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PubMed1990

[Fractionated radiation and thermal-radiation actions on transplantable tumors].

The paper is concerned with the results of fractionated thermal-radiation action on Brown-Pearce tumor in rabbits, sarcoma-37 (C-37) and Lewis carcinoma (LLC) in outbred and hybrid F1 (C57B1/6 x CBA) mice. Rabbit tumors were subjected to hyperthermia on UHF Plot units 4 h after irradiation, and in mice with a water-bath directly before irradiation. The frequency of Brown-Pearce tumor regression was increased as a result of hyperthermia in 4 h. The comparison of the effectiveness of fractionated radiation or thermal-radiation action on murine tumors (2 of 3 fractions for 4 days) indicated different type changes of the value of the coefficient of thermal enhancement of hyperthermia. For C-37 it was decreased with an increase in the number of fractions, for LLC it was increased, probably as a result of reoxygenation and high radiosensitivity of C-37.

Animals↗

PubMed1990

[The results of the radiation treatment of cervical cancer using low, sensitizing doses of radiation].

Combined radiation treatment for cervical cancer is associated with radiation injury to the intestine, bladder, hemopoietic system and suppression of T-system, nonspecific immunity and thyroid function. Modified gamma-ray teletherapy was suggested which included low-dose (0.1 Gy) sensitizing irradiation of tumor and zones of regional dissemination prior to delivering therapeutic dose (1.9 Gy). The procedure assured lower incidence of radiation-induced reactions and complications, leukopenia and T-lymphocyte function suppression, stimulated nonspecific resistance and thyrotropic function of the pituitary, and provided normal function of the thyroid. As a result, five-year survival rate in patients with stage III cancer increased by 14%.

Adult↗

PubMed1989

Dose delivered by secondary electrons radiated by metallic objects implanted in human tissue during radiation therapy using high energy photons.

This abstract summarizes the results of a research project undertaken during 1983 to 1985 to evaluate the dose to the surrounding tissue contributed by secondary electrons originating from metallic surgical sutures and total hip prosthesis implanted in human tissue, upon interaction with high energy photons during radiation therapy. To date, no such work, has been undertaken on metallic prostheses or sutures but the effect of breast prosthesis made of silicone gel, during radiation therapy with high energy photons and electrons has been reported in two research papers. In this investigation, film and TLD methods of dosimetry are used to evaluate the dose due to these secondary electrons in a polystyrene phantom. Two types of films are used: they are Dupont 7L and Dupont 6 PLUS. Calibrated beams of X-ray photons of 4 MeV and electrons of 8.6 MeV energy are used as the sources of X-ray photons and electrons. The difference in optical density with film and the difference in response in the case of TLDs with and without the metallic objects is a measure of the dose contributes by the secondary electrons. This dose is taken off from the corresponding calibration curves for film and TLDs and this dose varies from 2.5% to 6.72% to soft tissue and the dose to bone varies from 4% to 12% approximately. In certain clinical situations, this amount of dose could be quite significant. Knowing such contribution, a more effective course of radiation therapy can be planned.

Electrons↗

PubMed1987

[Increased radiation reactions of the efferent urinary system following gynecologic radiation therapy. Incidence, prevention and therapy].

Basing on the newer literature and own experiences a survey is given concerning radiation reactions occasionally to be seen with kidney, ureter, urinary bladder and urethra in connection with the radiation therapy in gynecology. Hints are given to prophylaxis and therapy of these radiation reactions with special emphasis of the treatment with instillation solutions in case of raised reactions of the urinary bladder.

Female↗

PubMed1985

[Lumbar radiation myelopathy. Case report on localization of lumbar radiation sequelae].

The case of a patient with a radiation lesion of the lumbosacral cord following prophylactic radiation therapy of the paraortic lymph nodes for seminoma is reported. Seven months after radiotherapy he suffered from a pure anterior cell syndrome, followed by a loss of pain and temperature sensation. Ten years later he developed a complete transversal syndrome at the level of L 1. This case indicates the existence of a lumbar radiation myelopathy caused by a lesion at the level of the conus medullaris.

Adult↗

PubMed1978

[Measurement of the radiation load to bladder and rectum in gynecological brachytherapy with a mobile radiation source (author's transl)].

Measurement of the maximal radiation dose in bladder and rectum in intravaginal radiation therapy using a mobile source (afterloading technique) is only possible integrating with a multichannel dosimeter. For this purpose we apply a 5 mm plastic probe being equipped with five semiconductor dosimeter crystals; the latter are fixed within the probe at equidistances of 2 cm from each other. The dose maximum can be obtained by graphic interpolation using the five different values measured. The dosimeter employed is read immediately and permits observation of the doses delivered to the bladder and rectum during radiation therapy.

