The role of nuclear medicine in oncology

Nuclear Medicine offers screening methods for oncology such as bone and bone marrow scintigraphy. During the last two decades, special procedures have gained widespread application. This paper is centered around the “tumor-specific” radiopharmaceuticals. In patients with thyroid cancer, I-131 still plays a significant role. Ga-67 still has its indications in lymphoma, while in other diseases Tl-201 cloride is now the agent of choice. Especially in thyroid cancer, Tl-201 has proved to be a reliable tumor imaging radiopharmaceutical. More recently, Tc-99m MIBI was introduced for tumor imaging. Tc-99m HMPAO may also be used for tumor scintigraphy, especially in brain lesions. In addition, I-123 IMP has successfully been used for imaging malignant melanoma. Another promising field of tumor diagnosis is receptor imaging. In neuroblastoma and malignant pheochromocytoma, I-131/123 mIBG is the radiopharmaceutical of choice and may be considered as a receptor imaging agent also. First clinical results with In-111 octreotide show potentials as somatostatine-receptor radiopharmaceutical in insulinoma, islet cell carcinoma, medullary and lung cancer, while I-123 estradiol needs some improvement until it may be recommended as diagnostic tool in breast cancer. Since 1978, radiolabeled poly- or monoclonal tumor antibodies and their fragments have gained widespread application. Especially the Tc-99m 225.28S melanoma antibody, I-131 or Tc-99m CEA and In-111/I-131 labeled OC-125 antibodies have proven to be of clinical significance in melanoma, colorectal and ovarian cancer.     

The Edgecombe County High Blood Pressure Control Program: the process of medical care and blood pressure control

As part of the Edgecombe County High Blood Pressure Control Program, a medical record review was conducted within a multispecialty private group practice in the county. The purposes of the review were to assess the relationship between the process of medical care and blood pressure control and to explore the variation in level and impact of medical care by race and sex. At the end of a three-year period, 41 percent of 628 hypertensive patients from the practice had uncontrolled diastolic blood pressure (DBP), as defined by Hypertension Detection and Follow-up Program criteria. The percentage of uncontrolled hypertensives ranged from 53 percent for black men to 34 percent for white women. Hypertensive patients whose physicians were more aggressive in their use of antihypertensive drug therapy were more likely to be controlled. The effect of the level of physician drug aggressiveness tended to be more pronounced for blacks than for whites. Differences by race in exposure to and efficacy of aggressive drug treatment may influence racial variation in blood pressure control.     

A laboratory study of cyromazine on Aedes aegypti and Culex quinquefasciatus and its activity on selected predators of mosquito larvae

In a laboratory study, the insect growth regulator, cyromazine, exerted a high level of biological activity on Aedes aegypti and Culex quinquefasciatus treated in the 4th larval instar. At 1.5 and 1.0 ppm this IGR produced 97 and 99% inhibition of emergence in adult Ae. aegypti, respectively. In Cx. quinquefasciatus, there was 99% inhibition at 1 ppm and complete inhibition at 1.5 ppm. The overall pupal mortality was higher than larval or adult stages of both species. This material induced different types of morphogenetic abnormalities in pupae and adults of the 2 species similar to those induced by other IGRs. However, most abnormalities were observed in the pupal stage. Adverse effects were not detected on the 4 mosquito predator species during the acute or posttreatment tests.     

Chemotherapy in patients with resectable liver metastases from colorectal cancer

New chemotherapy drugs and, more recently, targeted therapies have significantly improved the outcome of patients with resected stage III colon cancer (adjuvant chemotherapy) and patients with unresectable metastases (palliative therapy). These advances raise several questions about the place of chemotherapy after and before surgery in patients with resectable liver metastases. To date, only a combined intra-arterial plus systemic fluoropyrimidine-based chemotherapy regimen has clearly demonstrated a relapse-free survival benefit. Yet, this approach is restricted to specialized centers, mainly because of technical difficulties and locoregional toxicities. The role of systemic use of oxaliplatin- and irinotecan-based regimens is currently under investigation. Planned trials will assess the role of anti-angiogenic and anti-epidermal growth factor receptor agents. We review the main trials performed in patients with resectable metastases, and discuss their potent impact on clinical practice.     

