RESUMEN
An extrapolation chamber of type Böhm 23392, used for the dosimetry of RQR beam qualities at the Secondary Standard Dosimetry Laboratory of King Faisal Specialist Hospital, is presented. A computer-based motorized system consisting of a stepping motor coupled to the chamber's built-in micrometer screw was designed to expedite the measurements process, giving a linear relationship between the number of motor steps and the chamber depth with a Coefficient of Determination (COD) equal to 0.9990. The extrapolation chamber along with the motorized system was used to determine the extrapolation curves. The slope of the extrapolation curves, measured for the eight RQR beam qualities with a relative uncertainty between 0.17% and 0.58%, varies linearly with the beam quality expressed in terms of HVL, with a COD between 0.9995 and 1.0000.
RESUMEN
We report a case of idiopathic membranoproliferative glomerulonephritis (MPGN) recurring 2 years after a living-unrelated kidney transplantation. The disease was refractory to intravenous immunoglobulin and plasmapheresis. Treatment with 2 doses of rituximab resulted in remission of the disease. The disease relapsed 18 months later after an episode of cytomegalovirus pneumonitis. After treatment of the pneumonitis, a lung biopsy was performed owing to persistent chest symptoms, which revealed bronchiolitis obliterans with organizing pneumonia. Bone marrow examination and culture revealed presence of acid-fast bacilli, and culture grew Mycobacterium tuberculosis. A repeated course of rituximab was withheld because of infection with tuberculosis, the patient's chest symptoms, and rare reports of noninfectious lung disease after the use of rituximab. The patient continues to have proteinuria with impaired kidney function.
