment and the myeloid compartment. Recent developments in research and the clinical use of PET tracers have made possible the analysis of additional properties such as cellular metabolism and proliferative activity, using ¹⁸F-FDG and ¹⁸F-FLT. These tracers may lead to better quantification and targeting of different cell systems in the bone marrow. In this review the imaging of different bone marrow targets with radionuclides including PET tracers in various bone marrow diseases are discussed.

Age-Related Changes in the Metabolic Activity and Distribution of the Red Marrow as Demonstrated by 2-Deoxy-2-[F-18]fluoro-d-glucose-Positron Emission Tomography

OBJECTIVES

The objective of the study was to determine age-related changes occurring in red marrow with regard to its distribution and the degree of its metabolic activity by whole-body 2-deoxy-2-[F-18]fluoro-D-glucose (FDG)-positron emission tomography (PET).

METHODS

This retrospective study included 112 patients (56 male, 56 female, mean age 40 years, range 2-85) who underwent whole-body FDG-PET scans for assessment of disorders that were determined not to affect red marrow activity. These patients were categorized into the following groups with equal gender distribution: 0-15 years (12 individuals), 16-25 years (20), 26-35 years (10), 36-45 years (20), 46-55 years (14), 56-65 years (16), 66-75 years (14), and 76-85 years (6). Whole-body FDG-PET images were performed at 60 min after the intravenous administration of 0.14 mCi/kg of FDG. By employing a dedicated whole-body PET scanner. Maximal standardized uptake value (SUV(max)) was calculated from three consecutive transverse sections of the upper thirds of the humeri and femora, manubrium of the sternum, 12th thoracic and 5th lumbar vertebra and anterior superior iliac crests of the pelvis. All available results from other imaging examinations [magnetic resonance imaging (MRI), computed tomography (CT), and conventional radiolography], laboratory data, biopsies, and the clinical course of these subjects were reviewed to make certain that the bone marrow sites examined were free of any known pathologies.

RESULTS

SUV(max) in the extremities showed significant decline with aging (correlation coefficient of -0.60 to -0.67, p < 0.01). In contrast, a weak correlation was noted in the axial skeletal activity with advancing age (correlation coefficient of -0.28 to -0.48, p < 0.05).

CONCLUSIONS

These data suggest that FDG metabolic activity of the red marrow in the extremities decline significantly with normal aging, while that of the axial skeleton show minimal decrease related to this biologic phenomenon. These findings are of value in assessing the effects of hematological and other disorders in the distribution and the metabolic activity of this important tissue and testing therapeutic interventions that are employed for treating such maladies.

Structural and functional imaging of normal bone marrow and evaluation of its age-related changes

A number of noninvasive imaging techniques have been used for the evaluation of bone marrow, including magnetic resonance imaging (MRI) and bone marrow scintigraphy. The appearance of bone marrow on MRI varies considerably depending on the proportion of red and yellow marrow, and the composition of the red marrow and its distribution with relation to age and sex. The composition of bone marrow also can vary under physiological and pathological conditions. MRI is a highly sensitive technique for evaluating the bone marrow, but it is limited in its practical use for whole-body bone marrow screening. Bone marrow scintigraphy with radiolabeled compounds such as technetium-99m-labeled nanocolloid and monoclonal antibodies has the advantage of evaluating the entire bone marrow, and has been used for the diagnosis of various bone marrow disorders. In addition, (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) imaging can be used to evaluate bone marrow metabolism and disease and to provide information about the state of the primary tumor, lymph nodes, and distant metastases. Understanding of the appearance of normal bone marrow, including age- and sex-specific differences with each of these imaging modalities, is essential to permit accurate diagnosis of benign and malignant bone marrow disorders. We present a review of MRI and scintigraphy of normal bone marrow with some emphasis on FDG-PET imaging in assessing marrow activity in normal and abnormal states and also present preliminary data regarding normal age-related changes in bone marrow through use of FDG-PET, as well as the role of segmentation of bone marrow on MRI for quantitative calculation of the metabolic volumetric product for red marrow metabolism using FDG-PET.

A comparison of the biodistribution and biokinetics of (99m)Tc-anti-CD66 mAb BW 250/183 and (99m)Tc-anti-CD45 mAb YTH 24.5 with regard to suitability for myeloablative radioimmunotherapy

