Basics of particle therapy II: relative biological effectiveness

Abstract

In the previous review, the physical aspect of heavy particles, with a focus on the carbon beam was introduced. Particle beam therapy has many potential advantages for cancer treatment without increasing severe side effects in normal tissue, these kinds of radiation have different biologic characteristics and have advantages over using conventional photon beam radiation during treatment. The relative biological effectiveness (RBE) is used for many biological, clinical endpoints among different radiation types and is the only convenient way to transfer the clinical experience in radiotherapy with photons to another type of radiation therapy. However, the RBE varies dependent on the energy of the beam, the fractionation, cell types, oxygenation status, and the biological endpoint studied. Thus this review describes the concerns about RBE related to particle beam to increase interests of the Korean radiation oncologists' society.

Characterization of a multilayer ionization chamber prototype for fast verification of relative depth ionization curves and spread‐out‐Bragg‐peaks in light ion beam therapy

“…Moreover, the relative biological effectiveness (RBE) values of higher Z ion beams (carbon ions, in particular) enhance the therapeutic gain, when compared with photons and lower Z particle beams, such as protons. RBE varies with LET; therefore, it depends on the penetration depth along the ionization curve (IC) …”

Particle Therapy for Breast Cancer: Benefits and Challenges

“…The relative biologic effectiveness (RBE) concept has been introduced to account for this increased efficiency of cell killing. At clinical institutions, an RBE value of 1.1 to 1.2 has been documented for proton therapy, while for the heavier carbon ions, the RBE distribution in the targeted tissues varies between 2 and 5 ( 4 ). The direct-killing effect of heavy ions maintains their ability to kill malignant cells irrespective of oxygen concentration.…”

Clinical Limitations of Photon, Proton and Carbon Ion Therapy for Pancreatic Cancer

“…As a result, investigations into heavier particles which induce more severe DNA damage continue (compared to both PT and XRT). Carbon-ion therapy (Cion) utilises charge carbon-12 ions of larger mass to increase direct DNA damage effectiveness by a factor of approximately two to four [13][14][15][16]. Recently established at a handful of institutions, the improved dose conformation and potential for overcoming effects of hypoxia is currently being investigated as a potential solution for LAPC [11,17].…”