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At least 55 records · Page 3Linked to original sources
PubMed2004

Quantitative analysis of radioisotope cisternography in the diagnosis of intracranial hypotension.

OBJECT: The authors attempted a quantitative analysis of conventional radioisotope cisternography for the purpose of more accurate diagnosis of intracranial hypotension. METHODS: Fifty-seven patients suspected of having intracranial hypotension underwent radioisotope cisternography. Whole-body images were obtained 2.5, 6, and 24 hours after intrathecal injection of 111In-diethylenetriamine pentaacetic acid. Radioactivity in the cerebrospinal fluid (CSF) space was counted during scanning, and radioisotope clearance was studied. Direct signs of radioisotope leakage into the spinal epidural space were found in 25 patients. Most leaks were located in the lumbosacral region. Analysis of the radioisotope clearance curve revealed two different patterns. In patients without a radiographically demonstrated radioisotope leak, absolutely exponential curves were observed (R2 > 0.99). The activity of the radioisotope decreased at a rate of e(-003) to e(-0.107) (mean +/- standard deviation, e(-0.056 +/- 0.018); 32 patients). Clearance in patients with an overt radioisotope leak was not a simple exponential curve; it could be divided into an early rapid phase and a late slow phase. The clearance rate during the first 6 hours was e(-0.219 +/- 0.127) (25 patients) and e(-0.076 +/- 0.021) thereafter. The authors speculated that the early escape of undiluted radioisotope solution through an aberrant CSF outlet, such as a traumatic spinal dural tear, was responsible for this phenomenon. CONCLUSIONS: The quantitative analysis featured in this study seems to be useful in the diagnosis of intracranial hypotension. A small CSF leak below the limit of radioisotope cisternography resolution might be detected using this technique.

Adolescent↗
PubMed2003

Radioisotopes for metastatic bone pain.

BACKGROUND: Bone metastases manifest through pain, which can arise even before the injury is radiologically detected. Pain occurs as a result of bone destruction and, as more destruction ensues, more pain can be experienced. Radiculopathies, plexopathies and shrinkage of spinal nerves due to tumour growth and fractures are very frequent in these patients. Relief of pain from bone metastasis can be achieved by treating the cancer itself; radiotherapy; conventional analgesics; and specific drugs that work on the bone tumour-induced alteration: biphosphonates, calcitonin or radioactive agents. OBJECTIVES: To determine the efficacy of radioisotopes to control metastatic pain in patients with bone metastases and complications due to bone metastases (hypercalcaemia, bone fracture and spinal cord compression) as well as its efficacy in terms of patient survival and adverse effects. SEARCH STRATEGY: Randomised and controlled clinical trials related to this review were retrieved electronically using MEDLINE (1966-2003), EMBASE (1974-2003) and Cochrane Central Register of Controlled Trials (CENTRAL) (Issue 1 2003). general strategies to identify RCTs were combined with specific commands to identify trials of radioisotopes and metastatic bone pain. SELECTION CRITERIA: The inclusion criteria were: randomised trials of patients with metastatic bone pain that compared treatment with radioisotopes and placebo, and where the major outcome was either pain or complications of bone metastases (eg, hypercalcaemia, bone fracture, spinal cord compression) assessed at least four weeks after treatment. DATA COLLECTION AND ANALYSIS: The quality of included studies was assessed using the Jadad scale and the Oxford Pain Validity Score. Two independent reviewers extracted the data and completed a standard form designed for that purpose. An intention-to-treat analysis was performed, and global estimates of effect were calculated using a random effects model. MAIN RESULTS: Four trials (325 patients) provided data that suggest a small effect of radioisotopes on pain control both at short and medium term (one to six months). No evidence was available to assess long-term effects (12 months). Only one study provided data on analgesia use and concluded that patients given either radioisotopes or placebo showed similar levels of analgesic use when compared to baseline use. Leukocytopenia and thrombocytopenia are secondary effects associated with the administration of radioisotopes. The incidence of leukocytopenia is significantly greater in patients treated with radioisotopes (RR=4.56, 95% CI (1.22,17.08)). There were also a greater number of thrombocytopenia events in the treatment group, without reaching statistical significance. REVIEWER'S CONCLUSIONS: The efficacy of radioisotopes has been assessed in clinical trials with small sample sizes and short-term evaluations of the outcomes. There is some evidence indicating that radioisotopes may give complete reduction in pain over one to six months with no increase in analgesic use, but adverse effects, specifically leukocytopenia and thrombocytopenia, have also been experienced.