Radioimmunotherapy (RIT) with radiolabelled monoclonal antibodies (mAbs) is an effective method of achieving myeloablation in leukaemia patients prior to stem cell transplantation (SCT). We wished to compare the approaches of specific binding to leukaemic blasts and non-specific binding to benign red marrow cells, which results in a myeloablative "cross-fire" effect. Therefore, we prospectively evaluated the biodistribution and biokinetics of the anti-CD45 mAb YTH 24.5 and the anti-CD66 mAb BW 250/183 with regard to their suitability for myeloablative RIT. The red marrow selective anti-CD66 mAb BW 250/183 (IgG1) binds to normal granulopoietic cells. In contrast, the anti-CD45 mAb YTH 24.5 (IgG2b) binds to 85-90% of acute leukaemic blasts and almost all haematopoietic white cells. Patients with leukaemic blast infiltration of the marrow <25% and assigned for RIT and SCT were included. Twelve patients (eight male, four female; median age 46+/-7 years) with AML (5), CML (5) or ALL (2) were examined. Both mAbs were labelled with technetium-99m. Within 48 h, 906+/-209 MBq (99m)Tc-anti-CD66 mAb and 760+/-331 MBq (99m)Tc-anti-CD45 mAb were injected consecutively. Scintigraphic and urinary measurements were performed 1, 2, 4 and 24 h after injection. Serum activities were evaluated 2, 5, 10, 15, 30 and 60 min and 2, 4 and 24 h after injection. Compared with the anti-CD45 mAb, the anti-CD66 mAb showed an approximately fourfold higher accumulation in the red marrow, a 2.5-fold lower accumulation in the liver and similar accumulation in the kidneys. The serum activity (% of the injected dose) initially decreased faster for the anti-CD45 mAb but was similar for the two mAbs 24 h after injection: 3.3%+/-1.2% (anti-CD66 mAb) and 2.4%+/-1.1% (anti-CD45 mAb). The cumulated urinary excretion was 17%+/-6.6% (anti-CD66 mAb) and 27.3%+/-7.9% (anti-CD45 mAb) 24 h after application. In these patients with low tumour load, the anti-CD66 mAb BW 250/183 showed more favourable properties in terms of biodistribution and pharmacokinetics. Thus, it appears superior to anti-CD45 mAb YTH 24.5 in selectively increasing the marrow dose and avoiding extramedullary organ toxicity.

The value of bone marrow scintigraphy using 99mTc monoclonal antigranulocyte antibodies in complement to bone scintigraphy in detecting bone metastases from primary breast cancer

This prospective study evaluates bone marrow scintigraphy (BMS) in detecting bone metastases from primary breast cancer when performed in complement to conventional bone scan (BS). Sixty women predominantly with low-stage disease underwent BS followed by BMS within 1-35 days using BW250/183 antigranulocyte antibodies. A receiver operating characteristic (ROC) analysis was performed to compare BS to BS+BMS on a patient-by-patient basis using a 'gold standard' composed of subsequent computed tomography, magnetic resonance imaging, X-ray or BS examinations and at least a 12 month follow-up. Metastases were present in eight out of 60 patients (13%). Specificity was improved by BS+BMS compared to BS alone (90%, 65%) as well as positive predictive value (62%, 27%), accuracy (87%, 72%), positive (10.4, 2.4) and negative (0.20, 0.00) likelihood ratios. Sensitivity (100%, 88%) and negative predictive value (100%, 97%) were similar for BMS+BS and BS alone. As a result of BMS, clinical management was modified in 15 patients (25%). In conclusion, BMS supplements BS by improving specificity, positive predictive value and accuracy in detecting breast cancer bone metastases. The ROC curves show improved specificity for BS+BMS at the same sensitivity compared to BS alone. Consequently, BMS may be useful in low-stage subjects with positive or equivocal BS for metastases.

Bone marrow immunoscintigraphy in haematological patients with pancytopenia: preliminary results

The aim of this study was to assess the clinical value of bone marrow immunoscintigraphy using the (99m)Tc labelled anti-NCA-95 antigranulocyte antibodies (AGAb) and of AGAb bone marrow uptake ratio (UR) in the initial diagnostic work-up of diseases with depression of the bone marrow. Twenty-four whole-body bone marrow scans were performed in 23 patients (11 women, 12 men; median age 46 years, range 17-74 years) 5 h after i.v. injection of 370 MBq of AGAb. The UR was calculated from the posterior view drawing an irregular region of interest around the sacroiliac and a background areas. The mean UR in pancytopenic patients was 2.3+/-1.5 (range 0.3-5.8), thus being significantly lower (P=0.45 x 10(-6)) than the mean UR in a control group of 50 patients (mean UR 7.3+/-2.3; range 4.4-12.6) obtained previously. Considering patient age, there was no overlap between UR of pancytopenic patients and the respective normal ranges. The bone marrow appearance on scans seemed to be characteristic for the different haematological diseases investigated. In six patients with myelofibrosis, bone marrow scans demonstrated diffusely decreased bone marrow activity and prominent splenic uptake, possibly related to extramedullary haematopoiesis. In aplastic anaemia, highly reduced and patchy marrow uptake was observed in four patients (five scans), in one of them persisting even after blood cell counts had recovered to the near-normal range. In another two patients with aplastic anaemia, diffusely decreased bone marrow uptake was obtained. In patients with myeloid leukaemia, bone marrow patterns were almost normal probably because the target antigen is often expressed on neoplastic myeloid cells, too. Bone marrow extension was a common finding in these patients. There is an obvious differentiation between haematological patients with pancytopenia and normal subjects by means of AGAb bone marrow uptake ratio. The distinct patterns of AGAb distribution may be indicative for particular haematological diseases.

