Advances in radiotherapy technology for pediatric cancer patients and roles of medical physicists: COG and SIOP Europe perspectives

Abstract

Over the last two decades, rapid technological advances have dramatically changed radiation delivery to children with cancer, enabling improved normal-tissue sparing. This article describes recent advances in photon and proton therapy technologies, image-guided patient positioning, motion management, and adaptive therapy that are relevant to pediatric cancer patients. For medical physicists who are at the forefront of realizing the promise of technology, challenges remain with respect to ensuring patient safety as new technologies are implemented with increasing treatment complexity. The contributions of medical physicists to meeting these challenges in daily practice, in the conduct of clinical trials, and in pediatric oncology cooperative groups are highlighted. Representing the perspective of the physics committees of the Children's Oncology Group (COG) and the European Society for Paediatric Oncology (SIOP Europe), this paper provides recommendations regarding the safe delivery of pediatric radiotherapy. Emerging innovations are highlighted to encourage pediatric applications with a view to maximizing the therapeutic ratio.

Keywords: COG; SIOP; medical physicist; pediatric cancer; radiation therapy.

FIGURE 1

Comparison of conventional parallel opposed field (A) and three-arc VMAT (B) plans for an adolescent female who received involved site RT for Hodgkin lymphoma. Clinical target volume (CTV) and PTV are shown in green and red, respectively. The delivered VMAT plan provided significant sparing of the heart, left lung, and left breast.

FIGURE 2

An example of a robust optimized IMPT plan for craniospinal irradiation of a 12-year-old male with medulloblastoma. No junction changes were required during the RT course. Dose distributions, from left to right, are for the brain treatment fields (A), the upper spine field (B), the lower spine field (C), and the sum of all fields (D).

FIGURE 3

An 11-year-old male with Hodgkin lymphoma who underwent 4D MRI to define the ITV for consolidative RT to the spleen. The spleen position differed by 16 mm between the end of exhalation (A) and the end of inhalation (B). The radiation dose distribution of the photon therapy plan is shown at right (C).