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Biomedical subjects

H Macapinlac

Publications and source records attributed to H Macapinlac.

26 records · Page 2Linked to original sources
PubMed1994

Tracer imaging in lung cancer.

Lung cancer is the leading cause of death from cancer in males. Adequate staging is essential if proper treatment is to be administered. Current morphological imaging modalities are confronted with problems in the staging of lung cancer, in the evaluation of treatment response, and in establishing whether a residual mass is due to fibrosis, residual tumors or local recurrence. Nuclear medicine imaging techniques have advanced from planar gallium-67 citrate scans in the 1970s to multihead-detector single-photon emission tomography for 67Ga, Thallium-201 chloride, technetium-99m SestaMIBI, monoclonal antibodies, and octreotide compounds. Results of positron emission tomography (PET) with fluorine-18 deoxyglucose or carbon-11 methionine are very promising. PET units are now employed in centers all over the world and the recently introduced whole-body PET units will be ideal for the correct staging of malignant diseases. The current status of various nuclear medicine imaging procedures is reviewed. The problems and advantages of each scintigraphic procedure are discussed. It appears that many of the problems that confront morphological imaging will be solved by nuclear medicine techniques in the future.

Aged↗
PubMed1994

Current status of radioimmunodetection.

Radioimmunodetection is a nuclear medicine technique that depends on in vivo detection of localization of antibodies and antibody forms carrying radioactivity for the purpose of diagnosis in patients with cancer. Current methods take advantage of tracers suitable for high resolution gamma-camera imaging, such as 99mTc and 111In, for common tumors, such as colon and lung cancers. In addition, tracers such as 125I have been used for the intraoperative detection of metastatic deposits. These methods detect from 75 to 90% of metastatic deposits with high specificity, and typically contribute important diagnostic information, even in 25-40% of patients with occult disease.

Clinical Trials as Topic↗
PubMed1994

Clinical applications of fusion imaging in oncology.

Recent developments in tumor imaging, made possible by advances in instrumentation and radiopharmaceuticals, has led to an increasing need for accurate anatomic correlation of single photon emission computed tomography (SPECT) and positron emission tomography (PET) images. Fusion imaging permits the functional strengths of SPECT and PET to be combined with the anatomic resolution of computed tomography (CT) and magnetic resonance imaging (MRI). Clinical applications of fusion imaging include the evaluation of brain tumors, lymphoma, hepatic lesions and monoclonal antibody studies. The continued development of these techniques will eventually allow fusion imaging to become a routine part of nuclear medicine practice.

Antibodies, Monoclonal↗
PubMed1993

Development of a method to measure kinetics of radiolabelled monoclonal antibody in human tumour with applications to microdosimetry: positron emission tomography studies of iodine-124 labelled 3F8 monoclonal antibody in glioma.

We present a method to assess quantitatively the immunological characteristics of tumours using radiolabelled monoclonal antibody and positron emission tomography (PET) to improve dosimetry for radioimmunotherapy. This method is illustrated with a glioma patient who was injected with 96.2 MBq of iodine-124 labelled 3F8, a murine antibody (IgG3) specific against the ganglioside GD2. Serial PET scans and plasma samples were taken over 11 days. A three-compartment model was used to estimate the plasma to tumour transfer constant (K1), the tumour to plasma transfer constant k2, the association and dissociation constants (k3, k4) of antibody binding, and the binding potential. Tumour radioactivity peaked at 18 h at 0.0045% ID/g. The kinetic parameters were estimated to be: K1 = 0.048 ml h-1 g-1, k2 = 0.16 h-1, k3 = 0.03 h-1, k4 = 0.015 h-1 and BP = 2.25. Based on these kinetic parameters, the amount of tumour-bound radiolabelled monoclonal antibody was calculated. This method permits estimates of both macrodosimetry and microdosimetry at the cellular level based on in vivo non-invasive measurement.

Brain↗
PubMed1993

NR-LU-10 monoclonal antibody scanning. A helpful new adjunct to computed tomography in evaluating non-small-cell lung cancer.

UNLABELLED: Computed tomographic scanning has improved the noninvasive staging of lung cancer but has the deficiency of not distinguishing benign from malignant lesions. This prospective trial evaluated the usefulness of a new radiolabeled monoclonal antibody, NR-LU-10, as an adjunct to computed tomography by assessing its clinical applicability and accuracy in detecting malignancy in primary lung tumors and mediastinal nodes. NR-LU-10 is a technetium 99m-labeled Fab fragment of a murine immunoglobulin G2b monoclonal antibody that recognizes a 40 kD glycoprotein expressed in lung and other epithelial cancers. METHODS: (1) Patients with potentially resectable non-small-cell lung cancer were eligible; (2) all patients had computed tomographic scans of the chest; (3) whole body and single photon emission computed tomographic imaging were performed 14 to 17 hours after intravenous infusion of 20 to 30 mCi of NR-LU-10; (4) subsequent mediastinoscopy or thoracotomy with complete mediastinal nodal mapping provided pathologic correlation. RESULTS: Twenty-four patients were entered, 14 men and 10 women. No allergic reactions or other adverse effects were seen. Interference from a prior ventilation-perfusion scan precluded adequate imaging in 1 patient, but high-quality images were obtained in the other 23 patients. The 22 primary malignant tumors all had uptake and there was no uptake in 1 lung nodule found to be benign. In 21 patients who had surgical correlation of mediastinal nodal involvement, NR-LU-10 was false-positive in 5 and false-negative in 1; results of computed tomography were false-positive in 6 and false-negative in 1. In this preliminary study, NR-LU-10 antibody scanning was safe and easily performed, it produced high-quality images of the lung and mediastinum, and it was accurate in detecting primary non-small-cell lung cancers. Further evaluation of its value in staging the mediastinum is needed, in particular, its role as an adjunct to computed tomography to help distinguish benign from malignant lesions.

Antibodies, Monoclonal↗
PubMed1992

The relationship between thallium uptake, blood flow, and blood pool activity in bone and soft tissue tumors.

Twenty patients with known primary untreated and recurrent bone and soft tissue tumors underwent thallium imaging and three-phase bone imaging in the same session. The ratio of thallium uptake in the tumor tissue to the contralateral normal tissue areas was compared with the same ratio for phase 1 (blood flow or arterial phase), phase 2 (blood pool), and phase 3 (delayed medroxy-diphosphonate, MDP, uptake). There was poor correlation between Tl uptake and phases 1 and 3 of the bone scan ratios; r = 0.37 and 0.46; P = 0.097 and 0.047, respectively. The thallium uptake ratios correlated well with blood pool ratios (phase 2) (r = 0.84 and P less than 0.01). In contrast to uptake into normal muscle, Tl-201 uptake into tumor is not highly dependent on blood flow alone and other factors predominate in determining its magnitude.

Bone Neoplasms↗