The safety and efficacy of carbon-ion radiotherapy for advanced non-small cell lung cancer have not been established. We evaluated the clinical outcomes and dose-volume histogram parameters of carbon-ion radiotherapy compared with photon therapy in T2b–4N0M0 non-small cell lung cancer. Twenty-three patients were treated with carbon-ion radiotherapy between May 2011 and December 2015. Seven, 14, and 2 patients had T2b, T3, and T4, respectively. The median age was 78 (range, 53−91) years, with 22 male patients. There were 12 adenocarcinomas, 8 squamous cell carcinomas, 1 non-small cell lung carcinoma, and 2 clinically diagnosed lung cancers. Eleven patients were operable, and 12 patients were inoperable. Most patients (91%) were treated with carbon-ion radiotherapy of 60.0 Gy relative biological effectiveness (RBE) in 4 fractions or 64.0 Gy (RBE) in 16 fractions. Local control and overall survival rates were calculated. Dose-volume histogram parameters of normal lung and tumor coverages were compared between carbon-ion radiotherapy and photon therapies, including three-dimensional conformal radiotherapy (3DCRT) and intensity-modulated radiotherapy (IMRT). The median follow-up of surviving patients was 25 months. Three patients experienced local recurrence, and the 2-year local control rate was 81%. During follow-up, 5 patients died of lung cancer, and 1 died of intercurrent disease. The 2-year overall survival rate was 70%. Operable patients had a better overall survival rate compared with inoperable patients (100% vs. 43%; P = 0.04). There was no grade ≥2 radiation pneumonitis. In dose-volume histogram analysis, carbon-ion radiotherapy had a significantly lower dose to normal lung and greater tumor coverage compared with photon therapies. Carbon-ion radiotherapy was effectively and safely performed for T2b–4N0M0 non-small cell lung cancer, and the dose distribution was superior compared with those for photon therapies. A Japanese multi-institutional study is ongoing to prospectively evaluate these patients and establish the use of carbon-ion radiotherapy.

HF-WBI is superior to CF-WBI in terms of acute skin reaction and has the same short-term efficacy.

Radiochromic films are useful as dosimeters in high-precision radiotherapy owing to their high spatial resolution. However, when a particle beam is measured using a radiochromic film, the dose cannot be estimated accurately because the film darkness varies with variations in linear energy transfer (LET). This paper proposes a novel method for estimating the LET and the dose based on the film darkness. In this method, after a high-LET particle beam, such as a carbon-ion beam, was incident on the film, the film was digitized and its net optical density was determined. Further, the non-linearity of the film response curve between the dose and the darkness, depending on LET, was used. Then, calibration curves were created using 290 MeV u−1 mono energetic carbon-ion beams. We used LETs of 20, 50, 100, and 150 keV µm−1 and a physical dose of 2–14 Gy. The calibration curves were approximated for each LET using a quadratic function. The correlations between the coefficients of the quadratic function and the LET were also obtained. To verify the proposed method, the films were irradiated under 12 different conditions corresponding to various depths and doses. Four depths of −2, −5, −10, and −20 mm with respect to the Bragg peak, and three different preset values were used for the film measurements. The films were analyzed in four groups, where each group comprised films irradiated at the same depth. The LETs obtained from the film analysis, ordered from the upstream of the beam, were 20, 41, 56, and 97 keV µm−1, and the doses for the lowest preset value were 3.95, 4.07, 4.03, and 3.99 Gy for the four groups. The LETs obtained from the film analysis increased toward the Bragg peak, and the doses measured in the ionization chamber were almost equal to 4 Gy.

Background/Aim: This study compared the dose distributions of carbon ion radiotherapy (C-ion RT) and intensity-modulated radiotherapy (IMRT) in patients with locally advanced hepatocellular carcinoma (LAHCC). Patients and Methods: A retrospective analysis was conducted in 10 consecutive patients with LAHCC who had undergone C-ion RT. The dose-volume histogram parameters of clinical plans using C-ion RT at 60 Gy and simulated plans using IMRT at 60 Gy and 50 Gy were compared. We measured the percentage of the normal liver volume that received at least 5 Gy (V 5), 10

Background. Studies comparing the dose distributions of carbon ion radiotherapy (C-ion RT) and intensity-modulated radiotherapy (IMRT) in patients with locally advanced hepatocellular carcinoma (LAHCC) are lacking. This study aimed to investigate the dose distributions of these modalities and identify any advantages to using C-ion RT. Methods. Patients with LAHCC who had undergone C-ion RT between June 2010 and November 2018 were retrospectively analyzed. From among 210 patients with hepatocellular carcinoma who received C-ion RT, 10 consecutive patients with LAHCC were included. The dose-volume histogram parameters of clinical plans using C-ion RT at 60 Gy (relative biological effectiveness [RBE]) and simulated plans using IMRT at 60 Gy and 50 Gy were compared. We evaluated the three plans in terms of the following parameters: the percentage of the minimum dose that covered 95% of the target volume (D95); mean liver dose (MLD); and percentage of the normal liver volume that received at least 5 Gy (V5), 10 Gy (V10), 20 Gy (V20), 30 Gy (V30), 40 Gy, and 50 Gy. Patients at high risk of developing radiation-induced liver disease (RILD) were those with MLD and V30 of >23 Gy and >28%, respectively. Results. The V5, V10, V20, and MLD were significantly lower in patients who received 60 Gy (RBE) of C-ion RT than in those who received 60 Gy of IMRT, although the D95 values were not significantly different. The V5, V10, and V20 were also significantly lower in patients who received 60 Gy (RBE) of C-ion RT than in those who received 50 Gy of IMRT; moreover the D95 was significantly superior in the former group. The numbers of high-risk patients who developed RILD when administered 60 Gy (RBE) of C-ion RT, 60 Gy of IMRT, and 50 Gy of IMRT were 1, 7, and 6, respectively. Conclusions. C-ion RT exhibits a better dose distribution to the liver than does IMRT when treating patients with LAHCC. C-ion RT made it possible to treat patients with LAHCC who otherwise could not be treated using IMRT because of the high risk of RILD.