y assaying these items in a suitable radioactivity calibration system immediately following completion of administration of all components of the dosimetric step. Calculate and record the dose delivered to the patient by subtracting the residual activity in the syringe and the infusion set components from the activity of Iodine I 131 Tositumomab in the syringe prior to infusion.
Discard all materials used to deliver the Iodine I 131 Tositumomab (e.g., syringes, vials, in-line filter set, extension set and infusion sets) in accordance with local, state, and federal regulations governing radioactive and biohazardous waste.
Determination of Dose for the Therapeutic Step (see Calculation of Iodine-131 Activity for Therapeutic Dose): The method for determining and calculating the patient-specific dose of Iodine-131 activity (mCi) to be administered in the therapeutic step is described below. The derived values obtained in steps 3 and 4 and calculation of the therapeutic dose as described in step 6 may be determined manually [see “Workbook for Dosimetry Methodology and Administration Set-Up”] or calculated automatically using the GlaxoSmithKline proprietary software program [BEXXAR Patient Management Templates]. To receive training and to obtain the “BEXXAR Patient Management Templates” call the BEXXAR Service Center at 1-877-423-9927. For assistance with either manual or automated calculations call the BEXXAR Service Center at 1-877-423-9927.
Following infusion of the Iodine I 131 Tositumomab dosimetric dose, obtain total body gamma camera counts and whole body images at the following timepoints:
a. Within one hour of infusion and prior to urination
Assess biodistribution. If biodistribution is altered, the therapeutic step should not be administered.
Determine total body residence time (see Graph 1, “Determination of Residence Time”, in the “Workbook for Dosimetry Methodology and Administration Set-Up”).
Determine activity hours (see Table 2, “Determination of Activity Hours”, in the “Workbook for Dosimetry Methodology and Administration Set-Up”), according to gender. Use actual patient mass (in kg) or maximum effective mass (in kg) whichever is lower (see Table 1, “Determination of Maximum Effective Mass”, in the “Workbook for Dosimetry Methodology and Administration Set-Up”).
Determine whether the desired total body dose should be reduced (to 65 cGy) due to a platelet count of 100,000 to <150,000 cells/mm3.
Based on the total body residence time and activity hours, calculate the Iodine-131 activity (mCi) to be administered to deliver the therapeutic dose of 65 or 75 cGy.
The following equation is used to calculate the activity of Iodine-131 required for delivery of the desired total body dose of radiation.
Preparation for the Therapeutic Step
Tositumomab Dose
Required materials not supplied:
A. One 50 mL syringe with attached 18-gauge needle (to withdraw 450 mg of Tositumomab from two vials each containing 225 mg Tositumomab)
B. One 50 mL bag of sterile 0.9% Sodium Chloride for Injection, USP
C. One 50 mL syringe for drawing up 32 mL of saline for disposal from the 50 mL bag of sterile 0.9% Sodium Chloride for Injection, USP
Method:
Withdraw and dispose of 32 mL of saline from a 50 mL bag of sterile 0.9% Sodium Chloride for Injection, USP.
Withdraw t
