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At least 55 records · Page 3Linked to original sources
PubMed1994

Episcleral iridium-192 wire therapy for choroidal melanomas.

PURPOSE: To evaluate the effectivity of high-dose episcleral iridium-192 wires in the treatment of choroidal melanoma. METHODS AND MATERIALS: In 1983, the Departments of Radiation Oncology and Ophthalmology at the Clínica Puerta de Hierro, Madrid, Spain, initiated a clinical study using removable episcleral iridium-192 wires in the treatment of choroidal melanoma. Sixty-six evaluable patients were treated from January 1983 through July 1992. Two patients had a small sized tumor (3%), 28 had a medium sized tumor (42%), and 36 patients had a large tumor (54%). The mean follow-up was 40 months (6-118 months). The dose to the apex of the tumor ranged from 66 to 97 Gy (mean 76.6 Gy), and the doses at 2 mm depth ranged from 77 to 433 Gy (mean 200 Gy). RESULTS: Tumor regression or stabilization was observed in 53 of the 66 patients (90%). Visual acuity improved following treatment in 5 out of 54 patients (9%), remaining unchanged in 30 out of 54 (56%), and decreased in 19 out of 54 (35%) patients. The remaining seven patients had undergone enucleation. Late complications have been documented in 20 out of 66 patients (30%), including 6 patients in whom enucleation was required because of radiation-related complications. The probability of survival and survival free of local progression was 93% at 5 years and 79% at 10 years. The probability of retaining the treated eye is 82% after the fifth year posttreatment. CONCLUSIONS: Treatment of choroidal melanomas with episcleral iridium-192 wires is as effective as treatment with other radioactive applications. We feel that our results using iridium-192 wires are comparable to the other methods. However, we think that our technique is simple to implement, relatively inexpensive, and well tolerated.

Brachytherapy↗
PubMed1989

[Results and indications of curietherapy of the eustachian tube with iridium 192 in chronic otitis in the adult].

Between January 1985 and January 1988, 56 patients received radioactive implant therapy of the Eustachian tube with Iridium 192 in the context of tympanoplasty for chronic otitis with tubal dysfunction. After reviewing the method used, we present the results by category of chronic otitis and attempt to propose its indications. Tubal dysfunction was assessed on clinical and otoscopic data and tubal manometry in each patient. A randomised study would appear to be necessary to confirm the interesting results obtained in chronic mucous otitis, in the sequelae of chronic otitis, in evolving retraction pockets and finally for certain manifestly discharging cavities.

Adolescent↗
PubMed1992

Brachytherapy of choroidal melanomas.

In the management of patients with primary malignant melanoma of the uvea, treatment techniques have included not only enucleation but also photocoagulation, cryotherapy, photoradiation, a limited resection, as well as circumstances indicating exenteration of the orbit. Surgical management has been the primary treatment program for over 100 years. In a compilation of nine reported series consisting of 2,024 enucleations, the five- and ten-year survivals following surgery were 63% and 43%, respectively. The 25-year survival has been reported to be 40%. In 1974 at Wills Eye Hospital and Hahnemann University, the cobalt-60 plaques technique was introduced. During the following years, other radioactive isotopes were introduced including iridium-192, iodine-125, ruthenium-106/rhodium-106 and more recently palladium-103. At the present time, iodine-125 is the most widely used radionuclide. Until now, 302 patients treated with plaque brachytherapy showed an actuarial survival of 77% and 67.8% at five and eight years, respectively. There was no significant survival difference when compared with a similar group of patients undergoing enucleation. Other retrospective studies show similar excellent results. In spite of these convincing results, the decision making process in management melanoma remains unsettled primarily due to the absence of prospective randomized trials. Because of this, the Collaborative Ocular Melanoma Study was initiated. From the standpoint of toxicity, the data are available on ocular radiation toxicity. In an analysis of 77 patients from the Wills Eye Hospital with pretreatment visual acuities of 20/25 or better, it was noted that 90% of patients who had received less than 500 Gy to the fovea retained visual acuity of 20/200 or better while only 52% of patients receiving more than 5,000 Gy to the fovea had vision of 20/200 or better. A serious late effect of radioactivity plaque treatment is scleral necrosis which may require repair or enucleation even in the absence of tumor progression. Enucleation may be necessary in approximately 10% of patients. We conclude that malignant melanoma of the uvea can be safely treated with radioactive plaques.

