RT treatment details Flashcards
Involved Field Borders for Unilateral Cervical/SCL
Sup: 1-2 cm above lower tip of mastoid process and midpoint through chin unlesss only SCL is involved in which case superior border is at level of larynx
Inf: 2 cm below clavicle
Lat: include medial 2/3 of clavicle
Medial:
1. Include vertebral body (if medial nodes near vertebrae) to contralateral TP
2. Contralateral transverse process (if SCL nodes involved)
3. Otherwise, limit to ipsilateral transverse process
Dose threshold to start for larynx block
19.8 Gy
Dose threshold to start cord block
40 Gy
Involved Field Considerations for Bilateral Cervical/SCL
- Use posterior mouth block
2. Treat full fields regardless of extent of disease on each side
Involved field Mediastinum or hilar nodes
Sup: C5-C6 interspace
Inf: 5 cm below carina or 2 cm below pre-chemo border (whichever is lower)
Lateral: post-chemo volume
Hilum + 1 cm (not involved) or OR + 1.5 cm (if involved)
Include medial SCL nodes even if not clinically involved
Involved Field Axilla
Sup: C5-C6 interspace
Inf: Tip of scapula or 2 cm below lowest axillary node (whichever is lower)
Lateral: flash axilla
Medial: ipsilateral cervical transverse process
Involved Field Spleen
Treat post-chemo volume + 1.5 cm
Involved Field Paraaortic
Sup: Top of T11 Inf: Bottom of L4 Lat: Edge of transverse processes >2 cm on post-chemo volume for lateral Consider kidneys when designing blocks Include porta hepatis if originally involved
Involved Field Femoral/External Iliac
Sup: Middle of S-I joint
L4-L5 if common iliacs involved
Inf: 5 cm below lesser trochanter
Lateral: Greater trochanter >2 cm outside involved nodes
Medial: Medial border of obturator foramen
>2 cm outside involved nodes
IFRT dose for CR to chemo?
30.6 Gy at 1.8 Gy per fraction in 17 fractions
IFRT dose for bulky disease initially?
36 at 1.8 Gy per fraction in 20 fractions or
39.6 Gy at 1.8 Gy per fraction in 22 fractions
What is meant by Subtotal lymphoid irradiation?
It includes mantle and inverted Y fields but sans the inguinal/femoral nodal regions
When do you perform CT simulation with arms up?
When treating the axilla, so that the nodes are drawn up and less radiation will be provided to the lungs.
What should be targeted when treating DLBCL involving Waldeyers ring?
- Bilateral tonsil
- Base of tongue
- Nasopharynx
- Bilateral cervical neck
- Bilateral SCL nodes
What nodal regions does a Mantle Field include?
- Bilateral cervical
- supraclavicular
- infraclavicular
- mediastinal
- axillary