International Journal of Medical Physics, Clinical Engineering and Radiation Oncology

Journal Information
ISSN / EISSN : 21685436 / 21685444
Current Publisher: Scientific Research Publishing, Inc, (10.4236)
Total articles ≅ 248
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M. F. Uddin, R. Khatun, S. Akter, H. M. Jamil, A. N. Monika, M. A. Rahaman, R. P. Das, R. A. Sharmin, M. M. Rahman, M. M. Ahasan
International Journal of Medical Physics, Clinical Engineering and Radiation Oncology, Volume 8, pp 1-8; doi:10.4236/ijmpcero.2019.81001

Abstract:High resolution (4 mm) tof PET-CT (positron emission tomography-computed tomography) from Philips of model Ingenuity TF is newly installed at Institute of Nuclear Medical Physics (INMP). 128 slice CT component incorporated with PET provides comparatively lower dose than the 511 keV annihilation photons associated with positron decay from PET scan. So, for designing shielding in our PET-CT facility, only 511 keV annihilation photons energy has been considered. The main objective of this paper is to show what measures have been taken to protect patients, occupational workers as well as environment from PET-CT radiation hazard through a cost effective design that satisfy the national regulatory demand. In this paper, AAPM (American Associations of Physicists in Medicine) Task group 108 analysis for PET and PET-CT shielding requirements is followed for our PET-CT facility shielding design. From theoretical calculation as shielding requirement, 1.1 cm Pb thickness or, 13 cm concrete thicknesses are found. Practically, all walls and ceiling are of 30.48 cm (1 foot) thick made of concrete with density 2.35 gcm-3 for more safety. As x-ray from CT is not taken into account for shielding analysis, Bangladesh Atomic Energy Commission (BAEC) conducted an extensive radiation survey at controlled, supervised and public area for CT. The report that is found meets the national regulatory requirements.
Chunhui Han, Nayana Vora, Sean Zhang, An Liu, Jeffrey Y. C. Wong
International Journal of Medical Physics, Clinical Engineering and Radiation Oncology, Volume 8, pp 151-162; doi:10.4236/ijmpcero.2019.83014

Abstract:Purpose/Objectives: We aimed to report clinical effects on critical organ dose and cardiac toxicity from implementation of the deep inspiration breath-hold (DIBH) technique in post-operative extern-beam radiotherapy of patients with left-sided breast cancer, using longitudinal clinical data. Materials/Methods: We retrieved three groups of patients who received post-operative radiotherapy of left-sided breast cancer in our institution in recent years: Groups A and B consist of patients whose treatment did not include internal mammary nodes (IMN) and who were treated with the free breathing technique and with the DIBH technique, respectively, and Group C consists of patients whose radiotherapy included internal mammary nodes with the DIBH technique. Dose parameters for the heart and left lung were retrieved from the treatment plans. Radiation-induced cardiac risks were estimated using existing risk models. Results: The average heart dose was 2.65 ± 0.98 Gy, 1.10 ± 0.29 Gy, and 1.26 ± 0.25 Gy in Groups A, B, and C, respectively. The average heart volumes receiving at least 25 Gy were 7.10 ± 9.79 cc in Group A, 0.07 ± 0.22 cc in Group B, and 0.03 ± 0.08 cc in Group C. On average, the excessive risk of having ischemic heart disease was estimated to be 19.6%, 8.1%, and 9.3% in Groups A, B, and C, respectively. The mean left lung doses were 5.73 ± 1.86 Gy, 5.93 ± 1.55 Gy, and 9.13 ± 1.57 Gy in Groups A, B, and C, respectively. Conclusion: Implementation of the DIBH technique significantly lowered heart dose and decreased the ischemic heart disease risk in patients receiving post-operative radiotherapy for left-sided breast cancer, without significant increase in left lung dose.
Mukesh Kumar Zope, Deepali Bhaskar Patil, Angel Kuriakose, Aslam Rahman, Vinita Trivedi, Shekhar Kumar Keshri
International Journal of Medical Physics, Clinical Engineering and Radiation Oncology, Volume 8, pp 175-192; doi:10.4236/ijmpcero.2019.83016