Brachytherapy↗
PubMedDate not supplied

[Intraoperative brachytherapy in the management of keloids. Apropos of 114 cases] .

PURPOSE: Keloid scars are unsightly, especially when located on the face or bare zones. The purpose of this study was to evaluate the therapeutic results of intraoperative brachytherapy in the management of keloids. MATERIAL AND METHODS: This retrospective study was based on the study of 82 patients with keloids treated in Salah Azaiz Institute (Tunisia) between 1982 and 1994 (65 women and 17 men). The mean age of patients was 23.4 years (+/- 8.4). A total of 114 lesions have been treated with surgical resection and intraoperative brachytherapy using an iridium source placed under the surgical scar. The length of iridium was chosen with the result that the radioactive thread exceeded 5 mm on each side of the surgical scar. The iridium source was loaded less than six hours after resection. Average iridium activity was 1.5 +/- 0.3 mCi/cm. Average iridium length was 56.8 +/- 34 mm. The referred isodose chosen for the target volume included the surgical scar and a margin of 5 mm around the iridium source, which was placed under the surgical scar. The average administered dose was 20.4 Gy (+/- 3.2 Gy). RESULTS: The 2-year local control rate was 87% for the whole group of lesions treated (n = 114). Local control rate of keloids processed by resection and intraoperative brachytherapy as the first treatment (59 cases) was 96% at two years. This rate was better than the local control of lesions that had been previously treated with anterior surgical resection (84% in 55 cases). For the latter group, lesions treated with a dose of more than 20 Gy had better local control, but the difference was not statistically significant (87 vs. 65% at two years, P = 0.41). CONCLUSION: Intraoperative brachytherapy is effective for improving local control of keloids and preventing a recurrence. A rigorous technique and an adequate dose according to previous surgical treatment allows very good results.

Adult↗
PubMed1993

Experimental and clinical studies on dose reduction effects of spacers in interstitial brachytherapy for carcinoma of the mobile tongue.

The difference of radiation dose reduction effect with spacers of different materials, a heat-curing denture base resin and a silicon impression material, was examined experimentally and clinically. Radium needles and iridium hairpins were used as radioactive sources. In both studies, it was revealed that a dose reduction effect of silicon impression material was greater than that of denture base resin. Silicon impression material was thought to be a better material for spacers because of its larger radiation dose reduction effect and the time saving to produce the spacer.

Brachytherapy↗
PubMed1994

[Brachytherapy in cancer of the urethra].

Carcinomas of the male and female urethra are serious cancers because they frequently present late with lymph node involvement. Brachytherapy plays a significant role, often associated with external beam irradiation and surgery, in the conservative management of these tumors. This radiation treatment uses a catheter or a vaginal mould applicator for intraluminal/intracavity brachytherapy, and hypodermic needles or guide gutters for the interstitial portion. The radioactive source usually employed is iridium 192. The total dose administered is usually between 60 and 70 Gy. Disease free survival is 50%, local control 70%, and the complication rate is 20%.

Brachytherapy↗
PubMed1998

192IrCl acid skin burn: case report and review of the literature.

A worker was contaminated following a chemical explosion that splashed an HNO3 radioactive solution containing approximately 180 MBq (5 mCi) 192Ir onto the left side of his face. Initial efforts reduced the contamination at least fivefold. Removal of a patch of contaminated hair was necessary. Most of the contamination was fixed to the skin; only a small amount of contamination was absorbed.

Acids↗
PubMed1975

[Use of lithium fluoride in clinical dosimetry. Application to the measurement of the dose delivered to axilla by iridium 192 with endocurietherapy for carcinoma of the breast].

