In vivo comparison of macrocyclic and acyclic ligands for radiolabeling of monoclonal antibodies with 177Lu for radioimmunotherapeutic applications

The studies reported herein present the first in vitro and in vivo comparison of radioimmunoconjugates (RIC) radiolabeled with 177Lu using the acyclic CHX-A"-DTPA ligand and the macrocyclic ligands, C-DOTA and PA-DOTA. The in vivo studies include pharmacokinetics and biodistribution of the formed 177Lu-labeled immunoconjugates in a tumor bearing murine model with engineered monoclonal antibody HuCC49DeltaCH2. The in vitro analysis indicated that the CHX-A" RIC was superior with respect to immunoreactivity, radiolabeling with 177Lu, and specific activity. The in vivo pharmacokinetic data by itself indicated that the Lu(III)-PA-DOTA complex may not be as stable as Lu(III) complexes with CHX-A" or C-DOTA. All three RICs demonstrated tumor targeting of human colon carcinoma xenografts in athymic mice. In these biodistribution studies, there appears to be no overall pattern or trend of one RIC over the other two. Based on these in vitro and in vivo studies, the CHX-A" DTPA ligand should be considered a suitable bifunctional chelate for the radiolabeling of monoclonal antibodies with 177Lu for radioimmunotherapy applications.     

Lymphoedema: lymphoscintigraphy versus other diagnostic techniques--a clinician's point of view

This paper overviews the problem of the clinical basis, diagnosis and available therapy modalities for lymphoedema. Regarding diagnostics, the measurement of circumference, volume and thickness of the limb are presented, as well as diagnostic imaging modalities. These include direct and indirect lymphography, MRI, CT, ultrasound imaging and lymphoscintigraphy, which is currently considered the leading technique in primary diagnosis of lymphoedema and its follow-up. This paper discusses the treatment of lymphoedema and the role of lymphoscintigraphy in the follow-up of patents with lymphoedema.     

Development of an effective short introductory course in diagnostic radiology

As part of a general medical curriculum renewal, a new one-week course in diagnostic radiology was given to students at the beginning of their third year. The course format consisted of didactic presentations to the entire class, a single afternoon session of small group discussions of unknowns, and three daily case-of-the-day unknowns with prizes for correct responses. One hundred fifty-eight students were tested on the first and last days of the course; testing consisted of two parallel 46-item multiple choice questions given in a crossed design. Questions covered radiographic anatomy and pathology as well as proper test ordering. Differences in achievement before and after the course as measured by the pre- and post-tests were highly significant. The class achieved a mean of 27 (59%) correct responses on the pre-test and a mean of 37 (80%) on the post-test (F(1156) = 15.79; P less than .001). The reliability coefficient of the pre- and post-tests was about .30. A course critique was returned by 88 students. There was anticipated variation in the evaluations of the different didactic lecturers. Instructors receiving the highest scores were cited for their enthusiasm, clarity, and the relevance of their presentation. Conversely, those receiving low marks were cited as being unenthusiastic and boring, merely presenting example after example of radiographic abnormalities with little explanation. The afternoon small group discussions were perceived as the best part of the course. Despite the fact that moderator experience ranged from second year resident to full professor, the seminars received uniformly positive comments.     

Use of radiolabeled monoclonal antibodies for diagnostic imaging

Monoclonal antibodies (MoAbs) are expected to carry radionuclides selectively to target tissues and to offer antigen-specific diagnosis. Indium (In)-111 has many favorable nuclear properties and is efficiently labeled with MoAbs using DTPA as a bifunctional chelating agent. In-111 labeled MoAbs are clinically employed for the diagnosis of malignant melanoma, colorectal cancer and acute myocardial infarction in Japan. Although non-specific deposit of In-111 was seen in liver and bone-marrow, scintigraphy using In-111 labeled MoAbs was encouraging, since it detected about 80% of tumors, tumors missed by conventional diagnostic methods such as CT, and tumors in patients with normal serum CEA values, and acute myocarditis as well as acute myocardial infarction was positive with In-11 labeled Fab fraction of anti-myosin Ab. Acute or subacute toxicity was not observed. Human anti-murine antibody (HAMA) was detected in 53 of 64 (82.8%) patients who were intravenously administered with 20 to 42 mg of anti-melanoma or anti-CEA MoAbs (whole IgG). In contrast, only 5 of 406 (1.2%) patients had detectable levels of HAMA in their serum after receiving 0.5 mg of Fab fraction of MoAb. Recently mouse-human chimeric Ab has been produced by recombinant DNA techniques, which localized well in xenografted tumors and seems to be promising for clinical use. Investigations are under way to increase the tumor to non-tumor ratio by modifying chelating agents for coupling MoAbs with radionuclides.     

