Cyberknife VSI, one touched recently, another about to be

[rhody]

Cyberknife VSI:

Life saving technology, bests the Gamma knife, one friend was treated successfully for prostate cancer and another about to be with a benign tumor behind the 8th cranial nerve (above and behind his left ear). He is waiting for consultation at the moment.

The Technology:

The CyberKnife® Robotic Radiosurgery System (Accuray Incorporated, Sunnyvale, CA, USA) has undergone almost twenty years of technical development from its conception (1) to its most recent version, the CyberKnife VSITM System, the first of which was installed in April 2010. The CyberKnife System, as described in a series of technical papers in the late 1990s (2-7), began as a frameless alternative to existing stereotactic radiosurgery systems such as the Gamma Knife (Elekta AB, Stockholm, Sweden) and conventional linear accelerators (LINACs) equipped with head frames and stereotactic beam collimators. In the original CyberKnife configuration, a LINAC mounted on a robotic manipulator delivered many independently targeted (non-isocentric) and non-coplanar treatment beams with high precision under continual X-ray image guidance

and...

Treatment planning begins with obtaining one or more three-dimensional (3D) images that allows the target volume and nearby organs at risk (OARs) to be visualized. Once acquired the 3D images are transferred to the MultiPlan® Treatment Planning System (TPS) via a dedicated database server.

and...

The number of nodes in the different path sets ranges from 23 to 133.

Direction points are determined automatically based on the beam generation mode, which is either isocentric or non-isocentric. The isocentric mode allows the user to position one or more pseudo-isocenters within the patient model resulting in one candidate beam from each node to each pseudo-isocenter. The non-isocentric mode takes advantage of the ability of the robotic manipulator to direct each beam at a unique point within the patient, without any need to reposition the patient between beams, by generating a large number of direction points (typically 1,000–6,000) semi-randomly within the target volume and distributes these uniformly among the nodes to form the candidate beam set. The user can choose to prevent candidate beams from passing through OARs, which can be a method to minimize the dose delivered to small radiosensitive structures such as the lens of the eye or the thyroid gland.

and...

The user then selects between one and three fixed collimator sizes, or between one and twelve Iris Collimator field sizes, which are assigned to subsets of the candidate beam set.

See the Figure 2 below this section. How are the beams controlled such that a focal point is chosen that nothing is affect behind it ? Think poke a hot steel needle into the tumor and then stop, can be done with a solid object, but a beam traveling at the speed of light, not so easy. A detailed explanation of collimator focusing, and an analogy or visual description would be appreciated. Details of the Collimator and the beams below:

Figure 3 shows the Iris Variable Aperture Collimator projecting a conical beam, that converges to a precise point. The Iris Collimator contains 12 triangular collimator segments, oriented to define a dodecagon-shaped beam aperture. The 12 segments are divided into 2 banks of 6 segments that are mounted in series, with the 2 banks rotated by 30 degrees relative to each other. See dodecagon google image capture below, here is the dodecagon wiki:

http://img841.imageshack.us/img841/1674/tridodecagon.jpg

My friend with the 8th cranial benign tumor and has found who he believes is the most experienced Doctor and research scientist in the field, Dr Chang, who studied under Dr Adler (who helped the development and testing of the CyberKnife) and treated the patient, Tony Boxer successfully in the http://www.cs.umb.edu/~dqg/newone/tony_b.htm link here with few side effects and no more hearing loss. This all happened in 2001. He is waiting for a consultation, and Dr Chang's team responded within four hours of his sending diagnosis information for a consultation.

I am happy to report my other friend was treated successfully for prostate cancer with Cyberknife two years ago. Knock on wood, so far so good. I wish him the best with his treatment of the benign tumor behind his left ear. Is the 8th cranial nerve inside the pia mater,it is hard to tell, see the Meninges figure here, wiki.

Rhody...

 

[Moonbear]

Sounds interesting and promising. Just to clarify, does this allow a surgical procedure without an actual incision by focusing the energy (um, or whatever it is) past the skin and toward a specific point, or is it more that it allows for a finer or more delicate touch to perform surgery with better precision through a smaller incision?

As for CN VIII, like all except one cranial nerve, it originates on the brain, and in this case, the brainstem. So for a short distance, it is surrounded by all three layers of the meninges. This one pretty quickly reaches its hole in the skull (when Mom told you she needed something like another hole in the head, she wasn't kidding! We have a LOT of holes in the head where cranial nerves travel), so has a fairly short "intradural" course before traveling through its own tunnel to the ear. That nerve carries information for both hearing and balance/equilibrium, so I'm sure your friend is more concerned about dizziness caused by the tumor compressing the nerve than hearing loss in one ear! I hope his procedure goes well!

