Week 6 :Hot lab and Nuclear Medicine (NM) imaging room

In addition to briefly shadowing doctors read NM images for patients, I spent some time in the hot lab and NM imaging room.

The hot lab (‘hot’ as in radioactive) is where different doses for NM diagnostic imaging and therapy are prepared based on the doctors’ placed orders. A typical day begins with calibration of the Dose Calibrator (DC), which is the device used for measuring activity (radiation level) of the radiopharmaceuticals when preparing patients’ doses. During the calibration of the DC, some readings are noted down such as the background radiation as measured by the DC. The DC is then calibrated by using two isotopes, Cobalt and Cesium, whose half-life is ten plus years, if I heard the Technician correctly. Because Cobalt and Cesium have an almost constant activity over a long time, they can be used for DC calibration.

Then I observed preparation of different isotope doses, which are used for different diagnostic and/or therapeutic purposes. The doses may be administered differently to different patients. For example, a Sulfur Colloid-Tc(99m) dose was mixed in a patient’s breakfast (scrambled eggs) and was used for checking gastric clearance. Indium-111(I-111) isotope, on the other hand was IV injected. This was done by taking white blood cells (WBC) from a patient, mixing WBC with I-111 and re-injecting the resulting dose into the patient (When mixed, I-111 atoms attach to WBCs). This dose is used for infection diagnosis; WBC migrate to site of infection therefore I-111 radiation can be picked during imaging. These are just some of Isotope doses I observed being prepared in the hot lab for diagnosis imaging.

Of the therapeutic isotope doses, I observed Xofigo preparation. This is a Radium-223 isotope used for killing bone metastasis from prostate cancer using Beta radiation. The Radium-223 is IV injected.

In the NM imaging room, I observed patients’ imaging such as brain, spleen and, kidneys. Compared to CT, which is anatomy/structure imaging, NM imaging is physiologic/function imaging of the organs. Compared to MRI, NM imaging offers a higher resolution.

For brain imaging ioflupane was used for Parkinson disease diagnosis. For spleen/kidneys imaging, I observed NM images taken first then CT images. The two image sets are then combined to form a 3D image set for analysis/reading. I was also able to observe how collimators are changed based on the type of NM imaging about to take place. Collimators are used in order to ensure radiation is collected only from the region of interest(perpendicular to the respective collimator hole) and unwanted radiation is blocked. Medium Energy General Purpose(MEGP) collimators are used for medium energy isotopes such as Indium, which is used during infection diagnostic imaging. Low Energy High Resolution (LEHR) collimators are used for Low radiation energy isotopes such as Tc-99m which is used for bone, liver and spleen diagnostic imaging. High Energy General Purpose (HEGP) collimators are used during imaging Iodine-131 based radiation which is used for therapy. So Based on the imaging about to take place, the right collimator had to be placed. So far for this week.