Practical Application of planning techniques Flashcards
what does ICRU stand for?
International commission on radiation units and measurements
what is the iCRU 50
Promote use of common language for specifying/reporting doses in radiation therapy and volumes in which they’re prescribed
what volumes must be contoured according to ICRU 50?
GTV - primary tumour
CTV - GTV and sub clinical disease
PTV - allow for uncertainties such as patient motion
treated volume - recognise that isodose often does not conform perfectly to PTV - 20% isodose line
what dose do you report (50)?
minimum dose to ptv
max dose to ptv
mean dose to ptv
dose at icru ref point
what is the ICRU Reference point
point in PTV where dose is prescribed to (100% of prescription)
centre of PTV
What is the ICRU 62?
new techniques rely on modern imaging procedures to provide more complete information on location, shape and limits of target volumes and OARS
what is the internal target volume?
Accounts for variation of GTV
What is systematic error
affects all fractions
wrongly placed tattoos
wrong set up information
what is a random error
affects one fraction
imaging mismatch
what is ICRU 83
remainging volume at risk difference between volume enclosed by external contour of patients + that of GTV and OARS on imaged slices
