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Biomedical subjects

U Y Ryo

Publications and source records attributed to U Y Ryo.

At least 55 records · Page 3Linked to original sources

Intense bone imaging agent uptake in the soft tissues of the lower legs and feet relating to ischemia and cold exposure.

We present a patient with diffuse and intense uptake in the soft tissues of both lower legs and feet seen on 99mTc-HMDP bone scintigraphy. This finding presumably resulted from compromised blood supply to the lower legs plus a cold environment. The extraosseous bone imaging agent localization was presumably related to an existing ischemic condition that was exacerbated by cold. Differential diagnosis of the scan pattern should be differentiated from the artifact of socks contaminated by radioactive urine.

Aged↗

Paget's disease mimicing skeletal metastases in a patient with coexisting prostatic carcinoma.

We present a 93-year-old man with prostatic carcinoma whose 99mTc-HMDP skeletal images showed multiple areas of abnormally increased radioactivity in the bone and virtual absence of renal activity. These findings were interpreted as representing multiple skeletal metastases. When correlated with concurrent radiographs, the abnormalities were found to be due to Paget's disease. Multiple areas of bone involvement are not rare in Paget's disease. We reemphasize that an abnormal bone scintigram should always be correlated with regional radiographs to rule out conditions other than malignancy.

Aged↗

Blood-flow measurement in muscle with Xe-133.

An alternative method to the conventional miniature probe system for the measurement of blood flow in muscle has been developed. Xenon-133 was injected into the quadriceps muscles of ten subjects. A gamma camera and an online computer were then used to measure the half-clearance time of the Xe-133 while the subject was both at rest and exercising on an upright bicycle ergometer. The blood flow in the muscle was then calculated from the acquired data.

Adult↗

Radiation-induced thyroid carcinoma. Clinical course and results of therapy in 296 patients.

Of 5379 patients who had received radiation treatment at our institution for benign conditions of the head and neck, 318 developed thyroid cancer 3 to 42 years later. We report follow-up observations (median interval from diagnosis to recurrence or last contact, 10 years; longest interval, 31) for 296 of these patients. Three patients died of thyroid cancer and 40 had recurrences. The rate of recurrence during the 10 years after the detection of thyroid cancer, determined by life-table analysis, was 1.1%/yr. Factors that correlated with the risk of recurrence were tumor size, histologic type, number of lobes involved, vessel invasion, and lymph node metastases. The time from radiation exposure to the discovery of thyroid cancer (latency) and the age at diagnosis both inversely correlated with recurrence. The administration of thyroid hormones reduced the number of recurrences in patients with combined papillary and follicular cancer, but no reductions could be associated with the extent of surgery done or the prophylactic use of radioactive iodine ablation. We conclude that the course of radiation-induced thyroid cancer is the same as that of thyroid cancer found in other settings. We advocate a conservative approach to the treatment of small tumors that have no associated risk for thyroid cancer other than that they developed many years after the patient had been exposed to radiation.

Actuarial Analysis↗

Evaluation of a patient with splenosis by various imaging modalities.

Three different noninvasive imaging procedures were performed in a patient after an intravenous pyelogram suggested a suprarenal mass. Presence of a mass was confirmed by ultrasonogram. Computed tomography revealed two masses in the splenic bed that showed contrast enhancement. Radionuclide scans demonstrated multiple splenic masses (splenosis). The specificity of the splenic tissue as well as the anatomic resolution were best with the radionuclide liver and spleen scan.

Adult↗

Radiation-induced tumors of the head and neck following childhood irradiation. Prospective studies.

