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The Dextroscope
The Dextroscope is a Virtual Reality (VR) environment designed to provide medical professionals deeper understanding of a patient's complex 3D anatomical relationships and pathology. Although its main intended purpose is to enable surgeons to plan a surgical procedure (in particular, neurosurgery ), it has also proven useful in radiology and medical education.

The Dextroscope allows its user to intuitively interact with a Virtual Patient. The Virtual Patient is made of computer-generated 3D multi-modal images obtained from any DICOM tomographic data including CT, MRI, MRA, MRV, functional MRI and CTA, PET, SPECT and DTI. It can work with any multi-modality combination, supporting polygonal meshes as well.

The user sits at the Dextroscope 3D interaction console and manipulates the Virtual Patient using both hands in a similar manner to how one would manipulate a real object. Using stereoscopic visualization technology reflected on a mirror, the Dextroscope user sees the Virtual Patient floating behind the mirror but within easy reach of the hands and uses flexible 3D hand movements to rotate and manipulate it. The Dextroscope allows to segment organs and structures, make accurate 3D measurements etc.

In one hand the user holds an ergonomically shaped handle with a switch that, when pressed, allows the 3D image can be moved freely as if it were an object held in real space. The other hand holds a pencil shaped stylus that is used to select tools from a virtual control panel and perform detailed manipulations and operations on the 3D image. The user does not see the stylus, handle or his/her hands as they are hidden behind the mirror, instead he/she see a virtual handle and stylus which are calibrated to appear in exactly the same position as the real handle and stylus. On the business end of the virtual handle can be selected anything - drill tool, measurement tool, cutter – that the software can create. Experience has shown that it is unnecessary to model the users hands provided they can see and feel the real tools and these perceptions match with the virtual scene – a big advantage since real hands clutter the workspace and obscure the view .

One of the uses of the Dextroscope is to allow surgeons to interact with and manipulate the Virtual Patient and plan the ideal surgical trajectory - for example, by simulating inter-operative viewpoints or the removal of bone and soft tissue.

Apart from being much faster to work this way than using a mouse and keyboard, this approach also provides the medical professional, typically a surgeon, with a greater degree of control over the 3D image - with the hands literally being able to reach inside to manipulate the image interior.

Manipulating the Virtual Patient – Virtual Reality Toolsets
The Dextroscope provides an extensive set of virtual tools that can be used to manipulate the 3D image. For example, there are dedicated tools to perform data segmentation to extract surgically relevant structures like the cortex or a tumor , extract blood vessels , adjust the color and transparency of displayed structures to see deep inside the patient and even simulate some surgical procedures – such as the removal of bone using a simulated skull drilling tool. Typical structures that can be segmented are tumors, blood vessels, aneurysms, parts of the skull base, and organs. Segmentation is done either automatically (when the structures are demarcated clearly by their outstanding image intensity such as the cortex) or through user interaction (using for example an outlining tool to define the extent of the structure manually). A virtual ‘pick’ tool allows you to pick a segmented object and uncouple it from its surroundings for closer inspection. A measurement tool provides accurate measurement of straight and curving 3D structures such as the scalp, measure angles, such as those between vessels or bony structures (for example, when planning the insertion of a screw in the spine).

Neurosurgery Planning - Case Studies and Evaluations
The use of the Dextroscope has been reported for several neurosurgical clinical scenarios;

- cerebral arteriovenous malformations ,

- aneurysms ,

- cranial nerve decompression (in cases of trigeminal neuralgia and hemifacial spasm) ,

- meningiomas (convexity, falcine or parasagittal) ,

- ependymomas or subependymomas ,

- and a great variety of deep-brain and skull base tumors (pituitary adenomas, craniopharyngiomas, arachnoid cysts, colloid cysts, cavernomas, hemangioblastomas, chordomas, epidermoids, meningiomas, gliomas, jugular schwannomas, aqueductal stenosis, stenosis of Monro foramen, hippocampal sclerosis) .

Not only brain, but also spine pathology such as cervical spine fractures, syringomyelia, and sacral root neurinomas has been evaluated .

For more details of the use of the Dextroscope in neurosurgery refer to.

Other surgical specialties
The Dextroscope has been applied also outside of neurosurgery to benefit any patient presenting a surgical challenge: an anatomical or structural complexity that requires planning of the surgical (or interventional) approach, for example, ENT , orthopedic, trauma and cranio-facial , cardiology and liver surgery .

Dextroscope and Diagnostic Imaging
Dextroscope is not just for surgeons - radiologists benefit from it too. The rapid growth in multi-modal 2D diagnostic imaging data routinely available has increased their workload tremendously. Using Dextroscope, radiologists can quickly and accurately reconstruct 3D virtual reality models from high volumes of 2D image sequences – hence eliminating the need for separate analysis of individual images and facilitating a better understanding of the 3D anatomical structures and more accurate diagnosis.

Furthermore, the Dextroscope virtual reality environment helps bridge the gap between radiology and surgery - by allowing the radiologist to easily demonstrate to surgeons important 3D structures in a way that surgeons are familiar with. This demonstration capabilities makes it also useful as a base for medical educators where to convey 3D information to students.

The Dextroscope (and/or the Dextrobeam) was installed, (among other medical institutions) at:

The Dextroscope was a product of Volume Interactions Pte Ltd, a spin-off company from the Kent Ridge Digital Labs research institute in Singapore. It received FDA 510(k) clearance and CE Marking.

The company was founded in 2000 in Singapore and acquired by the [Bracco Group] in 2002. Volume Interactions ceased commercial operations in 2008.