Myeloablative radioimmunotherapy with Re-188-anti-CD66-antibody for conditioning of high-risk leukemia patients prior to stem cell transplantation: biodistribution, biokinetics and immediate toxicities

BACKGROUND

Stem cell transplantation (SCT) is potentially curative for high-risk leukemia patients. Conditioning regimens affect relapse rate and treatment-related mortality. We evaluated biodistribution, radiation absorbed organ doses and immediate toxicities of myeloablative radioimmunotherapy with marrow selective 188rhenium (188Re)-labeled anti-CD66 monoclonal antibody (mAb).

METHODS

Fifty high-risk leukemia patients were treated 14 +/- 2 days prior to SCT. Dosimetric measurements were performed at 1.5, 3, 20, 26, and 44 hours after about 1 GBq of 188Re followed by radioimmunotherapy with about 10 GBq 188Re. Standard conditioning consisted of high-dose chemotherapy and 12 Gy total-body irradiation. Forty-six patients received allogenic, and four received autologous, stem cell grafts.

RESULTS

The mean radiation absorbed doses (in Gy) were: marrow, 13.9 +/- 4.6; liver, 5.7 +/- 2.7; spleen, 22.6 +/- 25.5; kidneys, 6.8 +/- 2.6; lungs, 0.8 +/- 0.7; total body, 1.4 +/- 0.3. The tumor-to-organ-ratios were 2.4 for liver, 0.6 for the spleen, 2.0 for the kidneys and 17.8 for the lungs. Type of leukemia did not affect radiation absorbed doses of marrow, lungs, kidneys and liver. Mean marrow dose of transplanted patients in complete remission was 1.37 +/- 0.43 Gy/GBq, compared with 1.34 +/- 0.29 Gy/GBq for patients with leukemic blast marrow infiltration of 5-25%. Immediate side effects were moderate. All patients showed primary engraftment. After a median follow-up of 11.0 +/- 7.4 months 28/50 patients (56%) are in ongoing complete remission. Nine patients (5%) have relapsed, seven (4%) of them have died. Another 13 patients (7%) died of treatment-related causes.

CONCLUSIONS

Due to its biodistribution, radiation absorbed organ doses, low toxicity and clinical data, myeloablative radioimmunotherapy with 188Re-labeled anti-CD66 mAb seems to be a promising method for improving standard conditioning of high-risk leukemia patients prior to SCT.

Bone marrow scintigraphy with 99m Tc labelled monoclonal anti-NCA 90 Fab' fragment: a feasibility study and comparison of bone marrow uptake with 99m Tc labelled monoclonal anti-NCA 95 antigranulocyte antibody

The aim of this retrospective study was to evaluate the usefulness of 99mTc labelled monoclonal anti-NCA 90 antigranulocyte antibody Fab' fragment (MN3 Fab') as a bone marrow imaging agent. One hundred and ten planar scans (88 patients) of the lumbar and sacroiliac regions as well as whole-body scans were performed after 1, 5 and 24 h. All the scans were evaluated visually and bone marrow uptake was determined semiquantitatively as count density ratio from sacroiliac-minus-background to background area. Results were compared to 50 age-matched patients with normal bone marrow scans obtained with the intact 99mTc labelled monoclonal anti-NCA 95 antigranulocyte antibody (BW 250/183) in a previous study. Seventy-three patients showed a physiological activity distribution in the central bone marrow. Ten patients showed a bone marrow extension, while in two patients central bone marrow depression was observed. Evaluation of the ribs, lower thoracic and upper lumbar spine was hampered by soft-tissue activity. Bone marrow uptake was 1.36+/-0.56 after 1 h, decreased thereafter and was significantly lower than that of BW 250/183 (P < 0.001). In conclusion, MN3 Fab' cannot be recommended for bone marrow scintigraphy, because relevant parts of the haemopoietically active bone marrow are not accessible to visual evaluation. A significant role of the semiquantitative evaluation of MN3 Fab' bone marrow uptake in patients with potential marrow depression seems unlikely.

18-fluorodeoxyglucose positron emission tomographic imaging in the detection and monitoring of infection and inflammation

During the past decade, 18-fluorodeoxyglucose (FDG) positron emission tomography (PET) has rapidly evolved from a pure research modality to a clinical necessity. FDG-PET was introduced to determine the state of brain function in physiologic and pathologic states. Its use as a powerful tool to diagnose, stage, and monitor patients with a variety of malignancies has been truly revolutionary. However, FDG is a nonspecific tracer and it has been found to accumulate at sites of infection and inflammation. It is becoming evident that PET imaging will play a major role in the treatement of patients with suspected infection and inflammation. PET has been shown to be particularly valuable in the evaluation of chronic osteomyelitis, infected prostheses, sarcoidosis, fever of unknown origin, and acquired immunodeficiency syndrome. Because of its ability to quantitate the rate of FDG uptake, PET may prove to be a powerful modality for the monitoring of disease activity and response to therapy. Novel PET tracers are being tested for imaging infection and inflammation that may further enhance the role of this technique in the appropriate clinical setting. PET imaging to detect and characterize infection and inflammation may become a major clinical indication in the day-to-day practice of medicine.

