Medical Radiation – Neutrons vs Protons

NEUTRONS vs PROTONS

 

NEUTRONS

PROTONS

Type of particle

Neutral, mass=1

Positively charged, mass=1 

Production [high energy]
(iThemba)

Nuclear reactions [40-70 MeV protons or deuterons on beryllium]
(66 MeV protons)

Accelerator beams [>150  MeV]
(200 MeV)

Interactions with tissue

Nuclei (mainly hydrogen)

Electrons 

No. of centres

5
(2 high-energy)

34
(6 low energy) 

Beam delivery

(iThemba)

Vertical, horizontal, mainly isocentric beams. [Fixed, variable, multileaf collimators] 
(Isocentric, variable collimator, multiblade trimmer)

Mainly horizontal, vertical, isocentric beams; passive, active beam spreading. [Fixed, multileaf collimators] 
(Horizontal, fixed collimators)

Major clinical advantage

Biological effect
[large, slow-growing lesions] 

Dose distribution
[lesions close to critical structures] 

No. of patients treated wordwide
(iThemba)

40 000 (estimated)

(1690)

67097

(511)

No. of fields
(iThemba)

1 – 6
(1 – 8)

1 – 12
(1 – 5)

No. of 
treatments
(iThemba)

12 – 20

12

1 – 36

(1 – 5)

Lesions
* definite cure for most cases 

(Malignant only)
Salivary gland*, paranasal sinus,
head and neck, soft tissue sarcoma*,
uterine sarcoma, prostate * ,
melanoma, bone tumour, breast 

(Benign and malignant) 
Uveal melanoma*, pituitary adenoma * , meningioma*, prostate,
arteriovenous malformation * , cervix, acoustic neuroma*,
paranasal sinus, chondrosarcoma *

Top of Page

From the Director’s Office

A New Year brings new opportunities to share a vision, build collaborations and shape the future.

Read more

Corporate Profile

Corporate profile of iThemba LABS in February issue of Leadership Magazine p. 68-69

Read more p. 68-69

Physics Masterclasses

The International Masterclasses in Particle Physics will be held on 1st April at iThemba LABS. These classes give secondary school students the opportunity to discover the world of quarks and leptons for themselves.
See Gallery of images from last year's masterclass

Read more ...

SA-CERN Collaboration

Big data science in South Africa reaching new funding highs through the South African CERN collaboration

Read more ...

News Archive