FLA stands for ‘Focal Laser Ablation’.

FLA is also referred to as laser interstitial thermotherapy. It uses a laser which emits high-energy light causing heat to ablate (destroy) targeted tissue1. During FLA prostate ablation, this energy is delivered to the prostate using a laser fiber, which may be housed inside a water-cooled applicator4. Using a needle guide, this laser fiber is pushed into the prostate either through the rectum (transrectal), or through the perineum (transperineal), the area between the rectum and the testicles. The very tip of the laser fiber emits light energy in a spherical pattern that gets absorbed by the prostate tissue, heating it up to high enough temperatures to ablate the prostate tissue2. This procedure is typically performed under the guidance of real-time MR imaging1.

TULSA stands for ‘Transurethral Ultrasound Ablation’.

The urethra is a structure located inside the prostate. During the TULSA Procedure, a device is inserted into the urethra (transurethral), which delivers thermal ultrasound energy (heat created by ultrasound energy) into the prostate. This device rotates, creating a sweeping heating pattern that is directional and reaches the edge of the targeted prostate region. The ability to ablate from within the natural channel of the urethra means the TULSA Procedure is incision-free and requires no needle to puncture the rectal wall or the perineum to reach the prostate. The TULSA Procedure always takes place in an MRI suite, using real-time MR imaging, to plan and control the ablation, ensuring the procedure is predictable. The TULSA Procedure also actively cools the urethra and rectum to help preserve the patient’s natural urinary, bowel, and sexual functions. During the TULSA Procedure, no needle or thermal energy passes through the rectal wall. Instead, a cooling device is inserted into the rectum, protecting the tissue from the ultrasound energy. Simultaneously, the transurethral device cools the urethra, also protecting it from the ultrasound energy.

Ablation Size

The ablation size can also be described as the maximum distance that the ‘heat’ from a device can reach the prostate tissue. Having the ability to target larger areas may be beneficial when needing to target larger areas of the prostate. According to one study, the targeted prostate volume needing ablation was approximately less than 2cm3, and the maximum FLA ablation diameter was 15 millimetres (mm) (3). With FLA, larger prostate zones are ablated by retracing the laser and repeating the ablation, or by inserting the laser in another location. Another approach is to use two different sized laser applicators, to target small and large tumours4. Another study with 24 months of follow-up data published in 2019 with the largest cohort for MRI guided FLA, has similar inclusion criteria regarding lesion size and volume5. With the TULSA Procedure, you can ablate the prostate tissue with an ablation volume anywhere between 1cc to > 100cc. More specifically, the ultrasound heating extends to a radial depth of 30mm away from each of the ten independent 5mm-long elements, enabling ablation of regions with up to 60mm diameter and 50mm length. This enables the TULSA Procedure to be flexible and customizable, with the ability to target a wide range of prostate tissue volumes depending on the patient’s disease and desired outcomes.

To learn more about the benefits of the transurethral delivery method and the benefits of having an incision-free procedure such as the TULSA Procedure, visit our ‘About TULSA Procedure‘ page today.


  1. Ganzer, Roman, et al. “Which technology to select for primary focal treatment of prostate cancer?—European Section of Urotechnology (ESUT) position statement.” Prostate cancer and prostatic diseases2 (2018): 175-186.
  1. Van Luijtelaar, Annemarijke, et al. “Focal laser ablation as clinical treatment of prostate cancer: report from a Delphi consensus project.” World journal of urology10 (2019): 2147-2153.
  1. Eggener, Scott E., et al. “Phase II evaluation of magnetic resonance imaging guided focal laser ablation of prostate cancer.” The Journal of urology6 (2016): 1670-1675.
  1. Feller, John F., Bernadette M. Greenwood, and R. Jason Stafford. “Transrectal Laser Focal Therapy of Prostate Cancer.” Imaging and Focal Therapy of Early Prostate Cancer. Springer, Cham, (2017). 325-343.
  1. Walser, Eric, et al. “Focal laser ablation of prostate cancer: results in 120 patients with low-to intermediate-risk disease.” Journal of Vascular and Interventional Radiology3 (2019): 401-409.

Dec 7, 2020 | TULSA Procedure

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