The aim of the work was the evaluation of the dose delivered to the axilla during endocurietherapy for carcinoma of the breast using Iridium 192. The position of the radioactive material with respect to the axillary zone differing with the patient seated or lying, the authors carried out an vivo dosimetric study using Lithium fluoride. They refer to the chief properties of Lithium fluoride which render it the dosimetric agent of choice for clinical work and give details of their experimental conditions, stressing the problems encountered in practice (response in relation to dose, mass of thermoluminescent powder to use, fading, regeneration etc.). They then describe the technique used for placing the thermoluminescent dosimeter in the axillary zone adjacent to the target volume irradiated. Results concerning 43 patients made possible the establishment of a significant correlation between the dose delivered to the axillary region and the site of implantation of the radioactive material in the breast, and show that, with identical tumour doses, this dose is little dependent upon the structure of the radioactive implant itself. They conclude that the dose delivered to the axillary region is of the order of 25% of the tumour dose if the radioactive implant is localised in the axillary tail, 10% if it is in the upper outer quadrant and negligeable if it is elsewhere.

Breast Neoplasms↗
PubMed1983

Sequential morphological changes in the dog brain after interstitial iodine- 125 irradiation.

Iodine- 125 seeds (3.55 mCi) were stereotactically implanted into the subcortical white matter of the left coronal gyrus in six beagle dogs. Morphological changes were studied at intervals ranging from 25 to 368 days after implantation. In all of the animals, there was a calcifying necrosis 3 to 6 mm in diameter with an adjacent small zone of demyelination. There were no signs of delayed radiation damage outside the demyelinated perifocal zone. The central tissue necrosis was sharply delineated and did not increase in size after 70 days, i.e., an accumulated dose of 18,000 cGy. In addition, widespread vasogenic edema was present in the homolateral hemisphere. The morphological changes observed differed in many aspects from those found with other radioactive sources, such as gold-198, yttrium-90, or iridium-192. The low energy gamma radiation, the absence of beta radiation, and the half-life of 60.2 days makes iodine-125 a favorable radioactive source to produce a well-defined necrosis without delayed radiation damage in the surrounding brain.

Animals↗
PubMed2000

Gamma radiography with 75Se sources: consequences of a violent fire.

Due to the volatile nature of selenium and selenium dioxide, an important atmospheric dispersion of 75Se can occur in case of a violent fire (>800 degrees C). This type of accident is possible when transporting or using a highly active 75Se source for gamma radiography. The consequences of this dispersion are analyzed. From the point of view of radiological protection, it can be concluded that in radiography the unprotected 75Se sealed sources have to resist for 1 h to a temperature of 1,200 degrees C. If this is not the case, x-ray equipment and 192Ir sources have to be preferred above 75Se sources.

Adult↗
PubMed1994

Dose-reducing effect of Lipowitz metal-embedded spacers in interstitial brachytherapy for carcinoma of the mobile tongue.

Dose-reducing effects of spacers with and without a Lipowitz metal plate for the purpose of decreasing osteoradionecrosis after interstitial brachytherapy for tongue cancers were examined experimentally and clinically. The thicker the sample or spacer and the thicker the metal plate, the greater was the dose reduction achieved. A more marked dose reduction was achieved with iridium than with radium because of lower gamma ray energy of iridium. Iridium has been used widely as a radioactive source for interstitial brachytherapy. It was concluded therefore that a metal plate should be used as a shield into the spacer in interstitial brachytherapy both to reduce the radiation dose to surrounding normal tissues and to help prevent osteoradionecrosis.

Alloys↗
PubMedDate not supplied

The effect of geometric errors in the reconstruction of iridium-192 seed implants.

In the treatment of tumors using interstitial implants of radioactive seeds, the accuracy of computed dose distributions depends upon the accuracy with which the three-dimensional source geometries are reconstructed from radiographs of the implants. The effect of geometric reconstruction errors in iridium-192 seed implants were studied, using tumor dose as the measure. Tumor dose was defined as the average dose around the periphery of the treatment volume. Three ideal mathematical implants and five actual patient implants were used. The implants were distorted by randomly moving a specified number of seeds a specified distance. Tumor doses were directly calculated for the ideal implants. For the actual implants, isodose distributions were plotted and were read by a radiotherapist. For both types of implants, percentage errors in the tumor doses were calculated for the distorted reconstructions relative to the correct reconstructions. It was found that the tumor dose was accurate to within 5% if all the seeds were reconstructed to within 0.5 cm of their actual positions. Furthermore, up to 5% of the seeds could be mismatched between films, or otherwise incorrectly reconstructed, with position errors as large as 20 cm, and not change the tumor dose by more than 5%.

