Maximum Permissible Dose Research Articles

Radioactivity in the Diet

An extensive survey is presented of data collected from various sources relating to radionuclides, both naturally occurring and originating from fallout, in diets in different geographic areas of the United States. Data are also provided showing the bone doses of Sr/sup 90/ and thyroid doses of I/sup 131/ and the possible hazards of retained doses to the health of individuals of various age groups are discussed. In general, it is estimated that from 1/3 to 1/2 of the dietary intake of Sr/sup 90/ is from liquid milk, 1/4 from cereals, and 4 to 8% from eggs, fresh meat, and poultry. In general, it appears that the highest daily average intake reported was about 17 Sr units (1 unit = 1 c Sr/sup 90//g Ca) for 1961-62. From assays of Sr/sup 90/ in human vertebrae, it can be seen that the highest value (3.5 Sr units) in the bone in 1961-62 corresponds to about 10 Mrem per year to bone and about 4 Mrem to bone marrow. Monitoring programs indicate that I/sup 131/ levels accumulated during 1961 to a value such that the estimated radiation dose to the thyroid of young children is about 1 1/2 times the annual background frommore » naturally occurring materials, as a national average, and about 5 times the annual background in several areas. There is some evidence that the amounts of I/sup 131/ in human thyroid may be less than the estimates. It also appears that I/sup 131/ is considerably less effective than comparable doses of externally applied x rays in producing thyroid cancer, x rays being from 5 to 15 times as effective as I/sup 131/. The radionuclide maximum permissible doses recommended by the Federal Radiation Council Radiation Protection Guides are discussed, and possible measures for removal of Sr/sup 90/ and I/sup 132/ from milk are outlined. It was concluded, however, that their present levels do not warrant adoption of such measures. (TCO)« less

Ionizing Radiations - The Size of the Problem

The maximum permissible dose of exposure to radiation from non-medical sources was determined for the general public, taking into account exposure to natural and medical sources. A figure was also established for the annual rate of exposure for radiation workers, and a third factor is the maximum permissible body burden of radioactive materials as a source of internal radiation. From these three fundamentals, recommendations, and regulations that govern the industrial, medical, and scientific uses of radiation were constructed. (TCO)

Living with the Atom

The author is professor of international relations at the University of Edinburgh. He was moderator of one of the conferences between scientists and science writers at the University of Chicago in 1960. In the introduction of the book, tribute is paid to Fermi, and individually to the many scientists who preceded him. On those names the author hangs a very concentrated summary of the beginnings of the atomic age. The first chapter concerns public fears and misunderstandings, particularly of the meaning of maximum permissible dose and of quantitative statements in rads and curies; also, the bold assertions by scientists and politicians who are presuming to make judgments in each others' fields. More of this emerges in the next chapter on responsible reporting. Reactors for power and the problems associated with fallout and waste disposal get a chapter each. The resulting injuries to health are then elaborated upon. The chapter on

Plutonium in man and his environment.

S> An investigation was conducted on inhalation as the mode of entry of fall-out Pu into man. Analysis of air filter sanaples collected ia Washington, D. C., in the spring of 1959 gave an average ground-level air concentration of 0.14 dpm/ 100 m/sup 3/, ~1% of the Pu maximum permissible concentration for the general population. Pu analyses were also made on human tissues from the New York metropolitan area and on steer tissues and beef. The results show a high percentage of the maximum permissible dose (0.3 to 0.7%) from Pu in the lungs, pulmonary lymph glands, and gonads and high Pu activities in beef spleen. stewing beef. and fluid extract from stewing beef. It is concluded that inhalation is the main mode of Pu entry into man and that the pulmonary lymph nodes are the critical organ for Pu inhalation. (D.L.C.)

Current concepts in radiation protection. I.

The Federal Council was established in 1959 in order to apply all relevant knowledge to the formulation of decisions about radiation protection standards. In its 1960 report the Council introduced and defined the term Radiation Protection Guide (RPG) to supplement the concepts embraced under the term maximum permissible dose. The RPG's (either in rems or in micrograms of Ra-226) are here tabulated for radiation workers and for the general population. The individual deviations from the average exposure are considered, as are the differences in sensitivity of various organs and differences in the characteristics of such nuclides as Ra-226, I-131, Sr-90, and Sr-89. For each of the latter the observed environmental radioactivity, when compared with the RPG, decides whether the situation calls for confirmatory surveillance, quantitative surveillance, or additional control meas

Cs 137 dose measurements in tissue--II.

