Stereotactic cases, why we prescribe to the isodose line we do

Good topic on the Medphys list server.
Scott Dube posted this link to a good paper on the topic and gave the following commentary:


QUESTION:
What is the rationale behind cranial SRS prescriptions lines laying
> somewhere around 80-90%??

The dose falloff outside the target is steeper when you prescribe to 80%.
This paper even recommends 70%.


http://www.ncbi.nlm.nih.gov/pubmed/22422384

Linac Guts

Siemens Primus

Just a couple of shots with the cover off. I love these, I think I need to brush up my photography skills, or keep the Nikon camera with me. This is an older machine and Siemens has exited the radiotherapy business so you won't see them around much longer. Had to replace a serial cable.

Good overview article on motion management in radiation therapy

http://iopscience.iop.org/0031-9155/57/23/R161/pdf/0031-9155_57_23_R161.pdf

FSCK -y

It always seem like such an obscene command, but it is quite useful.

http://www.thegeekstuff.com/2012/08/fsck-command-examples/

Fellow TGP'er, nice guitar based blog

Stumbled across this blog from a fellow TGP member, pretty nice guitar based blog.

Alex Doyle

Brain rules for Baby Practical tips

John Medina has two excellent books, Brain Rules and Brain Rules for Baby. Here are some practical tips from Brain Rules for Baby, for anyone who is expecting, or already has young children.

Brain Rules Practical Tips

Daily calorie requirement estimator

http://bwsimulator.niddk.nih.gov/

Music uploads

I am going to upload some music clips, mostly of courses I'm working on as well as little music clips demoing gear and ideas for songs I have.

There are many sites I could upload this to. One of the most popular sites to upload to is Soundcloud.
I have an account at David Roeseners Sound Cloud

I also noticed tonight that Tumblr blogs easily allow music integration, so here is my tumblr blog.
davidroesener.tumblr.com

MLC Leaf width and plans

http://www.aapm.org/meetings/amos2/pdf/59-14909-99229-745.pdf

Quick summary of findings

Surprisingly, we noticed no difference in TV coverage and sparing of OARs. Furthermore, the isodose distributions and DVHs for the RPC and TG-119 phantoms show no major dosimetric gains for the smaller MLC widths, the cord for the RPC phantom received lower doses with the 1cm MLC system (our benchmark reference), for the same TV coverage across the systems. For the clinical cases, all systems gave comparable TV coverage and sparing of the OARs, with the Primus MLC system again, to provide slightly better conformity (lower CI). This better dose conformity is the reason that the dose fall-off within the "Ring" structure is higher, for the Primus system.

Conclusions:
This study is the first that comprehensively compares the majority of today’s MLC systems and has shown no significant indication that smaller MLC widths can lead to optimal plans, when multi-field IMRT techniques are used for planning.

3 day monk

I love this post and many others from Leo Babauta
http://zenhabits.net/3-day-monk/

ACR related

For later review
http://www.acr.org/Quality-Safety/Appropriateness-Criteria/Oncology

Another physicist/musician blog.

Looking forward to hearing some of his music, his early composition work looks promising. I think he has inspired me to start working on recording some compositions of my own. I do this off and on but haven't released anything for public consumption yet.

markstuartramsay.blogspot.co.uk

Link to Google Drive folder on Guitar

https://drive.google.com/folderview?id=0Bwt0HVuAI74IZklFd1N5MGJWMkU&usp=sharing

Neoclassical Guitar

Back in the 80's i had one of Dave Celentanos books, for neoclassical guitar. He has a great youtube video where he plays Pachabel Canon.

http://www.davecelentano.com/wp-content/uploads/2010/11/Pachelbels-Canon-taps-part-1.pdf

Canadian Medical Physics

http://www.medphys.ca/content.php?doc=281

Proton center tour@IU

 

This all looks good, weekend is pretty booked up so far.

 

Particle Beam Therapy Symposium

Symposium
$10
ticket required
Saturday, August 3 • 8:00am - 3:45pm
Room 103, Indiana Convention Center

Tour
$5
separate ticket required; limited to the first 150 registrants due to limited space
Saturday, August 3 • 4:00pm - 9:00pm
(inclusive of bus ride to Indiana University Health Proton Therapy Center, Bloomington)
Depart from Indiana Convention Center
Moderators: Indra Das and Lei Dong

Schedule
8:00am - 8:30am	An Overview of Proton Beam Therapy: Clinical PerspectiveHerman Suit: Massachusetts General Hospital
8:30am - 10:00am	Particle Beam Technology and Delivery This session will focus on the pros and cons of different methods of beam production; cyclotron, synchrotron, synchrocyclotron and newer devices in the context of technology, beam energy, treatment delivery options, reliability, and throughput. It will focus on science with big picture and a neutral view. Moderator: Jay Flantz Speakers: Jay Flanz: Synchrotron Vladimir Derenchuk: Cyclotron Rock Mackie: unconventional acceleration (laser, dielectric etc)
10:00am - 10:15am	Break
10:15am - 12:00pm	Proton Center Specific Configuration and Clinical Implementations Machine type, delivery system, patient load, morning QA, monthly QA, patient QA, calibration protocol and innovative approaches Moderators: Ron Zhu and Chee-Wai Cheng MGH: Hsiao-Ming Lu Loma Linda: Baldev Patyal IUHPTC: Chee-Wai Cheng MD Anderson: Narayan Sahoo University of Florida: Roelf Slopsema ProCure: Niek Schreuder University of Pennsylvania: James McDonough Washington University: Eric Klein Scripps: Anthony Mascia
12:00pm - 12:30pm	Boxed Lunch Pick Up
12:30pm - 2:15pm	Vendor-Specific Technology and Beam Delivery Techniques Vendors provide 15-minute presentations with Q&A during lunch. Moderators:  Indra Das and Lei Dong IBA: Yves Jongen Varian: Jan Timmer Hitachi: Masumi Umezawa Mevion: Lionel Bouchet ProNova: Joe Matteo Sumitomo: Yukio Kumata
2:15pm - 3:45pm	Treatment Planning, Outcome, and Economics of Proton Therapy Proton-specific treatment planning, plan evaluation, relative biological effectiveness, outcome, work flow, and reimbursement Moderator:  Radhe Mohan Treatment planning: Tony Lomax RBE, Neutron, Outcome: Harald Paganetti Economics: Peter Johnstone
4:00pm - 5:30pm	Travel to Indiana University Health Proton Therapy Center, Bloomington
5:30pm - 8:00pm	Tours and Dinner
8:00pm - 9:30pm	Return to Indiana Convention Center

