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The mean energy of the photon spectra calculated by each one of the annular detectors just below the flattening filter holder.
Source publication
The current study aimed to: a) utilize Monte Carlo simulation methods for the assessment of radiation doses imparted to all organs at risk to develop secondary radiation induced cancer, for patients undergoing radiotherapy for breast cancer; and b) evaluate the effect of breast size on dose to organs outside the irradiation field. A simulated linea...
Citations
... This study is the first study that estimate the effect of collimator scatter, phantom scatters, collimator and MLC transmission on dose calculation in breast cancer sing the different types of phantoms in the same study and the estimation of impact of these scatter factors on doses reach the organ at risk. Berris et al. (23) study was utilized Monte Carlo simulation methods for the assessment of radiation doses imparted to all organs at risk to develop secondary radiation induced cancer, for patients undergoing radiotherapy for breast cancer but not consider these scatter factors, Zurl et al. (24) study was estimated the risk factor from doses reach the contra lateral breast in young women patient with different mode of breathing but it wasn't evaluated these the scatter factors. ...
... Unfortunately, this data base is not able to use some MCNP codes. In PHITS, the user is able to utilize it through the tools of PSFC4PHITS, as mentioned before [6][7][8]. ...
... Other results presented by T. Berris et al. showed similar results compared to ours. In their study, there is almost a 60% difference at the out-of-field regions but differences of 2% and 2 mm at the plateau region [6]. In consideration that the abovementioned study was conducted for the modeling of a linear accelerator, our results are acceptable as well. ...
The Message Passing Interface (MPI) technique is an old solution and an improvement on the Monte Carlo N-Particle Transport (MCNP) method’s enormous computational time, which has not been evaluated based on PHITS code—a recently developed Monte Carlo simulation code. We conducted simulations on Varian Clinac iX 6MV phase space data from the IAEA. Venselaar et al.’s method and criteria were used to validate the Monte Carlo simulation. The PC cluster has also been tested in terms of processor count and bch, which stands for unit calculation count per operation. The MPI version PHITS code’s speedup factor and the K-factor, which represent the serial portion of the cluster, were both evaluated. All calculated data met the criteria except δ2, high dose, and high gradient of the beam profile data set. It was very clear that PC clusters with MPI were better than simple nodes up to 70.6%. Additionally, the speedup factor shows a tendency to follow Amdahl’s law. At the same time, the K-factor was saturated by a certain measure. The study concludes by arguing that the cluster has limitations that come from its serial composition. If we consider how improvements in specifications affect simulation time, this cluster system could be more effective.
... In our study, while the absorbed dose in TPS was calculated as 0 cGy for all treatment techniques, we dosimetrically determined that the doses in TLD readings for 3D-CRT, 5 MSS-IMRT, 5 SW-IMRT, 7 MSS-IMRT, 7 SW-IMRT, 9 MSS-IMRT and 9 SW IMRT techniques were 3.36 ± 0.19 cGy, 9.32 ± 0.91 cGy, 10.29 ± 1.19 cGy, 12.35 ± 1.42 cGy, 12.99 ± 1.46 cGy, 13.18 ± 1.53 cGy and 16.10 ± 2.04 cGy, respectively. Berris et al. [11] calculated the radiation dose of OARs by using the 3D-CRT technique using Monte Carlo simulation model for breast RT and calculated the uterine dose between 1.5 and 3 cGy. In our current study, similar to the findings in the study by Berris et al. our mean TLD measurement for the plan made using the 3D-CRT technique and mutual tangential angles was 3.36 ± 0.19 cGy. ...
... The most commonly used methods to analyze the effects of secondary cancers involve the utilization of human phantoms to measure secondary doses using devices such as the thermo-luminescent dosimeter (TLD) and radio-photoluminescent glass dosimeter (RPLD), and the calculation of doses using commercialized treatment planning system (TPS) [4,8,[18][19][20]. Recently, studies have also been conducted to calculate scattered radiation for in-field and out-field, which has a significant impact on SCR using physics-based analysis algorithms [21][22][23][24]. ...
Background
The purpose of this study is to develop a clinical application program that automatically calculates the effect for secondary cancer risk (SCR) of individual patient. The program was designed based on accurate dose calculations using patient computed tomography (CT) data and Monte Carlo engine. Automated patient-specific evaluation program was configured to calculate SCR.
