Adjusting Focus Depth in RF Mode

[hamidmoradik]

Could anyone please explain how to change the focal depth in RF mode?

I can manually adjust the focal depth in B-mode, then switch to RF mode and expand the yellow region of interest to cover the entire imaging area. However, when I record the data, the resulting files, [filename]_env.YML and [filename]_rf.YML, display different focal depths. The first file shows the manually selected depth next to "focal depth," while the second file indicates half of that depth.

Does anyone know why this discrepancy occurs? Which of these values represents the actual focal depth used for imaging: the one in [filename]_env.YML (manually set) or the one in [filename]_rf.YML (half depth)?

[clariusk]

When you manually adjust focal depth, you get control over the greyscale data on where the transmit focus is occurring. The RF data transmit focus is determined by the vertical mid-point of region of interest (ROI). For example, if you use the manual focus at 2cm at an imaging depth of 10cm, and increase your ROI to the maximum, then record raw data, your greyscale focus will be at 2cm, whereas your RF focus will be at 5cm.

[hamidmoradik]

Thank you for the quick response!

1. Are you also saying that we don't have control over focus in RF mode? In our case, we enlarge the ROI to cover the entire imaging area and would like to move the focus farther away and not necessarily at the center of the ROI.

2. When I did a test similar to the example you mentioned—manual focus at 2 cm and RF focus at 5 cm—the probe became very warm, which didn’t seem normal in my hand. It’s probably because it's performing imaging twice at these two different focal points in parallel. Do you anticipate any changes in a future software update?

[clariusk]

1. Correct, the transmit focus for RF signals is always at the center of the ROI
2. The probe's heat is entirely dependent on imaging duty cycles, mainly due the frame rates that the device is imaging at. In pure greyscale mode there's typically a break in the duty cycle, but in all other imaging modes, you can imagine there's no break to acquire the additional data required. Our PowerFan accessory has been created for these occurences.