Varian EDW

21 mu's and above

Great article from 1941 on the Varian brothers

http://upload.wikimedia.org/wikipedia/commons/6/61/The_Klystron_boys%2C_Radio%27s_miracle_makers_in_Saturday_Evening_Post_Feb_8%2C_1941.pdf

Great article on the Varian brothers from 1941. Reminded me of the book Tuxedo Park by Jennet Conant.

Interesting stat on Marginal Corporate Income Tax Rates

Country	Marginal Corporate Income Tax Rate
United States	40%
Japan	38%
France	33.3%
Australia	30%
Germany	29.5%
China	25%
South Korea	24.2%
United Kingdom	23%
Sweden	22%
Global Average	24%

Source: KPMG

 

 

Running again

I am hoping to start running more frequently again. The greatest part about signing up for races, is you can publicly shame yourself with lousy running times, which should serve as a motivator for future performance.

One site called Athlinks, accumulates some of your results and can even compare your results to other runners who have ran in the same races as you head to head. This site doesn't have all my results, but you can even submit race results to it. For instance it currently shows that i haven't ran a race since 2010, but there is at least one race from 2011 that should be posted.

Time to sign up for some races, I plan to run a slow 5-k this month.

For results check it out. Athlinks
http://athlinks.com/myresults/73871534/David-Roesener.aspx

And yes those horribly slow marathon results are mine.

Notes on VNC screen refresh issues

http://tightvnc.10971.n7.nabble.com/No-screen-refresh-using-TightVNC-client-on-XP-to-Vine-Server-server-on-OS-X-td2397.html




http://tightvnc.10971.n7.nabble.com/No-screen-refresh-using-TightVNC-client-on-XP-to-Vine-Server-server-on-OS-X-td2397.html

VNC install for remote viewing

Installing x11vnc on Fedora Core

This is a very short guide how to install x11vnc to your Fedora Core.

x11vnc allows one to view remotely and interact with real X displays (i.e. a display corresponding to a physical monitor, keyboard, and mouse) with any VNC viewer. In this way it plays the role for Unix/X11 that WinVNC plays for Windows.

x11vnc is by far the easiest available vnc server for Linux. Just download, configure/make, and off you go! And it works like a charm over ssh tunnel!

Here's how I installed x11vnc on my FC8:

1) Download .tar.gz from http://www.karlrunge.com/x11vnc/

2) Make sure you have X Software Development packets installed on your FC. To be sure, just open your sytem >> add/remove software, scroll down to development, and make sure you have X on your "x11 development".

3) After downloading http://www.karlrunge.com/x11vnc/x11vnc-0.9.4.tar.gz, just tar zxvf x11vnc-0.9.4.tar.gz, ./configure, make and make install

4) Now you have your x11vnc server ready to be tested... It's propably installed at /usr/bin/x11vnc, and you can test drive it by just typing the command "x11vnc".

 

 

FROM: http://thelinuxguru.blogspot.com/2008/02/installing-x11vnc-on-fedora-core.html

Referenced in: Evaluation of multiple image-based modalities for image-guided radiation

The probability of correct target dosage: dose-population histograms for deriving treatment margins in radiotherapy

Part of this material was presented at the 1998 ASTRO meeting in Phoenix, AZ.

Abstract 

Purpose: To provide an analytical description of the effect of random and systematic geometrical deviations on the target dose in radiotherapy and to derive margin rules.
Methods and Materials: The cumulative dose distribution delivered to the clinical target volume (CTV) is expressed analytically. Geometrical deviations are separated into treatment execution (random) and treatment preparation (systematic) variations. The analysis relates each possible preparation (systematic) error to the dose distribution over the CTV and allows computation of the probability distribution of, for instance, the minimum dose delivered to the CTV.
Results: The probability distributions of the cumulative dose over a population of patients are called dose-population histograms in short. Large execution (random) variations lead to CTV underdosage for a large number of patients, while the same level of preparation (systematic) errors leads to a much larger underdosage for some of the patients. A single point on the histogram gives a simple “margin recipe.” For example, to ensure a minimum dose to the CTV of 95% for 90% of the patients, a margin between CTV and planning target volume (PTV) is required of 2.5 times the total standard deviation (SD) of preparation (systematic) errors (Σ) plus 1.64 times the total SD of execution (random) errors (σ′) combined with the penumbra width, minus 1.64 times the SD describing the penumbra width (σ_p). For a σ_p of 3.2 mm, this recipe can be simplified to 2.5 Σ + 0.7 σ′. Because this margin excludes rotational errors and shape deviations, it must be considered as a lower limit for safe radiotherapy.
Conclusion: Dose-population histograms provide insight into the effects of geometrical deviations on a population of patients. Using a dose-probability based approach, simple algorithms for choosing margins were derived.