silicon and Multiple-Myeloma

To describe a method and evaluate the efficacy of using a p-type silicon diode as an alternative to thermoluminescent dosimeters for verifying the accuracy of total marrow irradiation setups and calculations.. A calibration factor has been measured for a 6 MV photon beam incident horizontally onto a polystyrene phantom inside an in-house built total marrow irradiation stand. Signal responses due to positioning and orientation of the diode with respect to the source were compared to a 0.6 cc cylindrical ionization chamber inside a polystyrene phantom. Procedures for predicting the diode reading and taking entrance measurements have been developed and action levels established to determine causes for discrepancies when ratios between predicted and actual values fell outside a +/- 5% tolerance range. Measurements were taken at the skin surface over the umbilicus calculation point for alternating 1.5 Gy anterior and posterior fractions given bidaily over a 3-day period.. A total of 137 measurements taken from January to September 1994 for 23 patients were analyzed using a frequency histogram. The histogram indicated a mean reading of 1.002 +/- 2.6, and that three of the measurements fell outside the 5% tolerance. Investigation into the cause of the discrepancies showed that the diode had been improperly placed one time and that further patient immobilization needs to be considered.. It is possible to use a diode as an in vivo dosimeter for a total marrow irradiation technique. The ease of implementation and immediate readouts make a diode system preferable to a thermoluminescent system for identifying systematic errors and verifying treatment configurations and monitor unit calculations.

Topics: Bone Marrow; Humans; Immobilization; Multiple Myeloma; Particle Accelerators; Radiotherapy Dosage; Silicon; Transplantation Conditioning

Forty-four patients with progressive symptomatic multiple myeloma were treated with a protocol combining cyclophosphamide (10 mg/kg weekly), procarbazine (2 mg/kg daily), prednisolone (20 mg daily), and either BCNU (1 mg/kg weekly) (BCPP protocol) or MCNU (0.8-1 mg/kg) (MCPP protocol). Of these, 34 patients were treated with the former, and 10 patients with the latter. With BCPP protocol, 12 achieved a complete response, 11 evidenced a 75% response, and 7 displayed a 50% response. With MCPP protocol, on the other hand 2 achieved a complete response, 6 showed a 75% response, and 1 exhibited a 50% response. The median tumor halving time in both groups was 77 days and 57 days respectively. The 5-yr disease-free survival of patients treated with BCPP protocol was 62.0 +/- 10.8%. In MCPP group, 8 of 10 patients are alive with more than 49-87 weeks survival. Although myelotoxicity was moderate, other toxicities were moderate. Toxicity requiring dose modification and discontinuation of the scheduled therapy was observed.

Topics: Aged; Aged, 80 and over; Agranulocytosis; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Carmustine; Cyclophosphamide; Drug Administration Schedule; Drug Evaluation; Female; Fluorouracil; Humans; Male; Middle Aged; Multiple Myeloma; Myeloma Proteins; Nitrosourea Compounds; Prednisolone; Procarbazine; Remission Induction; Silicon; Trimethylsilyl Compounds