Electrophysiologic target localization in posteroventral pallidotomy

Summary The current interest in stereotactic posteroventral pallidotomy (PVP) for treating Parkinson's disease and the variability of published results have raised questions regarding techniques for target localization. In our technique the probe is guided to the optimum target at the most ventral pallidum and ansa lenticularis by macroelectrode stimulation of the internal capsule and optic tract from within the globus pallidus, with the thresholds providing a relative measure of the electrode proximity to these structures. We have characterized these localizing macroelectrode stimulation parameters in 57 posteroventral pallidotomies with consistent anatomic lesion placement, excellent outcome, and no complications.Using a 1.8 × 2.0 mm radiofrequency electrode for macroelectrode stimulation (RFG-3C, Radionics Inc.), minimum voltages (thresholds) to activate motor (at a frequency of 2 Hz) or visual (at a frequency of 100 Hz) responses as well as impedance measurements were obtained at the final target (Tf) and at distances proximal to Tf along the electrode trajectory. The visual and motor threshold voltages at Tf via our standard approach angles (50 ° above base plane, 20 ° from the sagittal plane), had a range of 1.0 to 1.5 V, and 2.0 to 3.5 V respectively. We also found that as the probe approaches Tf there is a significant decrease in voltage thresholds for motor (P<.0001) and visual (P<.0001) responses in an individual patient indicating that the probe is converging on these structures. Increases in impedance between Tf, 2–3 mm, and 4–5 mm proximal to Tf were also statistically significant (P<.0001). Microelectrode recording of electrophysiological neuronal activity at various points along the trajectory towards the target showed distinct firing patters providing identification of the globus pallidus externus and internus, ansa lenticularis, and optic tract.Macroelectrode electrophysiological stimulation within the target volume, inducing threshold responses in the internal capsule and optic tract, provides for accurate localization of the most effective PVP target in the ansa lenticularis. In unresponsive patients, the utilization of microelectrode recording for the identification of the pallidal borders and the optic tract improves safety.     

KAP study on mothers of children with Down syndrome

We evaluated 50 mothers of children with Down syndrome attending Genetic Clinic of the Institute of Child Health and Hospital for Children, Madras, with special reference to their knowledge, belief and attitudes in the care of these children. After evaluation, they were educated individually and in groups with demonstration, picture cards and pamphlets, on the causation, expected health problems, developmental potential of Down syndrome and the ways and means to help the child to attain the maximum developmental potential. They were taught on preventive aspects of Down syndrome as well. Re-evaluation was done after three months, and considerable improvement was noted in the mother's knowledge, and attitude towards bringing up such a child. The mothers also showed an improvement in the skills in providing developmental enrichment to these children. Thus this study has formulated a programme in the management of such children, which can be practised on any population, anywhere, especially, in rural areas, and by less affluent folk, with poor educational background.     

Comparison of dobutamine stress echocardiography and technetium-99m sestamibi single-photon emission tomography for the diagnosis of coronary artery disease in hypertensive patients with and without left ventricular hypertrophy

Stress echocardiography has been considered an accurate method for the diagnosis of coronary artery disease in hypertensive patients and in patients with left ventricular hypertrophy. In contrast, the specificity of myocardial perfusion scintigraphy in these patients has been questioned. The aim of this study was to compare the accuracy of these two imaging modalities in conjunction with dobutamine stress test for the diagnosis of coronary artery disease in hypertensive patients with and without left ventricular hypertrophy. Dobutamine (up to 40 μg kg^–1min^–1) stress echocardiography in conjunction with sestamibi (MIBI) single-photon emission tomography (SPET) was performed in 84 patients with the diagnosis of systemic hypertension who had been referred for evaluation of myocardial ischaemia. Ischaemia was defined as new or worsened wall motion abnormalities at echocardiography and reversible perfusion defects at SPET. Significant coronary artery disease (≥50% luminal diameter stenosis) was detected in 66 patients (79%). The sensitivity, specificity and accuracy of the ischaemic pattern at echocardiography for the diagnosis of coronary artery disease were 73% (CI 63%–82%), 83% (CI 75%–91%) and 75% (CI 66%–84%), those for MIBI were 67% (CI 57%–77%), 83% (CI 75%–91%) and 70% (CI 60%–80%) respectively (P = NS vs echocardiography). Significant stenosis was detected in 123 (49%) of the 252 analysed coronary arteries. The sensitivity, specificity and accuracy of echocardiography for the regional diagnosis of coronary artery disease were 63% (CI 56%–69%), 90% (CI 86%–94%) and 77% (CI 72%–82%). Those for MIBI were 58% (CI 51%–64%), 91% (CI 87%–94%) and 75% (CI 69%–80) respectively (P = NS vs echocardiography). Left ventricular hypertrophy was detected in 59 patients (70%) by echocardiography and did not influence the overall or regional specificity of echocardiography or MIBI SPET. It is concluded that in hypertensive patients, dobutamine stress echocardiography and MIBI SPET have a comparable accuracy for the overall and regional diagnosis of coronary artery disease. Hypertensive patients with or without left ventricular hypertrophy should not be considered unsuitable candidates for stress myocardial perfusion scintigraphy. Received 10 July and in revised form 19 September 1997