Target Volume Determination 2015

Determining GTV: CT • Challenges for radiotherapy planning: – Atelectasis – Effusion – Lymph node involvement • Use of lung and soft tissue window side-by- side – Lung window for lung interfaces – Soft tissue window for mediastinal and hilar interfaces – Bone window if infiltration suspected • Use of MPR display • Lymph nodes remain difficult

Determining GTV: PET/CT • Change of GTV from CT alone in 52% • Increase of concordance among observers from 37% to 84% Black: CT, Purple: PET/CT

Determining GTV: PET/CT • PET adds essential information to CT – Significant consequences on GTV, CTV and PTV

» Range 21 -100 % of patients » Lymph node involvement

» Differentiation tumor vs. atelectasis – Shortcoming: Inflammatory disease • Generally recommended for all dose escalation studies

Steenbakkers et al Radiother Oncol 2005

Grosu et al Strahlenther Onkol 2005

Ashamalla et al, IJROBP 2005

3.4 ± 1.6 ML Lung Tumor Mobility

Lung Tumor Mobility after Radiotherapy

9.5 ± 4.9 7.2 ± 1.8 4.3 ± 2.4 CC 4.3 ± 2 4 9.5 ± 4.9 7.2 ± 1.8 4.3 ± 2.4 CC

6.1 ± 3.3 4.3 ± 2.2 2.8 ± 1.3 AP 6.1 ± 3.3 4.3 ± 2.2 2.8 ± 1.3 AP 2.8 ± 1.3 AP

6.0 ± 2.8 4.3 ± 2.4 3.4 ± 1.6 ML 6.0 ± 2.8 4.3 ± 2.4

Lung motion

Tumor mobility during shallow breathing [mm]

Plathow et al. 2005