. 2015 Sep 8;16(5):14–34. doi: 10.1120/jacmp.v16i5.5768

Table 6.

Heterogeneous TPS photon beam validation tests

Test	Objective	Description	Tolerances ^a	Reference
6.1	Validate planning system reported electron (or mass) densities against known values	CT‐density calibration for air, lung, water, dense bone, and possibly additional tissue types	–	TG 65, ⁽²⁶⁾ IAEA TRS‐430 ⁽⁷⁾
6.2	Heterogeneity correction distal to lung tissue	$5 \times 5 {cm}^{2}$ , measure and calculate dose ratio above and below heterogeneity, outside of the buildup region	3%	IAEA TRS‐430, ⁽⁷⁾ Carrasco et al. ⁽²⁸⁾

Tolerances are relative to local dose unless otherwise noted.