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Biomedical subjects

J R Cameron

Publications and source records attributed to J R Cameron.

At least 19 recordsLinked to original sources
PubMed2005

Moderate dose rate ionizing radiation increases longevity.

This paper presents little-known data to support the hypothesis that we need increased background radiation to improve our health. Attention will be drawn to results that demonstrate health benefits of ionizing radiation that have been largely ignored by the news media.

Background Radiation↗
PubMed2003

Adaptive response studies may help choose astronauts for long-term space travel.

Long-term manned exploratory missions are planned for the future. Exposure to high-energy neutrons, protons and high charge and energy particles during a deep space mission, needs protection against the detrimental effects of space radiation. It has been suggested that exposure to unpredictable extremely large solar particle events would kill the astronauts without massive shielding. To reduce this risk to astronauts and to minimize the need for shielding, astronauts with highest significant adaptive responses should be chosen. It has been demonstrated that some humans living in very high natural radiation areas have acquired high adaptive responses to external radiation. Therefore, we suggest that for a deep space mission the adaptive response of all potential crew members be measured and only those with high adaptive response be chosen. We also proclaim that chronic exposure to elevated levels of radiation can considerably decrease radiation susceptibility and better protect astronauts against the unpredictable exposure to sudden and dramatic increase in flux due to solar flares and coronal mass ejections.

Adaptation, Physiological↗
PubMed2002

Is it useful to assess annual effective doses that are less than 100 mSv?

Questions such as 'How small is small?' and 'How low is low enough?' have long plagued radiation dosimetrists and risk management personnel. Unfortunately, our knowledge about the biological effects of low levels of ionising radiation is scarce and uncertain. If we look to the results of epidemiological studies, we find that it is not easy to arrive at firm conclusions. However, some current radiobiological experiments using microbeams of various radiations, along with improved theoretical models of radiation action, may shed new light on the effects of low levels of ionising radiation. What shall we do in the meantime? Both of our debaters agree that monitoring of radiation workers is necessary, yet careful consideration must be given to the rationale for providing personal monitoring. There is no question that we have done a good job of protecting radiation workers for many years, but we also must be aware of the many implications of our efforts.

Adult↗
PubMed2002

Very high background radiation areas of Ramsar, Iran: preliminary biological studies.

People in some areas of Ramsar, a city in northern Iran, receive an annual radiation absorbed dose from background radiation that is up to 260 mSv y(-1), substantially higher than the 20 mSv y(-1) that is permitted for radiation workers. Inhabitants of Ramsar have lived for many generations in these high background areas. Cytogenetic studies show no significant differences between people in the high background compared to people in normal background areas. An in vitro challenge dose of 1.5 Gy of gamma rays was administered to the lymphocytes, which showed significantly reduced frequency for chromosome aberrations of people living in high background compared to those in normal background areas in and near Ramsar. Specifically, inhabitants of high background radiation areas had about 56% the average number of induced chromosomal abnormalities of normal background radiation area inhabitants following this exposure. This suggests that adaptive response might be induced by chronic exposure to natural background radiation as opposed to acute exposure to higher (tens of mGy) levels of radiation in the laboratory. There were no differences in laboratory tests of the immune systems, and no noted differences in hematological alterations between these two groups of people.

Adaptation, Physiological↗
PubMed1999

Symptom control in hospice--state of the art.

There are a myriad of physical symptoms which can complicate the care of patients with advanced disease. Without knowledge of and attention to these distressing symptoms, the rest of the work of the interdisciplinary hospice team is greatly hampered. In this article, we review the management of ten prevalent symptoms in hospice care and to identify areas of clinical investigation underway and point of future areas ripe for investigation.

Depression↗
PubMed1990

Evaluation of a commercial diode monitor for mailed quality control of therapy units.

A commercial diode dosimeter was evaluated for use in a mailed radiotherapy quality control package. The quality control package contained the commercial diode dosimeter and four thermoluminescent dosimeters to measure the given dose, and it also contained a photographic film to measure the light/radiation field coincidence. The film also served as a backup dosimeter. Twenty small Midwestern hospitals participated in field measurements; approximately half of the hospitals had a consulting physicist and the others had one full-time physicist. Each hospital was asked to deliver 1.5 Gy (150 rads) to the device, which was returned to our laboratory for evaluation. Reliable results were obtained from three measurements at each hospital at about 3-month intervals. The diode dosimeter was more precise than thermoluminescent dosimeters or film.

Calibration↗