Comparative detectability of bone metastases and impact on therapy of magnetic resonance imaging and bone scintigraphy in patients with breast cancer

OBJECTIVE

to evaluate the comparative impact of magnetic resonance imaging and bone scintigraphy in bone metastases of breast cancer.

METHODS AND PATIENTS

in 81 patients with histologically proven breast cancer magnetic resonance imaging of the axial skeleton and whole-body bone scintigraphy had been performed. Images were retrospectively reviewed and compared for detection of metastases, extent of metastatic disease and therapeutic implications according to the patients' records.

RESULTS

about 54/81 (67%) patients revealed bone metastases. In 7/54 (13%) patients with bone metastases, scintigraphy was false negative. In one patient a solitary sternal metastases was seen. In 26/53 [49%] patients with spinal metastases, magnetic resonance imaging showed more extensive disease. Local radiotherapy or surgery was indicated in ten patients with metastases not evident in bone scintigraphy, in 20 patients with positive results by both imaging modalities and in six patients with metastases of pelvis imaged by bone scintigraphy only.

CONCLUSION

magnetic resonance imaging of the axial skeleton and pelvis appears superior for staging as only one patient had metastases merely outside the axial skeleton and local therapy was indicated even in spinal regions negative in bone scintigraphy.

Rhenium 188-labeled anti-CD66 (a, b, c, e) monoclonal antibody to intensify the conditioning regimen prior to stem cell transplantation for patients with high-risk acute myeloid leukemia or myelodysplastic syndrome: results of a phase I-II study

The conditioning regimen prior to stem cell transplantation in 36 patients with high-risk acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) was intensified by treating patients with a rhenium 188-labeled anti-CD66 monoclonal antibody. Dosimetry was performed prior to therapy, and a favorable dosimetry was observed in all cases. Radioimmunotherapy with the labeled antibody provided a mean of 15.3 Gy of additional radiation to the marrow; the kidney was the normal organ receiving the highest dose of supplemental radiation (mean 7.4 Gy). Radioimmunotherapy was followed by standard full-dose conditioning with total body irradiation (12 Gy) or busulfan and high-dose cyclophosphamide with or without thiotepa. Patients subsequently received a T-cell-depleted allogeneic graft from a HLA-identical family donor (n = 15) or an alternative donor (n = 17). In 4 patients without an allogeneic donor, an unmanipulated autologous graft was used. Infusion-related toxicity due to the labeled antibody was minimal, and no increase in treatment-related mortality due to the radioimmunoconjugate was observed. Day +30 and day +100 mortalities were 3% and 6%, respectively, and after a median follow-up of 18 months treatment-related mortality was 22%. Late renal toxicity was observed in 17% of patients. The relapse rate of 15 patients undergoing transplantation in first CR (complete remission) or second CR was 20%; 21 patients not in remission at the time of transplantation had a 30% relapse rate. (Blood. 2001;98:565-572)

Radioimmunoimaging and radioimmunotherapy: will these be routine procedures?

Despite major progress made during the past 25 years in the genetic engineering and labeling of monoclonal antibodies (Mab) and in the understanding of the uptake and kinetics of radiolabeled Mab by normal and tumor tissues, immunoscintigraphy never succeeded in becoming a routine procedure, compared with a bone or gallium scan. The more and more generalized availability of positron emission tomography (PET) with Fluorine-18 fluorodeoxyglucose (FDG) for diagnosis and staging of malignant diseases will probably definitively seal the fate of radioimmunodiagnosis as it has been conceived up until now. With respect to the nonspecificity of deoxyglucose uptake by tumor cells, it is not to be excluded that antibodies, or more likely antibody fragments, labeled with positron emitters might be used for tissue characterization. The recent success of radioimmunotherapy, especially in B-cell malignancies, entitles us to expect that RIT will become part of standard therapy of patients with malignancies. In that case, immunoscintigraphy will be needed for treatment planning (patient selection and dosimetry). One might even speculate that the oncologists who are becoming familiar with nuclear medicine tracer techniques for pretreatment evaluation might be interested in extending them to distribution and kinetic studies of other cytotoxic drugs. The close cooperation between nuclear medicine specialists, oncologists, and hematologists is essential to make radioimmunotherapy a routine procedure.

Early detection and accurate description of extent of metastatic bone disease in breast cancer with fluoride ion and positron emission tomography

PURPOSE

Previous studies have shown that bone metastases are revealed by magnetic resonance imaging (MRI) or bone marrow scintigraphy several months before they are visible by conventional bone scintigraphy (BS). We present a new approach for detecting bone metastases in patients with breast cancer. We compared findings obtained with fluoride ion (F-18) and positron emission tomography (PET) with those obtained with conventional BS.

