What is Proton Beam Therapy?

ASHYA KING is a five year old British boy with a Grade IV* brain tumour. His parents, disapproving of the treatment he was receiving, removed him from the hospital and drove to Spain.


The hospital alerted the police and an EU arrest warrant was issued.


A legal battled ensued, during which Ashya became a ward of the court.


And while Ashya was in hospital in Spain, his parents were in prison awaiting the decision of an extradition tribunal.


But following several intense rounds of legal wrangling, they were granted permission to leave Spain and travel via plane to Prague, where Ashya will start receiving a treatment called proton beam therapy. It is the treatment originally sought by his parents, as it is their belief the therapy is the only chance Ashya has of surviving.


*Grade IV Tumours: Tumours in which the malignant tissue has cells that look most abnormal and tend to grow quickly.



Control panel of the synchrocylotron at the 
Orsay proton therapy Centre, France

What exactly is Proton beam therapy? (Source: Wikipedia)

Proton beam therapy is a medical procedure that uses a beam of protons to irradiate diseased tissue, most often in the treatment of cancer.

Proton therapy's chief advantage over other types of external beam radiotherapy is that it can more precisely localize the radiation dose.In proton therapy, medical personnel use a particle accelerator to target a tumor with a beam of protons.[1] These charged particles damage the DNA of cells, ultimately killing them or stopping their reproduction. Cancerous cells are particularly vulnerable to attacks on DNA because of their high rate of division and their reduced abilities to repair DNA damage. 

Proton therapy shares risks and side effects of other forms of radiation therapy. However the dose outside of the treatment region can be significantly less for deep-tissue tumors than x-ray therapy, because proton therapy takes full advantage of the *Bragg peak.


Proton therapy has been in use for over 40 years, and is a mature treatment technology. However, as with all medical knowledge, understanding of the interaction of radiation (proton, X-ray, etc.) with tumor and normal tissue is still imperfect.[2][3]


*Bragg peak: The Bragg curve plots the energy loss of ionizing radiation during its travel through matter. For protons, the peak on the Bragg curve occurs immediately before the particles come to rest. The phenomenon is exploited in cancer therapy, to concentrate the effect of light ion beams on the tumor being treated while minimizing the effect on the surrounding healthy tissue.[4] Whereas with photons (X rays) the curve is mainly exponential.
  


UPDATE

March 23, 2015  Ashya King Gets 'All Clear'





REFERENCES

[1]  "Zap! You're not dead." Economist, 8 September 2007. 384 (8545):13-14

[2] Joel E. Tepper, MD, and A. William Blackstock, MD "Randomized Trials and Technology Assessment" Annals of Internal Medicine 151(8) 2009
[3] Federal Agency for Healthcare Research and Quality "Technical Brief: Particle Beam Radiation Therapies for Cancer" 2009
[4] Trikalinos, TA et al (2009). Particle Beam Radiation Therapies for Cancer [Internet]. Comparative Effectiveness Technical Briefs, No. 1. Rockville (MD): Agency for Healthcare Research and Quality (US). pp. ES1–ES5.

https://www.youtube.com/watch?v=3o2JFGekqcg
http://www.dailymail.co.uk/news/article-2745606/Finally-family-little-Ashya-win-fight-fly-Prague-proton-beam-therapy-save-life.html
http://www.cancer.net/cancer-types/brain-tumor/staging-and-prognostic-factorshttp://www.cancer.gov/cancertopics/wyntk/brain/page3
http://en.wikipedia.org/wiki/Proton_therapy
O. Jakel: State of the art in hadron therapy. AIP Conference Proceedings, vol. 958, no.1, 2007, pp. 70-77

IMAGE CREDIT

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