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Biomedical subjects

K E McCarthy

Publications and source records attributed to K E McCarthy.

22 records · Page 2Linked to original sources

Pulmonary arterial hypertension: value of perfusion scintigraphy.

Records of 34 patients with established causes of pulmonary arterial hypertension were retrospectively reviewed. The ventilation-perfusion scans were blindly classified according to standardized criteria as normal or high, low, or intermediate probability of pulmonary embolism as the cause of pulmonary arterial hypertension. Twelve of 13 patients with primary pulmonary hypertension had normal or low-probability scans, but the perfusion pattern was not helpful in distinguishing between histologic subtypes. All eight patients with large-vessel thromboembolic hypertension had high-probability scans; however, three of 13 patients with nonembolic secondary pulmonary hypertension also had high-probability scans. While a normal or low-probability scan excluded proximal pulmonary emboli as a cause of pulmonary hypertension, a high-probability scan may be associated with a variety of other nonembolic causes of secondary pulmonary hypertension.

Adult↗

Diphosphonate intestinal activity seen on two bone images in neuroblastoma.

Neuroblastoma is well recognized as a cause of soft tissue uptake of Tc-99m MDP. Two cases of neuroblastoma arising in the midline from the celiac axis are reported. Bone imaging performed on two separate days showed not only typical soft tissue uptake, but also the appearance of the radiopharmaceutical in the bowel. At surgery, a midline upper abdominal neuroblastoma was found in both patients without evidence of involvement of the liver, kidneys, bowel, gallbladder or mesentery. It became apparent with delayed images in the second patient that this activity was in the bowel and moving around the abdomen in a typical large bowel pattern. Bowel activity was not seen in other patients having bone scans at this time. Follow-up bone imaging on the first patient after resection of the tumor did not demonstrate diphosphonate activity in the bowel. These authors have never seen or read of this finding previously in this condition, and report it in these two patients.

Abdominal Neoplasms↗

In situ radiotherapy with 111In-pentetreotide: initial observations and future directions.

PURPOSE: Somatostatin and its analogues, such as octreotide and lanreotide, are used to treat neuroendocrine malignancies. Somatostatin analogues bind to somatostatin receptors (sst 1-5), which are differentially expressed in a wide variety of neoplasms. Following ligand receptor binding, a fraction of these complexes internalize. Internalization of radiolabeled somatostatin analogues, especially those that emit Auger electrons, may allow treatment of somatostatin-receptor-positive tumors by delivering a radioactive isotope to the cancer cell in a targeted fashion. 111In-pentetreotide, an sst-2-preferring somatostatin analogue, has been used for scintigraphic evaluation and management of neuroendocrine cancer patients. We hypothesized that binding and internalization of 111In-pentetreotide, an Auger electron emitter, may induce receptor-specific cytotoxicity and could be a useful therapeutic agent in somatostatin-receptor-expressing malignancies. METHODS: To test this hypothesis, subjects who had failed conventional therapy and had somatostatin-receptor-positive malignancies, as determined by positive uptake on a 6.0 mCi 111In-pentetreotide scan, were treated with two monthly 180 mCi intravenous injections of 111In-pentetreotide. CT scans were obtained before therapy and within 30 days following the completion of the second 111In-pentetreotide dose. Toxicity was evaluated using standard criteria. RESULTS: Fourteen patients were studied from February 1997 to August 1997. Clinical benefit occurred in six of 10 gastroenteropancreatic tumor patients. Objective partial radiographic responses occurred in two of 14 patients, and significant tumor necrosis (defined by changes in Hounsfield units) developed in six of the 10 gastroenteropancreatic tumor patients. Possible treatment-related toxicity included two patients experiencing grade 3/4 myelosuppression, and two patients had no measurable toxicity. The most common toxicity was grade 1/2 hemoglobin (N = 6). CONCLUSION: One hundred eighty millicurie (180-mCi) doses of 111In-pentetreotide are well tolerated and are an effective therapy in some subjects with somatostatin receptor-expressing tumors. The maximal tolerated dose of 111In-pentetreotide and the optimal dosing schedules remain to be determined.

Adult↗