 

[bobze]

Sounds interesting and promising. Just to clarify, does this allow a surgical procedure without an actual incision by focusing the energy (um, or whatever it is) past the skin and toward a specific point, or is it more that it allows for a finer or more delicate touch to perform surgery with better precision through a smaller incision?

Correct, without any actual incision. Its really a type of radioablation. It can be used for lots of things, from some small tumors to extra-nodal origins of action potentials in the heart.

As for CN VIII, like all except one cranial nerve, it originates on the brain, and in this case, the brainstem. So for a short distance, it is surrounded by all three layers of the meninges. This one pretty quickly reaches its hole in the skull (when Mom told you she needed something like another hole in the head, she wasn't kidding! We have a LOT of holes in the head where cranial nerves travel), so has a fairly short "intradural" course before traveling through its own tunnel to the ear. That nerve carries information for both hearing and balance/equilibrium, so I'm sure your friend is more concerned about dizziness caused by the tumor compressing the nerve than hearing loss in one ear! I hope his procedure goes well!

Just to add to this excellent explanation for Rhody. Sounds like your friend has an acoustic neuroma (aka vestibular schwannoma). They are relatively common and normally arise from the myelin cells of the PNS (schwann cells) after the nerve has actually exited its meningeal coverings. Imagine if you were inside a trash bag (the meninges) and poked your arm out (the nerve). You'd have a little bit of a covering following along your arm and then thinning out, then eventually lost. Nerves do this as they exit the CNS.

In the case of CN8 (vestibulocochlear nerve) it looses this little bit of meningeal covering in the internal acoustic meatus as it travels out of the cranial vault to get to the inner ear.

Hope it goes well for your friend, I'm sure he'll do great.

 

[rhody]

Just to clarify, does this allow a surgical procedure without an actual incision by focusing the energy (um, or whatever it is) past the skin and toward a specific point, or is it more that it allows for a finer or more delicate touch to perform surgery with better precision through a smaller incision?

It is best described by the excerpt from the wiki link above, it is 6MV xray radiation that is collimated using fixed tungsten collimators:

Mounted on the Robot is a compact X-band linac that produces 6MV X-ray radiation. The linac is capable of delivering approximately 600 cGy of radiation each minute - a new 800 cGy / minute model was announced at ASTRO[6][7] 2007. The radiation is collimated using fixed tungsten collimators (also referred to as “cones”) which produce circular radiation fields. At present the radiation field sizes are: 5, 7.5, 10, 12.5, 15, 20, 25, 30, 35, 40, 50 and 60 mm. ASTRO 2007 also saw the launch of the IRIS[7] variable-aperture collimator which uses two offset banks of six prismatic tungsten segments to form a blurred regular dodecagon field of variable size which eliminates the need for changing the fixed collimators.

My friend has a week scheduled for evaluation and treatment at Stanford in San Francisco next week. Consultation and meeting the team the first day, second day, being cast in a mask for perfect alignment, then the next three days, a treatment of about twenty minutes each I believe, then he and his wife fly home.

Here is a video: Steven D. Chang, MD, on Brain Tumors and Cerebrovascular Disease
Cyberknife starts at 5:33



Rhody...

 

[rhody]

My friend is back from treatment and is posting on his medical blog, he agreed to allow me share his experiences, hoping to helps to decide if this treatment with a similar diagnosis could help them.

He has nothing but praise for Dr Chang and his team. They were very gracious and did everything possible to ease their fear and sense of anxiety. When you enter the facility, there is a pianist on a grand piano playing soothing music. They have an on campus shuttle service that picked them up and returned them following treatment and they did a "practice run" before the real treatment began to check that the beams would be delivered where targeted and for the duration desired.

He experiences tinnitus and sense of fullness and/or pressure (near tumor location), his hearing loss is about the same, has some problems with imbalance, facial numbness and what he describes as medium fatigue, vague headaches that come and go, but nothing debilitating. He has had acupuncture treatment for the after effects of cyberknife and will continue to do so for the near future. He plans on making changes to his diet to include foods that he believes may help keep his benign tumor from regrowing. As he says, he thought he was doing everything possible (before diagnosis), and only people with risky behaviors and those who abuse their bodies have things like this happen to them, and how he always took his health for granted, not any more though.

Rhody...

 

[mcknia07]

I had a family member go for this treatment just last week, I never knew much about the procedure actually, but it was talked about alot.

 

[rhody]

I had a family member go for this treatment just last week, I never knew much about the procedure actually, but it was talked about alot.

mcknia,

I wish your loved one the best.

Rhody...

 

[mcknia07]

mcknia,

I wish your loved one the best.

Rhody...

Thank you, rhody! I will find out more today when I get to work.