Bone Neoplasms↗
PubMed2001

[Radioisotopic diagnostic examination as a factor responsible for the Polish population exposure to ionizing radiation].

For the general population, in vivo radioisotopic radiological examinations are the second, after x-ray diagnostics, artificial source of ionizing radiation used for medical purposes. The 1981 survey was the first review of the radioisotopic examinations in Poland and revealed that 80,000 examinations are performed annually (2 examinations per 1,000 population on average). It was also found that 131 I was the most common isotope used during thyroid examinations very frequently performed at that time. According to the 1996 data published by the National Consultant on Nuclear Medicine, "In Poland there are 36 centers of nuclear medicine within the network of public health care services. Every year about 130,000 radioisotopic examinations are performed." In order to estimate real exposure of the Polish population resulting from radioisotopic diagnostic examinations it is necessary to gather detailed data on the age structure of patients, as well as on the type and activity of radiopharmaceutical be administered. The paper presents the preliminary results of the follow-up study on radioisotopic examinations in Poland carried out by the Department of Radiological Protection, Nofer Institute of Medicine, Łódź. The data have been collected according to the adopted schedule, taking account of the organ (system) examined, the type of administered radiopharmaceutical, the kind and activity of radioactive isotopes used to mark radiopharmaceutics, age and sex of examined patient. By the end of December 2000 the data on radioisotopic examinations performed in 12 centers of nuclear medicine (Warsaw--7; Kielce--2; Gdańsk, Łódź and Zgierz--one center in each city) had been collected. Thus far almost 40,000 radioisotopic examinations have been registered. According to the above mentioned procedure it was possible to collect data on all examinations performed in 1998. In addition, general numbers of examinations performed in the centers visited in 1999 were registered; the 2000 data are now being completed. It was finally established that the thyroid and musculoskeletal examinations constitute about 50% of the total number of examinations, which is in agreement with the data applying to the countries classified as those with the first level of health care. However, while an average effective dose per examination in those countries accounts for about 4 mSv, in the Polish centers the analogues indicator, estimated on the basis of the results collected thus far, is about 9 mSv, of this number, over 7 mSv is contributed by thyroid examinations with the use of iodine (131I). The obtained result is a strong stimulus to supplement and complete the data already gathered and to carry out a thorough analysis of radioisotopic examination in view of patients' exposure. Such an analysis would provide the subject matter arguments for the optimization of radiological protection in nuclear medicine in Poland.

Adult↗
PubMed2000

Current and potential therapeutic uses of lanthanide radioisotopes.

In the last 25 years, diagnostic nuclear medicine has come to depend on the versatile chemistry of a single radioisotope, technetium-99m (Tc-99m). Different chelating molecules can be used to guide Tc-99m through various physiological pathways in the body to gain information about disease states. No single radioisotope similarly dominates therapeutic applications. In the field of radioisotope therapy, much discussion and debate have focused on what radioisotope might be "ideal" for treatment of malignant tumors. The ideal may not be a single radioisotope, but rather the class of very closely related radiolanthanides and lanthanide-like radioisotopes. These radioisotopes possess strikingly similar chemistries and thus all may be conjugated to biomolecules using a single chelate, the DOTA moiety (and its chemical analogs). They also provide a wide range of physical characteristics, such as half-lives and beta energies, that can be chosen to match the biological properties of the conjugated biomolecule and the malignant tumor. Thus, the radiolanthanide-DOTA bioconjugate model provides a set of physically diverse, but chemically very similar, therapeutic radiopharmaceutical agents, the individual members of which can be tailored to treat specific types of cancers.

