Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.3.1.51 (HDR)
 605 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Modern high technology has recently brought a precision treatment modality in the field of brachytherapy for cancer patients. Ir-192 manual afterloading (hair pin technique of Ir-192 wire) replaced the technique utilizing Ra-226 needles at our department in 1973. In May 1991, microSelectron-HDR (Ir-192 micro-source of 370 GBq) was installed in Osaka University Hospital. Preliminary analysis of phase I/II study resulted in no significant differences between the incidence of an acute mucosal reaction as well as early tumor response after high and low dose rate interstitial brachytherapy for oral cancer. Since April 1992, a phase III study has been under way to completely eliminate the problem of hospital personnel exposure to radiation in the field of brachytherapy. The introduction of remote after-loading of Ir-192 micro-source has resulted in improvements in elderly patient care during the interstitial brachytherapy for malignancies. The indications for HDR brachytherapy have been expanded, and new technology was developed to improve the local cure of the disease, such as linked double button technique for oral cancer, template interstitial brachytherapy for perineal cancer, and postoperative brachytherapy using intraoperative flexible catheter placement for locally unresectable disease or microscopically residual disease. Through these meticulous efforts, HDR interstitial brachytherapy will soon become a satisfactory substitute for traditional LDR interstitial brachytherapy.
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PMID:[192Ir brachytherapy]. 823 75

A new technique of high dose rate intracavitary brachytherapy is introduced for treating patients with early and superficial squamous cell carcinoma of the nasal vestibule. This method is illustrated by a case report. A customized intranasal mould was fabricated in which afterloading catheters were placed. These catheters were loaded with a high activity 192Ir pointsource, using the HDR-microSelectron. In this way the patient was treated twice daily over 5 days without hospitalization. The indications for the use of this technique and the advantages in comparison with low dose rate interstitial irradiation are discussed.
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PMID:High dose rate intracavitary brachytherapy of early and superficial carcinoma of the nasal vestibule as an alternative to low dose rate interstitial radiation therapy. 832 37

Conventional use of Thermoluminescence (TL) in radiation dosimetry is very time-consuming. It requires repeating the procedures of preheating and annealing. In an attempt to simplify these procedures, we conducted an experiment of non-annealing TL dosimetry. This article reports the experiment's results. We adopted Lithium Fluoride (LiF) chip (TLD-100) in polystyrene under the exposure of Co-60, and the result was taken by HAR-SHAW-4000 TL reading system. The TL response was analyzed, including linearity, reproducibility and fading test. Because non-annealing TL response was greatly influenced by residual electron, TLD calibration curves were separated into two parts: (1) high dose region (HDR, 50-1500 cGy); (2) low dose region (LDR, 0-50 cGy). When TL dosimeters were exposed to a single high does (about 500 cGy), the HDR could be reproduced within 3% and fit a good linearity. For LDR, we had to give up the tail of glow curve in the high temperature region. We could then get good linearity and reproducibility. Furthermore, fading of non-annealing was apparently larger than annealing. We could control the fading of non-annealing was apparently larger than annealing. We could control the fading influence within 1% by taking the TL reading one hour after exposure. On the other hand, a combination of photon and electron exposure was also performed by non-annealing TL dosimetry. The results were compatible with Co-60 exposure in the same system.
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PMID:[The application of non-annealing thermoluminescent dosimetry (TLD)]. 833 53

We have previously reported results for treatment of adenocarcinomas and squamous cell carcinomas of the mid and distal esophagus as well as the use of intraluminal high-dose rate radiation (HDR-RT) for palliation of carcinoma of the esophagus. In this report we describe the results of a chemotherapy/HDR-RT/esophagectomy management program. Examination of the surgical specimens revealed a complete response in only 13% of patients and locoregional recurrence was disappointing. There were no operative deaths nor were there major complications attributable to the preoperative treatment. Two-year survival was 33%, only slightly better than that previously achieved by us with either primary surgery or primary external beam radiation among "curative" candidates with locoregional disease. HDR in combination with our selected chemotherapy regimen is insufficient for locoregional control and must be supplemented either by esophagectomy or external beam radiation for even modest long-term survival.
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PMID:High dose rate intraluminal radiation in a combined modality treatment plan for carcinoma of the esophagus. 844 Dec 72