Methods
The application program is designed to re-calculate the beam sequence of treatment plan using the Monte Carlo engine and patient CT data, so it is possible to accurately calculate and evaluate scatter and leakage radiation, difficult to calculate in TPS. The Monte Carlo dose calculation system was performed through stoichiometric calibration using patient CT data. The automatic SCR evaluation program in application program created with a MATLAB was set to analyze the results to calculate SCR. The SCR for organ of patient was calculated based on Biological Effects of Ionizing Radiation (BEIR) VII models. The program is designed to sequentially calculate organ equivalent dose (OED), excess absolute risk (EAR), excess relative risk (ERR), and the lifetime attributable risk (LAR) in consideration of 3D dose distribution analysis. In order to confirm the usefulness of the developed clinical application program, the result values from clinical application program were compared with the manual calculation method used in the previous study.
Results
The OED values calculated in program were calculated to be at most approximately 13.3% higher than results in TPS. The SCR result calculated by the developed clinical application program showed a maximum difference of 1.24% compared to the result of the conventional manual calculation method. And it was confirmed that EAR, ERR and LAR values can be easily calculated by changing the biological parameters.
Conclusions
We have developed a patient-specific SCR evaluation program that can be used conveniently in the clinic. The program consists of a Monte Carlo dose calculation system for accurate calculation of scatter and leakage radiation and a patient-specific automatic SCR evaluation program using 3D dose distribution. The clinical application program that improved the disadvantages of the existing process can be used as an index for evaluating a patient treatment plan.
... Mazonakis et al. [10] designed a targeted 6 MV and 50 Gy tangential 3D-CRT treatment plan in their study on the phantom and showed that the fetus was exposed to a total dose of 2 to 8 cGy in TLD measurements taken using the phantom. In our study, while the absorbed dose in TPS was calculated as 0 cGy for all treatment techniques, we dosimetrically determined that the doses in TLD [11] calculated the radiation dose of OARs by using the 3D-CRT technique using Monte Carlo simulation model for breast RT and calculated the uterine dose between 1.5 and 3 cGy. In our current study, similar to the findings in the study by Berris et al. our mean TLD measurement for the plan made using the 3D-CRT technique and mutual tangential angles was 3.36 ± 0.19 cGy. ...
This study aimed to measure the dose exposed by the fetus during three-dimensional conformal radiotherapy (3D-CRT) and intensity-modulated radiotherapy (IMRT) treatment techniques in pregnant patients who had to undergo radiotherapy due to breast cancer with thermoluminescence dosimetry (TLD) and compare these measurements with treatment planning system (TPS). 2.5 mm-thick computed tomography (CT) images of Alderson Rando phantom device were taken for measurements. Heart, ipsilateral lung, contralateral lung and contralateral breast were defined as critical organs at risk (OARs) and planned tumor volume (PTV) as target volume. In TPS (Eclipse, version 15.1), using 3D-CRT and IMRT treatment methods, the criterion that 95% of the PTV volume should receive more than 95% of the predicted dose was taken into consideration. OAR has been preserved as much as possible in the used techniques. In order to compare the TPS and TLD readings in PTV, 60 TLDs were placed in the target volume in the Rando phantom. Twenty-four TLDs were placed in the 30th and 31st sections of the phantom, which is likely to be in the volumetric size of the first trimester of pregnancy which is also located 25.84 cm from the lower limit of the PTV. Six MV were used in seven different treatment techniques and the measurements were repeated 5 times for each technique and averaged. The differences between the average TPS and TLD readings for PTV were 1.34%, 0.86%, 1.04%, 0.64%, 0.48%, 0.84% and 0.73% for 3D-CRT, 5 MSS-IMRT, 5 SW-IMRT, 7 MSS-IMRT, 7 SW-IMRT, 9 MSS-IMRT and 9 SW-IMRT, respectively. Fetal doses for all treatment techniques in TPS were found as 0.00 cGy. However, in TLD measurements fetal doses were found as, 3.36 ± 0.19 cGy, 9.32 ± 0.91 cGy 10.29 ± 1.19 cGy, 12.35 ± 1.42 cGy, 12.99 ± 1.46 cGy, 13.18 ± 1.53 cGy and 16.10 ± 2.04 cGy for 3D-CRT, 5 MSS-IMRT, 5 SW-IMRT, 7 MSS-IMRT, 7 SW-IMRT, 9 MSS-IMRT and 9 SW-IMRT, respectively. In 3D-CRT treatment technique the fetus received the lowest dose. In addition, for plans made using the IMRT method, it is seen that the MSS-IMRT technique provides better fetal protection compared to the SW-IMRT technique. The 3D-CRT should be the first priority for a pregnant patient who has to undergo left breast RT, but if the desired dose-volume histogram (DVH) cannot be obtained with 3D-CRT, 5 MSS-IMRT technique may be preferred.
... Pada tahap kedua,running program dilakukan dengan input user code tally F6 untuk mengetahui energi yang diserap pada tiap voxel (MeV/kg) [8,9]. Spesifikasi komputer yang digunakan adalah intel core i5 RAM 2GB dengan jumlah foton 210 8 foton. ...
