Safety considerations in the power injection of contrast media via central venous catheters during computed tomographic examinations.

RATIONALE AND OBJECTIVES: This study addresses the theoretical, experimental, and clinical application of using a central venous catheter system (CVS) for the rapid injection of contrast media during computed tomography (CT). METHODS: Application of Poiseuille's law and the Reynolds equation yielded theoretical data. In-line pressures were measured in experimental models and patients undergoing CT. Diatrizoate meglumine and iohexal contrast media were evaluated. RESULTS: The Reynolds number was consistent with laminar flow, allowing the application of Poiseuille's law. The calculated and experimental catheter tubing-chamber connection pressures were safe for both contrast media, at rates of 1 mL/second for long catheter tubing and 2 mL/second for short tubing. Thirteen patients had measured pressures within safety limits with no complications. CONCLUSIONS: This study establishes that power injection of contrast media via a CVS during CT is a safe procedure. Benefits include no need for peripheral intravenous catheter placement, decreased paramedical staff radiation exposure, and improved CT image quality.

Broad beam transmission properties of some common shielding materials for use in diagnostic radiology.

Broad beam geometry was used to measure the x-ray transmission properties of gypsum wallboard, steel, plate glass, and concrete for x-ray tube potentials of 50-125 kVp using an x-ray generator having a three-phase, twelve-pulse waveform and total initial beam filtration sufficient to provide half-value layers representative of those found in common practice and required by regulatory agencies. Measurement results are presented graphically and as numerical fits to a mathematical model of broad beam transmission to permit their use in the design of protective barriers for medical diagnostic x-ray facilities.

Solid tumor models for assessment of different treatment modalities: therapeutic strategy for sequential chemotherapy with radiotherapy.

A therapeutic strategy for combined radiotherapy and chemotherapy of experimental solid tumors has been devised. More effective utilization of combined chemotherapy and radiotherapy may be realized clinically if comparable information is obtained in man. The overall treatment efficiency of successive courses of treatment has been determined by a method that defines tumor response quantitatively over an entire spectrum of tumor responses. The findings of this study have shown that an individual tumor that responds well to the first course of therapy will respond well to the second and third courses of combined modality therapy. Various solid tumors in different animal species have demonstrated variability of response to treatment, analogous to the many types of response found clinically.