The silver phosphate glass dosimetry system was used to measure the beta and gamma radiation dose from Cs/sup 137/ to the testicles, muscle, liver, and kidneys of dogs. The size of the dosimeter rods (1 x 6 mm) permitted surgical placement within the tissues, and use of lucite shields allowed measurement and comparison of the beta and gamma exposure relationships from known amounts of the ingested Tadioactivity. Two groups of dogs were used in the in vivo experiments. One group was given a single meal of Cs/sup 137/ and killed after 28 days. The second group was given the radioactivlty daily for a 56-day period. Blood and muscle blopsles were taken for determination of radioactive concentratlons throughout the exposure periods, and extensive tissue sampling was done at autopsy. The beta -dose to muscle, when calculated from concentration- time data, compared favorably with that measured with dosimeters. It was estimated that gonads would receive a radiation dose of 0.05 to 0.10 rad/ mu c Cs/ sup 137/ ingested when calculated with an exposure time of 1 year. No difference in the delivered radiation dose per microcurie ingested was observed between the two groups. Extrapolation of the dog data to man wasmore » made. It is calcuated from the data that an intake of 80- 160 mu c Cs/sup 137/ would deliver the maximum permissible dose (MPD) of 5 rads/ year. This range spans the 110- 160 mu c Cs/ sup 137/ estimate for standard man computed from NBS Handbook 69 values. (auth)« less

Radiation dose in dental roententgenography, with special reference to enlargement dental radiography.

Dosimetry was used to estimate the radiation dose received by dertal patients and dentists in dental clinics in Japan, and the results were compared with those obtained by an enlargement technique. The phantom of paraffin used for measuring exposure doses was based on a whole-body plaster of panis cast of a Japanese of medium size. The lungs in the phantom were made of cork with a specific gravity of 0.2, and three holes were constructed in the oral cavity, lower abdomen (ovary region), and testicular region for insertion of a dosimeter. Since in most dental clinics in Japan the x-ray apparatus is installed in the corner of the treatment room without any Pb protection, dose distribution of scattered x rays was also surveyed. Four types of x-ray units were used, and measurement was performed at distances 50 to 200 cm at levels of 50 and 100 cm from the floor. The gonads received a dose of about 0.5 to 3 mr per exposure in males, and 0.03 to 1 mr in females. Patients received radiation doses of 10 to l000 mr per exposure at the eye lens, 1500 mr on the nasal apex, and 500 mr on the thyroid region.more » Not less than 100 mr of radiation was distributed in the regions of the pharynx and cervical spine. For dentists holding the film in the patient's mouth, about 1 to 3 r were received per exposure. They also received whole-body irradiation of scattered rays of about 500 to 2000 mr/hr. Since in Japan, even at present, the dentist usually holds the fllm in the patient's mouth during radiography, and if he conducts dental radiography 10 times a day, he should receive 10 to 30 r on his hands a day, or 3000 to 9000 r a year. Furthermore, the dentist standing near the patient is exposed to scattered rays of about 1.4 mr per exposure. Therefore 11 exposures per day give the upper limit of irradiation dose according to maximum permissible dose. The long-cone method, it is suggested, is of value not only for making enlargement radiograms but also for diminishing the exposure dose of dentists since it prevents the production of scattered rays. (BBB)« less

Maximum permissible fluxes of intermediate energy neutrons and their measurements

The maximum and mean doses of neutrons absorbed by human tissue are calculated from data given in the literature over the range from thermal energies to 1 MeV. The results are averaged for the typical 1 E spectrum and for various conditions of irradiation. The maximum permissible dose of intermediate neutrons is 680 n/cm 2/sec. The application of known methods of neutron detection to the dosimetry of intermediate neutrons is considered and it is shown that, with certain reservations, shielded thermal neutron detectors are suitable for this purpose.

Radiation--industry's best understood problem.

