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Biomedical subjects

J W Somers

Publications and source records attributed to J W Somers.

5 recordsLinked to original sources
PubMed1984

Radiation exposure during fluoroscopically controlled percutaneous lithotripsy.

Radiation measurements in the vicinity of a standard urologic table modified for fluoroscopic-guided lithotripsy demonstrate radiation levels as high as 3000 mrem per hour at the edge of the table. Excessive radiation exposure to the physician, exceeding the annual maximum permissible dose to the eyes and thyroid, can be expected after only 10 cases. Suggested radiation protection measures include the use of finger, wrist and neck radiation monitors, eye and thyroid shields and improved shielding of both collimator and patient scatter radiation.

Fluoroscopy↗
PubMedDate not supplied

Measurement of the effect of inhomogeneities and compensating bolus in clinical pion beams.

Measurement of the effects of Telfon and air inhomogeneities on the ionization distributions of clinical negative-pion beams have been made at the Los Alamos Meson Physics Facility. Inhomogeneity location and pion-beam energy vary the effect of multiple coulomb scattering on the dose distribution lying in the penumbra of the inhomogeneity. CH2 bolus adequately corrects for the effects of these inhomogeneities. Bolus misalignment less than 0.5 cm does not seem critical because of large multiple coulomb scattering of the pion beam. However, this and secondary particles emitted from pion stars prevent the pion beam from being precisely shaped with sharp edges, as demonstrated by measurements under a patient bolus.

Elementary Particles↗
PubMedDate not supplied

Computer interface for a linear accelerator.

A computer interface for the Clinac-18 linear accelerator has been developed, using a standard CAMAC interface plus buffer amplifiers to isolate the CAMAC from the accelerator electronics. Buffer amplifiers are employed because direct connection of the CAMAC system to the accelerator was found to affect accelerator operation. The total interface accommodates the four gantry position analog signals and thirteen digital signals describing all available treatment options. The interface also allows the computer to inhibit beam operation.

Computers↗