roentgen ray

roentgen ray

n.

See x-ray.

---

roentgen ray.

See x-ray, def. 1.

---

ray(s),

n a line of light, heat, or other form of radiant energy. A ray is a more or less distinct or isolated portion of radiant energy, whereas the word
rays is a very general term for any form of radiant energy, whether vibratory or particulate.

ray, alpha,

n See particle, alpha.

ray, beta,

n See particle, beta.

ray, cathode,

n See electron stream.

ray, central,

n the center of a radiographic beam.

ray, cosmic,

n radiation that originates outside the earth's atmosphere. Cosmic rays have extremely short wavelengths. They are able to produce ionization as they pass through the air and other matter and are capable of penetrating many feet of material such as lead and rock. The primary cosmic rays probably consist of atomic nuclei (mainly protons), some of which may have energies of the order of 1010 to 1015 eV. Secondary cosmic rays are produced when the primary cosmic rays interact with nuclei and electrons (e.g., in the earth's atmosphere). Secondary cosmic rays consist mainly of mesons, protons, neutrons, electrons, and photons that have less energy than the primary rays. Practically all the primary cosmic rays are absorbed in the upper atmosphere. Almost all cosmic radiation observed at the earth's surface is of the secondary type.

ray, gamma,

n photons with a shorter wavelength than those ordinarily used in diagnostic medical and dental radiography and that originate in the nuclei of atoms. A quantum of electromagnetic radiation emitted by a nucleus as a result of a quantum transition between two energy levels of the nucleus; e.g., as a radioisotope decays, it gives off energy, some of which may be in the form of gamma radiation.

ray, grenz

n roentgen rays that are greater in length than 1 Å; used in radiography of soft tissues, insects, flowers, and microscopic sections of teeth and surrounding tissues. These rays are the result of using approximately 10 to 20 kV in a specially constructed radiation-generating device. They have a wavelength of about 2 Å.

ray, neutron,

n particulate ionizing radiation consisting of neutrons. On impact with nuclei or atoms, neutrons possess enough kinetic energy to set the nuclei or atoms in motion with sufficient velocity to ionize matter or enter into nuclear reactions that result in the emission of ionizing radiation. The former variety is usually called the fast neutron, and the latter the thermoneutron, with gradations of epithermal and slow neutrons between them.

ray, roentgen (r)

n an international unit based on the ability of radiation to ionize air. The exposure to x- or gamma radiation such that the associated corpuscular emission per 0.001293 g of air produces, in air, ions carrying 1 esu of quantity of electricity of either sign (2.083 billion ion pairs).

---

roentgen

a superseded international unit of x- or γ-radiation; it is the quantity of x- or γ-radiation such that the associated corpuscular emission per 0.001293 g of air produces, in air, ions carrying 1 electrostatic unit of electrical charge of either sign. Abbreviated R. Now replaced by coulomb/kg (C/kg); see coulomb. 1 R = 2.58 × 10⁻⁴ C/kg; 1 C/kg = 3876 R.

---

roentgen equivalent man (rem)

see rem.

roentgen equivalent physical (rep)

see rep.

roentgen ray

x-ray.

---

Patient discussion about roentgen ray.

Q. Is an X- Ray dangerous to my fetus? I fell down while I am pregnant and was sent to the ER. I was given an x- ray there, is the radiation dangerous to my fetus?

A. As far as I know one x-ray cannot harm your fetus since there is not enough radiation there to harm it. If you are worried consult a Doctor.

Q. I know that mammogram is required for diagnosis but aren’t they harmful as they use x-rays? My daughter is suspecting her lump on her right breast to be a breast cancer. Though she is not pretty sure but she has her experience of this as one of her friend had breast surgery last year. I know that mammogram is required for diagnosis but aren’t they harmful as they use x-rays?

A. The x-rays used are of low dose which only facilitates the diagnosis of breast cancer but they do not harm any tissues. I know that x-rays can be the cause for cancer if given in high dose. This dose is low and harmless to humans.
http://www.youtube.com/watch?v=jnJH1OlMgr8&eurl=http://www.imedix.com/health_community/vy2kl%5EeOWEtc_nurse_sandy_interview_1_breast_cancer?q=mammogram&feature=player_embedded