RT treatment details

Question 1

Involved Field Borders for Unilateral Cervical/SCL

Answer 1

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

Question 2

Dose threshold to start for larynx block

Answer 2

19.8 Gy

Question 3

Dose threshold to start cord block

Answer 3

40 Gy

Question 4

Involved Field Considerations for Bilateral Cervical/SCL

Answer 4

1. Use posterior mouth block

2. Treat full fields regardless of extent of disease on each side

Question 5

Involved field Mediastinum or hilar nodes

Answer 5

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

Question 6

Involved Field Axilla

Answer 6

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

Question 7

Involved Field Spleen

Answer 7

Treat post-chemo volume + 1.5 cm

Question 8

Involved Field Paraaortic

Answer 8

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

Question 9

Involved Field Femoral/External Iliac

Answer 9

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

Question 10

IFRT dose for CR to chemo?

Answer 10

30.6 Gy at 1.8 Gy per fraction in 17 fractions

Question 11

IFRT dose for bulky disease initially?

Answer 11

36 at 1.8 Gy per fraction in 20 fractions or

39.6 Gy at 1.8 Gy per fraction in 22 fractions

Question 12

What is meant by Subtotal lymphoid irradiation?

Answer 12

It includes mantle and inverted Y fields but sans the inguinal/femoral nodal regions

Question 13

When do you perform CT simulation with arms up?

Answer 13

When treating the axilla, so that the nodes are drawn up and less radiation will be provided to the lungs.

Question 14

What should be targeted when treating DLBCL involving Waldeyers ring?

Answer 14

1. Bilateral tonsil
2. Base of tongue
3. Nasopharynx
4. Bilateral cervical neck
5. Bilateral SCL nodes

Question 15

What nodal regions does a Mantle Field include?

Answer 15

1. Bilateral cervical
2. supraclavicular
3. infraclavicular
4. mediastinal
5. axillary

Question 16

What are the draw backs to simulating with ams up?

Answer 16

1. SCL skin folds will be present

Question 17

What are the sites that you use the post-chemo volume for?

Answer 17

1. Hilar/Mediastinum
2. Spleen
3. Paraaortic nodes