Various aspects of detecting and reducing occupational radiation exposure are discussed, with particuiar reference to the uranium-processing industry. The health problems associated with the processing of uranium for reactors involve basic problems: external radiation; internal emitters (airborne radioactive material or ingested material); chemical hazards; and other hazards. The maximum permissible dose for external penetrating radiation is 5 rad/yr; from uranium mines through all the processing plants up to the production of reactor fuel elements, there are no serious difficuities in operating at or below this dose for external penetrating radiation. The maximum permissible dose for soft or relatively nonpenetrating radiation is 30 rad/yr, which does not present a serious problem in the uranium industry. For internal emitters maximum allowable concentrations have also been established for breathing air. However, control of airborne radioactive material is the most serious problem. Other health problems encountered in uranium processing include those involving thermal heat, high- voltage electricity, handling of high-density materials, caustics, and pyrophoricity of the metal. (P.C.H.)

Methods of control of exposure to radiation in factories.

Protective measures are outlined for risks from x and gamma rays and alpha and beta particles. Discussion is given on the maximum permissible dose, principles of protection; personal protection; monltoring, training, and medical control; and practical applications with x and gamma radiography, x-ray fluoroscopy, static eliminators and measuring devices, and storage and transport.

Reduction of radiation hazards in the use of radium and similar sources. I. Radiation hazards and nursing staff.

The International Commission on Radiological Protection has laid down certain maximum permissible doses of radiation and in doing so they have had to consider two risks and three types of population. The risks are: the risk to individual health and the risk to genetic material. The three groups are those occupationally exposed to radiation, those exposed in or near the areas in which radiation is used and the population at large. Nursing staff in a hospital may, according to the circumstances, come into any of these three groups. A properly protected diagnostic X-ray department should present no problem to the nursing staff, since the protection from radiation at all the voltages likely to be applied for diagnostic work can be so efficient that the doses received by any nurse accompanying a patient into the department should be less than the maximum permissible dose for anyone not occupationally exposed. In the radiotherapy department the occupational exposure can also be reduced to a negligible amount in...

Rectal and bladder injuries in relation to radiation dosage in carcinoma of the cervix: A 5 year follow-up

A survey was made of 500 patients with invasive carcinoma of the cervix treated at the Radiumhemmet, who were followed for more than 5 yr with particular attention to the development of radiation injuries. Increased dosage of radiotherapy used on an experimental basls during the time of this study appears to be responsible for improvement in survival rates but was accompanied by a higher rate of injuries. There is a direct correlation between dosage levels in bladder and rectum and injury rate. A dose of more than 5,000 gamma r or a total dose of more than 6,000 r to the rectal mucosa is accompanied by a very high injury rate as is a dose of more than 6,000 gamma r or more than 9,000 total r to the bladder. Because of these results, treatment of carcinoma of the cervix, beginning in 1956, was modified on the basis of direct dosage measurements in the bladder and rectum at the time of treatment. Currently, 4,000 gamma r to an area of more than 2 cm in diameter is considered the maximum permissible dose in the average patient. There is also a correlation between intensity of treatment and injury rate in bothmore » the bladder and rectum. A total of 2,400 gamma r to the rectum in 24 hr is the maximum intensity which is now permitted. Both rectum and bladder injuries are usually transient, with those in the rectum generally occurring sooner than those in the bladder. The incidence of permanent disability due to therapy in this series (1% of patients treated) is very low compared with the overall 5-yr survival rate of 54.5%. (H.H.D.)« less

Aspects of the emission of X-rays from television receivers

The principles involved in x-ray dosimetry are reviewed. The characteristics and limitations of ionization chambers, photographic film, Geiger and proportional counters and scintillation detectors when used for low intensity dose-rate measurement are discussed. A proportional counter is used to study the spectra of x-radiation from cathode ray tubes and rectifiers. The energy response characteristics necessary in a counter for dose rate measurements are given.A proportional counter is used to measure the x-ray dose rates from typical television receiver cathode ray tubes. The radiation level is found to be considerably below the present maximum permissible dose rate. A theoretical treatment of the x-ray spectrum transmitted through a glass envelope shows general agreement with the observed spectra from cathode ray tubes.