Makalah ini mengkaji pola kurva isodosis dari teknik tangensial radioterapi pada kasus sel kanker payudara dini yang berada di dalam payudara kiri. Dari kondisi ini, sudut penyinaran yang diambil adalah tangensial kanan dengan sudut 120° dan 300°. Berkas sinar gamma yang ditembakkan berada pada energi 1,17 dan 1,33 MeV sebagai berkas profil datar dengan ukuran SSD 80 cm dan luas medan radiasi (10x10) cm2. Dosis serap pada tiap titik di dalam organ dada ditentukan berdasar riwayat hidup perjalanan sinar gamma dengan metode Monte Carlo menggunakan program MCNPX. Gabungan pola isodosis dari kedua sudut penyinaran menggambarkan distribusi dosis maksimum dan minimum di tiap tiap titik organ rongga dada. Dosis maksimum terjadi pada sel kanker dan bagian atas payudara kiri. Dari sini, dapat dikatakan penyinaran tangensial dengan sumber profil datar tidak disarankan untuk tindakan terapi kanker payudara stadium dini. Kata Kunci: profil datar, tangensial, MCNPX, isodosis
This paper presented the isodose curve pattern form tangential radiotherapy technique on early stadium breast cancer within the left-breast. Due to such condition, it was chosen a right tangential of 120° and 300° irradiation angle, respectively. The emitted gamma ray beam were on its energy of 1.17 and 1.33 MeV as a flat-profile beam along with SSD of 80 cm and a (10 x 10) cm2 radiation field area. The absorbed dose on each point within chest's organs were determined base on gamma transport history by means of Monte Carlo method using MCNPX program. Overlaying both isodose curve patterns from each tangential angle, showed some maximum and minimum absorbed dose onto each point along chest's organs. Maximum dose found onto the cancer cell and some part of top site of left-breast. Hence, it could be said that tangential irradiation with flat-profile source were not recommended for early stage breast cancer treatment.
... Monte Carlo (MC) radiation simulation has been increasingly used for dosimetric assessment of internal organs following radiation treatment [3]. Geant4 is one of the newest MC code packages, which provides accurate probability estimation of radiation events, with flexible geometric manipulation for various purposes, especially in medical physics. ...
This study aimed to evaluate the absorbed doses received by the organs at risk (OARs) following prostate treatment with permanent Iodine-125 (125 I) brachytherapy seeds. In order to simulate an enlarged abnormal prostate due to malignancy, the MIRD5 adult male anthropomorphic phantom (readily available in the Geant4 Monte Carlo package) was modified by increasing the prostate volume to 35 cm 3. The permanent seeds were constructed with an outer cylindrical dimension of 4.5 mm (length) × 0.8 mm (diameter). The effects of various activity per seed (0.5, 0.6 and 0.8 mCi), number of seeds (62, 78, 94 and 110 seeds) and radionuclides, i.e. Palladium-103 (103 Pd), 125 I and Cesium-131 (131 Cs), towards the absorbed dose to the OARs (i.e. rectum, urinary bladder and both testicles) were investigated. In this study, prostate dose of up to 237 Gy was simulated, which resulted in 11 Gy dose to rectum, 7 Gy to urinary bladder and 4 Gy to each testicle. The doses were considered as reasonable, given the low dose rate nature of the treatment, allowing tissue repair for the OARs. Optimal seeds arrangement was found to consist of 78 or fewer seeds, as it resulted in the lowest dose to the OARs. For similar prostate dose, 103 Pd resulted in the lowest dose to the OARs, followed by 125 I and 131 Cs. Permanent seed brachytherapy allows high dose to be delivered to the prostate, while ensuring minimal dose to the OARs.
... B reast cancer is one of the most common cancers among women in the world [1][2][3]. Early diagnosis and radiotherapy treatment can decrease the mortality rate [4][5][6] and increase the survival rate of these patients [6,7]. Despite the advantages of radiotherapy for cancer treatment as one of the third treatment modalities, radiotherapy is a "two-edged swords" that may cause cancer [8][9][10]. ...
... B reast cancer is one of the most common cancers among women in the world [1][2][3]. Early diagnosis and radiotherapy treatment can decrease the mortality rate [4][5][6] and increase the survival rate of these patients [6,7]. Despite the advantages of radiotherapy for cancer treatment as one of the third treatment modalities, radiotherapy is a "two-edged swords" that may cause cancer [8][9][10]. ...
... The finding in this study is comparable with the results in Berris et al. (2012) [6] study in some organs. Their measurement was in a single energy (6 MeV energy) and single technique. ...