Brachytherapy↗
PubMed1996

Does brachytherapy have a role in the treatment of prostate cancer?

The goal of radiation therapy is to deliver a high dose to the tumor while preserving normal surrounding tissue. For early-stage prostate cancer, the ultimate conformal irradiation is to place radioactive sources directly into the gland either as permanent or temporary seeds. Permanent seed implantation is capable of delivering two times the radiobiologically equivalent dose of external beam irradiation to the prostate and tumor. In the past, the results of prostate brachytherapy were likely poor owing to the technical difficulty in accurately placing the radioactive seeds uniformly throughout the prostate. The use of low-dose-rate I-125 to treat high-grade cancers probably also contributed to the poorer results as compared with external beam irradiation. Over the last 10 years, however, technologic advances in transrectal ultrasonography, computer dosimetry, and template-based transperineal techniques have dramatically improved the accuracy and consistency of the brachytherapist to place radioactive sources directly into the prostate gland. Transperineal ultrasound or CT directed seed implantation has replaced the older retropubic method. Brachytherapists are now able to accurately map out the gland prior to the implant and carefully evaluate preoperatively seed placement. The availability of such radioactive sources as iodine-125, palladium-103, and iridium-192 has also given the brachytherapist isotopes that can be more carefully matched to the biology and stage of the tumor. More sensitive definitions of failure have prompted radiation oncologists and urologists to carefully evaluate the efficacy of external beam irradiation and surgery. Accurate comparison of the efficacy of brachytherapy to surgery and to external beam radiation requires a randomized study. Comparisons of retrospective studies are fraught with the problems of the heterogeneous nature of early-stage prostate cancer. Imbalances in stage, grade, initial PSA extraprostatic disease, and nodal status of patient groups make comparisons difficult. Most of the long-term data for permanent seed implantation are the result of work at a single institution. These results will need to be repeated at other institutions treating patients in a similar manner. Because techniques vary from institution to institution, permanent implant results will need to be carefully evaluated for technique as well as stratified for pretreatment variables. Pretreatment PSA and grade appear to be more sensitive variables than stage in predicting failure after radiation. As more patients are diagnosed with very early and nonpalpable disease, future studies will need to stratify patients based on these pretreatment factors. Patients with early-stage disease but identified as high risk for extraprostatic disease will require more intensive regimens. The treatment outcomes based on biopsy results are inconclusive. A lack of consensus on the definition of a truly positive biopsy remains forthcoming. The value of a positive prostate biopsy as an outcome predictor for clinical failure is still unclear. The use of prostate nuclear cell antigen staining may help clarify the issue. Comparison of treatment outcome based on absolute PSA is also difficult. The Seattle series suggest that brachytherapy by permanent seed implantation is as efficacious as external beam irradiation for early-stage disease in patients with a low PSA (< 10 ng/mL). As the PSA value rises above 10 ng/mL, the probability of failure after external beam rises substantially. Results from the Seattle series suggest an advantage to seed implant alone or the judicious application of seed implant boost to external beam radiation for these patients with more advanced cancer. The most sensitive measurement of therapeutic outcome is progression-free survival. Few studies to date have evaluated progression-free survival.

Biopsy↗
PubMed1988

Treatment of brain tumors with iridium-192 seeds.

Interstitial radiation therapy of brain tumors requires positioning of the radioactive sources with good precision in order to achieve a sufficient dose in the tumor without too much damage to surrounding tissues. A method for application of 192Ir seeds in brain tumors is described and preliminary results in seven patients reported. The method, which uses CT-guided stereotactic localization and computerized dose planning, is at present fairly complicated. The preliminary results are promising and no serious complications have so far been observed.

Adult↗