This paper describes a new type of applicator system for the intracavitary radiothermotherapy of gynaecological tumours. Hyperthermia and radiation can be delivered by one and the same applicator. The hyperthermia is delivered by a modified capacitive heating technique (27.12 MHz) combined with cooling systems, the radiation by the numerically controlled oscillation of a gamma source on the inside of the main applicator, the RF gamma applicator (HDR afterloading technique). Isotherms and isodoses can be adapted to the anatomical-pathological situation. Interactions between the applicator system and the surrounding tissue were investigated in a theoretical model (FEM). Complex two-dimensional SAR calculations as well as three-dimensional temperature calculations were carried out. The RF gamma applicator was also examined by thermography; the thermography proved the theoretical modelling to be correct. The applicators were also tested in animal experiments.
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PMID:Theoretical and experimental investigations of a newly developed intracavitary applicator system for the radiothermotherapy of gynaecological tumours. 851 48

Between 1984 and 1992, 27 patients with clinical stage I-II histologically proven adenocarcinoma of the endometrium who had significant medical risks precluding surgery underwent radiotherapy (RT) as the primary treatment. The median age at diagnosis was 74 years. There were 20 patients (74%) with stage I and 7 patients (26%) with stage II disease. Patients were treated with high-dose-rate brachytherapy (HDRB) alone (19/27) or with a combination of external-beam RT and HDRB (2 stage I; 6 stage II). HDRB was delivered using a cobalt-60 HDR remote afterloading unit, with a median dose of 2000 cGy to point A, in two to three fractions given once a week. All HDRB treatments were performed under spinal anesthesia on an outpatient basis. External-beam irradiation to the pelvis was given using 4- to 6-MV photons and a median dose of 4200 cGy was delivered. In all patients, vaginal bleeding was controlled within a few days after completion of RT. With a median follow-up of 47 months, the 8-year disease-specific survival rate was 76%. Patients with stage I had an 8-year survival rate superior to that of patients with stage II (95% vs 21%, P < 0.001). No complications were experienced during HDRB. Late serious complications were seen in 3 patients (11%). Based on this retrospective review, primary RT with HDRB appears to be an effective and safe treatment for those patients with medically inoperable clinical stage I endometrial carcinoma. Because HDRB is given on an outpatient basis, it is an attractive option for these patients. However, in stage II disease the results of treatment are poor and RT alone should be considered only when the surgical risks are too high.
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PMID:High-dose-rate brachytherapy as the primary treatment of medically inoperable stage I-II endometrial carcinoma. 852 57

For precise localization of the center and determination of the dimensions of the radioactive material within the capsule of brachytherapy sources, we have developed a method based on simultaneous pin-hole autoradiography of two sources. We constructed a variable magnification pin-hole camera consisting of two telescopically fitted Plexiglas cylinders which can accommodate two radioactive sources on the plate covering the top cylinder. The 192Ir pulsed and high dose-rate sources were studied and an 192Ir seed was used as a reference source. The magnification factor was determined from the dimensions of the 192Ir seed image, which was geometrically well defined by a separate transmission radiography experiment. The observed position for the center of radioactivity in the PDR and the HDR source capsules are in agreement with the vendor specifications. The distance from the tip of the PDR capsule to its center of radioactivity was found in this way to be 0.79 +/- 0.21 mm, which agrees with the position (0.85 mm) of the pellet situated closer to the tip as specified by the vendor. Quantitative verification of the internal source structure using this method enhances the accuracy with which the dose distribution near brachytherapy sources can be predicted by three-dimensional Monte Carlo calculations.
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PMID:Quantitative verification of 192Ir PDR and HDR source structure by pin-hole autoradiography. 858 29

The results are reported of HDR intracavitary brachytherapy in 134 esophageal carcinoma patients (110 men and 24 women) treated in 10 Italian centers. Forty-one patients received radical treatment and brachytherapy was often combined with external irradiation and/or chemotherapy. Clinical response rates follow: 56% complete remissions, 34% partial remissions, 10% no response/disease progression and not assessed. Ninety-three patients underwent palliative treatment: dysphagia was reduced in 80% of them and pain was reduced in 71% of them. Treatment-induced esophageal damage consisted in G3-G4 esophagitis (5% of patients), strictures (10%) and fistulas (3%). Complication rates were correlated with fraction dose (9.5% complications for fraction doses < 500 cGy, 20% with doses ranging 500-800 cGy and 38% with fraction doses > 800 cGy). Moreover, the esophagus was more severely injured when small tubes were used (24% with tubes phi < 2 mm, 19% with tubes phi 2-6 mm and 5% with tubes phi > 6 mm). When external irradiation was combined with brachytherapy, dysphagia was more relieved than with brachytherapy alone (89% vs. 71%), with no increase in complication rates. Also the chemotherapy-brachytherapy combination improved swallowing more than brachytherapy alone (88% vs. 79%) and once again complication rates did not increase. To conclude, in the radical treatment of esophageal carcinoma, HDR brachytherapy permits higher radiation doses to be delivered, with fair complication rates. As for palliative treatment, HDR brachytherapy is safe, has low morbidity and provides adequate relief of dysphagia in 80% of patients. We suggest the use of tubes phi > 6 mm and fraction doses ranging 5-6 Gy.
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PMID:[High-dose-rate brachytherapy in esophageal carcinoma: the Italian experience]. 861 12

