Lower GI 2017

Pelvic OARs constraints: genitals

- Dose to testicles vs testosterone levels and sexual libido: a controversial issue - Few prospective studies including dose estimates (Piroth 2003, Dueland 2003, Hermann 2005, Yau 2009, Hennies 2012) - Very large range of dose (<1 – 15 Gy), Evidence of transient and permament azoospermia for testicle doses above 1 and 2 Gy respectively (Yau 2009); higher rates Pragmatically: reducing the dose to testicles as much as possible (possibly < 2 Gy)

of ipogonadism with EBRT vs HDRB (testicles dose: 1.3 vs 0.3 Gy) - Lack of relationship between testicle dose & testosterone/libido decrease (Dueland 2003, Hennies 2012) - relevant issues on accuracy in dose calculation/estimates («out-of-field» dose in TPS = high uncertainty) - IMRT highly efficient (blocking options in VMAT/tomo) - Patient set-up, testicle shielding for very caudal field borders (head scatter)

Hennies 2015