Q: What distinguishes the Paritic navigation system from other existing systems?
A: There are several aspects:

1. Shorter time About 2 minutes extra time for a skilled person to apply the pari-pathTM navigation system becasue of the system's easy operation

2. Special register method  Easy register operation with a mouse click, no skin markers to handle. Register accuracy <1 mm RMS typically in a larger region, not just near to register sensors

3. Good accuracy for navigation directions About 0.50 to 1.00 degree when using in a good condition in a wide region, not just near to register sensors

4. Sensor reusable. Expensive sensors are reusable, other disposal parts are affordable

5. Applicable for different needle instruments. Sensors can be easily mounted on various of needle-like instruments

6. Easy and accurate for CT & Ultrasound fusion CT and Ultrasound images are overlapped for a better observation, Easy opearation without selecting common spots on CT images and on B-ultrasound images. Accurate (<2 mm RMS typically )

7. Available to work with surgical robots for guidance

8. Detailed specified  surgical planning feature Simulating ablation area and needle placement are planned for needle tip to cover whole lesion region for optimal region treatment



Pari-path surgical navigation

Other surgical navigation

Position accuracy

about 1~2 mm* in a wide region

In a region close to sensor

Direction accuracy

about 0.50~10 * in a wide region



popular needle-liked instruments

special needles only



expensive, disposal

Register method

(mapping image with world space)

pari-pathTM method

1. accurate in a wide region

2. register accuracy <1 mm*

displayed on the screen

3. no need surgeons to handle markers

just a mouse click


metal-markers method

need to handle markers

sensors as markers

1. good accuracy in a region near to sensors

2. poor accuracy in a region far from sensors

3. no need to handle markers

Fusion of CT & US


1. robust accuracy about

1~2 mm*

2. no need surgeons to select common spots on images

1. accuracy not robust, maybe poor to ~cm

2. need surgeons to select common spots on images

*Parameters (in root mean square) are typical on static objects with normal operations, may vary and are not guaranteed.


Q:  How long does it take additionally to apply the pari-pathTM navigation system compared with a conventional mini-invasive procedure?

A:About 2 minutes extra time for a skilled person to apply the pari-pathTM navigation system during the mini-invasive procedure, including attaching a sensor clip on a surgical needle. 

                      Comparation of time spent

Step ID 

Use pari-path navigation system

Time  (min)

Without navigation system

Time (min)


Attach localization box on the skin

about 1

Attach localization metal grids on the skin

about 1


CT scanning


CT scanning



Transfer CT images to the navigation system via local network

about 0.3




Software operation:

segment, route plan and register

optional operation: connect ultrasound, fuse CT and ultrasound

about 2

Software operation on CT system:     

measure,route plan

about 1


Attach reusable sensor clip

to the needle 

about 1








Measure and

mark an inserting point on the skin surface

about 1


Advance needle:

few times


Advance needle:

multiple times

























Q: Does the system allow flexibility for utilizing the various types of needles and probes selected for the procedure?

A: Yes, the system allows for utilizing various of needle-liked intruments. The Paritic sensor clip can be easily mounted on needle instruments.


Q: How accurate is the navigation system?
A: The surgical needle’s position is tracked and is accurate to within 2mm RMS typically and the needle’s direction is accurate to within 1.50 degree typically, when there is no significant interference from other electrical equipments or magnetic materials in the operating environment. Check with user manual for factors of interference from other electrical equipments or magnetic materials.


Q: How is the patient’s respiration taken into consideration when focusing on system accuracy?
A: The Ultrasound system is used to monitor the real time anatomical structure of a patient and it is co-worked with the navigation system to present high accuracy during the procedure.


Q: Are the parts and fixtures of the navigation system reusable?  How should they be sterilized?
A: Though the reusable plastic sensor parts has no contact with patients and are protected by sterile plastic covers during procedures, they can be sterilized by those disinfectants recommended in the user manual. They cannot be gas sterilized or autoclaved.


Q: How detailed and specific is the Pari-path navigation system when planning a procedure involving a large lesion requiring multiple ablation needle insertions to cover the entire treatment area?
A: This problem underlines the importance of optimal insertion, advance and positioning of each needle path so the tip is able to treatment the specific shape and total lesion according to the different type of ablation needle. This is key to the procedural integrity and success and minimizing damage to healthy surrounding tissues. The Pari-Path navigation system presents the simulated ablation region readily on the monitor in 3D so the operator can confidently observe and evaluate the procedure as it progresses to its defined completion.