ion set (Item E) with 0.9% Sodium Chloride from the 50 mL bag of sterile, 0.9% Sodium Chloride for Injection, USP (Item G).
After the flush, disconnect the extension set (Item E), 3-way stopcock (Item F) and syringe. Disconnect the primary IV infusion set (Item B) and in-line filter set (Item A). Determine the combined residual activity of the syringe(s) and infusion set components (stopcock, extension set, primary infusion set and in-line filter set) by assaying these items in a suitable radioactivity calibration system immediately following completion of administration of all components of the therapeutic step. Calculate and record the dose delivered to the patient by subtracting the residual activity in the syringe and 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.
DOSIMETRY
The following sections describe the procedures for image acquisition for collection of dosimetry data, interpretation of biodistribution images, calculation of residence time, and calculation of activity hours. Please read all sections carefully.
IMAGE ACQUISITION AND INTERPRETATION
Gamma Camera and Dose Calibrator Procedures
Manufacturer-specific quality control procedures should be followed for the gamma camera/computer system, the collimator, and the dose calibrator. Less than 20% variance between maximum and minimum pixel count values in the useful field of view is acceptable on Iodine-131 intrinsic flood fields and variability <10% is preferable. Iodine-131-specific camera uniformity corrections are strongly recommended, rather than applying lower energy correction to the Iodine-131 window. Camera extrinsic uniformity should be assessed at least monthly using 99mTc or 57Co as a source with imaging at the appropriate window.
Additional (non-routine) quality control procedures are required. To assure the accuracy and precision of the patient total body counts, the gamma camera must undergo validation and daily quality control on each day it is used to collect patient images.
Use the same setup and region of interest (ROI) for calibration, determination of background, and whole body patient studies.
Gamma Camera Set-Up
The same camera, collimator, scanning speed, energy window, and setup must be used for all studies. The gamma camera must be capable of whole body imaging and have a large or extra large field of view with a digital interface. It must be equipped with a parallel-hole collimator rated to at least364 keV by the manufacturer with a septal penetration for Iodine-131 of <7%.
The camera and computer must be set up for scanning as follows:
Parallel hole collimator rated to at least 364 keV with a septal penetration for Iodine-131 of <7%
Symmetric window (20-25%) centered on the 364 keV photo peak of Iodine-131 (314-414 keV)
Matrix: appropriate whole body matrix
Scanning speed: 10-30 cm/minute
Counts from Calibrated Source for Quality Control
Camera sensitivity for Iodine-131 must be determined each day. Determination of the gamma camera’s sensitivity is obtained by scanning a calibrated activity of Iodine-131 (e.g., 200−250 μCi in at least 20 mL of saline within a sealed p
