The ultrasonic beam generates heat as it propagates due to the atenuation of acoustic energy, including absorption and scattering phenomena. Given that the acoustic field generated by a transducer is unique, each transducer generates a distinct thermal field. There is ample scientific evidence that therapeutic ultrasound equipment produces different heating patterns, even if they are from the same manufacturer. In view of this knowledge, the objective of the present study is to test the heating pattern with a specific dosage for the treatment of dissolution of muscular trigger points, using ex-vivo bovine muscle tissue and an infrared thermal camera. Two therapeutic devices that are routinely used in clinics were tested using the protocol proposed by the DoSys App calculator. The heating patterns of both devices were completely different and may promote different treatment outcomes, although they are being used currently in clinical routine. The output power of one of them as measured by a radiation force balance is below the 20% limit established by the IEC 61689:2022 norm. Considering the specific treatment of muscular trigger points, such device may not produce heating enough to reach the preconized therapeutic temperature range (42 to 45 ℃). This study underscores the significance of regular calibration of ultrasound equipment routinely used in Physiotherapy clinics. The study's limiting factors include the necessity to test a larger variety of ultrasound devices from different manufacturers and to conduct a greater number of trials.