PATIENTS AND METHODS

Thirty-four breast cancer patients were prospectively examined using F-18-PET and conventional BS. F-18-PET and BS were performed within 3 weeks of each other. Metastatic bone disease was previously known to be present in six patients and was suspected (bone pain or increasing levels of tumor markers, Ca(2+), alkaline phosphatase) in 28 patients. Both imaging modalities were compared by patient-by-patient analysis and lesion-by-lesion analysis, using a five-point scale for receiver operating characteristic (ROC) curve analysis. A panel of reference methods was used, including MRI (28 patients), planar x-ray (17 patients), and spiral computed tomography (four patients).

RESULTS

With F-18-PET, 64 bone metastases were detected in 17 patients. Only 29 metastases were detected in 11 patients with BS. As a result of F-18-PET imaging, clinical management was changed in four patients (11.7%). For F-18-PET, the area under the ROC curve was 0.99 on a lesion basis (for BS, it was 0.74; P <.05) and 1.00 on a patient basis (for BS, it was 0.82; P <.05).

CONCLUSION

F-18-PET demonstrates a very early bone reaction when small bone marrow metastases are present, allowing accurate detection of breast cancer bone metastases. This accurate detection has a significant effect on clinical management, compared with the effect on management brought about by detection with conventional BS.

Expression and characterization of anti-NCA-95 scFv (CEA 79 scFv) in a prokaryotic expression vector modified to contain a Sfi I and Not I site

The CEA 79 antibody has been used in bone marrow scintigraphy for the differential diagnosis of skeletal tumors and the evaluation of the bone marrow status of patients with various hematological disorders. The specific localization of radio-labeled CEA 79 antibody in bone marrow depends on its reactivity with NCA-95 (nonspecific cross-reacting antigen-95) present on the surface and in the cytosol of human granulocytes and myelopoietic cells. To make a CEA 79 scFv molecule that would be less immunogenic and more penetrating than the intact mouse immunoglobulin, we constructed a pRSET Sfi I/Not I expression vector. The scFv gene was then excised from a pCANTAB 5 E phage display vector by digestion with Sfi I and Not I and inserted into the pRSET Sfi I/Not I expression vector. Upon transformation of a BL21(DE3)pLysS strain of E. coli, CEA 79 scFv became expressed in inclusion bodies requiring a renaturation process for solubilization. The final yield of CEA 79 scFv was 5 mg per a liter of culture. The refolded CEA 79 scFv exhibited an affinity (Kd = 2.1 x 10(-9) M) equivalent to that of the original CEA 79 antibody (K(d) = 3.3 x 10(-9) M) and the same immunoreactivity to CEA and NCA-95 in Western blots and in immunohistochemical staining experiments.

Skeletal metastases from breast cancer: imaging with nuclear medicine

Breast cancer is a disease that commonly metastasizes to bone, increasing morbidity, mortality, and health service costs. The 99m technetium (99mTc) diphosphonate bone scan historically has played a significant part in the evaluation of skeletal disease and continues to be one of the most clinically utilized investigations in the staging and follow up of breast cancer patients. More tumor-specific radiopharmaceuticals are now being evaluated and, in particular, 18-fluoro-2-deoxyglucose positron emission tomography (18FDG PET) may have a greater role in this disease in the future.

Bone marrow scintigraphy using technetium-99m antigranulocyte antibody in malignant lymphomas

BACKGROUND

The purpose of this study was to elucidate the clinical reliability of immunoscintigraphy (IS) to detect infiltration of the bone marrow in patients with malignant lymphoma.

PATIENTS AND METHODS

Whole body IS was performed in 103 patients with Hodgkin's disease (HD) or non-Hodgkin's lymphoma (NHL) using Tc-99m labelled anti-NCA-95 which allows visualization of the granulopoietic bone marrow. Of these, 52% were studied prior to any therapy. Findings were compared to posterior iliac crest biopsy as well as MRI and/or follow-up examination. Criteria of marrow infiltration were a positive biopsy, positive follow-up, or positive results of MRI.

RESULTS

Comparison of IS and biospy revealed concordant findings in 69 and discordant findings in 34 of 103 patients. Of the 34 patients with discordant results, IS showed lesions suspicious of bone marrow infiltration in 29 patients despite normal biopsy findings. When follow-up and additional examinations were taken into consideration, 10 patients remained with probably false positive and five with false negative IS findings. IS proved to be highly sensitive and specific in patients with HD (100% and 84%, respectively) and high-grade NHL (93% and 84%, respectively). Moderate sensitivity (60%) was found in low-grade NHL. This was possibly due to false negative IS in three to five patients with chemotherapy in contrast to one of five false negative results in patients without chemotherapy.

CONCLUSION

Bone marrow scintigraphy using antigranulocyte antibodies is highly sensitive in HD and high-grade NHL. Positive findings in IS subsequent to a negative biopsy should be followed by guided re-biopsy or MRI.