An Introduction to Health Physics Measurements

A review is given on: forms of radiation and units of measurement; maximum permissible doses and concentrations of radioactivity, means of detection and monitoring radioactivity, and other general principles of health physics in controlling radiation hazards. (P.C.H.)

Safety and health control of uranium factory.

Health and safety control of a uranium milling factory in Nagoya City, Japan, was conducted for the past 2 years. External irradiation from the uranium ingot was negligible. Concentration of uranium in air was a little increased in the operating room, though variation of radioactivity lay nearly within the range of maximum permissible concentration. Uranium concentration in the waste water of the factory was below the maximum permissible dose. Medical examination, including general physical examination, revealed no new abnormalities as the result of uranium exposure. (Pub. Health Eng. Abstr.)

The radiation hazard from contaminated aircraft.

A study of the relative importance of the external, inhalation, and ingestion hazards associated with surface contamination of aircraft that have penetrated atomic clouds or the stratosphere is described. Experiments were conducted at Operations Redwing and Plumbbob. They included - and helial phagocyt - -aircraft surveys, air sampling, swipe sampling, radiochemical and biological analyses, and personnel dosimetry. The latest maximum permissible total radiation dose limits and the NCRP total organ burdens are interpreted in terms of the aircraft maintenance problem. Curves are drawn to show the maximum permissible concentration of mixed fission products in air as a function of age of the debris assuming a 40-hr work week for both controlled and uncontrolled situations. Similar curves are given for the ingestion hazard. The radiological hazard from external radiation is compared with that presented by inhalation and ingestion. It is found for mixed fission debris on aircraft ranging in age from 1 hr to 1 year that the external radiation hazard is dominant by large factors under all normal working conditions. It is concluded that -surveying is generally adequate to define the radiation problem. Release to uncontrolled areas appears warranted if the average measured -field in potential working areas around themore » aircraft or its parts is less than 0.5 mr/hr regardless of age. Swipe sampling cannot be used to evaluate the local air concentration and thus the inhalation hazard. For mixed fission products on aircraft surfaces swipe sampling is no more reliable than the close helial phagocyt -survey of the surface for estimating the potential ingestion hazard. (auth)« less

The Radiological Health Program in Rensselaer County, N.Y.

A VOID all unnecessary ionizing radiation. With this the objective, the Rensselaer County Health Department in New York State developed over the past 4 years a modest but effective radiological health program. Accomplishment of the objective is attempted by providing advice, guidance, and techiical service in the use of ionizing radiation sources. New York State became actively concerned with the health and safety aspects of ionizing radiation as a result of waste disposition problems of the early Atomic Energy Commission installations in the State. In 1952, the State health and labor departments took a census of shoe-fitting fluoroscopes. Under the then existing regulation 2 of chapter IX of the State Sanitary Code a program was initiated for controlling the specific hazards associated with the use of these machines. (As of July 1, 1958, the New.York State Health Department outlawed the use of the shoe-fitting fluoroscope by unlicensed pra.ctitioners.) Both departments then appointed committees of experts to assist them in a study of the entire ra.diation problem in New York State. The State health department's Advisory Comnmittee conclude.d tha.t there was a sig,nificant and steadily increasing radiation problem in the State and that the health department should prepare to meet this situation. This culminated in June 1954 with the preparation and acceptance by the commissioner of health of a program plan for radiological health. The objectives of this plan were education and training, regula.tion of radiation exposure, enforcement of laws and regulations, and research. A radiological health section was subsequently established in the State department's bureau of environmental sanitation, and chapter XVI was added to the Sanitary Code, effective September 1, 1955, as the basis for a program of inspection, education, and correction. Chapter XVI is intended to control the location or facility where radiation equipment is used or where radioactive material is produced, transported, stored, or used for any purpose. The regulations cover registration of radiation installations with the health officer having jurisdiction, definitions, construction, maintenance and operation, maximum permissible doses, personnel protection, medical examinations, patient protection, disposal of radioactive wastes, radiatioin instruments, handling of cadavers, monitoring of radiation installations, therapy rooms, warning signs, accounting for radioactive materials, radiation illnesses, injuries, emergencies, accidents, electrical hazards, vacated premises, and limitations on application of radiation to humans. The interest of the Rensselaer County Health Department in radiation lhazards was aroused Mr. Lanzillo is a sanitarian with the division of environmental hygiene, Rensselaer County Health Department, N.Y. This paper is a revision of the one he presented at the 55th New York State Annual Health Conference in Lake Placid, N.Y., May 26, 1959.