髌骨轴位X线片的结构化报告：诊断和定量测量要点

髌骨轴位X线片在髌股关节疾病诊断方面具有重要作用,本文介绍了髌骨轴位X线检查的诊断要点和定量测量方法,并构建了结构化报告,旨在提高报告的规范性及可读性。     

How patients view the efficient use of diagnostic radiation.

Patients who are subjected to diagnostic x rays sometimes feel victimized by their dependence on large and very complex medical-care systems which treat them with over-all indifference. Some of these individuals are confronted with physicians and dentists who seem to order radiographs without giving reasons, as well as with employers and hospitals who require radiographs without seeming to "need" them. Other patients feel that they are acting as guinea pigs in training programs to technologists who appear to require retakes because they are working in a rapid and slapdash manner. When questioned by patients, personnel who are responsible for ordering or conducting x-ray examinations often inform them that someone else in the system is responsible for any unnecessary radiation exposure. Patients, dentists, physicians, radiologists, technologists, health physicists, and radiation control officers all bear responsibility for the efficient use of diagnostic radiation. People working in these capacities should cooperate more closely in the mutual sharing of responsibility for the well-being of patients.     

Quality Assurance in diagnostic radiology: an irreverent view of a sacred cow: annual oration in honor of Albert Soiland, M.D.

The problem of federal regulation of radiologic practice is examined via an in-depth analysis of the Proposed Recommendations for Diagnostic Radiology Facility Quality Assurance Programs as published in the Federal Register by the Commissioner of Food and Drugs. It is shown that the need for such recommendations is not established, that the program proposed by the Commissioner is potentially burdensome for the radiologist, that it does not address the most significant causes of unnecessary patient irradiation, and that the benefits expected to derive from it are, in fact, negligible. This is not to denigrate the value of well-conceived quality assurance efforts, and measures are suggested that might more reasonably be expected to reduce the radiation exposure of the public. The radiologist is urged to 1) conduct his practice in as faultless a manner as possible; and 2) exercise his right to respond to proposals of the federal regulatory agencies.     

Radiologic methods in cases of coronary heart disease: diagnostic requirements from the cardiology point of view

Radiological and especially scintigraphic methods are important tools in diagnosis finding, diagnosis evaluation, risk stratification and therapy control in patients with coronary artery disease. The major task is to document or exclude myocardial perfusion defects. Within this framework, thallium scintigraphy and radionuclide ventriculography occupy a definite place for non-invasive evaluation. The decision for revascularisation (bypass surgery, angioplasty) and the evaluation of the risk frequently depends on the results of the scintigraphic methods. Conventional radiological techniques and computer tomography are helpful in differential diagnosis of acute chest pain syndromes.     

The diagnostic and therapeutic impact of MRI: an observational multi-centre study

AIM: To provide information about the diagnostic and therapeutic impact of magnetic resonance imaging (MRI) and to compare the findings across diagnostic groups. MATERIALS AND METHODS: A prospective, observational study of 2017 consecutive referrals for MRI of the head, spine or knee at four imaging centres. Clinicians completed questionnaires before MRI stating initial diagnoses, diagnostic confidence and treatment plans. After imaging, a second questionnaire evaluated clinicians' revised diagnosis and treatment plans in the light of imaging findings. Patients were grouped into nine diagnostic categories for analysis. Comparison between pre- and post-imaging was used to assess the diagnostic and therapeutic impact of MRI. RESULTS: In seven of nine diagnostic groups MRI findings were associated with a diagnostic impact. Diagnoses were revised or discarded following normal MR findings and diagnostic confidence was increased by confirmative MR findings. There was no statistically significant diagnostic impact for suspected pituitary or cerebello-pontine angle lesions. In five of nine diagnostic groups (knee meniscus, knee ligament, multiple sclerosis, lumbar and cervical spine) MRI findings had a clear impact on treatment plans. CONCLUSION: This study demonstrates that in most diagnostic categories, MRI influences diagnosis and treatment. However, experimental studies are needed to prove that these diagnostic and therapeutic impacts lead to improved health.Hollingworth (2000). Clinical Radiology55, 825-831.     

Congenital hypothyroidism: diagnostic scintigraphic evaluation of an organification defect

Quantitative Tc-99m pertechnetate thyroid imaging was performed on a hypothyroid neonate. The image revealed markedly increased trapping in an enlarged, bilobed, eutopic gland. A perchlorate washout test using quantitative imaging with I-123 confirmed an organification problem.