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Biomedical subjects

L L Doss

Publications and source records attributed to L L Doss.

13 recordsLinked to original sources
PubMed1986

A 192Ir nomogram system for single plane implants.

Nomograms for square planar arrays spanning the range from 3 X 3 cm to 10 X 10 cm were developed. The nomograms are intended to be used for pretreatment planning of implant geometry, so that the therapist may enter the operating room with a plan for the optimal implant in mind. We show that clinically useful implants are those in which the reference isodoses are fully coupled. Decoupling occurs when ribbon spacing exceeds approximately 1.2 cm and leads to undesirable "cold spots" within the treatment volume. Ribbon spacing of 1.0 cm is recommended. This represents a trade-off between adequate ribbon coupling and minimum tissue damage from trocar placement. For clinically useful arrays, the area enclosed by the reference isodose contour (85% of the maximum dose rate) is approximately 50% of the array area. Reference isodose contour and its enclosed area are independent of seed strength for a given array, as long as all seeds within the array are of equal strength.

Brachytherapy↗
PubMed1979

The influence of location of the crossing needle on dose distributions from planar implants.

Three typical planar radium implants with one uncrossed end were investigated for optimization of the crossing needle location. Isodose distributions in a plane 0.5 cm from the plane of the implant were calculated and the sizes and shapes of the areas receiving at least 85% of the maximum dose were evaluated. The merits of each implant geometry are discussed along with certain clinical considerations. As a refinement to the Paterson-Parker rules of geometry, it was found that an optimum distribution is achieved when the crossing needle is located near the physical ends of the parallel needles.

Brachytherapy↗
PubMed1978

Simultaneous extramedullary plasmacytomas of the vagina and vulva: a case report and review of the literature.

An unusual case of simultaneous plasmacytomas of the vagina and vulva is presented along with a review of the literature on urogenital extramedullary plasmacytoma. The diagnosis in this case was obtained by vaginal cytological smear and later confirmed by histological examination of tumor biopsies. Of the four previously reported cases of malignant plasmacytoma of the vagina, one recurred locally and none was associated with metastases. In the case presented, local recurrence as well as multiple osseous metastases occurred.

Adult↗
PubMedDate not supplied

Prevention of ionizing radiation-induced liver microcirculation changes by the use of flow improvers.

Platelet aggregation and adhesiveness, as well as TpO2 responses to hypoxia were measured as microcirculation parameters in beagle dogs subject to Co60 ionizing radiation to a dose of 4600 rads in 5 weeks. Simultaneously, changes in blood chemistry and coagulation were also determined. Marked changes in all studied parameters in the post radiation period lead to the conclusion that the radiation liver damage, which is at least in part mediated through microcirculation disturbances, can be prevented with the flow improver, Rheomacrodex.

Animals↗