RapidArc, SmartArc and TomoHD compared with classical step and shoot and sliding window intensity modulated radiotherapy in an oropharyngeal cancer treatment plan comparison

Table 2 Dose-volume constraints for PTVs and organs at risk

Target/Organ at risk	Median absorbed dose or D50%	Mean absorbed dose	ALARA	Dnear-min or D98%	Dnear-max or D2%
PTV 56	56 Gy		V59.9 Gy	≥ 95% of planned absorbed dose
PTV 69	69.12 Gy			≥ 95% of planned absorbed dose	≤ 107% of planned absorbed dose
PRV Spinal cord			D2		≤ 50 Gy
PRV Brainstem	≤ 55 Gy		D2		≤ 59 Gy
Parotid gland contralateral		≤ 23 Gy	Mean D, V27
Parotid gland ipsilateral		≤ 27 Gy	Mean D, V27
Submandibular gland		≤ 39 Gy	Mean D
Oral mucosa		≤ 27 Gy	Mean D, V27
Mandible			V60
Soft palate		≤ 27 Gy	Mean D, V27
Constrictor muscles		≤ 55 Gy	Mean D, V20
Cricopharyngeal muscle		≤ 55 Gy	Mean D, V20
Base of tongue		≤ 55 Gy	Mean D, V20
Larynx		≤ 40 Gy	Mean D, V40
Esophagus superior		≤ 35 Gy	Mean D, V35
Top of lung			V20
Inner ear			Mean D, V45

PTV = planning target volume; PRV = planning risk volume; Vx =% volume receiving x Gy; Dx = dose to x% of the volume; D = dose; ALARA = as low as reasonable achievable.

ISSN: 1748-717X