New diagnostic imaging procedures in Hodgkin's disease

A variety of new diagnostic imaging methods have been developed in recent years for patients with Hodgkin's disease in an attempt to improve the detection of spleen and bone marrow involvement within the scope of staging and to discriminate between fibrosis and vital lymphoma after treatment. Somatostatin receptor scintigraphy has been performed only in a small number of patients to date and further studies must be conducted. Magnetic resonance imaging (MRI), as the established method, has shown its potential in several studies in detecting both spleen and bone marrow involvement; MRI investigations, however, only visualize a limited portion of the body and therefore must be performed in areas of clinically suspected disease. Immunoscintigraphy with radiolabeled antibodies is still in a preclinical or at most early clinical stage of evaluation and first results have to be confirmed in a controlled trial. Positron emission tomography (PET) with [18F]fluorodeoxy-glucose (FDG) is a technique which is still not a routine clinical procedure. However, whole-body FDG-PET seems to be a promising method in staging and follow-up of lymphoma, because it offers the unique capability of visualising metabolic activity throughout the entire body. Long-term multicenter studies are necessary to confirm these promising initial data. In the future, wholebody FDG-PET will probably be the technique of choice for immunoscintigraphic studies with radiolabeled monoclonal antibodies and studies on the pharmacokinetics of cytostatic compounds.

Double-tracer dosimetry of organs in assessment of bone marrow involvement by two monoclonal antibodies

Five patients with ductal breast cancer were studied using simultaneous administration of 99Tcm-labelled BW250/183 and 131I-labelled B72.3 monoclonal antibodies (MAbs). The distribution and dosimetry of these tracers were evaluated using the information from simultaneous anterior and posterior whole body scintigrams, together with 99Tcm and 131I standard activity sources, recorded on an average of 1, 4, 24, 90 and 224 h after injection. A method to eliminate 131I Scatter on 99Tcm-channel was developed. The geometric means of conjugate views and region-of-interest analysis were used to determine organ uptakes, mean residence times and absorbed radiation dose estimates of organs induced by the tracers. Organ uptakes (% of injected activity/ml) varied from 6.2 x 10(-3 /red marrow to 3.1 X 10(-2)/liver for 99Tcm-MAb and from 3.1 x 10(-2)/red marrow to 1.8 x 10(-1)/liver for 131I-MAb, one hour after injection. Calculated average residence times of organs for 99Tcm-labelled BW250/183 were in the range of physical mean-life of 99Tcm and from 71 to 95 h for 131I-B72.3 respectively. The average total absorbed dose from 99Tcm-MAb to the bone marrow was 0.01 and to the spleen 0.14 mGy/MBq and from 131I-MAb the corresponding values were 0.48 and 10.76 mGy/MBq. This double-tracer technique provides information from two antibodies having different kinetic behaviour and may facilitate in distinguishing various antigens in targeting and control MAb applications.

In vivo and in vitro interactions between idiotypic and antiidiotypic monoclonal antibodies against placental alkaline phosphatase

A monoclonal antiidiotypic antibody alpha H7, was generated against a monoclonal antibody H7 with specificity towards placental alkaline phosphatase. The in vitro and in vivo effects of alpha H7 were investigated. The antiidiotypic antibody was found to generate stable complexes with the radiolabeled idiotypic antibody, visualized both in vivo and in vitro, as revealed by PAGE and autoradiography. Using biosensor technology (BIAcore, Pharmacia) the interactions were followed in real time and the association rate, dissociation rate, and affinity constants between the reactants were determined (KA H7/PLAP 6.7 x 10(9) M-1, KA H7/alpha H7 3.2 x 10(9) M-1). By in vivo injection of the antiidiotype, a rapid dose dependent clearance of circulating radiolabeled idiotypes was demonstrated and a decrease in total body radioactivity was recorded with a concomitant dramatic increase in non-protein-bound 125I excreted in the urine. It is concluded that idiotypic-antiidiotypic interactions offer advantages in the regulation of antibody levels in vivo.

Scintigraphic evaluation of the haemopoietic bone marrow using a 99mTc-anti-granulocyte antibody: a validation study with 52Fe

To specify the validity of bone marrow scanning using a monoclonal anti-granulocyte antibody labelled with 99mTc (BW 250/183) for the functional assessment of haemopoiesis, we compared this method with 52Fe scan in 16 patients with haematological disorders. The examinations were performed using a rectilinear whole-body scanner and the distribution of the two tracers was assessed visually and quantitatively in anatomical bone marrow segments, the spleen and liver. Qualitative comparison showed concordance in the bone marrow distribution of the two tracers in 83% of the segments. Discrepancies were found in six patients with hypoplastic or aplastic marrow. The spleen was visualized in all cases with the 99mTc-Moab, including nine patients without splenic haemopoiesis (i.e. without spleen uptake of 52Fe). The uptake of the two tracers, quantified in bone marrow segments and the spleen, correlated well (P < 0.001), but not in the liver (NS). The correlation between the uptake values for each patient was excellent, except in cases of aplastic bone marrow. In conclusion, bone marrow scanning using a 99mTc labelled anti-granulocyte monoclonal antibody enables functional evaluation of the distribution of haemopoiesis. Limitations include the evaluation of bone marrow aplasia and identification of splenic haemopoiesis, for which 52Fe remains the tracer of choice.

