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At least 487 records · Page 27Linked to original sources
PubMed2000

Efficacy of immunoscintigraphy for detection of lymph node metastases.

The size of a lymph node is not in principle a limitation for the detection of cancer by Nuclear Medicine techniques. A radioactive pinhead is detectable if it has enough radioactivity on it. The approach of Nuclear Medicine to the demonstration of impalpable lymph nodes or to those lymph nodes detected by radiological techniques that are under 1 cm as to whether or not they contain cancer, is to increase the activity attached to cancer cells in such a lymph node as much as possible and to use sophisticated image analysis techniques to distinguish such uptake from its environment. This may be undertaken using a non specific technique such as F-18 Deoxyglucose and Positron Emission Tomography which is highly sensitive and which has been successful. The alternative approach is to use a highly specific and sensitive agent, such as a radio-labelled peptide or a radio-labelled monoclonal antibody together with image analysis. This paper describes these approaches and in particular the use of Tc-99m SM3 monoclonal antibody in the detection of impalpable axillary nodes in patients with breast cancer before surgery, using a change detection analysis providing a probability map of the significance of uptake of this radiopharmaceutical. It is a robust approach, providing the patient and the surgeon with information as to the likely need for extensive axillary surgery well prior to operation. A negative study should be followed by a sentinel node evaluation at surgery.

Axilla↗
PubMed2000

Probe-guided surgery for colorectal cancer.

Anti-CEA-scintigraphy turned out to be very reliable in detecting primary and recurrent colorectal cancer, its overall accuracy being more than 90%. The intraoperative application of this technology should provide similar results when focussing at extrahepatic tumor deposits, for example in lymph nodes, thus allowing accurate staging of the underlying disease. To test this hypothesis we launched the following feasibility study the results of which are compared to those reported in the recent literature. We investigated 20 patients, six with rectum and 14 with colon cancer. 24 hours before surgery they were intravenously given 1 ml of a fab'-fragment-antibody to CEA, labeled with 25 mCi of 99mTc (CEA-Scan). During surgery the radioactivity in lymph glands regional to the tumors was measured and compared to the much lower activity in healthy nodes. For this we used a scintillation probe (C-Trak, Care Wise, Inc., Morgan Hill, CA). All lymph nodes of interest were then excised and submitted to frozen section pathology. In 7 out of 20 cases scintimetry led to an up-staging of the disease. In addition we found metastatic spread to lymph nodes that were basically not regional to the primary tumor (retroperitoneum, renal hilum etc.). Scintimetry can precisely identify even very small tumor deposits. So it leads to accurate staging while surgery is still ongoing. In a further step the concept of sentinel node diagnosis, which is right now being clinically evaluated, may some day be applied in colorectal surgical oncology.

Adenocarcinoma↗
PubMed2000

Identification of lymph node metastases in recurrent colorectal cancer.

Lymph node metastases are an important prognostic prediction factor in patients with recurrent colorectal cancer, particularly those with liver metastasis. Fifty-six patients with recurrent colorectal cancer were operated by us using the RIGS (radioimmunoguided surgery) technology. Patients were injected with 1 mg monoclonal antibody (MoAb) CC49 labeled with 2 mCi 125I. In surgery, traditional exploration was followed by survey with a gamma-detecting probe. Sixty of 151 patients enrolled in the Neo2-14 Phase III study for recurrent colorectal cancer were diagnosed with liver metastases based on preoperative CT. In 17/56 patients (30%), RIGS identified at least one tumor site confirmed by pathology (H&E). This resulted in 16 major changes in surgical plan. RIGS performance varied between lymphatic and non-lymphatic tissue, with positive predictive value (PPV) of 100% and negative predictive value (NPV) of 94% for non-lymphoid tissue, compared to PPV of 46.5% and NPV of 100% for the lymphoid tissue. Thirty-five out of 60 patients were considered resectable after traditional evaluation. RIGS identified occult tumor in 10 of these patients (28.5%). 7/10 occult patients expired (70%), while only 7/25 of the non-occult patients expired (28%) (P = 0.046). In localizing patients, no RIGS activity in lymph nodes signifies no tumor, while H&E confirmation is needed for decisions based on RIGS activity in the lymph nodes. RIGS provides important staging information, identifying patients for whom surgery may be done with curative intent.

Adenocarcinoma↗
PubMed1993

An integrated approach to biodistribution radiation absorbed dose estimates.

An integrated approach to existing methods of extracting biodistribution data, pharmacokinetics and radiation absorbed dose estimates from serial scintigraphic images is described. This approach employs a single computer-generated user interface to reformat planar scans into a standard file type, align conjugate (anterior and posterior) images, draw regions of interest (ROIs) over selected organs and lesions and generate count data for anterior and posterior views and calculated geometric means. Using standard correction methods, the fraction injected activity is obtained for all ROIs and total body. This methodology has been applied to the analysis of indium-III-labelled breast-cancer-directed antibodies and technetium-90m-labelled CEA-specific antibody fragments in non-small-cell lung cancer. It is anticipated that this approach will be useful for evaluating the dosimetry of other radiolabelled monoclonal antibodies, as well as other radiopharmaceuticals.

