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Results for “IRIDIUM, RADIOACTIVE”

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At least 19 recordsLinked to original sources
PubMedDate not supplied

An overview of interstitial brachytherapy and hyperthermia.

Interstitial thermoradiotherapy, an experimental cancer treatment that combines interstitial radiation implants (brachytherapy) and interstitial hyperthermia, is in the early stages of investigation. In accordance with the procedure used in a current national trial protocol, a 60-minute hyperthermia treatment is administered after catheters are placed into the tumor area while the patient is under general anesthesia. This is immediately followed by loading of radioactive Iridium-192 seeds into the catheters for a defined period of time. Once the prescribed radiation dose is delivered, the radioactive sources are removed and a second, 60-minute hyperthermia treatment is administered. Clinical trials with hyperthermia in combination with radiation have increased in recent years. Nurses caring for these patients need to become more knowledgeable about this investigational therapy. This paper provides an overview of the biologic rationale for this therapy, as well as a description of the delivery method and clinical application. Specific related nursing interventions are defined in a nursing protocol.

Brachytherapy↗
PubMed2005

The influence of hydrogen peroxide and histamine on lung permeability and translocation of iridium nanoparticles in the isolated perfused rat lung.

BACKGROUND: Translocation of ultrafine particles (UFP) into the blood that returns from the lungs to the heart has been forwarded as a mechanism for particle-induced cardiovascular effects. The objective of this study was to evaluate the role of the endothelial barrier in the translocation of inhaled UFP from the lung into circulation. METHODS: The isolated perfused rat lung (IPRL) was used under negative pressure ventilation, and radioactive iridium particles (18 nm, CMD, 192Ir-UFP) were inhaled during 60 minutes to achieve a lung burden of 100-200 microg. Particle inhalation was done under following treatments: i) control perfusion, ii) histamine (1 microM) in perfusate, iii) luminal histamine instillation (1 mM), and iv) luminal instillation of H2O2. Particle translocation to the perfusate was assessed by the radioactivity of 192Ir isotope. Lung permeability by the use of Tc99m-labeled diethylene triamine pentaacetic acid (DTPA). In addition to light microscopic morphological evaluation of fixed lungs, alkaline phosphatase (AKP) and angiotensin converting enzyme (ACE) in perfusate were measured to assess epithelial and endothelial integrity. RESULTS: Particle distribution in the lung was homogenous and similar to in vivo conditions. No translocation of Ir particles at negative pressure inhalation was detected in control IPL, but lungs pretreated with histamine (1 microM) in the perfusate or with luminal H2O2 (0.5 mM) showed small amounts of radioactivity (2-3 % dose) in the single pass perfusate starting at 60 min of perfusion. Although the kinetics of particle translocation were different from permeability for 99mTc-DTPA, the pretreatments (H2O2, vascular histamine) caused similar changes in the translocation of particles and soluble mediator. Increased translocation through epithelium and endothelium with a lag time of one hour occurred in the absence of epithelial and endothelial damage. CONCLUSION: Permeability of the lung barrier to UFP or nanoparticles is controlled both at the epithelial and endothelial level. Conditions that affect this barrier function such as inflammation may affect translocation of NP.

Journal Article↗
PubMed1994

[Perspectives in diagnosis and therapy of orbital diseases].

New or prospectively promising developments in diagnostics and therapy of orbital diseases are presented. Essential improvement concerns computerized tomography (finer stratification) and magnetic resonance tomography (specific imaging methods like suppression of the orbital fat signal). Three dimensional reconstruction is particularly useful. Diagnostic of vascular processes is facilitated by color doppler imaging. The Doppler signal is superimposed in color over a conventional gray-scale ultrasound image, thus giving additional information about blood flow in vessels. Application of endonasal surgery, which in ENT has been developed to great perfection, enables different surgical interventions, e.g. extraction of favourably positioned foreign bodies and decompressive procedures in Graves' disease. More precise and less side-effect-producing radiotherapy is permitted by a new procedure in which special plastic tubes are implanted, which tips are positioned as closely as possible to the area to be irradiated. Irradiation commences by insertion of radioactive iridium into these tubes by a computer-controlled injection-device. As a prospect for near future the possibility of endoscopical orbital interventions, e.g. biopsies is to be mentioned.

Brachytherapy↗
PubMed1984

Biliary tract neoplasms: a simple management technique.

This paper presents a simple, fast, and accurate afterloading method of delivering high radiation dose to tumors of the biliary tract, using radioactive iridium through a biliary drainage catheter. A Tuohy Borst sidearm adaptor permits concurrent drainage. The dose delivered in this manner can be used to supplement the palliative external beam radiotherapy, with minimal side effect.

Adult↗
PubMed1986

Percutaneous renal surgery and local radiotherapy in the management of renal pelvic transitional cell carcinoma.

