Gerald A. Russ

Metabolic studies with radiobismuth. I. Retention and distribution of 206Bi in the normal rat.

The retention of tracer doses of bismuth citrate in mature female rats indicated that there were three compartments which cleared exponentially. Two of these compartments were renal and accounted for 30 percent and 44 percent of the administered dose. The biological half-times of bismuth in these compartments were less than 30 min and 13 hr, respectively. The nonrenal compartment accounted for the remainder of the dose and its retention half-time was 122 hr. The major site of bismuth accumulation was in the kidney. Autoradiographs showed

Distribution of oxygen-15 in the dog at the steady-state.

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The Use of C150 and 1502 Steady-State Imaging to Monitor Radiation Treatment Effects

Bi to be localized in the renal cortex. The kidney is shown to secrete

Regional Imaging with Oxygen-14

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Expression of Tissue Isotope Distribution

Bi into the urine and the renal extraction ratio is in excess of 0.92 for bismuth citrate. Whole-body scans at 24 hr do not reveal any other areas of concentration and demonstrate the applicability of this radionuclide as an imaging agent with conventional equipment. (auth)

Radiation dosimetry of 204Bi- and 206Bi-citrates.

Abstract Severe limitations imposed by rapid decay have not permitted conventional imaging techniques to be applied using the radioactive isotopes of oxygen. This has been overcome by the application of a steady-state procedure in which the agent is delivered to and utilized by the subject at a constant rate. Air, containing 15O2, was administered continuously by inhalation to a normal dog. Levels of activity were monitored over several body regions using external probes. At the steady-state, either regional or whole body imaging was performed. High levels of activity permitted well defined images of the brain, heart, lungs, liver, kidney and testes.

Assessment of labeled 5-fluorouracils for nuclear scintigraphy

Methods for monitoring the response of tumor and normal tissues to radiation therapy are extremely limited. Development of a method for monitoring physiologic parameters of these tissues sensitive enough to provide evidence of tumor regrowth and possibly predicting unacceptable effects upon normal tissues at an early time would be highly desirable. The aim of this preliminary study was to determine if serial C150 and 1502 steady-state images taken before, during and post-radiation therapy would show changes sufficiently large to suggest their application as therapy monitoring methods. A canine with a spontaneous osteosarcoma in the distal tibia was treated with a two week course of cobalt-60 radiotherapy and monitored. The ratio of tumor to contralateral control first increased in both the C150 and 1502 images to 170 and 140%, respectively, and then gradually decreased to 80 and 60% of their initial values by day 39. When venous blood normalized C150 images were subtracted from 1502 images taken on the same day, the decrease at day 39 reached 60%. The large changes observed in this study provides positive evidence that these methods may prove useful as monitors for radiotherapy treatment.

Further Characterization of a Transplantable Murine Osteogenic Sarcoma

The metabolic significance of the distribution of labeled oxygen was studied in the dog by inhalation of gas mixtures labeled with oxygen-14 (T1/2 = 71 seconds) maintained at a constant level of activity. Under steady-state conditions, whole body images were developed by detection of the positron annihilation emissions with a dual head rectilinear scanner in the coincidence mode.