Nodules were found in 1108 subjects who received childhood radiation for benign conditions of the cervical area at our institution. This is 37.5% of 2958 subjects, out of a total of 5379, for whom there is follow-up information. Of the 848 subjects who have had thyroidectomies, 297 (35.0%) had thyroid cancer. In addition to thyroid tumors, salivary, neural, and probably parathyroid tumors also occurred as a late consequence of childhood radiation. Prospective studies of the subjects indicate that thyroid nodules are continuing to occur at a constant rate. The measurement of serum thyroglobulin is helpful in identifying individuals for whom the risk of developing a nodule is increased. Follow-up of patients with nonsurgically-treated nodules indicates that some of their nodules are progressive. At the present time there is no indication that radiation-induced cancers behave differently than ones in other settings. However, some of their characteristics, especially their multicentricity and occurrence in younger individuals, indicate that continued follow-up is necessary. On the basis of the data generated by the follow-up program at our institution and programs elsewhere, recommendations for screening, treatment, and follow-up are made. The recommendations stress the importance of estimating risk based on radiation dose, previous tumors, and serum thyroglobulin, in arriving at clinical decisions for these subjects.

Adult↗

Prospective serum thyroglobulin measurements in assessing the risk of developing thyroid nodules in patients exposed to childhood neck irradiation.

We examined 327 patients with a history of cervical radiation treatment for benign conditions and followed them for an average of 5.6 yr. These patients were selected because they initially had normal examinations and normal serum thyroglobulin levels. Of the 327 patients, 48 developed thyroid nodules, and an additional 30 had other clinical changes in their thyroids. Serum thyroglobulin increased by 4.0 +/- 0.6 (+/- SEM) ng/ml in those who remained normal, by 13.4 +/- 5.2 ng/ml in those who were no longer normal, and by 17.1 +/- 8.2 ng/ml in those who developed nodules. We conclude that increasing levels of serum thyroglobulin identify patients who should be examined and followed more carefully for thyroid nodules and thyroid cancer.

Age Factors↗

Visualization of the liver, gallbladder, and intestine on bone scintigraphy.

Images of the liver, gallbladder, and/or intestine were visualized on bone scans on several occasions. Radiopharmaceutical quality control data, including molybdenum-99 and aluminum ion content in the Tc-99m eluate, free unbound Tc-99m, and hydrolyzed reduced Tc-99m in the labeled MDP, were all satisfactory. A minor defect in the quality of the Tc-99m generator was considered to be the probable cause of the unusual localization of the bone imaging agent.

Bone and Bones↗

Metastatic calcification of the stomach imaged on a bone scan.

A whole body bone scan obtained on a 21-year-old woman with sickle cell disease and chronic renal failure showed localization of the radionuclide diffusely in the stomach. The localization of the radionuclide represented metastatic calcification of the stomach caused by secondary hyperparathyroidism.

Adult↗

The effects of inadvertent administration of antineoplastic agents prior to Ga-67 injection: concise communication.

Alteration of the gallium-67 (Ga-67) distribution after administration of chemotherapeutic agents has been demonstrated in experiments on both normal and tumor-bearing animals. We have encountered eight patients who had Ga-67 scintigrams in which the findings were similar to those in the animals experiments: markedly increased uptake in bone, with suppressed uptake in liver, muscle, and tumor. Five of the patients had hematologic neoplasms, and three had solid tumors, and each had received one or more chemotherapeutic agents during the 24 hr preceding Ga-67 administration. In three patients while not on antineoplastic medication subsequent Ga-67 images showed a return to the usual Ga-67 distribution pattern. The altered Ga-67 distribution may result from inhibition of protein synthesis or of a serum-binding agent for Ga-67, or from competitive blockage of specific Ga-67 organ receptors by the antineoplastic agents.

Adolescent↗

Thyroid imaging agents: a comparison of I-123 and Tc-99m pertechnetate.

Tc-99m pertechnetate and I-123 were used to perform thyroid scanning in 122 patients with history or clinical evidence of thyroid disease. Thyroid scans were abnormal in all patients, while thyroid palpation was abnormal in all but 19. The quality of thyroid imaging was similar with both agents in 42%, better with I-123 in 18%, and better with Tc-99m in 7%. In the remaining 33% (40 cases), there were discrepancies between Tc-99m and I-123 images. The most frequent discrepancies were "hot" or "warm" lesions on Tc-99m scans that were "cold" or normal on I-123 scans. Results from this study indicate that neither Tc-99m nor I-123 is always superior to the other as a thyroid imaging agent.

Adult↗