Breast Neoplasms↗
PubMed1993

Uptake of radiolabeled anti-CEA antibodies in human colorectal primary tumors as a function of tumor mass.

An inverse correlation has been demonstrated between tumor uptake (u, in units of % injected dose/kg) of monoclonal antibody (Mab) and tumor mass (m, in units of g) for colorectal carcinoma in a series of 19 consecutive patients. The correlation (rho = -0.510), developed using surgical samples was of the form u = amb and was significant at the 2% level of confidence. All tumors were positive for carcinoembryonic antigen (CEA) and the radiopharmaceutical was an iodine-131 labeled anti-CEA Mab. Such correlations have been predicted earlier from murine and rat tumor uptake data. The slope parameter (b) was -0.362, a number consistent with the previous value (-0.382) found in anti-CEA experiments in mice bearing human xenograft LS174T tumors.

Carcinoembryonic Antigen↗
PubMed1993

N-(2-diethylaminoethyl)-4-[123I]iodobenzamide as a tracer for the detection of malignant melanoma: simple synthesis, improved labelling technique and first clinical results.

In order to evaluate the behaviour of N-(2-diethylaminoethyl)-4-[123I]iodobenzamide in malignant melanotic disease, we synthesized the bromo compound in a simple one-step reaction. Labelling was performed by non-isotopic bromine-iodine-123 exchange in radiochemical yields up to 60%. By means of isocratic high-performance liquid chromatography, the iodinated product could be isolated with high apparent specific activity. First clinical studies in patients with malignant melanoma using N-(2-diethylaminoethyl)-4-[123I]iodobenzamide showed moderate uptake of the tracer in the tumour and the suspected metastases in all patients. Most of the lesions were detectable with technetium-99m-diethylene triamine penta-acetic acid (DTPA) scintigraphy too, but we were able to detect additional, previously unidentified metastases with benzamide scintigraphy. This changed the therapeutic procedure in two of the five cases investigated so far.

Aged↗
PubMed1992

Superimposition of computed tomography and single photon emission tomography immunoscintigraphic images in the pelvis: validation in patients with colorectal or ovarian carcinoma recurrence.

A method of superimposing computed tomography (CT) and immunoscintigraphic (IS) single photon emission tomography (SPET) slices is presented and has been applied to 10 patients with suspected cancer recurrence. IS was performed with carcinoembryonic antigen (CEA)-specific indium-111 monoclonal antibodies (MoAbs) in 5 patients with colorectal cancer, and with OC125 111In-MoAbs in 5 patients with ovarian cancer. All patients had an abnormal CT image result in the pelvis, which was interpreted 5 times as recurrence, once as doubtful and four times as scar fibrosis. Recurrence was subsequently proven in all patients. Bone scintigraphy (BS) SPET was recorded at the same time as IS. No special technique was used during BS, IS or CT acquisition. CT images were fed into a computer using a CCD camera. Using the internal anatomical landmarks provided by the pelvic bone structures seen on CT and BS, an operator had to select corresponding fiducial points, which were used by the software to register the images. The final results were CT-BS and CT-IS superimposed images. CT-BS images were used for quality control. In all patients, the inspection of CT-BS and CT-IS showed that the registration process is accurate and assists in the co-interpretation of CT and IS images.

Colorectal Neoplasms↗
PubMed1992

Volume rendering and bicolour scale in double isotope studies: application to immunoscintigraphy and bone landmarking.

Combining the volume rendering and bicolour visualization techniques is proposed as an aid in interpreting single photon emission tomography (SPET) immunoscintigraphy (IS) recorded simultaneously with SPET bone landmarking (BL). The combination helps in localizing abnormal monoclonal uptake and in differentiating it from a physiological radioactivity distribution. The so-called rendered images (RIs) are obtained in both IS and BL studies according to a depth- weighted maximum activity projection algorithm. Fused BL and IS RIs are constructed by a simple, pixel by pixel addition. They are displayed using a bicolour grey-red scale, which makes it possible to visualize both studies by a transparency effect. This method was applied to patients suspected of suffering colorectal or ovarian cancer recurrences, in whom monoclonal antibodies against carcinoembryonic antigen, B72-3 or OC125 labelled with indium-111 were used.

Bone and Bones↗
PubMed1992

Does immunoscintigraphy serve clinical needs effectively? Is there a future for radioimmunotherapy?

