Prompt Radiation Fields due to Protons and Ions

INTRODUCTION: Cervical cancer is the second most frequent cancer among Indian women. Radiotherapy is the cornerstone of treatment in all its stages. Three-dimensional conformal radiotherapy (3DCRT) combines multiple radiation fields to deliver precise dose of radiation to the affected area. Tailoring each of the radiation fields to focus on the tumor delivers a high dose of radiation to the tumor and avoids nearby healthy tissue. The present study is done to compare conventional radiotherapy versus 3DCRT in cancer cervix for compliance, clinical response and toxicity. MATERIAL AND METHODS: Fifty patients were enrolled and randomised into two radiotherapy plans with radical intent - Group A treated by conventional radiotherapy and group B treated by 3DCRT. Concurrent cisplatin was delivered on weekly (35mg/m2) or tri-weekly (75mg/m2) basis during external beam Radiotherapy and was followed by High Dose Radiotherapy Brachytherapy. Clinical response and complication assessment were evaluated.Collected data was analyzed using standard statistical methods and softwares to calculate level of significance using “p” value by chi square test. RESULTS: In this study mean age of the patients was 48 years (26-67 years). The anemia was the most common side effect seen in both groups (96% vs 88%, p=0.29). Neutropenia was more in group B (36% vs 44%, p= 0.56). Lower GI toxicity was seen only in patients in group A (20% vs 0%, p=0.018). In follow up there were no significant early rectal and bladder reactions in both groups and 2 patients in each group had late rectal reactions of grade I and II (p= 0.312). No significant skin, bladder and small intestinal toxicity were seen in both groups. CONCLUSION: Conventional radiotherapy gives equally efficacious response though accompanied by toxicities which were acceptable.

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Simulating the interstellar medium of galaxies with radiative transfer, non-equilibrium thermochemistry, and dust

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa3249 ◽

2020 ◽

Vol 499 (4) ◽

pp. 5732-5748 ◽

Cited By ~ 1

Author(s):

Rahul Kannan ◽

Federico Marinacci ◽

Mark Vogelsberger ◽

Laura V Sales ◽

Paul Torrey ◽

...

Keyword(s):

Interstellar Medium ◽

Galaxy Formation ◽

State Of The Art ◽

Complex Function ◽

Ionization State ◽

Radiation Fields ◽

Stellar Feedback ◽

Wide Range ◽

Dust Distribution ◽

Non Equilibrium

ABSTRACT We present a novel framework to self-consistently model the effects of radiation fields, dust physics, and molecular chemistry (H2) in the interstellar medium (ISM) of galaxies. The model combines a state-of-the-art radiation hydrodynamics module with a H and He non-equilibrium thermochemistry module that accounts for H2 coupled to an empirical dust formation and destruction model, all integrated into the new stellar feedback framework SMUGGLE. We test this model on high-resolution isolated Milky-Way (MW) simulations. We show that the effect of radiation feedback on galactic star formation rates is quite modest in low gas surface density galaxies like the MW. The multiphase structure of the ISM, however, is highly dependent on the strength of the interstellar radiation field. We are also able to predict the distribution of H2, that allow us to match the molecular Kennicutt–Schmidt (KS) relation, without calibrating for it. We show that the dust distribution is a complex function of density, temperature, and ionization state of the gas. Our model is also able to match the observed dust temperature distribution in the ISM. Our state-of-the-art model is well-suited for performing next-generation cosmological galaxy formation simulations, which will be able to predict a wide range of resolved (∼10 pc) properties of galaxies.

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Constraining physical conditions for the PDR of Trumpler 14 in the Carina Nebula

Astronomy and Astrophysics ◽

10.1051/0004-6361/201832595 ◽

2018 ◽

Vol 618 ◽

pp. A53 ◽

Cited By ~ 10

Author(s):

Ronin Wu ◽

Emeric Bron ◽

Takashi Onaka ◽

Franck Le Petit ◽

Frédéric Galliano ◽

...

Keyword(s):

Uv Radiation ◽

Massive Stars ◽

Local Heating ◽

Spectral Lines ◽

Ionization Front ◽

Thermal Pressure ◽

Line Energy ◽

Physical Conditions ◽

Radiation Fields ◽

Carina Nebula

We investigate the physical conditions of the CO gas, based on the submillimeter imaging spectroscopy from a 2′ × 7′ (1.5 × 5 pc2) area near the young star cluster, Trumpler 14 of the Carina Nebula. The observations presented in this work are taken with the Fourier Transform Spectrometer (FTS) of the Spectral and Photometric Imaging REceiver (SPIRE) onboard the Herschel Space Observatory. The newly observed spectral lines include [CI] 370 μm [CI] 609 μm, and CO transitions from J = 4−3 to J = 13−12. Our field of view covers the edge of a cavity carved by Trumpler 14 about 1 Myr ago and marks the transition from H ii regions to photo-dissociation regions. The observed CO intensities are the most prominent at the northwest region, Car I-E. With the state-of-the-art Meudon PDR code, we successfully derive the physical conditions, which include the thermal pressure (P) and the scaling factor of radiation fields (GUV), from the observed CO spectral line energy distributions (SLEDs) in the observed region. The derived GUV values generally show excellent agreement with the UV radiation fields created by nearby OB-stars and thus confirm that the main excitation source of the observed CO emission is the UV-photons provided by the massive stars. The derived thermal pressure is in the range 0.5−3 × 108 K cm-3 with the highest values found along the ionization front in Car I-E region facing Trumpler 14, hinting that the cloud structure is similar to the recent observations of the Orion Bar. We also note a discrepancy at a local position (<0.17 × 0.17 pc2) between the photo-dissociation region (PDR) modeling result and the UV radiation fields estimated from nearby massive stars, which requires further investigation on nearby objects that could contribute to local heating, including outflow. Comparing the derived thermal pressure with the radiation fields, we report the first observationally derived and spatially resolved P ~ 2 × 104 GUV relationship. As direct comparisons of the modeling results to the observed 13CO, [O I] 63 μm, and [C II] 158 μm intensities are not straightforward, we urge the reader to be cautious when constraining the physical conditions of PDRs with combinations of 12CO, 13CO, [C I], [O I] 63 μm, and [C II] 158 μm observations.

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