Table 2 Advocated safety margins

Schefter et al. 2005 [20]

SBRT of liver metastases

Minimum distance between GTV and PTV surfaces:

— 0.5 cm, axial planes

— 1.0 cm, superior/inferior

Cumulative maximum tumourdiameter: < 6 cm

Katria et al. 2010 [21]

IGRT of abdomen and pelvis

Stroom's and Van Herk's margins (cm):

— 0.39 and 0.35 mm, anterior-posterior

— 0.94 and 0.46 mm, medial-lateral

— 0.40 and 1.09 mm, superior-inferior

Wysocka et al. 2010 [22]

Median 3.8 mm intrafraction craniocaudal displacement for coeliac axis with smaller displacements for other axes

RTOG consensus guidelines [23]

Inguinal lymph nodes

Caudad extent of the inguinal region : 2 cm to the saphenous/femoral junction

Kim et al. 2011 [24]

Inguinal and femoral nodes

2.2 - 2.9 cm around femoral vessels

Van Weieringen et al. 2011 [25]

Pelvic lymph nodes

For offline and online correction protocols, respectively:

— 7 and 5 mm, left-right

— 6 and 5 mm,craniocaudal

— 8 and 7 mm,dorsoventral