Human Exposure to Radiation

A review is given on the maximum permissible radiation doses to humans considering both industrial and medical exposures. A comparison of common x-ray exposures is made between various medical examinations. (C.J.G.)

National Committee on Radiation Protection And Measurements

HomeRadiologyVol. 71, No. 1 PreviousNext EditorialNational Committee on Radiation Protection And MeasurementsPublished Online:Jul 1 1958https://doi.org/10.1148/71.1.108MoreSectionsPDF ToolsImage ViewerAdd to favoritesCiteTrack CitationsPermissionsReprints ShareShare onFacebookTwitterLinked In AbstractThe increased uses of radiation in both medicine and industry have resulted in a sharp increase in interest in the work of the National Committee on Radiation Protection and Measurements (NCRP). This committee was activated in 1928 with the concurrence of the various radiological societies in an effort to consolidate our national recommendations for presentation on an international basis. The Committee has been in effective operation since then, ever growing and enlarging its terms of reference as the need arose; at present its recommendations are widely recognized and used in the medical, industrial, military, and related applications of radiation, and have become the principal legal support for the enforcement of radiation protection practices in the United States. Many of the recommendations have also been adopted in principle or in toto by the corresponding international groups dealing with radiation protection and measurements.Sponsorship of the Committee encompasses many interests in the field, including the major radiological societies, the American medical and dental associations, industrial and labor groups, and government agencies interested in atomic energy, public health, and military aspects. The Committee is operated by the National Bureau of Standards as a public service, and its recommendations, prepared as National Bureau of Standards Handbooks, are published and sold by the Superintendent of Documents, Government Printing Office, Washington, D. C. The list of the Committee's recommendations given herewith indicates the wide range of interests covered by its eighteen working groups.This introduction to the NCRP is primarily for the benefit of those who are not familiar with the current work of the group. However, a great number of its current activities are of immediate interest to those concerned with radiation protection and measurements as evidenced by the number of requests for information on forthcoming recommendations, and an effort will therefore be made to describe these activities in more detail than has been available in the past.NOTE: Addenda to H 59 and 60 embodying the revised (1957) maximum permissible dose levels have been issued and are available on request from the National Bureau of Standards, Publications Section, Washington, D. C. An addendum to H 54 is in the process of publication.Revisions of Handbooks 42, 52, 54, 56, 60, and 61 are in preparation; the revision of H 56 (H 65) is expected to become available within the next few months. Announcements will be made as these and new publications are completed.Article HistoryPublished in print: July 1958 FiguresReferencesRelatedDetailsRecommended Articles RSNA Education Exhibits RSNA Case Collection Vol. 71, No. 1 Metrics Altmetric Score PDF download

放射能汚染魚の放射性物質-V

The radioactive elements in the liver of the same big-eyed tuna, reported in the previous paper, have been fractionated with an ionexchage resin (Dowex 50 X 8). In the liver, Mn54, Sr90 and Y90 were confirmed together with the formerly identified nuclides 1-3), such as Zn65, Fe55, 59, Cd113m, 115m, Ba140 and La140 (Fig. 1-9). A new nuclide, Mn54, has never been recognized as a radioactive contaminant, resulting from the atomic bomb tests. The confirmation of S190 was also carried out by the group separation method using carriers. The quantity of radioactive nuclides in 100g of the liver was calculated as follows: Fe55 (Fe59) 0.5 μc, Zn65 0.05 μc, Cd115m (Cd113m) 0.012 μc, Mn54 0.0022 μc, S190 0.002 μc, Y90 0.002 μc and Ba140 and La140 trace (Tab. 1). A special attention should be paid for the presence and amount of Sr90 among these nuclides detected, judging from the maximum permissible dose given by the International Commission On Radiological Protection in 1954.