At the University of Florida Davis Cancer Pavilion, a variety of medical linear accelerators (LINACs) are used to provide patients with external beam radiation therapy. External beam therapy is a common technique used to treat malignant tumors or benign lesions through the delivery of high doses of x-rays or electrons.
A LINAC is a device that generates high-energy x-rays and electrons in the range of mega voltage energy, or MV, for cancer treatment. The high-energy x-ray beams penetrate deep into the body and spare more superficial tissues, whereas electron beams are more beneficial for superficial lesions and can spare deeper normal structures. X-ray and electron beams of different energies allow the radiation oncologist to customize the treatment based on the shape and location of the target volume. The LINAC is capable of rotating around a patient lying on a treatment couch, treating the tumor from different angles. This allows the delivery of high doses of radiation to the tumor while reducing the dose to the surrounding normal tissues.
The department of radiation oncology operates four Elekta LINACs (two Elekta Versa HD and two Elekta Synergy) at the Davis Cancer Pavilion location and one Varian Trilogy at the main UF Shands Hospital. All LINACs are equipped with multileaf collimator capable of delivering 3D conformal, intensity-modulated radiation therapy (IMRT), or volumetric modulated arc therapy (VMAT) treatment. All LINACs are also equipped with gantry-mounted cone-beam CT (CBCT) systems (Elekta xvi or Varian OBI) for patient positioning verification. A recent installed MR LINAC will be described in the “MR-Guided Radiation therapy” session below.
In addition to most of the conventional treatment techniques, some of our LINACs are also commissioned to perform special treatment techniques, such as:
- Total skin electron therapy (TSET): a special treatment technique to treat cutaneous T-cell lymphoma (CTCL), a disease that affects the skin of the entire body. An in-house-designed stand is used to treat the entire skin to a shallow depth, thereby limiting radiation to normal structures.
- Total body irradiation (TBI): a treatment technique to treat the entire body to a uniform, low dose for immunosuppression. This is a standard part of the conditioning regimen for bone marrow transplantation (BMT).
- Prone breast irradiation: a technique to treatment breast cancer with patients lying in the prone (face downward) position using a customized prone breast board. As compared to the conventional treatment position with patients lying in the supine (face upward) position, the prone position increases the distance between the target volume and the lung and heart, thereby reduces radiation toxicity to these critical organs, especially for left-sided breast cancer. The board is indexed to the treatment couch, ensuring positioning reproducibility and patient safety.
- Prostate treatment with SpaceOAR: a minimally invasive, pre-treatment procedure administered by the radiation oncologist, prostate treatment with SpaceOAR involves the injection of a liquid Hydrogel material between the prostate and rectum. The extra space between the prostate and rectum allows our planning team to design treatment plans that better reduce rectal toxicity than could otherwise be achieved. Clinical trials have provided strong evidence for the benefit of hydrogel spacer use in maintaining the quality of life after prostate radiation therapy. This outpatient procedure is typically done two weeks before the start of radiation treatment.