Background:
Given the importance of scattered and low doses in secondary cancer caused by radiation treatment, the point dose of critical organs, which were not subjected to radiation treatment in breast cancer radiotherapy, was measured.
Objective:
The purpose of this study is to evaluate the peripheral dose in two techniques of breast cancer radiotherapy with two energies.
Material and methods:
Eight different plans in two techniques (conventional and conformal) and two photon energies (6 and 15 MeV) were applied to Rando Alderson Phantom's DICOM images. Nine organs were contoured in the treatment planning system and specified on the phantom. To measure the photon dose, forty-eight thermoluminescence dosimeters (MTS700) were positioned in special places on the above nine organs and plans were applied to Rando phantom with Elekta presice linac. To obtain approximately the same dose distribution in the clinical organ volume, a wedge was used on planes with an energy of 6 MeV photon.
Results:
Point doses in critical organs with 8 different plans demonstrated that scattering in low-energy photon is greater than high-energy photon. In contrast, neutron contamination in high-energy photon is not negligible. Using the wedge and shield impose greater scattering and neutron contamination on patients with low-and high-energy photon, respectively.
Conclusion:
Deciding on techniques and energies required for preparing an acceptable treatment plan in terms of scattering and neutron contamination is a key issue that may affect the probability of secondary cancer in a patient.
... Some authors have used the MCNP code to simulate radiotherapy procedures and calculate PTV and OAR absorbed doses. 3,4 However, only simplified computational analytical phantoms were employed in these studies. Donovan et al. 5 used the Rando phantom and thermoluminescent (TLD) dosimeters to provide experimental measurements of the mean absorbed dose and estimate the second cancerincidence risk for different breast-RT procedures. ...
Objective:
The aim of this work was to simulate a 6MV conventional breast 3D conformational radiotherapy (3D-CRT) with physical wedges (50Gy/25#) in the left breast, calculate the mean absorbed dose in the body organs using robust models and computational tools and estimate the secondary cancer-incidence risk to the Brazilian population.
Methods:
The VW female phantom was used in the simulations. PTV was defined in the left breast. The 6MV parallel-opposed fields breast-RT protocol was simulated with MCNPx code. The absorbed doses were evaluated in all the organs. The secondary cancer-incidence risk induced by radiotherapy (RT) was calculated for different age groups according to the BEIR VII methodology.
Results:
RT quality indexes indicated that the protocol was properly simulated. Significant absorbed dose values in red bone marrow - RBM (0.8 Gy) and stomach (0.6 Gy) were observed. The contralateral breast presented the highest risk of incidence of a secondary cancer followed by leukemia, lung and stomach. The risk of a secondary cancer-incidence by breast RT, for the Brazilian population, ranged between 2.2 - 1.7% and 0.6 - 0.4%. Conclusion: RBM and stomach, usually not considered as OAR, presented high risks of secondary cancer incidence of 0.5 - 0.3% and 0.4 - 0.1%, respectively. This study may be helpful for breast RT risk/benefit assessment. Advances in knowledge: MCNPX-dosimetry was able to provide the scatter radiation and dose for all body-organs in conventional breast-RT. A relevant risk up to 2.2% of induced-cancer from breast-RT , considering the whole thorax organs and Brazilian cancer-incidence.
... It has been indicated in several studies that radiotherapy reduces locoregional recurrence and improves survival (6)(7)(8)(9) . However, radiation therapy inevitably exposes the organs/tissues that are partially or entirely excluded from the treatment volume (10) . In addition, in some cases, patients with breast cancer are treated with high energy beams (e.g. ...
This research aimed to measure the received photon and thermal neutron doses to contralateral breast (CB) in breast cancer radiotherapy for various field sizes in presence of physical and dynamic wedges. The measurement of photon and thermal neutron doses was carried out on right breast region of RANDO phantom (as CB) for 18 MV photon beams. The dose measurements were performed by thermoluminescent dosimeter chips. These measurements obtained for various field sizes in presence of physical and dynamic wedges. The findings of this study showed that the received doses (both of the photon and thermal neutron) to CB in presence of physical wedge for 11 × 13, 11 × 17 and 11 × 21 cm2 field sizes were 5.92, 6.36 and 6.77% of the prescribed dose, respectively as well as for dynamic wedge were 2.92, 4.63 and 5.60% of the prescribed dose, respectively. The results showed that the received photon and thermal neutron doses to CB increase with increment of field sizes. The received photon and thermal neutron doses to CB in presence of physical wedge were more than dynamic wedge. According to obtained findings, it is suggested that using a dynamic wedge is preferable than physical wedge, especially for medial tangential field.