Six patients with a history of bladder carcinoma and a radiographic filling defect of the pelvicaliceal system have been investigated or treated percutaneously. In two cases of doubtful diagnosis, percutaneous pyeloscopy showed that no pelvicaliceal tumour was present. In four patients with multifocal or recurrent transitional cell carcinoma and difficult clinical problems, intrarenal tumours were cauterised or resected percutaneously. Radioactive iridium wire (192Ir) was inserted into the surgical track to deliver prophylactic irradiation (4500 cGy) to prevent tumour seeding. Follow-up was from 7 to 36 months. One operated patient developed early wide-spread multifocal disease throughout the urothelium, including the operated kidney, and died of uraemia. The other three patients have shown no recurrence in the operated kidney, though two have developed recurrences in the bladder or ureter. There have been no track recurrences.

Aged↗
PubMed1981

Newer techniques in the diagnosis and treatment of proximal bile duct carcinoma--an analysis of 41 consecutive patients.

The clinical course of 41 consecutive patients with primary bile duct carcinoma at or near the liver hilum was analysed to determine whether the outcome was improved by newer techniques of diagnosis and treatment. The age range was wide, with one third under 50 years. The only aetiological factor identified was long-standing ulcerative colitis (present in 9.8 per cent of patients). In one third of patients initial symptoms were misleading. The tumour had been missed in 11 (61 per cent) of 18 patients undergoing an exploratory laparotomy at other hospitals, despite operative cholangiography. None had pre-operative percutaneous cholangiography which was shown to be the best investigatory technique, giving the correct diagnosis in all cases in whom it was performed. Greyscale ultrasonography was useful and endoscopic retrograde cholangiography less so. Median survival in those treated by surgical T- or U-tube drainage (21 patients) or bypass (three) was nine months from diagnosis, as opposed to three months in the 36.5 per cent of patients in whom biliary drainage was not obtained. Radiotherapy, including insertion of a radioactive iridium wire through the tumour via a T- or U-tube, or percutaneously, was performed in nine patients and improved the duration of survival compared with tube drainage alone. The new percutaneous techniques offer a useful alternative to surgery for palliative drainage and radiotherapy.

Adult↗
PubMed1994

[Cancer of the penis. 1989].

Cancer of the penis is the rarest male genital tract tumour, accounting for only 1% of all cancers in men. It is highly lymphophilic. Complex diagnostic problems are posed by both the primary tumour and lymph nodes. The prognosis depends on the degree of lymphatic spread. This cancer occurs in uncircumcised men with poor personal hygiene. The diagnosis is based on biopsy of all persistent lesions on the glans. In every case, treatment requires complete removal of the prepuce. Small noninvasive cancers can be treated by application of radioactive iridium wire. Inguinal lymph node biopsy is performed on a palpable node. Small cancers with lymph node involvement requires extensive inguinal lymph node dissection. Adjuvant irradiation is only indicated when the tumour has extended beyond the lymph node capsule. Cancer invading the corpora cavernosa has a poor prognosis (T3). It justifies large amputation of the penis with perineal urethrostomy and extensive lymph node dissection in the presence of positive nodes. Advanced cancers with unresectable lymph nodes (inguinal and iliac) and/or metastases (pulmonary) require combination chemotherapy with MTX-cisplatin-bleomycin.

Brachytherapy↗
PubMed2000

A novel platinum-iridium, potentially gamma radioactive stent: evaluation in a porcine model.

In-stent restenosis (ISR) is a major problem within stented arteries. Surface treatment of stents with platinum and gold were found to have the maximum charge with least neointima formation (NF). This study was designed to evaluate platinum (maximum electrical charge) as a material to make stents to reduce NF. Iridium was added to make an alloy suitable for stent manufacture, with the potential to make the stent radioactive. We implanted the novel platinum-iridium (PI) stent in 10 porcine coronaries and compared to the Palmaz-Schatz (PS) stent implanted in 8 coronary arteries. Six weeks after implantation, angiography of the stented vessel was performed before sacrifice. The coronaries were perfusion-fixed and stained, and vessel parameters were analyzed by computer-aided histomorphometry. The thrombus formation and the inflammatory response was less in the PI stent (0.04 +/- 0.1 vs. 0.24 +/- 0.2, P = 0.005; and 1.1 +/- 0.5 vs. 2.4 +/- 0.3, P < 0.001). The NF from PI-stented arteries was smaller in size than the PS controls (1.9 +/- 0.6 mm(2) vs. 2.4 +/- 0.4 mm(2), P = 0.06). However, PI stents presented with higher recoil than the PS stent (16% vs. 5%, P < 0.001). Platinum-iridium is a highly biocompatible material with high performance, low inflammatory response with small NF. This stent does not lead to thrombus formation and has the potential (due to the presence of iridium) to be irradiated to form a gamma radioactive stent. Cathet. Cardiovasc. Intervent. 51:364-368, 2000.

Animals↗