Alpha Particles↗
PubMed1986

[Computerized control system for administration of the radioisotope use].

An on-line computer system for administration of the radioisotope use has been developed. This system consists of a multi-job type host computer and two sets of personal computers with identification card-readers. The personal computers are employed as terminal devices for radioisotope users. By the use of an identification card, entrance and leaving times are recorded automatically. Furthermore, an easy operation of the personal computer permits users to access to the information of their registered radioisotopes, such as nuclides, chemical forms, updated activities, storage locations, and history of usage. A recording sheet on which those data are printed is provided from the personal computer. After the use of radioisotopes, users can record their data on the recording sheets. These records are used as the input data to this system to update the data of the used radioisotopes. Owing to the concise format of the recording sheet and various sorting programs developed in present work, this system enables us to grasp the exact flow of the radioisotopes from purchase to disposal. Out-put data from high-speed kanji printer can provide many important books which are legally requested to be kept for administration of the radioisotope use.

Computers↗
PubMedDate not supplied

Monte Carlo calculations of dose distribution for intramural delivery of radioisotopes using a direct injection balloon catheter.

PURPOSE: A unique method of delivering radiation dose to the coronary vessel wall to prevent restenosis is by direct injection of radioactive compounds into the vessel wall using a specially designed angioplasty balloon catheter. The radiation dose distribution resulting from such intramural delivery was investigated using Monte Carlo simulations. MATERIALS AND METHODS: The radioisotope source distribution was modeled for two configurations within the vessel wall: (1) uniform to a depth of 0.5 mm and (2) confined to discrete pools surrounding the delivery injection ports. Monte Carlo MCNP4B computer simulations were utilized to estimate the associated radiation dose distribution for the following radioisotopes: 188Re, 186Re, 32P, 153Sm, 111In, 123I, and 99mTc. RESULTS: For the uniform case where the radioisotopes are distributed uniformly to the depth of 0.5 mm into the vessel wall, an essentially constant radiation dose is delivered within the source distribution. Outside of the source volume, the dose falls off at a rate depending on the emission properties of the particular radioisotope. The nonuniform case involving discrete pools of activity showed the dose distribution being confined largely to the regions surrounding the delivery ports with significant regions between these ports receiving very little dose. CONCLUSIONS: Direct injection of selected radioisotopes into the arterial wall appears to represent a potentially effective method for delivering radiation dose for the prevention of restenosis. Sufficiently high doses may be obtained from relatively low activity and the dose falls off rapidly outside of the target area for certain radioisotopes.

Adult↗
PubMedDate not supplied

Optical and radioisotope indicator dilution measurements in pulmonary edema.

The objective of this study was a validation of an optical multiple indicator dilution technique for measuring microvascular exchange parameters in edematous lungs by comparison to conventional radioisotope multiple indicator dilution methods. Six anesthetized dogs were studied at baseline and after alloxan infusion to increase capillary permeability. In addition, 11 isolated, perfused dog lungs were studied at baseline and after edema was created by increasing venous pressure or by infusing alloxan to increase vascular permeability. Increased capillary permeability from alloxan infusion led to increases in most but not all capillary exchange parameters as analyzed by mathematical models and measured by both optical and radioisotope methods. Increased vascular pressure led to increased edema but no significant increases in capillary exchange parameters. Two-way analysis of variance (ANOVA; variations in baseline versus pressure or alloxan and variation in optical versus radioisotope for each transport parameter derived from the mathematical models) indicated few significant differences in capillary exchange parameters between optical and radioisotope measures. Newman-Keuls multiple comparison tests did uncover some variations between a few of the group-mean values derived from optical and radioisotope methods. However, optical and radioisotope parameter measurements were highly correlated for all studies regardless of the mathematical model used for analysis.

Alloxan↗