Female↗

PubMed1980

[The difference between delayed radiation-necroses of the cerebral hemispheres and midline: its bearing in radiation therapy (author's transl)].

Delayed cerebral necroses after irradiation are to be divided into hemispheric and midline lesions, as they differ from each other in sesveral aspects. Apart from the symptoms, they are differing in the duration of latency, in the course and prognosis, and also with regard to morphology. Though there is no doubt that radiation tolerance of cerebral midline structures is relatively limited, on biological grounds, evidence of a difference between the tolerated doses could not be given from the existent inhomogeneous radiation data, with the help of the NSD-concept. Radiation planning for the region of the head, nevertheless, carefully should avoid in every case to involve the structures of the cerebral midline.

Brain↗

PubMed1994

Ionizing radiation causes greater DNA base damage in radiation-sensitive mutant M10 cells than in parent mouse lymphoma L5178Y cells.

DNA base damage in radiation-sensitive mutant M10 cells and parent mouse lymphoma L5178Y cells was studied. Cells were exposed to ionizing radiation in the dose range of 48 to 400 Gy. Chromatin was isolated from cells and analyzed by gas chromatography-mass spectrometry. Ten DNA base products were identified and quantified. A dose-dependent formation of the products was observed. The yields of products in M10 cells were up to threefold greater than in L5178Y cells. Of the products measured, formamidopyrimidines had the highest difference in their yields between the two cell lines. The greater initial DNA base damage in M10 cells may play a role in their hypersensitivity to ionizing radiation.

Animals↗

PubMed1994

[A juvenile case of radiation-induced meningioma two years after radiation for craniopharyngioma].

The patient was a 7-year-old boy who received radiation therapy of 50 Gy after total gross removal of a craniopharyngioma. After two years a follow up CT scan showed a new enhanced lesion in the right temporal tip within the previous irradiation field. Total removal of the tumor was performed and its histological examination showed it to be an atypical meningioma. This atypical meningioma satisfied Cahan's criteria. So we diagnosed this atypical meningioma as radiation-induced meningioma. Immunohistochemically this meningioma stained for Vimentin. An electron-microscopical examination showed neither desmosome nor interdigitation. The score of Ki-67 and BrdU-L. I. was very small. Compared with previously reported juvenile radiation-induced meningioma, the latency was very short. The patient received growth hormone (GH) replacement therapy. We suspected relation between GH replacement therapy and short latency. He was discharged without any new neurological deficits and we haven't detected tumor recurrence for two years.

Child↗

PubMed1996

[Radiation burden in invasive cardiac diagnosis: extent, factors of influence and references for minimizing radiation dosage].

Despite great effort concerning quality control in diagnostic radiology, there exist only a few studies giving reliable details about x-ray exposure during heart-catheterization. The mean radiation dose-area product of 100 patients (male 65%, middle-aged 60.7 +/- 10.4 years) investigated was irrespective the technique according to Sones or Judkins 45.2 +/- 14.7 Sv x cm2. In comparison to an optimated x-ray chest the local x-ray entrance-expositions in case of changing (90 mSv) and constant (300 mSv) projections were 300- and 1000-fold respectively. Concerning the dose-area product and the effective dose the multiplicative factor reached 160 and 100 respectively. Radiation entrance-exposure during cinematography was 15-fold as during x-ray-examination sequences. The cinematographic radiation dose was influenced significantly by location of the contrasted coronary artery (p < 0.001) and plane of projection (p < 0.001): intensive in entrance surface dose were projections x-raying spinal column and sternum (RCA in PA- and LCA in LAO-projection). Independent variables were body mass index (BMI, p < 0.001) and sex (p < 0.005), but not age. X-ray-dose of heart catheterization was lower in women than in men, this fact being only significant in the elderly (> 60 years), indicating an effect of postmenopausal osteoporosis. An effective minimization of x-ray exposition in heart catheterization can be realized by avoiding needless cine-sequences (25-35%), rotating out bone structures of the x-ray beam ( < or = 22%) and reduction of overweight (BMI 35 > 23 kg/m2: 25-35%).

Aged↗

PubMedDate not supplied

[Current methods of radiation therapy in patients with prostatic cancer: subtotal body radiation, local hyperthermia].

