A three-dimensional CT-based target definition for elective irradiation of the neck

• Published in: International journal of radiation oncology, biology, physics Vol. 45; no. 1; pp. 33 - 39
• Main Authors: Nowak, Peter J.C.M, Wijers, Oda B, Lagerwaard, Frank J, Levendag, Peter C
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.08.1999; Elsevier
• Subjects: Biological and medical sciences; Cadaver; Conformal therapy; Dry mouth; Elective; Head and Neck Neoplasms - radiotherapy; Humans; Image Processing, Computer-Assisted; Lymph node levels; Medical sciences; Miscellaneous; Neck; Neck - anatomy & histology; Neck - diagnostic imaging; Neck Dissection; Radiation; Radiotherapy Planning, Computer-Assisted - methods; Radiotherapy. Instrumental treatment. Physiotherapy. Reeducation. Rehabilitation, orthophony, crenotherapy. Diet therapy and various other treatments (general aspects); Three-dimensional; Tomography, X-Ray Computed; Xerostomia; Three-dimensional; Dry mouth; Radiation; Conformal therapy; Neck; Elective; Xerostomia; Lymph node levels; Human; 3D imaging; Radiodiagnosis; Lymph node; Salivary gland; Selectivity; Malignant tumor; Radiotherapy; Conformal radiotherapy; Treatment; Medical imagery; ENT disease; Computerized axial tomography; Technique; Treatment planning
• ISSN: 0360-3016; 1879-355X
• DOI: 10.1016/S0360-3016(99)00049-8

Introduction: Elective treatment of the clinically node-negative neck by radiation results in excellent control rates. However, radiation therapy with its organ-preserving properties is not without morbidity. Side effects of elective neck irradiation are mainly due to damage of the major and minor salivary glands, resulting in the dry mouth syndrome. Given that RT is the preferred treatment modality in case of elective treatment of the neck in many institutions, it is of utmost importance to try and reduce the associated sequelae of RT. Material and Methods: With the introduction of CT-planning systems and the development of 3D conformal radiation therapy (3D CRT) techniques, it has become feasible to deliver adequate doses of radiation to the target (neck) and at the same time saving (parts of) the salivary glands from doses beyond tolerance. A prerequisite for these techniques is that they require a precise knowledge of the target (i.e., of the elective neck) on CT. To be able to correlate borders of the surgical levels in the neck (I–VI) with structures seen on CT, an anatomical study, using two fixed (phenol, formaldehyde) human cadavers, was performed. Subsequently, the 6 potential lymph node regions in the neck on CT were defined. Results and Discussion: The reference for the current 3D CT-based definition of the lymph node regions in the neck is the official report of the American Academy of Otolaryngology, describing, based on surgical anatomy, the lymph node groups in the neck by Levels I–VI. The present investigation depicts reproducible landmarks on transversal CT images, corresponding to anatomical reference structures known from surgical levels (I–VI) and, this way, CT-based lymph node regions (1–6) were constructed.