What does GTV stand for in radiation oncology?

GTV stands for Gross Tumor Volume in radiation oncology. This term is critical for treatment planning as it refers to the visible or palpable extent of the tumor as determined through imaging studies or by surgical assessment. Accurately delineating the GTV is essential for effective radiation therapy, as it directly influences the target volumes that need to be covered by the treatment plan to ensure effective tumor control while minimizing exposure to the surrounding healthy tissues.

The definition of GTV helps in understanding the anatomy of the cancer present before treatment, guiding oncologists and dosimetrists in determining the optimal radiation dose distribution to adequately target the tumor. The GTV is typically the starting point for developing additional target volumes, such as the Clinical Target Volume (CTV) and Planning Target Volume (PTV), which account for microscopic disease and variations in patient positioning, respectively.