The paper deals with the preliminary data of treatment of patients with prostatic cancer by using unconventional methods of radiation therapy (RT), such as subtotal radiation of the body (STRB) and thermoradiation treatment (TRT). Out of 72 patients receiving RT, 16 and 8 had STRB and TRT, respectively. Systemic and local drug therapies were made to prevent radiation reactions and injuries. In all cases, STRB and TRT showed a significant objective and subjective effect. To evaluate the long-term results of treatment needs further studies.

Aged↗

PubMed2006

Aircraft crew radiation workplaces: comparison of measured and calculated ambient dose equivalent rate data using the EURADOS in-flight radiation data base.

In May 2000, the chairman of the European Radiation Dosimetry Group (EURADOS) invited a number of experts with experience of cosmic radiation dosimetry to form a working group (WG 5) on aircraft crew dosimetry. Three observers from the Article 31 Group of Experts as well as one observer from the Joint Aviation Authorities (JAA) were also appointed. The European Commission funded the meetings. Full meetings were organised in January 2001 and in November 2001. An editorial group, who are the authors of this publication, started late in 2002 to finalise a draft report, which was submitted to the Article 31 Group of Experts in June 2003. The methods and data reported are the product of the work of 26 research institutes from the EU, USA and Canada. Some of the work was supported by contracts with the European Commission, Directorate General XII, Science, Research and Development. A first overview of the EC report was published late in 2004. In this publication we focus on a comparison of measured and calculated ambient dose rate data using the EURADOS In-Flight Data Base. The evaluation of results obtained by different methods and groups, and comparison of measurement results and the results of calculations were performed in terms of the operational quantity ambient dose equivalent, H*(10). Aspects of measurement uncertainty are reported also. The paper discusses the estimation of annual doses for given flight hours and gives an outline of further research needed in the field of aircraft crew dosimetry, such as the influence of solar particle events.

Aerospace Medicine↗

PubMed1997

Radiation dosimetry measurements with real time radiation monitoring device (RRMD)-II in Space Shuttle STS-79.

The real-time measurement of radiation environment was made with an improved real-time radiation monitoring device (RRMD)-II onboard Space Shuttle STS-79 (S/MM#4: 4th Shuttle MIR Mission, at an inclination angle of 51.6 degrees and an altitude of 250-400km) for 199 h during 17-25 September, 1996. The observation of the detector covered the linear energy transfer (LET) range of 3.5-6000 keV/micrometer. The Shuttle orbital profile in this mission was equivalent to that of the currently planned Space Station, and provided an opportunity to investigate variations in count rate and dose equivalent rate depending on altitude, longitude, and latitude in detail. Particle count rate and dose equivalent rate were mapped geographically during the mission. Based on the map of count rate, an analysis was made by dividing whole region into three regions: South Atlantic Anomaly (SAA) region, high latitude region and other regions. The averaged absorbed dose rate during the mission was 39.3 microGy/day for a LET range of 3.5-6000 keV/micrometer. The corresponding average dose equivalent rates during the mission are estimated to be 293 microSv/day with quality factors from International Commission on Radiological Protection (ICRP)-Pub. 60 and 270 microSv/day with quality factors from ICRP-Pub. 26. The effective quality factors for ICRP-Pub. 60 and 26 are 7.45 and 6.88, respectively. From the present data for particles of LET > 3.5keV/micrometer, we conclude that the average dose equivalent rate is dominated by the contribution of galactic cosmic ray (GCR) particles. The dose-detector depth dependence was also investigated.

Aerospace Medicine↗

PubMed2005

Adjustment of guidelines for exposure of the eye to optical radiation from ocular instruments: statement from a task group of the International Commission on Non-Ionizing Radiation Protection (ICNIRP).

A variety of optical and electro-optical instruments are used for both diagnostic and therapeutic applications to the human eye. These generally expose ocular structures to either coherent or incoherent optical radiation (ultraviolet, visible, or infrared radiation) under unique conditions. We convert both laser and incoherent exposure guidelines derived for normal exposure conditions to the application of ophthalmic sources.

Eye Injuries↗

PubMed1999

Protection of the public in situations of prolonged radiation exposure. The application of the Commission's system of radiological protection to controllable radiation exposure due to natural sources and long-lived radioactive residues.