Abstract:The advent of Intensity Modulated Radiation Therapy (IMRT) is rapidly changing the field of Radiation Oncology. IMRT has the potential to improve clinical implementation of highly conformal non-convex dose distributions. Nonetheless, a number of IMRT approaches including coplanar and noncoplanar beam techniques with 5 to 9 beams at different angles have been used in an effort to get the best dose distribution. The purpose of this study is to compare the dose to normal tissue and dose-limiting structures, conformity index, homogeneity index, number of monitor units required for the treatment of prostate cancer in 3 sets of five and seven beam IMRT plans and thus to select the best IMRT approach for patients with prostate cancer.
Debnarayan Dutta, Sathiya Krishnamoorthy, Ganapathy Krishnan, Harikrishnaperumal Sudahar
International Journal of Medical Physics, Clinical Engineering and Radiation Oncology, Volume 8, pp 131-140; doi:10.4236/ijmpcero.2019.83012

Gurtej S. Gill, Raphael Y. Jakubovic, Jameson Baker, Terry Button, Jenghwa Chang
International Journal of Medical Physics, Clinical Engineering and Radiation Oncology, Volume 8, pp 80-94; doi:10.4236/ijmpcero.2019.82008

Junya Ishikawa, Taro Morisaki
International Journal of Medical Physics, Clinical Engineering and Radiation Oncology, Volume 8, pp 95-105; doi:10.4236/ijmpcero.2019.82009

Abstract:Mutations in the Sfpi1 gene are essential for the development of radia-tion-induced acute myeloid leukemia. In this study, we investigated long-term interaction among immature hematopoietic cell number, intra-cellular reactive oxygen species contents, and oxidative DNA damage fre-quency after irradiation. Lin-/Sca-1+ cells were isolated from C3H/HeN mice on days 1 - 400 after 0 - 3 Gy total body irradiation. On days 1 - 7, the number of surviving cells decreased and reached a minimum; however, the number of cells gradually recovered until day 200. Intracellular reactive oxygen species contents significantly increased from day 1 to day 30. In addition, the frequency of oxidative DNA damage tended to increase from day 1 and day 30, and that at day 30 was significantly increased in the 3 Gy group compared with that in the control group. In contrast, decreased cell number, increased intracellular reactive oxygen species content, and decreased oxidative DNA damage frequency were observed on day 400. These results suggested that oxidative DNA damage was involved in intracellular reactive oxygen species generation induced by cell proliferation to compensate for cell death after irradiation.
Junfang Gao, Xiaoqian Liu
International Journal of Medical Physics, Clinical Engineering and Radiation Oncology, Volume 8, pp 9-20; doi:10.4236/ijmpcero.2019.81002

Abstract:In the linear accelerator-based stereotactic radio surgery (SRS) and stereotactic body radiotherapy (SBRT) programs, single isocenter-multiple metastases’ treatment has become more and more popular due to their high efficiency in treatment time. However, the absence of a comprehensive quality assurance program is still the challenge for medical physicists. The Winston-Lutz-Gao test, which we developed two years ago, was performed for the first time on a True Beam STx (Varian Medical System) linear accelerator in this study. Beams were designed by Eclipse with gantry, collimator, and couch full rotations, and a 200-pound weight was placed on the couch to mimic real treatment. The “frameless SRS QA target pointer” from the Brainlab company, with a 3.5-mm metallic ball embedded in the center, was used as a phantom. Images were acquired by the portal imager built-in linear accelerator and analyzed directly by the Image browser in ARIA. We found that the farther the metastases were from the linac isocenter, the worse the congruence was between the beam mechanical and the radiation center. The farthest metastases should be within 6 cm from the linac isocenter per the AAPM TG-142 and American Society for Radiation Oncology (ASTRO) white paper criteria. To the best of our knowledge, this is the first off-isocenter Winston-Lutz test performed on a True Beam STx linear accelerator.
Azza N. Taher, Rasha A. Elawady, Amr Amin
International Journal of Medical Physics, Clinical Engineering and Radiation Oncology, Volume 8, pp 121-129; doi:10.4236/ijmpcero.2019.82011

