IEEE Robotics & Automation Magazine - September 2023 - 92

was analyzed by visual inspection to ensure that no burns at
the coupling interface were produced. To verify the efficacy of
the treatment, the liver was removed and dissected after animal
suppression. The produced lesion was analyzed by means
of a digital microscope (KH-7700; Hirox-USA) equipped with
an MX-MACROZ IV lens (50× magnification).
RESULTS
Results are reported in Figure 9(c). No relevant burns at the
coupling interface were assessed, thus confirming the safety
of the HIFUSK treatment. The produced lesion featured
smaller dimensions with respect to the lesions produced in
the ex vivo scenario (namely, the lesion volume was 24.8 mm3
in vivo, while it was 1,509 mm3 ex vivo). As mentioned, this
may be caused by the thickness of the
pig rind, which attenuated the HIFU
beam. Therefore, a reduced quantity of
energy was delivered at the focal point.
DISCUSSION AND CONCLUSIONS
HIFU surgery is a promising noninvasive
and intrinsically safe therapeutic technology
that could potentially change the
treatment paradigm of various medical
conditions, including cancer. However,
the currently available systems lack flexibility
in terms of therapy delivery, thus
limiting the application of HIFU, especially
in a delicate field such as surgery.
Robotics could represent the enabling
technology for HIFU treatments, accelerating
the procedures' spread in clinical
scenarios. Robotics can guarantee precision
and automation in targeting different
anatomical areas, thus speeding up the procedure and
dealing with target motions. While the integration of robotics
and US was previously addressed for diagnostic application,
few studies reported on robot-assisted platforms for HIFU
therapy, and almost none of them took advantage of active
robotic control. Here, we presented the HIFUSK platform as
a computer-assisted robotic platform for USgHIFU treatments
on both static and moving organs. The use of a 7-DoF
robotic arm improves comfort both for patients and physicians.
Indeed, the patient lies on a standard operating room
bed, while the target area can be easily reached thanks to the
enhanced workspace of the robot.
For the first time, the design of our robot-assisted HIFU
rable with other existing FUS systems. This accuracy was
also demonstrated while addressing a moving target, indicating
a mean motion compensation error of 0.63 mm and going
beyond the relative state of the art. Indeed, Chanel et al. [17]
showed a 0.8-mm mean motion compensation error, while
An et al., reported a mean motion compensation error of
1.72 mm [18]. However, the tracking and compensation capabilities
were tested in a single direction (mainly perpendicular
to the HIFU axis).
Further testing on more sophisticated phantoms will
"
WHILE THE INTEGRATION
OF ROBOTICS AND
US WAS PREVIOUSLY
ADDRESSED FOR
DIAGNOSTIC
APPLICATION, FEW
STUDIES REPORTED
ON ROBOT-ASSISTED
shed light on multidirectional compensation (i.e., including a
motion component that is parallel to the HIFU axis). Additionally,
all the dry lab and ex vivo tests were performed inside
a water tank. The capability to keep acoustic coupling during
this compensation by taking advantage
of electronic axial steering and force
control needs to be specifically assessed.
Finally, a first in vivo experiment on a
porcine model was conducted, preliminarily
assessing the safety and efficacy
of the proposed platform in performing
a USgHIFU static treatment. Further in
vivo experiments will investigate in depth
the ability of HIFUSK to perform in vivo
sonication during motion compensation
and the possibility to treat other abdominal
organs (e.g., kidneys).
In addition, a few limitations of the
PLATFORMS FOR HIFU
THERAPY.
„
current system can be listed. The motion
tracking and compensation rely on the
physician's hand guidance to initially
identify the motion plane of the target.
An algorithm that automatically identifies
the motion plane could improve
platform takes into account strategies to ensure the safety
of the patient throughout the treatment (a key point for later
clinical translation). Our platform was validated in both a
dry lab and ex vivo scenarios, showing a HIFU sonication
accuracy in line with that required in HIFU surgical procedures.
Indeed, our results show a positioning accuracy of
the HIFU focus always lower than 0.5 mm in both static and
dynamic cases. Kraftt et al. [27] reported a total positioning
error of the US focus always lower than 2 mm and compa92
IEEE Robotics & Automation Magazine - September 2023

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