This report provides guidance on the application of the ICRP system of radiological protection to prolonged exposure situations affecting members of the public. It addresses the general application of the Commission's system to the control of prolonged exposures resulting from practices and to the undertaking of interventions in prolonged exposure situations. Additionally, it provides recommendations on generic reference levels for such interventions. The report also considers some specific situations and discusses a number of issues that have been of concern, namely: natural radiation sources that may give rise to high doses; the restoration and rehabilitation of sites where human activities involving radioactive substances have been carried out; the return to 'normality' following an accident that has released radioactive substances to the environment; and the global marketing of commodities for public consumption that contain radioactive substances. Annexes provide some examples of prolonged exposure situations and discuss the radiological protection quantities, radiation-induced health effects and aspects of the Commission's system of radiological protection relevant to prolonged exposure. Quantitative recommendations for prolonged exposures are provided in the report. They must be interpreted with extreme caution; Chapters 4 and 5 stress the upper bound nature of the following values: Generic reference levels for intervention, in terms of existing total annual doses, are given as < approximately 100 mSv, above which intervention is almost always justifiable (situations for which the annual dose threshold for deterministic effects in relevant organs is exceeded will almost always require intervention), and < approximately 10 mSv, below which intervention is not likely to be justifiable (and above which it may be necessary). Intervention exemption levels for commodities, especially building materials, are expressed as an additional annual dose of approximately 1 mSv. The dose limit for exposures of the public from practices is expressed as aggregated (prolonged and transitory) additional annual doses from all relevant practices of 1 mSv. Dose constraints for sources within practices are expressed as an additional annual dose lower than 1 mSv (e.g. of approximately 0.3 mSv), which could be approximately 0.1 mSv for the prolonged exposure component. An exemption level for practices is expressed as an additional annual dose of approximately 0.01 mSv.

Cosmic Radiation↗

PubMed1990

Cellular radiation dosimetry and its implications for estimation of radiation risks. Illustrative results with technetium 99m-labeled microspheres and macroaggregates.

Radiation absorbed doses at the cellular level were calculated for routine, human lung perfusion examinations after the intravenous injection of technetium 99m-labeled microspheres or macroaggregated albumin. In such studies, more than 90% of these particles are trapped in the precapillary arterioles of the lung, resulting in an extremely inhomogeneous distribution of radionuclide. We used a computer program that accounted for the inhomogeneity of radiopharmaceutical distribution and calculated the dose to individual lung cells. Absorbed doses to individual lung cells were found to vary by a factor of about 30,000. We believe that such findings call for a reevaluation of the justification for dosimetry at the organ level and an examination of the implications of absorbed doses calculated at the cellular level for the estimation of radiation risks.

Dose-Response Relationship, Radiation↗

PubMed2006

Prediction of radiation-induced changes in the lung after stereotactic body radiation therapy of non-small-cell lung cancer.

PURPOSE: To estimate the risk of radiation-induced changes in the lung before single-dose treatment (stereotactic body radiation therapy [SBRT]) of lung cancer, the quantitative dose-response and volume-response relations must be known. METHODS AND MATERIALS: A total of 64 patients treated for non-small-cell lung cancer with single doses of 20-30 Gy were classified according to the occurrence or nonoccurrence of perifocal changes in the lung detected by CT. Patients without toxic events in the lung were required to have >or=6 months of follow-up. The mean dose (D(mean)) in the ipsilateral lung and the volume receiving >7 or 10 Gy (V7 and V10, respectively) were used to calculate the dose-response and volume-response curves. The predictive value of additional variables was also investigated. RESULTS: Of the 64 patients, 83% exhibited the selected endpoint. The tolerance values at a 50% probability of toxic events were 1.2 +/- 0.7 Gy for the D(mean) and 5.8 +/- 3.0% and 3.1 +/- 2.0% for V7 and V10, respectively. A nonsignificant shift to higher doses was seen for the dose-response curve for the upper compared with the lower part of the lung. CONCLUSION: The D(mean), V7, and V10 can be used to predict the risk of lung toxicity after SBRT treatment of non-small-cell lung cancer. Because of the lack of patients with low prescribed doses, however, the related uncertainty of this prediction is still relatively large. The D(mean), V7, and V10 are equally well suited. The additional investigated variables did not provide significant advantages. The lower part of the lung appears to be more radiosensitive than the upper.

Adult↗

PubMed2005

Radiation exposure at ground level by secondary cosmic radiation.

The contribution of the charged component of secondary cosmic radiation to the ambient dose equivalent H*(10) at ground level is investigated using the muon detector MUDOS and a TEPC detector surrounded by the coincidence detector CACS to identify charged particles. The ambient dose equivalent rate H*(10)T as measured with the TEPC/CACS is used to calibrate the MUDOS count rate in terms of H*(10). First results from long-term measurements at the PTB reference site for ambient radiation dosimetry are reported. The air pressure corrected dose rate shows, as expected, a strong correlation with the neutron count rate as measured with the Kiel neutron monitor. The measured seasonal variations exhibit a negative correlation with the temperature changes in the upper layers of the atmosphere where the ground level muons are produced.

Atmosphere↗