A 3D Navigation Technology for Improved TRUS Prostate Biopsy
Introduction Prostate biopsy is a procedure in which small samples are removed from a man's
prostate gland to be later tested for the presence of cancer. It is typically performed when
the scores from a PSA blood test rise to a level that is associated with the possible
presence of prostate cancer.
The most common method for performing a prostate biopsy procedure is the ultrasound guided
transrectal procedure. The information obtained from the standard prostate biopsy is
deficient and even misleading. Cancers can be missed on initial and even in repeated biopsy.
Moreover, the detection of a tumor cannot predict accurately the tumor size and location1.
It was proven that the exact location of the obtained cores, even in an initial biopsy, can
influence the cancer detection rate2.
An imaging tool that will enable a three-dimensional navigation in the prostate volume and
selecting biopsy locations in view of previous core taken will allow building a "tumor map"
'(i.e. detecting tumor size and location). By mapping the prostate cancer an adequate
treatment can be chosen while avoiding over or insufficient treatment.
However, to be able to produce an accurate mapping of the malignant tissue, a complementary
optimized pathology method should be also implement in addition to the navigation system, it
has been shown that a pre-embedding procedure that keeps the specimen orientation,
unfolding, unity, and location along the needle notch improves the histological yield and
hence the cancer detection rate3.
The NaviGo™ Workstation (hereafter the NaviGo™ Workstation or the NaviGo™ System) allows
physicians to see the prostate gland together with the biopsy sites in a three dimensional
(3D) view, modeled from two dimensional (2D) images. The NaviGo™ Workstation was designed
as an adjunct to standard of care procedures, to work with standard rectal ultrasound
probes, and to be incorporated side by side with the techniques currently employed. No
change to the current employed procedures and techniques is required or suggested. In
complementary to the Navigo system a system for semi-automatic download of prostate biopsy
cores which keeps the orientation, unfolding and unity of the sample was developed to
increase the pathology utility.
OBJECTIVE AND RATIONALE Study objective Evaluate the contribution of the Navigo™ system, an
aiding navigation tool for TRUS prostate biopsy, to increase the prostate cancer detection
The Navigo™ system is a noninvasive navigation tool that produces on line 3D model of the
prostate that assist the physician to navigate in the prostate volume during the biopsy
procedure without changing the imaging system or the biopsy routine whatsoever. The ability
to create a 3D model of the prostate and accurately and evenly position the biopsy needle
will enable a more accurate biopsy and better analysis of the procedure and the pathological
results, hence it might improve the clinical outcomes and may lead to new
DEVICE DESCRIPTION AND INTENDED USE
The NaviGo workstation is used as an adjunct to the ultrasound imaging and biopsy procedures
of the prostate gland. When operated in conjunction with the standard equipment in a TRUS
guided prostate biopsy procedure, the NaviGo™ software may be used for the following:
- To assist the physician by transfer and display of ultrasound images on the workstation
- Build display and manipulate a 3D model of the prostate on screen;
- Archiving the ultrasound images and the 3D model;
- Providing data management solutions;
- Tracking, displaying and recording of the biopsy needle trajectory location in real
The NaviGo™ Workstation is designed to work with standard transrectal ultrasound system
without changing or interfering with the physician's flow of work. The ultrasound images are
displayed on the ultrasound system, and the information provided by the NaviGo provides
supplementary information to the physician during the procedure. The NaviGo™ Workstation
connects to the video output of the ultrasound system and tracks the ultrasound probe's
position using an off-the-shelf electromagnetic tracking system consisting of two sensors,
one on the ultrasound probe (at the base/ non invasive part of the probe) and the other on
the patient's back, a transmitter placed beneath the patient mattress, a processing unit, a
laptop computer and the workstation screen. Figure 1 below presents a general view of the
The NaviGo™ system is an aiding tool in the management of prostate biopsy procedure. The
NaviGo™ system allows prostate biopsy tracking, recording, and management solution. The
NaviGo™ system is designed to assist the physician in performing prostate biopsy procedures
by displaying a 3D model with real-time tracking and recording of the biopsy needle
location. The device includes means to compensate for patient body and prostate motion at
any time during the procedure. The 3D model can be rotated, manipulated and displayed in the
physician's preferable choice.
The Navigo™ system is intended to record and display in 3D the biopsy procedure of any
patient undergoing a prostate trans-rectal biopsy. The Navigo™ system is intended to record
all the data from the initial scan, the volume measurements, and the biopsy needle
insertion. All the images are saved and can be reviewed in post analysis, the needle
location can be updated according to the physician's marking on the recorded ultrasound
image and the pathology results will be displayed in color on the 3D model.
In post procedure, the physician defines the boundaries of the prostate on selected
ultrasound images and a 3D model of the prostate is displayed with all recorded biopsy
specimens' locations displayed in the prostatic volume. The physician will be able to
examine in post analysis the scattering quality of the biopsy specimens in the prostatic
volume and update the pathology results.