Since 1980, immunoscintigraphy has been performed in thousands of patients, and its clinical value has been demonstrated for selective indications in malignant (early detection of recurrences of colorectal and ovarian carcinomas) and non-malignant (cardiovascular and inflammatory) pathology. However, many clinicians are not yet very convinced of its efficiency. Opinions range between favourable interest and marked scepticism. The causes of this inconclusive verdict include an often moderate target-to-background ratio in images, the immunogenicity of injected murine antibodies and the fact that a true benefit for the patient has not yet been clearly demonstrated in large series of patients. Future prospects could significantly improve this and involve the reduction of non-specific activity in normal tissues (to improve disease target contrast and thus make image interpretation easier) and the decreased immunogenicity of injected immunoconjugates (to permit repetition of examinations). Radioimmunotherapy, an innovative and promising approach, is still limited by numerous problems. The results of clinical studies are still inconclusive, being encouraging only for specific indications. In the future, pre-targetting techniques should allow the rapid elimination of radioactivity from normal tissues, resulting in a significant increase in tumour-to-normal tissue ratios. Progress is also required in the choice of radionuclides and labelling techniques and in methods for dosimetric estimations. The clinical indications of radioimmunotherapy after systemic injection will concern mainly radiosensitive tumours such as lymphomas, small-cell lung cancers and neuroblastomas. After endocavitary injection, radioimmunotherapy could prove efficient in the treatment of micrometastases of ovarian carcinomas. For all indications, this new approach should be combined with other therapeutic modalities.

Evaluation Studies as Topic↗
PubMed1993

Use of immunoscintigraphy in the diagnosis of fever of unknown origin.

Fever of unknown origin (FUO) has been defined as an elevation in temperature (38 degrees C) for at least 2-3 weeks despite intensive investigation. The value of immunoscintigraphy with the technetium-99m-labelled anti-granulocyte antibody anti-NCA-95 (BW 250/183, IgG1) was studied retrospectively in 34 consecutive patients with FUO. Every effort was made to confirm a diagnosis, including methods such as ultrasonography, computed tomography, magnetic resonance imaging, bacteriological tests, surgical intervention and clinical follow-up. In 58.8% of the patients, an infectious cause for the fever was found, in 30.2% of the patients, a benign or malignant haematological disease, pancreatitis or thyrotoxicosis was found. No cause for fever could be found in 11%. The overall diagnostic sensitivity and specificity of immunoscintigraphy for infection were 40% and 92% respectively. The positive predictive value was calculated to be 88% and the negative predictive value was calculated to be 52%. False-negative scans were especially noted in patients with endocarditis, pneumonia and small brain abscesses, where the lesions did not exceed a diameter of 0.5 cm. If patients with endocarditis were excluded, the imaging sensitivity and specificity were increased to 57% and 95%. This study demonstrates that 99mTc-anti-NCA-95 scanning is able to localize infectious causes of FUO, other than endocarditis.

Adult↗
PubMed1991

Assessment of anthracycline-induced myocardial damage by quantitative indium 111 myosin-specific monoclonal antibody studies.

To assess chemotherapeutically induced myocardial damage, myosin-specific antibody scans and ejection fraction measurements were performed in 32 patients with breast cancer and in 9 patients with other tumours. All patients had received chemotherapy including anthracyclines. The ejection fraction decreased by less than or equal to 10% in 14 of 41 (34%) patients after chemotherapy. Antimyosin uptake in the myocardium was observed in 38 of 41 (92%) patients after chemotherapy. Antimyosin uptake was quantified by means of a heart-to-lung ratio, revealing a correlation between the degree of antimyosin uptake in the myocardium and the cumulative dose of anthracycline. Patients with a decreased ejection fraction showed more intense antimyosin uptake, indicating more severe myocardial damage. A higher degree of antimyosin uptake was found in 17 breast cancer patients treated with doxorubicin compared with 15 patients treated with mitoxantrone. We conclude that antimyosin studies provide a sensitive, non-invasive method to monitor myocardial damage in patients treated with anthracyclines. Antimyosin uptake in the myocardium precedes ejection fraction deterioration. This technique may be helpful in the early identification of patients at risk of congestive heart failure during chemotherapy including anthracyclines.

Adult↗
PubMed1991

Monoclonal antibody BW431/26 labelled with technetium 99m and indium 111: an investigation of the biodistribution and the dosimetry in patients.

As a competitive diagnostic tool for the detection of malignant tumours and other pathological conditions, monoclonal antibodies have long been established. Herein we give the biokinetic data of the antibody BW 431/26 and the consequent radiation dose to patients. These parameters were recorded in 39 patients, using the antibody labelled either with technetium 99m or indium 111. Remarkable differences were observed between the two radionuclides. Whereas the indium-labelled one showed biexponential elimination kinetics, the technetium-labelled one is eliminated linearly over time. The distribution pattern of the two is identical, although the radiation dose varies quite a lot, being 20-fold higher with indium 111 when total body exposure is taken into account (for 111In the whole-body radiation exposure is 0.1 mGy/MBq; for 99mTc it is 0.0047 mGy/MBq). With respect to these results and considering the general availability of the technetium-labelled Ab, it is the best choice for diagnostic use.

Humans↗