Development of bone marrow immunoscintigraphy using a Tc-99m labeled anti-NCA-95 monoclonal antibody

We evaluated the monoclonal antibody CEA-79.4 against carcinoembryonic antigen as an immunoscintigraphic agent for assessing the state of the bone marrow. Western blotting of human granulocyte extracts with the antibody could confirm that the binding was with the epitope of NCA-95. Immunocytochemical staining of bone marrow aspirates revealed specific uptake of this antibody by granulopoietic cells. The affinity constant was 2-9 x 10(9) L/mol. Immunoscintigraphy using 99mTc-labeled CEA-79.4 in a normal volunteer revealed high uptake in the bone marrow as compared to other organs.

Immunoscintigraphy using technetium-99m-labeled anti-NCA-95 antigranulocyte antibodies as an adjunct to echocardiography in subacute infective endocarditis

OBJECTIVES

This study was performed to assess the clinical value of immunoscintigraphy in subacute infective endocarditis.

BACKGROUND

Radiolabeled granulocytes can reveal inflammatory lesions.

METHODS

Using technetium-99m-labeled anti-NCA-95 anti-granulocyte antibodies, planar scintigraphy and single-photon emission computed tomography of the thorax were performed in 72 consecutive patients with suspected endocarditis. Each patient also underwent transthoracic and, if findings were negative, transesophageal echocardiography.

RESULTS

Thirty-three patients were found to have endocarditis on the basis of clinical criteria (surgical confirmation in 17 patients), and the remaining 39 served as control subjects. Initial scintigraphy was true positive in 26 patients (sensitivity 79%) and false positive in 7 (specificity 82%). Echocardiography was true positive in 29 patients (sensitivity 88%) and false positive in 1 (specificity 97%). Scintigraphy was positive in the four patients with false negative echocardiography, and echocardiography was positive in the seven patients with false negative scintigraphy. Thus, the combination of scintigraphy and echocardiography yielded a sensitivity of 100% and a specificity of 82%. In 10 of the 11 patients with two to three follow-up studies, scintigraphy became negative parallel to clinical improvement, indicating decreasing floridity of the inflammatory process.

CONCLUSIONS

Immunoscintigraphy in patients with subacute infective endocarditis provides valuable diagnostic information in equivocal echocardiographic findings and may be used to monitor antibiotic therapy.

The value of bone scintigraphy, bone marrow scintigraphy and fast spin-echo magnetic resonance imaging in staging of patients with malignant solid tumours: a prospective study

The purpose of this prospective study was to define the value of bone scintigraphy (BS), bone marrow scintigraphy (BMS) and the new fast spin-echo (FSE) magnetic resonance imaging (MRI) sequences in screening for bone metastases in patients with solid malignant tumours. It was our particular interest to classify patients into a group with and a group without bone metastases, and not only to compare the absolute number of metastases detected by each method. Thirty-two patients were examined using technetium-99m dicarboxy propane diphosphonate bone scintigraphy, 99Tc-labelled monoclonal anti-granulocyte antibodies for bone marrow scintigraphy and 1.5 T MRI using T1-weighted and FSE T2-weighted sequences. Against a reference standard obtained by re-evaluation of all clinical and imaging data 1 year after prospective BS, BMS and MRI had been performed, the three imaging modalities were falsely positive in two, eight and two cases and falsely negative in zero and four cases, respectively. BMS was falsely positive in eight patients because of vertebral marrow degeneration which caused photopenic defects which could not be differentiated from metastases. MRI showed these lesions to unequivocally contain fat. BMS and MRI were falsely negative in four cases because of the limited field of examination. In our study the key factor in classifying a patient as bone M1 or M0 was the possibility of surveying the entire skeleton, as is the case in BS, and not that MRI had a higher sensitivity compared to BS when analysis was on a lesion-by-lesion basis.(ABSTRACT TRUNCATED AT 250 WORDS)

Bone marrow immunoscintigraphy compared with conventional bone scintigraphy for the detection of bone metastases

Immunoscintigraphy of haematopoetic bone marrow was compared to conventional bone scanning in 141 patients with malignant disease. Forty patients had breast cancer, 25 prostatic carcinoma, 14 kidney or bladder cancer, 13 bronchial carcinoma, 39 malignant lymphoma and 10 multiple myeloma. A total of 18,800 skeletal regions were evaluated. Marrow scans showed more metastatic lesions than bone scanning in all patient subgroups. Computerized tomography was concordant with bone marrow scintigraphy in 83.3% of 323 skeletal sites. Bone marrow scans in 30 control patients with fever of unknown origin were abnormal only in 3 patients and in only 7 out of 2,135 skeletal regions examined. In patients with malignant lymphoma, bone marrow histology or aspiration cytology was concordantly positive in 14 and concordantly negative in 17 patients. We conclude that immunoscintigraphy of haematopoetic bone marrow provides a reliable, sensitive and safe novel approach for non-invasive detection of metastatic spread to the skeleton.

