scholarly journals Radiation protection in radiological imaging: a survey of imaging modalities used in Japanese institutions for verifying applicator placements in high-dose-rate brachytherapy

2020 ◽  
Vol 62 (1) ◽  
pp. 58-66
Author(s):  
Hiroyuki Okamoto ◽  
Satoshi Kito ◽  
Naoki Tohyama ◽  
Shunsuke Yonai ◽  
Ryu Kawamorita ◽  
...  
Keyword(s):  
Imaging Techniques ◽  
High Dose Rate ◽  
Imaging Modalities ◽  
Survey Study ◽  
High Dose ◽  
Ct Scanner ◽  
X Ray ◽  
Imaging Protocols ◽  
Imaging Dose ◽  
Brachytherapy Source

Abstract Institutional imaging protocols for the verification of brachytherapy applicator placements were investigated in a survey study of domestic radiotherapy institutions. The survey form designed by a free on-line survey system was distributed via the mailing-list system of the Japanese Society for Radiation Oncology. Survey data of 75 institutions between August 2019 and October 2019 were collected. The imaging modalities used were dependent on resources available to the institutions. The displacement of a brachytherapy applicator results in significant dosimetric impact. It is essential to verify applicator placements using imaging modalities before treatment. Various imaging modalities used in institutions included a computed tomography (CT) scanner, an angiography X-ray system, a multi-purpose X-ray system and a radiotherapy simulator. The median total exposure time in overall treatment sessions was $\le$75 s for gynecological and prostate cancers. Some institutions used fluoroscopy to monitor the brachytherapy source movement. Institutional countermeasures for reducing unwanted imaging dose included minimizing the image area, changing the imaging orientation, reducing the imaging frequency and optimizing the imaging conditions. It is worth noting that half of the institutions did not confirm imaging dose regularly. This study reported on the usage of imaging modalities for brachytherapy in Japan. More caution should be applied with interstitial brachytherapy with many catheters that can lead to potentially substantial increments in imaging doses for monitoring the actual brachytherapy source using fluoroscopy. It is necessary to share imaging techniques, standardize imaging protocols and quality assurance/quality control among institutions, and imaging dose guidelines for optimization of imaging doses delivered in radiotherapy should be developed.

scholarly journals Erratum to: Monte Carlo dosimetry of the IRAsource high dose rate 192Ir brachytherapy source

2016 ◽  
Vol 39 (2) ◽  
pp. 591-591 ◽  
Author(s):  
Akbar Sarabiasl ◽  
Navid Ayoobian ◽  
Hossein Poorbaygi ◽  
Iraj Jabbari ◽  
Mohammad Reza Javanshir
Keyword(s):  
Monte Carlo ◽  
Dose Rate ◽  
High Dose Rate ◽  
High Dose ◽  
Brachytherapy Source

Optimization of deterministic transport parameters for the calculation of the dose distribution around a high dose-rate I192r brachytherapy source

2008 ◽  
Vol 35 (6Part1) ◽  
pp. 2279-2285 ◽  
Author(s):  
Kent A. Gifford ◽  
Michael J. Price ◽  
John L. Horton ◽  
Todd A. Wareing ◽  
Firas Mourtada
Keyword(s):  
Dose Rate ◽  
Dose Distribution ◽  
High Dose Rate ◽  
High Dose ◽  
Transport Parameters ◽  
Deterministic Transport ◽  
Brachytherapy Source

scholarly journals Nanomelanin Potentially Protects the Spleen from Radiotherapy-Associated Damage and Enhances Immunoactivity in Tumor-Bearing Mice

Materials ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1725 ◽  
Author(s):  
Nguyen Thi Le Na ◽  
Sai Duc Loc ◽  
Nguyen Le Minh Tri ◽  
Nguyen Thi Bich Loan ◽  
Ho Anh Son ◽  
...  
Keyword(s):  
Cancer Treatment ◽  
Interleukin 2 ◽  
High Dose Rate ◽  
High Dose ◽  
X Rays ◽  
Necrosis Factor Alpha ◽  
Oh Groups ◽  
X Ray ◽  
Tumor Bearing ◽  
Tnf Α

Radiotherapy side-effects present serious problems in cancer treatment. Melanin, a natural polymer with low toxicity, is considered as a potential radio-protector; however, its application as an agent against irradiation during cancer treatment has still received little attention. In this study, nanomelanin particles were prepared, characterized and applied in protecting the spleens of tumor-bearing mice irradiated with X-rays. These nanoparticles had sizes varying in the range of 80–200 nm and contained several important functional groups such as carboxyl (-COO), carbonyl (-C=O) and hydroxyl (-OH) groups on the surfaces. Tumor-bearing mice were treated with nanomelanin at a concentration of 40 mg/kg before irradiating with a single dose of 6.0 Gray of X-ray at a high dose rate (1.0 Gray/min). Impressively, X-ray caused mild splenic fibrosis in 40% of nanomelanin-protected mice, whereas severe fibrosis was observed in 100% of mice treated with X-ray alone. Treatment with nanomelanin also partly rescued the volume and weight of mouse spleens from irradiation through promoting the transcription levels of splenic Interleukin-2 (IL-2) and Tumor Necrosis Factor alpha (TNF-α). More interestingly, splenic T cell and dendritic cell populations were 1.91 and 1.64-fold higher in nanomelanin-treated mice than those in mice which received X-ray alone. Consistently, the percentage of lymphocytes was also significantly greater in blood from nanomelanin-treated mice. In addition, nanomelanin might indirectly induce apoptosis in tumor tissues via activation of TNF-α, Bax, and Caspase-3 genes. In summary, our results demonstrate that nanomelanin protects spleens from X-ray irradiation and consequently enhances immunoactivity in tumor-bearing mice; therefore, we present nanomelanin as a potential protector against damage from radiotherapy in cancer treatment.

Monte Carlo and TLD dosimetry of an 192Ir high dose-rate brachytherapy source

1998 ◽  
Vol 25 (10) ◽  
pp. 1975-1984 ◽  
Author(s):  
P. Karaiskos ◽  
A. Angelopoulos ◽  
L. Sakelliou ◽  
P. Sandilos ◽  
C. Antypas ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Dose Rate ◽  
High Dose Rate ◽  
High Dose ◽  
High Dose Rate Brachytherapy ◽  
Brachytherapy Source
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