The induction of neoplastic transformation by exposure to high (HDR, 0.66 Gy/min) or very low (LDR, 4.8 x 10(-4) Gy/min) dose rates of 137Cs gamma-rays was studied in C3H/10T1/2 mouse embryo fibroblasts. Cells in stationary phase were exposed in the dose range 1-6 Gy in combination with a post-irradiation treatment with the tumor promoter, 12-O-tetradecanoylphorbol-13-acetate (TPA). The post-irradiation treatment with TPA during 6 weeks of transformation assay did not induce any notable increase in the slope of the dose response curves for transformation frequency, compared to the conditions without TPA treatment. The lack of an enhancing TPA effect at both dose rates applied in this study may be related to the fact that the cells were irradiated in the stationary growth phase. Thus, the results differ from those generally obtained when exponentially growing cells are exposed to gamma-rays and afterwards treated with TPA in the transformation assay. Earlier studies of exponentially growing C3H/10T1/2 cells exposed to different dose rates show a significantly higher transformation frequency for high dose rate. This study, using stationary phase cells, also shows that the slopes of dose response curves for transformed foci were somewhat higher (about 1.5-fold) for HDR exposure compared with LDR exposure. However, the difference was not statistically significant.
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PMID:Radiation-induced neoplastic transformation of stationary phase C3H/10T1/2 cells in response to different dose rates and to post-irradiation treatment with tumor promoter. 866 19

Four hundred and six patients with primary non-small cell carcinoma of the bronchus causing symptoms due to endobronchial disease, were treated with intraluminal radiotherapy (ILT) using the microSelectron-HDR machine at the Christie Hospital, Manchester, between April 1988 and the end of 1992. An assessment of morbidity for this treatment is presented, particularly with regard to the risk factors and causes of massive haemoptysis death. The most common early side-effect was a mild transient exacerbation of cough which usually resolved within 2-3 weeks. At various times following ILT treatment 83 bronchoscopies were carried out randomly in 55 patients. In bronchoscopies carried out within the first 3 months following ILT, no tumour was visible in 80% of cases. A mucosal radiation reaction score (RRS) was used to grade bronchoscopic appearance after ILT treatment. Overall, 55% of bronchoscopic examinations showed some degree of mucosal radiation reaction. The majority of radiation reactions from 6 months onwards after ILT demonstrated a degree of fibrosis. A radiation reaction was seen more frequently after treatment with 2000 cGy as opposed to 1500 cGy at 1 cm from the central axis of the radiation source. Thirty-two patients were identified who had died from massive haemoptysis (MH) as a terminal event. A Cox multivariate regression analysis showed that the treatment-related factors of increased dose at first ILT (P = 0.004), prior laser treatment at the site of ILT (P = 0.020) and second ILT treatment in the same location as the first ILT treatment (P = 0.047), all significantly increased the relative risk of MH death compared with their effect on the relative risk of death from other causes (OC). (In addition a fourth treatment-related factor, namely the concurrent use of ILT and external beam radiotherapy (EB) had a P value of 0.08). Twenty out of 25 assessable MH-death patients (80%) had evidence of recurrent or residual tumour before death but 5 patients (20%) did not. For surviving patients the instantancious risk of death at any one time (the cause-specific death rate expressed as deaths per 100 cases per month), showed a sharp peak for MH deaths between 9 and 12 months post ILT in contradistinction to OC death where the peak was between 3 and 6 months post ILT. These findings may imply a role for late radiation reaction in the treatment-related risk factors identified as increasing the relative risk of MH death and possible mechanisms are discussed. The results have implications for treatment regimes that use a dose of 2000 cGy at 1 cm in a single fraction technique, that have a high frequency of previous laser treatment, that use multiple, repeated ILT treatments in the same location and that use ILT concurrently with EB.
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PMID:Massive haemoptysis death and other morbidity associated with high dose rate intraluminal radiotherapy for carcinoma of the bronchus. 873 77


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