Microdosimetric Specification of Radiation Quality in Neutron Radiation Therapy

1990 ◽  
Vol 57 (4) ◽  
pp. 865-883 ◽  
Author(s):  
H.G. Menzel ◽  
P. Pihet ◽  
A. Wambersie
Keyword(s):  
Radiation Therapy ◽  
Neutron Radiation ◽  
Radiation Quality

High linear energy transfer (LET) radiation therapy in recurrent, metastatic, or unresectable rectal adenocarcinoma.

2011 ◽  
Vol 29 (4_suppl) ◽  
pp. 612-612
Author(s):  
P. Paximadis ◽  
D. Elliott ◽  
A. F. Shields ◽  
P. A. Philip ◽  
D. W. Weaver ◽  
...  
Keyword(s):  
Radiation Therapy ◽  
Local Control ◽  
Normal Tissue ◽  
Rectal Adenocarcinoma ◽  
Late Toxicity ◽  
Neutron Radiation ◽  
Neutron Dose ◽  
Mixed Beam ◽  
Photon Dose ◽  
High Let

612 Background: The purpose of this study was to retrospectively analyze the outcomes of patients with recurrent, metastatic, or unresectable rectal adenocarcinoma treated with mixed beam photon and high LET radiotherapy. Methods: Between 1995 and 2005, the high LET database was queried to identify patients with rectal adenocarcinoma. Local control and overall survival (OS) were calculated using the Kaplan-Meier method. Acute and chronic toxicities were graded using the common terminology criteria for adverse events (CTCAE) v4.0 grading system. Biological equivalent dose (BED) was calculated for tumor and normal tissue of both the photon dose and neutron dose for 10 patients. Results: 11 patients with recurrent, metastatic, or unresectable rectal adenocarcinoma were identified as being treated with mixed photon-neutron radiation. The median age of patients in the study was 58 (range: 38-79). There were 8 male patients and 3 female patients. Median follow-up was 6 months (range: 4-76 months). Patients received a median photon dose of 40Gy (range: 26-50.4Gy) and a median neutron dose of 8nGy (range: 6-10nGy). Seven patients received radiation given concurrently with 5-FU. The median OS was 16 months (range: 4-76 months), with 1 and 2-year OS of 56% and 22%, respectively. Local control was achieved in 9 of 11 (82%) patients. Local progression occurring in two patients occurred at 5 months after completion of RT. The median tumor BED in patients achieving local control was 72.5 Gy (range: 57.1-83.5 Gy). There was a nonsignificant difference in median normal tissue BED of patients with grade 3-4 late toxicity of 104.8 Gy (range: 81.1-115.1 Gy), compared with 95.3Gy (range: 89.0-104.6 Gy) for those patients with grade 1-2 late toxicity. Conclusions: Our experience demonstrates that treatment of unresectable rectal tumors with mixed photon-neutron achieved excellent local control. With the added capabilities of intensity modulated neutron radiation therapy (IMNRT), the incidence of treatment-related morbidity may be improved while taking advantage of the superior tumor control that high-LET radiation can impart. No significant financial relationships to disclose.

scholarly journals A Unique Prototypic Device for Radiation Therapy: The p53-Independent Antiproliferative Effect of Neutron Radiation

Acta Naturae ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 99-102 ◽  
Author(s):  
D. I. Yurkov ◽  
S. V. Syromukov ◽  
V. V. Tatarskiy ◽  
E. S. Ivanova ◽  
A. I. Khamidullina ◽  
...  
Keyword(s):  
Radiation Therapy ◽  
P53 Protein ◽  
Single Cells ◽  
Human Tumor ◽  
Neutron Radiation ◽  
High Energy ◽  
Antiproliferative Effect ◽  
Heavy Particles ◽  
M Phase ◽  
The Status

Radiation therapy with heavy particles including neutrons, an otherwise therapeutically perspective because of its high tissue penetration and efficient tumor damage, is currently limited by the lack of adequate equipment. An NG-24 generator (140 kg, 42 110 cm, ~1011 particles/s, 14 MeV) has been designed and engineered to replace the huge and environmentally harmful neutron reactors, cyclotrons, and accelerators with a compact, portable, safe, and potent source of high-energy neutrons. We demonstrate that the neutron beam produced by NG-24 causes a significant antiproliferative effect on human tumor cell lines regardless of the status of the anti-apoptotic p53 protein. Phosphorylation of histone 2A and increased amounts of p21, cyclin D, and phospho-p53 were detectable in HCT116 colon carcinoma cells (wild-type p53) irradiated with 4 Gy several days post-treatment, accompanied by G2/M phase arrest. These treatments dramatically reduced the ability of single cells to form colonies. In the HCT116p53KO subline (p53 -/-), the G2/M arrest was independent of the aforementioned mechanisms. Hence, the NG-24 generator is a source of a powerful, therapeutically relevant neutron flux that triggers a p53-independent antiproliferative response in tumor cells.

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