In 2014, the Choosing Wisely Initiative partnered with the American Physical Therapy Association to produce a list of low-value physical therapy (PT) practices, titled “Five Things Physical Therapists and Patients Should Question.” This publication described the limited value of deep heat, or therapeutic ultrasound (TUS), to improve long term outcomes for a myriad of musculoskeletal conditions, yet TUS continues to be used. It is unclear how often TUS is used in contemporary PT practice, how its use has changed after this initiative and for what specific conditions it is most used. PURPOSE: To assess the historical use of TUS by physical therapists before and after the Choosing Wisely Initiative across a regional health network. METHODS: A de-identified Clinical Research Data Warehouse was queried using i2B2 software to collect the history of TUS usage by PTs between 2008 and 2019. The specific CPT code 97035 was used to identify TUS episodes of care. In addition, the total number of unique patients in PT each year was collected. Indications for individual TUS treatment units were analyzed in 2018 and 2019 to yield the most frequent ICD-10 codes for which TUS was performed. RESULTS: Episodes of TUS were standardized by the total number of patients seen in PT each year to account for the growth of the health network. The percentage of patients who received TUS each year was reported. TUS usage rates between 2008 and 2019 were compared using Pearson's two proportion Z-test. Utilization was significantly lower in 2019 (5.2%) than it was in 2008 (24.0%) (χ 2 = 2059.6, p-value < 2.2e-16). Between 2018 and 2019, 5,936 units of TUS were performed by 118 unique PT providers. TUS was commonly performed for shoulder pain (13.0%), ankle or foot pain (9.6%), neck pain (9.6%), knee pain (7.7%), hip pain (6.1%), low back pain (6.0%), unspecified chronic pain (4.3%), and Achilles tendinopathy (4.1%). CONCLUSION: Over the last 12 years, there has been a significant decrease in use of TUS by PTs. This decline coincides with the Choosing Wisely Initiative. However, TUS continues to be used, albeit at a significantly lower frequency, for treating musculoskeletal conditions despite having little evidence in improving long term clinical outcomes. Supported by NIH Grant UL1TR001436.