Summary of features/capabilities incorporated in the NaviGo™ Workstation.
1. Patient data management (recording, retrieval, off-line analyses and addition of biopsy
2. Contour-based 3D model of the prostate (surface rendering).
3. Real-time tracking of the needle trajectory - the trajectory is displayed on the 3D
4. Recording of biopsy locations - using operator supplied information regarding where
biopsies were obtained, a 20mm long mark is provided on the bottom part of the 3D model
(where the trajectory crossed the 3D model), with each mark numbered and linked to the
relevant saved US image.
5. Prostate volume calculation and measurement - a 3D model is displayed with volume
calculation, and 2D measurement capabilities (point to point inside the model) are
6. Off line procedure planning - on the previous acquired 3D model with the updated
pathology results the physician can schematically place future biopsy locations.
7. Pathology results management and display - update of the pathology results to the 3D
model and a color display according to the severity of the results.
8. Procedure report - automatically generated by the end of each procedure in an HTML
format. The report can also be saved to an external memory device or viewed at a later
METHODS AND PROCEDURES Study Design
1. The study is an open prospective study.
2. The trans-rectal ultrasound guided prostate biopsy procedure will be conducted
according to the standard 12 biopsy scheme.
3. In addition to normal procedure set up, there will be Electromagnetic flat transmitter
under the patient's mattress, 2 externally attached sensors and the Navigo™ system
stand including a laptop computer and the workstation screen (detailed in appendix A -
4. Following the initial prostate scanning and the standard volume measurements done by
the physician, a 3D on-line model will be produced as supplementary information to the
B-mode standard image. The physician will navigate and determine the biopsy position
using the standard B-mode ultrasound image and the 3D prostate on- line model, both
shown on the working station screen.
5. The biopsy samples obtained will be placed straightened in a designated pathology
cassette or a kit for the orienting of biopsies, constituted from nitrate cellulose
filtering membranes. (See appendix B, C).
6. Patient details, core locations in the prostate volume are saved for future analysis
7. The data obtained in these experiments will be compared to a retrospective data from a
comparable cohort of patients who went through standard procedures with the same biopsy
scheme. (The control cohort will be chosen to have similar patient's characteristics-
age, PSA level).
- Cancer detection rate (via pathology) compared with a control group- standard 12 biopsy
from retrospective data.
- Analysis of positive cores distribution in the prostate volume.
- Detection rate vs. PSA level.
Study population will be recruited from the pool of patients who are scheduled for standard
trans-rectal biopsy procedure
POTENTIAL BENEFITS TO THE PATIENTS
The Navigo™ system is a navigation aiding tool which assists the physician to navigate in
the prostate volume. The physician can locate the biopsy core according to the desired
biopsy scheme. The physician can see on-line the location of the previous cores obtained,
and thus gaining the advisable dispersing of the cores and avoiding an overlap between
adjacent cores. Core positions are saved for post procedure analysis and future planning.
Therefore the patient can gain from an accurate positioning of the biopsy cores, which may
increase the cancer detection rate in the current biopsy and produce baseline information
for future procedures.
POTENTIAL RISKS TO THE PATIENTS
The Navigo™ system is an aiding tool that does not require any change in the procedure
performed today and doesn't come instead of the B-mode ultrasound, but works in parallel to
it, to add 3D information. The various components do not come in direct contact with the
patient or the physician and the computer and 3D tracking system are well within the
required safety protocols. Hence, there is no risk to the patients.
The 3D tracking system is approved by the FDA for medical use and is classified as Type CF
which is the most stringent classification, being required for those applications where the
applied part is in direct conductive contact with the heart or other applications as
considered necessary. The 3D tracking system is also part of an approved Helsinki trial in
Bnei-Zion hospital (monitoring of the birth progress, trial initiated by Dr. Yoav Paltieli)
Adverse effects, any pain or discomfort to the patients are not expected according to the
accumulated experience gained in a series of preliminary experiments preformed on 30
patients with the Navigo™ system in Bnei-Zion as part of a Helsinki trail (0101-10-BNZ). The
system is also approved to be used in Haemek medical center (Helsinki number, 0018-11) and
Meir medical center (?). Therefore, in view of the above mentioned information there is no
risk to the patients and to the users.
Allocation: Non-Randomized, Endpoint Classification: Efficacy Study, Intervention Model: Single Group Assignment, Masking: Open Label, Primary Purpose: Diagnostic
increased prostate cancer detection rate
prostate cancer detection rate would be compared to that of a retrospetive cohort of patients who underwent prostate biopsy without the Navigo device.
Ofer Nativ, Prof.
Bnai Zion Medical Center
Israel: Ethics Commission