Abstract:Purpose: To investigate if intensity modulated radiation therapy (IMRT) offers a better planning target volume (PTV) coverage and/or lower dose to normal thoracic structures in comparison to three dimensional conformal radiation therapy (3DCRT) in the treatment of mid and lower oesophageal carcinoma patients. Materials and Methods: A prospective study in the period from 2014 till 2015 was held in the radiation therapy department of the National Cancer Institute, Cairo University, in which 20 locally advanced or inoperable mid and lower oesophageal cancer patients were treated by chemo-radiation using 3DCRT technique. IMRT plans were generated for those 20 patients. The 3DCRT and IMRT plans were compared as regards PTV coverage and doses to critical organs at risk. Results: All plans had produced satisfactory PTV coverage with no significant differences noted. The lung V20 for both lungs in 3DCRT was 16.94% ± 4.2% which was increased to 21.42% ± 3.6% in IMRT (p = 0.017). The mean dose to the heart and V30 were higher in IMRT plans while the mean dose to the spinal cord was higher with 3DCRT plans, yet that didn’t reach a statistically significant level (p = 0.156). The dose delivered to the liver didn’t pose any difference between both techniques. Conclusion: 3DCRT remains to be a feasible cost effective treatment delivery option for mid and lower oesophageal cancer cases with a lower optimization and delivery time than that for IMRT. Moreover, that calls for further dosimetric studies and clinical trials to assess IMRT technique. In our study, IMRT using nine fields didn’t prove to be superior to 3DCRT.
He Wang, James N. Yang, Xiaodong Zhang, Jing Li, Steven J. Frank, Zhongxiang Zhao, Dershan Luo, Xiaorong Zhu, Congjun Wang, Samuel Tung, et al.
International Journal of Medical Physics, Clinical Engineering and Radiation Oncology, Volume 8, pp 106-120; doi:10.4236/ijmpcero.2019.82010

Abstract:Purpose: Fractionated stereotactic radiosurgery (FSRS) can be given with at least three modalities: Gamma Knife, with the noninvasive frameless extend system (GKE); linear accelerator-based volumetric modulated arc therapy (VMAT); and intensity-modulated proton therapy (IMPT). We extracted treatment plans for patients who had received FSRS with GKE for recurrent skull base or intracranial tumors, created corresponding plans for VMAT and IMPT, and compared the quality of the three sets of plans. Methods and materials: Plans were extracted for 9 patients with recurrent malignant skull-base tumors (n = 6) or large intracranial tumors (n = 3) who had received FSRS with GKE (median dose 24 Gy in 3 fractions) in 2013 through 2015. Plans for VMAT were generated with a TrueBeam STx LINAC machine using 6-MV photons, and plans for IMPT were generated with multi-field optimization. The optimized VMAT and IMPT plans were normalized to achieve the best possible target coverage while meeting the same dose-volume constraints on organs at risk (OARs) as the GKE plans. Plans were evaluated on the basis of target coverage, conformity index, homogeneity index, gradient index, and treatment efficiency. Results: The median target volume was 10.2 cm3 (range 1.9 - 33.8 cm3). The VMAT and IMPT plans met all OAR constraints, and target coverage and conformity were comparable among all plans. VMAT and IMPT plans showed significantly better target uniformity and treatment delivery efficiency (P P
Ryosuke Kohno, Wenhua Cao, Pablo Yepes, Xuemin Bai, Falk Poenisch, David R. Grosshans, Tetsuo Akimoto, Radhe Mohan
International Journal of Medical Physics, Clinical Engineering and Radiation Oncology, Volume 8, pp 32-45; doi:10.4236/ijmpcero.2019.81004