Radiological detection of bone and bone marrow metastases

Bone scintigraphy is the primary method for the diagnosis of skeletal metastases. This investigation is sensitive, but the interpretation must be performed in the knowledge that it is also nonspecific. Despite this, a correct diagnosis can usually be achieved. The first-hand supplementary investigation, after a doubtful scintigraphic finding, is radiography. In most cases this is sufficient for a diagnosis. When a scintigraphic abnormality cannot be adequately explained, usually because of a negative radiographic examination, a more sensitive modality must be used. Computerized tomography offers increased sensitivity and specificity, and is primarily used for this purpose. In this way contrast resolution is increased and problems caused by obscuring tissue and complicated anatomy are reduced. Since bone metastases migrate via the active bone marrow an alternative supplementary investigation is bone marrow scintigraphy. Its usefulness is restricted by disturbing activity, from the liver and the spleen, which obscures a significant part of the active marrow, and by the fact that a lesion must be of a certain size to become apparent. Magnetic resonance imaging yields excellent images of the extension of a tumor in soft tissue. Owing to high costs and restricted availability it is still mainly used for preoperative location of metastases.

Recent advances in bone marrow scanning

Interest in bone marrow scanning has been renewed as the result of the development of radiopharmaceuticals for evaluating specific aspects of bone marrow anatomy, physiology and pathology. This article provides a brief review of bone marrow structure, blood flow and function essential to the understanding of basic principles of bone marrow radionuclide imaging. The prospects and limitations of imaging haematopoietic bone marrow in man using indium 111 chloride, technetium-99m (99mTc)-labelled microcolloid or 99mTc-labelled monoclonal antigranulocytic and antimyelocytic antibodies are discussed in more detail. The technical aspects of bone marrow scintigraphy are presented. Results of more recent studies evaluating bone marrow scanning in circulatory, inflammatory and in systemic haematological disorders are summarized. Special attention is paid to the concept of bone marrow micrometastases and its implications for the follow-up of patients with malignant tumours. Recent results suggest that immunoscintigraphy of bone marrow may provide a novel and sensitive approach for establishing the presence and extent of bone marrow infiltration.

Minimal residual disease in leukemia: studies in an animal model for acute myelocytic leukemia (BNML)

The possibilities for studying minimal residual disease (MRD) in human acute myelocytic leukemia (AML) are limited. Animal models are, therefore, indispensable for gaining insight into the characteristics of leukemia growth during the MRD phase. Studies were done to compare AML to acute myelocytic leukemia in the Brown Norway rat (BNML). The BNML model exhibited a high degree of similarity to human AML with regard to its general growth characteristics, its cell kinetic parameters, its biophysical parameters and its response to chemotherapy. This implied that studies of the BNML model have predictive value for clinical application. In the BNML model a number of independent methods are available to quantify the number of leukemic cells, i.e., indirectly by means of various bioassays or directly by using monoclonal antibody labeling and flow cytometry. Studies of the BNML model in relation to the understanding of various aspects of MRD in leukemia are discussed in this concise review. Insight has been obtained with regard to the kinetics of MRD; the efficacy of certain treatment modalities, e.g., cytostatic drug treatment with or without total body irradiation to eradicate MRD; the efficacy of various methods for eliminating residual leukemic cells from autologous marrow grafts; the emergence of drug resistance during MRD; and the progression of residual disease during the remission phase ultimately leading to a relapse and the implications of these observations for staging leukemia patients during the phase of MRD.

Reduced technetium 99m labelled NCA-95/CEA-antibody uptake in liver due to gentle antibody reconstitution. Technical note

The influence of reconstituting a murine monoclonal IgG1 antibody kit with pertechnetate technetium 99m on antibody distribution in the liver, spleen and sternal bone marrow of patients was examined. The 99mTc-labelled antibody used is directed against non-specific cross-reacting antigen (NCA-95) and carcinoembryonic antigen (CEA) and has been successfully applied for imaging tissue inflammation and bone marrow scanning. Radioactivity uptake was determined in the liver, spleen, bone marrow and a precordial background region in a consecutive series of 25 patients, examined with an antibody preparation, routinely radiolabelled according to the manufacturer's recommendations and in 14 patients, in whom the antibody was reconstituted with special care, avoiding bubble formation and dropping of buffer into the antibody-containing vial. Gentle compared with routine antibody reconstitution caused a highly significant reduction of the antibody uptake in the liver, as determined by count densities, normalized to injected dose and acquisition time (13.2 +/- 5.5 vs 20.1 +/- 6.0 cpm per pixel, means +/- SD, P = 0.008). The liver to background ratio was reduced from 3.4 +/- 1.4 to 1.9 +/- 0.5 (P less than 0.001). Spleen, sternal bone marrow and precordial background count rates were not significantly affected. These results clearly demonstrate that gentle antibody reconstitution can decrease non-specific antibody uptake in the liver by 34% +/- 6.4% (means +/- SEM). Thus, scan quality is improved, and the potential deleterious camouflage of underlying structures is avoided.