Recently, a 1.173 million purchase to replace the Cancer Center’s CT simulator (Computed Tomography Simulator) has been approved by Cookeville Regional’s finance committee.
Radiation Oncologist Dr. Algis Sidrys said that the simulator is an integral part of planning a patient’s treatment. He said that every patient will use the simulator at least one time during their cancer care.
“It is not a treatment machine it’s strictly a planning,” Sidrys said. “It’s to help us map out as accurately as possible where the radiation is going to go, and more importantly where it’s not going to go.”
Sidrys said that without a working CT simulator, they are “dead in the water.” Chief Financial Officer Tommye Rena Wells said that they thought the 14-year-old technology could last longer, but that the system keeps failing.
Oncologist Dr. Deborah Jiang said that other CT scans are not suitable for the job because they don’t have the focused lasers needed for the task. Sidrys said that the success of the system requires very specific and precise mechanics.
What is Computed Tomography Simulator?
Computed tomography is an imaging method that uses x-rays to create cross-sectional images of the body. Unlike traditional x-ray techniques, which record a single image from one or two directions, CT data is acquired by rotating the x-ray source and detector around the patient. The resulting dataset contains hundreds of individual x-ray images, each acquired at a slightly different projection angle. Geometric reconstruction algorithms use this dataset to create a 3D volumetric representation of the patient’s internal anatomy.
In this applet, you can experiment with reconstructing volume data from undersampled projection data. The applet displays the projection data as well as the reconstructed volume as a series of slices through the center of the volume. To change the rotation angle and slice number, use the sliders on the right side of the window. To change parameters such as filter size and step size, move your mouse over one of the controls below and click on it to edit its value.
What does a CT simulator do?
Patients are imaged on a CT scanner specially configured to acquire three-dimensional images used for treatment planning. These images provide the radiation planner with information about the size and location of your tumor and surrounding normal anatomy.
Once the patient is brought in to have a CT simulator, they will change into a gown and be positioned on the treatment table.
First, the radiation therapist will mark the skin with ink. These marks are then used by the radiation oncologist to align the positioning of the patient each time they are treated. The area requiring radiation is then localized using x-rays and/or ultrasound. This information is then loaded into a computer that directs the treatment beams from different angles to target the tumor.
Then, CT scans are performed with special fields that match the beam directions of the radiation therapy machine. These images are reconstructed by a computer and viewed by the radiation oncologist for verification of proper targeting of tumors and surrounding structures. These images will be stored for future reference during treatment planning and delivery when appropriate.