The effect of high kilovoltage on hard and soft tissue definition in lateral cephalometric roentgenograms

• Published in: American journal of orthodontics Vol. 40; no. 11; pp. 837 - 849
• Main Author: Franklin, J.B.
• Format: Journal Article
• Language: English
• Published: Elsevier Science (USA) 01.01.1954
• ISSN: 0002-9416; 1557-8488
• DOI: 10.1016/0002-9416(54)90079-2

1. 1. The conventional radiation exposure technique (that is, 60 KVP, 20 Ma. for two and one-half seconds in cephalometric roentgenography) does not result, usually, in good soft tissue definition. 2. 2. Matter is composed of an element or combination of elements. Elements are composed of molecules and atoms. Molecules are composed of atoms. Atoms are composed of positively charged nuclei and negatively charged electrons. 3. 3. The electron is the smallest known particle in the universe, and the smallest unit of an electric current. Bodies, compounds, or elements, when charged with electricity or heated, emit electrons. A stream of electrons, also called cathode rays, generated in the x-ray tube, produces a form of energy upon bombardment of the opposite electrode, the anode. The form of energy is mostly heat and less than 2 per cent roentgen rays (x-rays). 4. 4. Roentgen rays are invisible and have the speed of light or electricity. Roentgen rays are characterized by their intensity and by their wave length. Intensity designates quantity of radiant energy, while wave length describes quality. In general, short wave lengths are more penetrating than long wave lengths. 5. 5. A x-ray machine more powerful than a dental x-ray machine is desirable. An x-ray should be so calibrated that the operator can manually control the milliamperage and kilovoltage. Such control is usually not incorporated in a dental x-ray machine. 6. 6. Milliamperage and kilovoltage are important factors in x-ray radiation. The milliamperage determines the density or blackness of a film. Kilovoltage brings out the contrast between hard and soft tissues. Milliamperage is the dangerous factor in x-ray radiation and should be reduced wherever feasible. The higher the kilovoltage, the greater the penetration. 7. 7. A high kilovoltage and a very low milliampere-second technique results in a better definition of soft tissues, at the same time retaining good hard tissue rendition. With this exposure factor there is a great reduction in exposure time and x-ray radiation hazard to both patient and operator. 8. 8. In this preliminary report the suggested high kilovoltage standardized technique for cephalometric roentgenography using focal-midline cephalostat distance of 60 inches, the exposure radiation factor in 90 KVP, 20 Ma. for 3 10 second for all orthodontic subjects, regardless of age. There seems to be very little difference in film densities of all anatomic landmarks at various age levels. 9. 9. More clinical experimentation is indicated to further improve this high kilovoltage technique. At the present time I am carrying on further investigations with the use of aluminum filters.