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Nuclear imaging studies currently play a major role in the detection, staging, and management of malignant disease. However, most imaging methods with agents currently in use localize malignant disease indirectly by revealing changes in "normal" anatomy or physiology. These methods are inherently nonspecific. The development of direct tumor scanning agents, which localize in the tumor itself, holds considerable promise. Substances currently in use include radiolabeled metabolites, radioactive cations, and radiolabeled anti metabolites. At least some of these agents show good specificity. Radiolabeled antibodies to tumor-associated antigens are currently undergoing initial investigation as direct scanning agents with high tumor specificity.

Radionuclide angiocardiography is auseful diagnostic technique in which a high-activity bolus of radiopharmaceutical is sequentially imaged as it passes through the various cardiac chambers and great vessels. Both physiological and anatomical information can be accumulated simultaneously. This review is addressed to the imaging aspects almost entirely, detailing our experiences with the most common types of congenital heart disease. Evaluation by perfusion lung scans of post-operative changes due to surgical correction or palliation is also described. The use of radionuclide angiocardiography to differentiate a primary cardiac process from one mainly affecting the lung parenchyma is a useful approach and is described in detail.

A computer-based gamma-ray imaging system has been developed for use with rectilinear scanners. It has been designed as a stand-alone system for the small nuclear medicine clinic. Completely processed images are produced in a time short compared with scanning times. The process for correction of gamma-ray scattering in the patient and penetration of gamma rays through the collimator septa produces marked improvement in the images.

A valid informed consent must be obtainedby the admitting physician for routine hospital services, diagnostic procedures, and medical treatment. The matter of consent for children for radionuclide studies is considered comparable to that for routine roentgenographic procedures and thus is covered by the general consent form signed by the parent upon admission to the hospital. A second consent must be obtained for the therapeutic use of radionuclides and for the use of radionuclides for research in children. Therapeutic research, implying the probability of immediate or delayed benefit to the child studied, requires a separate consent. Parental consent may not be valid for nontherapeutic research, i.e., research where there is little probability of benefit to the child studied. Recommendations for preparation of children for nuclear imaging are given in this review. Dosage tables for radiopharmaceuticals used in routine imaging studies, and potassium perchlorate and Lugol's solution dosage schedules are offered. Pediatric dosimetry is discussed elsewhere in this seminar. A sedation technique for younger children, including dosage schedule, is described. Children cannot be treated as small adults. They present special problems that relate to their age and stage of development. This review attempts to place these unique requirements in perspective and to help the reader become aware of them.

In 3 of 177 cases of differentiated thyroid carcinoma (papillary, follicular, or mixed), pulmonary metastases not visible on chest radiographs have been discovered by 131I imaging. The authors' 3 cases are reviewed, as are all published or known cases of this entity. Two patients from other institutions have had exploratory thoracotomy with subsequent histologic diagnosis of thyroid carcinoma metastatic to the lung in a micronodular distribution. The regular workup of patients found to have differentiated thyroid carcinoma should include imaging of the chest as well as the neck, since micronodular metastasis is more frequent than has previously been suspected and seems amenable to radioiodine treatment if detected early.