Study of dosimetric indices and dose constraints to critical organs for head and neck tumours treated with inverse planned simultaneous integrated boost intensity-modulated radiotherapy

• Published in: Journal of radiotherapy in practice Vol. 17; no. 2; pp. 179 - 187
• Main Authors: Atiq, Atia, Atiq, Maria, Iqbal, Khalid, Shamsi, Qurat-ul-ain, Ahmad Buzdar, Saeed
• Format: Journal Article
• Language: English
• Published: Cambridge, UK Cambridge University Press 01.06.2018
• Subjects: Brain damage; Brain stem; Cancer; Cancer therapies; Damage tolerance; Dosimetry; Head & neck cancer; Homogeneity; Larynx; Optic chiasm; Optic nerve; Organs; Original Article; Patients; Planning; Quality assurance; Quality control; Radiation therapy; Risk reduction; Spinal cord; Tumors; United States > US; conformity index; simultaneous integrated boost; dose constraints; head and neck cancer; homogeneity index
• ISSN: 1460-3969; 1467-1131
• DOI: 10.1017/S1460396917000668

Abstract Aim This study aimed to investigate tolerance dose to organs at risk (OARs) as well as degree of conformity and homogeneity for head and neck cancer patients by using simultaneous integrated boost intensity-modulated radiotherapy technique (SIB IMRT). Materials and methods This study analysed 15 head and neck cancer patients receiving treatment using inverse planned SIB IMRT technique. Using a beam energy of 6 MV, two dose levels of 70 and 55·4 Gy were used to treat the tumour. Doses of 2 Gy in 35 fractions and 1·68 Gy in 33 fractions were simultaneously delivered for effective planning target volume (PTV1) and boost planning target volume (PTV2), respectively. Results Dose distribution in PTV and critical organs lies within tolerance dose guidelines protecting spinal cord, brain stem, optic chiasm, optic nerve, thus reducing the risk of damage to normal tissues. Minor deviation from tolerance limit was observed for parotid glands. This technique provided highly conformal and homogenous dose distribution as well as better sparing of OARs, hence verifying quality assurance results to be satisfactory. Findings SIB IMRT technique offers best solution for preserving organ function by keeping dose below tolerance level. Treatment of head and neck carcinoma using SIB IMRT is feasible, more efficient, and dose escalation is achieved in a single plan.