25 Oesophageal Cancer

Oesophageal Cancer Brachytherapy

15

THE GEC ESTROHANDBOOKOF BRACHYTHERAPY | Part II Clinical Practice Version 1 - 10/06/2019

Table 27.1: Mucosal doses per fraction (absorbed dose, EQD2 3

) and total mucosal doses (EQD2 3

) in the curative setting for different applicator diameters and fraction doses (prescribed at reference depth

of 5 mm) – TPS calculations from simulation of a line source with 10 cm Active Source Length for absorbed dose; EQD2 calculations based on web calculator.

Fraction doses at 5mm ref depth absorbed dose (EQD2 10

) in Gy

Mucosal doses per fraction absorbed dose(EQD2 3

) in Gy by applicator diameter

5mm

10mm

15mm

20mm

6.7 (13) 11 (30.8) 13.5 (44.5) 16 (60.8)

6 (10.8) 10 (26) 12 (36) 14 (47.6)

4 (5.6) 6.3 (11.7) 7.9 (17.2) 9.4 (23.3)

3.9 (5.4) 6.2 (11,4) 7.8 (16.8) 9.3 (22.9)

2.5 (2.6) 4 (4.7) 5 (6.25) 6 (8)

Reference depth doses ( EQD2 10

) and total mucosal doses ( EQD2 3

) and after 60 Gy external beam radiotherapy in 2.0 Gy per fraction and 2 fractions of

brachytherapy

Fraction dose (total EQD2 10

) in Gy

Total mucosal doses (EQD2 3

) in Gy by applicator diameter

5mm

10mm

15mm

20mm

73.4 (86) 82 (121.6) 87 (149) 92 (181.6)

72 (81.6) 80 (112) 84 (132) 88 (155.2)

68 (71.2) 72.6 (83.4) 75.8 (94.4) 78.8 (106.6)

67.8 (70.8) 72.4 (82.8) 75.6 (93.6) 78.6 (105.8)

2.5 (65.2) 4 (69.4) 5 (72.5) 6 (76)

Reference depth doses ( EQD2 10

) and total mucosal doses ( EQD2 3

) and after 50 Gy external beam radiotherapy in 2.0 Gy per fraction and 2 fractions of

brachytherapy

Fraction dose (total EQD2 10

) in Gy

Total mucosal doses (EQD2 3

) in Gy by applicator diameter

5mm

10mm

15mm

20mm

63.4 (76) 72 (111.6) 77 (139) 82 (171.6)

62 (71.6) 70 (102) 74 (122) 78 (145.2)

58 (61.2) 62.6 (73.4) 65.8 (84.4) 68.8 (96.6)

57.8 (60.8) 62.4 (72.8) 65.6 (83.6) 68.6 (95.8)

2.5 (55.2) 4 (59.4) 5 (62.5) 6 (66)

Radial dose distribution endo-oesophageal catheter ASL 80 mm

Radial dose distribution Larger endo-oesophageal catheter ASL 80 mm

Radial dose distribution Small endo-oesophageal catheter ASL 80 mm

Radial dose distribution Larger endo-oesophageal catheter ASL 80 mm

Endo-oesophageal Catheter Diameter 12mm

Endo-oesophagealCatheter Diameter 4mm

100 % Prescribed dose at 6 + 3 = 9 mm (Curative intent)

100 % Prescribed Dose at 10 mm from the source axis at 10 mm Reference depth dose (5 mm from applicator) 148 % PD

Reference depth dose (5 mm from applicator) 79 % in tissue Maximum dose at applicator surface 155 % PD on surface 200 % PD in applicator 400 % PD in applicator

Maximum dose at applicator surface 540 % PD on surface 400 % PD in tissue 200 % PD in tissue

Fig 24.11 Radial dose distribution around a small applicator (4 mm).The ASL is 80mm with2mm step size and geometrical optimisation on distance. The Maximum surface dose is 540% of the prescribed dose at 10 mm. The 200% and 400% isodoses are in the tissues. (tumor and / or oesophageal wall) Fig. 27.11. Radial dose distribution around a small applicator (4 mm). The ASL is 80 mm with 2 mm step size an g ometrical optimisation on distan e. The maximum surface dose is 540% of the prescribed dose at 10 mm. The 200% and 400% isodoses are in the tissues (tumour and / or oesophageal wall).

Fig. 27.10. Radial dose distribution around a large applicator (12 mm). The ASL is 80 mm with 2mm step size and geometrical optimisation on distance. The maximum surface dose is 175% of the prescribed dose at 10 mm. The 200% and 400% isodoses are within the applicator. Fig 24.10 Radial dose distribution around a large applicator (12 m ). ASL is 80mm with applicator. 2mm step size and geometrical optimisation on distance. The Maximum surface dose is only 175% of the prescribed dose at 10 mm. The 200% and 400% isodoses are in the applicator.