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Appendix 2 - Levels of IGRT complexity

 

Level

Goal

Imaging Technique

Imaging frequency

Correction strategy

(or comment)

Treatment  (comparing surrogate anatomy)

1a

Reduce gross setup error 

Analyse using bony anatomy

First fraction only

Online: Correct  gross error

1b

Reduce initial systematic setup error

Analyse using bony anatomy

First 3-5 fractions and

weekly

 Offline: 1st 3-5 # Calculate  and correct systematic error *

Weekly-  check within threshold

1c

Continuous reduction of systematic error

Analyse using bony anatomy

 First 3-5 fractions and

weekly

 Offline: 1st 3-5# Calculate  and correct systematic error*

Weekly- re-calculate and correct systematic error 

1d

Reduce random and systematic error

Analyse using bony anatomy

Daily or less

 Online : if  <daily then calculate and correct systematic errors*

1e

Reduce uncertainty from anatomy changing trends

Analyse using  bony anatomy and/or  visual check/quantitative check of set up parameters

Weekly or more frequently

Off line: Consider intervention

 

 

Level

Goal

Imaging Technique

Imaging frequency

Correction strategy

(or comment)

Treatment  (comparing surrogate anatomy)

1a

Reduce gross setup error 

Analyse using bony anatomy

First fraction only

Online: Correct  gross error

1b

Reduce initial systematic setup error

Analyse using bony anatomy

First 3-5 fractions and

weekly

 Offline: 1st 3-5 # Calculate  and correct systematic error *

Weekly-  check within threshold

1c

Continuous reduction of systematic error

Analyse using bony anatomy

 First 3-5 fractions and

weekly

 Offline: 1st 3-5# Calculate  and correct systematic error*

Weekly- re-calculate and correct systematic error 

1d

Reduce random and systematic error

Analyse using bony anatomy

Daily or less

 Online : if  <daily then calculate and correct systematic errors*

1e

Reduce uncertainty from anatomy changing trends

Analyse using  bony anatomy and/or  visual check/quantitative check of set up parameters

Weekly or more frequently

Off line: Consider intervention

 

 

Level

Goal

Imaging Technique

Imaging frequency

Correction strategy

(or comment)

Treatment  (comparing target anatomy)

2a

Reduce gross setup error

Analyse using target anatomy or implanted markers 

First fraction only

Online: Correct gross error

 

2b

Reduce initial systematic error

Analyse using target anatomy or implanted markers 

First 3-5 fractions and

weekly

 Offline: 1st 3-5#

Calculate  and correct Systematic error*

Weekly-  check within tolerance

2c

Continuous reduction of systematic error

Analyse using target anatomy or implanted markers 

 First 3-5 fractions and

weekly

Offline: 1st 3-5#

Calculate  and correct systematic error 

Weekly- re-calculate and correct systematic error

2d

Reduce random and systematic error

Analyse using target anatomy or implanted markers 

Daily

Online: daily imaging ideally throughout treatment course**

2e

Reduce uncertainty from gross anatomy changes of  target or OAR

Analyse using target anatomy or implanted markers 

Weekly or more frequently

Online or offline: Consider intervention  

 

 

Level

Goal

Imaging Technique

Imaging frequency

Correction strategy

(or comment)

Treatment (correct intrafractional error)

3a

Reduce  intra-fraction errors

Online analysis using tracking (repeated imaging during delivery)

Real time or periodic intermittent imaging (can be in conj. with any other imaging freq.)

Online: Interrupt treatment during delivery and correct errors greater than action level

3b

Reduce uncertainty from physiological movements (i.e. respiratory)

Online analysis using automatically gated imaging system (delivered only when target within treatable position)

Real time monitoring

Online: System automatically gated to deliver only when tumour is within treatable position (following action level).

3c

Reduce uncertainty from physiological movements (i.e. respiratory) and automatically correct

Automatic online detection and analysis of target position

Real time monitoring

Online: System configured to change the treatment field to track the tumour.

 

 

Level

Goal

Imaging Technique

Imaging frequency

Correction strategy

(or comment)

Adaptive RT

4a

Reduce uncertainties from shape change  (pre-scheduled repeat planning CT)

Schedule repeat planning imaging during treatment course.

Offline dosimetric assessment

Once to weekly

Re-plan when dosimetric action level exceeded

4b

Reduce uncertainties from shape change

Treatment unit imaging  & online or offline  dosimetric analysis (identifying changes in probable tumour coverage from shape change)

As seen

Re-plan to assess for dosimetric changes.  Implement changes

 

4c

Reduce uncertainties from shape change (pre-planned treatment imaging assessments)

Treatment unit imaging  & online or offline  geometric analysis

Compare plan database for best fit (for that fraction)

Each fraction

Deliver ‘plan-of-the-day’ for that fraction

4d

Reduce uncertainties from shape change (react throughout treatment imaging session)

Treatment unit imaging  & online dosimetric analysis

Each fraction

Real-time (4D) ART

 

 

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