Recurrences of cervical cancer after definitive radiotherapy often occur at common iliac or para-aortic lymph nodes as marginal lymph node recurrences. Patients with these recurrences have a chance of long-term survival by optimal re-treatment with radiotherapy. However, the re-irradiation often overlaps the initial and the secondary radiotherapy fields and can result in increased normal tissue...

Background: In radiation therapy with ion beams, lateral distributions of absorbed dose in the tissue are important. Heavy ion therapy, such as carbon-ion therapy, is a novel technique of high-precision external radiotherapy which has advantages over proton therapy in terms of dose locality and biological effectiveness.Methods: In this study, we used Monte Carlo method-based Geant4 toolkit to s...

Among various types of ion species, carbon ions are considered to have the most balanced, optimal properties in terms of possessing physically and biologically effective dose localization in the body. This is due to the fact that when compared with photon beams, carbon ion beams offer improved dose distribution, leading to the concentration of the sufficient dose within a target volume while mi...

Cerebral radionecrosis is a significant side effect in radiotherapy for brain cancer. The purpose of this study is to calculate the relative biological effectiveness (RBE) of carbon-ion beams on brain cells and to show RBE-weighted dose distributions for cerebral radionecrosis speculation in a carbon-ion treatment planning system. The RBE value of the radionecrosis for the carbon-ion beam is ca...

Monitoring mice exposed to carbon ion radiotherapy provides an indirect method to evaluate the potential for second cancer induction in normal tissues outside the radiotherapy target volume, since such estimates are not yet possible from historical patient data. Here, male and female B6C3F1 mice were given single or fractionated whole-body exposure(s) to a monoenergetic carbon ion radiotherapy ...

In June 1994, the world's first clinical center offering carbon ion radiotherapy opened at the National Institute of Radiological Science (NIRS), Japan. Among several types of ion species, carbon ions were chosen for cancer therapy because they were judged to have the most optimal properties in terms of superior physical and biological characteristics. As of March 2010, 5,196 patients have been...

Carbon ion therapy is a type of radiotherapies that can deliver high-dose radiation to a tumor while minimizing the dose delivered to the organs at risk; this profile differs from that of photon radiotherapy. Moreover, carbon ions are classified as high-linear energy transfer radiation and are expected to be effective for even photon-resistant tumors. Recently, high-precision radiotherapy modal...

Background: High-velocity carbon ion beams represent the most advanced tool for radiotherapy of deep-seated tumors. Currently, the superiority of carbon ion therapy is more prominent on lung cancer or hepatomas. Materials and Methods: The data for lateral straggling and projected range of monoenergetic 290 MeV/u (3.48 GeV) carbon ions in muscle tissue were obtained from the stopping and range o...

PURPOSE The purpose is to evaluate the efficacy and toxicity of carbon ion radiotherapy for unresectable sacral chordomas. EXPERIMENTAL DESIGN We performed a retrospective analysis of 30 patients with unresectable sacral chordomas treated with carbon ion radiotherapy at the Heavy Ion Medical Accelerator in Chiba, Japan. Twenty-three patients presented with no prior treatment, and the remainin...

The aim of this work was to study the influence of Geant4 parameters on dose distribution and computational time for simulations of carbon ion therapy. The study was done using Geant4 version 9.0. The dose distribution in water for incident monoenergetic carbon ion beams of 300 MeV/u were compared for different values of secondary particle production threshold and different step limits. Variati...