Talk:Pencil (optics)

Pencil
I've never heard of this term used as "pencil" alone. I have heard of a "pencil beam", but never just a "pencil". Perhaps a rename is in order? --Bmk 16:14, 2 August 2006 (UTC)
 * Agreed. Done.  --zenohockey 04:38, 28 August 2006 (UTC)

I think we should go back to Pencil (optics). For the guy who has never heard the word used alone, see all these optics books. Dicklyon (talk) 23:16, 13 December 2010 (UTC)


 * An article title that doesn't require disambiguation is better than one that does. "Pencil beam" is clear and unambiguous.


 * But pencil beam is a much narrower topic than pencil. A pencil is a key concept in optics, much more general than a pencil (narrow) beam.  The original stub said "A Pencil is a beam of radiant energy in the form of a narrow cone or cylinder," which is itself a bit narrow.   Dicklyon (talk) 20:04, 14 December 2010 (UTC)


 * OK.--Srleffler (talk) 06:03, 16 December 2010 (UTC)


 * Thanks; maybe I'll get around to it... Dicklyon (talk) 07:00, 16 December 2010 (UTC)

Include charged particle beams or not?
The new paragraph contradicts the definition given in the first sentence of the article, which defines the topic of this article as narrow beams of electromagnetic radiation. Proton beams are not beams of electromagnetic radiation. We could broaden the article's subject, but we should talk about that and make sure it is the right thing to do. It's not clear to me that there is any point in having a general article on narrow beams of stuff. Better to have more specific articles, or merge the material into other general articles.

The new paragraph is also incoherent. I'll try to fix it another day, but it would be helpful if the author tried to make his intent more clear first.--Srleffler (talk) 06:21, 11 December 2010 (UTC)

"pencil beam [′pen·səl ‚bēm] (electromagnetism) A beam of radiant energy concentrated in an approximately conical or cylindrical portion of space of relatively small diameter; this type of beam is used for many revolving navigational lights and radar beams. McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc." Radiant energy vs. electromagnetic? New proton therapy machine (PRT) advertise that they use pencil beam scanning technology. I am already in a disagreement with someone who seems to work for LLU (WP:COI)? which has an older style PRT (Fermi) which has no pencil beam. As part of the info update I reference the pencil beam scan article which brought me here. He has reverted my addition of this info (both pencil beam and MLC) on the very IMRT biased Proton therapy wiki. Almost 500,000 people a year (2010) figures in the US alone, die of Cancer. Radiation therapy is one of the 4 treatment options available. Patients would be very interested in the IMRT vs PRT choice. Since PRT is more accurate and more effective (it works by LET or directly knocking out BOTH strands of DNA, causing cell death). IMRT only knocks out a single strand of DNA which cells can repair. IMRT's failure rate is high AND it gives secondary cancers. The latest to open PRT center in Hampton, Virgina was funded in part by the DOD. This is your tax$ at work. PRT is best for almost all cancer treatment. Here is what can happen using IMRT: http://www.nytimes.com/interactive/2010/01/22/us/Radiation.html?ref=health. You may complain about my coherence (correcting edits is a better strategy). You also stated that charged particles are not electromagnetic but you failed to state what you believe they are!!! Charged particles are controlled by magnets and magnetic force is used to accelerate or charge them but what would you define them as? Hadrons?? I asked at the library in sfo across the bay from where basic work on proton therapy technology was developed and I was given the proton therapy wiki as a resource. The current info plays into the hands of IMRT at the expense of the patient, thats wrong! BTW: Oncologist get 50% of their profits selling cancer drugs. IMRT needs oxygen to work better and tumors have poor O2 supplies (hypoxia) and need cancer drugs to work better. Oncologists may own the x-ray equipment that they use on patients. It is not hard to see the incentive to maintain the IMRT status quo. BTW: There are two different new compact proton therapy systems in late stage development. They could be improved with Gov't$ but people need to be able to find the basis info. Your expertise would be most helpful. Thank you for your edits and expert knowledge.Bgordski (talk) 19:17, 12 December 2010 (UTC)


 * It's not about whether to include, but maybe you need help from someone who understands English and wikipedia editing and has less of a POV to push; or read the edit summaries of the reverts and try again more carefully. There are book references you could use instead of the obscure unpublished document.  Dicklyon (talk) 04:47, 13 December 2010 (UTC)
 * I added a book ref. I didn't find anything about "newer", but there are mentions of proton beam scanning in books for over a decade.  I removed the obscure document ref.  Dicklyon (talk) 06:33, 13 December 2010 (UTC)


 * Bgordski, charged particles are not electromagnetic radiation. A charged particle beam is also not radiant energy by any conventional definition of the term. Anyway, this is beside the point now. Dicklyon has expanded the article to include charged particle beams and I'm not going to fight that.


 * It seems like you have an agenda here. Whatever the merits of the cause, editing Wikipedia articles with an agenda is strongly discouraged. We try to make our articles as neutral as possible. Influencing public opinion on the merits of different cancer therapies is not part of our function.--Srleffler (talk) 06:13, 14 December 2010 (UTC)