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1.
Aim
In this study, at different fields, energies and gantry angles, treatment couch and rails dose absorption ratio and treatment couch effect on surface and build-up region doses were examined.Background
It is assumed that radiation attenuation is minimal because the carbon fiber couches have low density and it is not generally accounted for during treatment planning. Consequently, it leads to a major dosimetric mistake.Materials and methods
Solid water phantom was used for relative dose measurement. The measurements were done using a Farmer ion chamber with 0.6 cc volume and a parallel plane ion chamber starting from surface with 1 mm depth intervals at 10 × 10 cm2 field, SSD 100 cm. Measurements were taken for situations where the beams intersect the couch and couch rails.Results
Dose absorption ratio of carbon fiber couch obtained at gantry angle of 180° was 1.52%, 0.69%, 0.33% and 0.25% at different field sizes for 6 MV. For 15 MV, this ratio was 0.95%, 0.27%, 0.20% and 0.05%. The absorption ratio is between 3.4% and 1.22% when the beams intersect with couch rails. The couch effect increased surface dose from 14% to 70% for 6 MV and from 11.34% to 53.03% for 15 MV.Conclusions
The results showed that the carbon fiber couch increased surface dose during posterior irradiation. Therefore, the skin-sparing effect of the high energy beams was decreased. If the effect of couch is not considered, it may cause significant differences at dose which reaches the patient and may cause tissue problems such as erythema. 相似文献2.
Ramya Rangarajan 《Reports of Practical Oncology and Radiotherapy》2018,23(1):57-60
Aim
The aim of the study is to evaluate the differences in dosimetry between tandem-ovoid and tandem-ring gynaecologic brachytherapy applicators in image based brachytherapy.Background
Traditionally, tandem ovoid applicators were used to deliver dose to tumor in intracavitary brachytherapy. Tandem-ring, tandem-cylinder and hybrid intracavitary, interstitial applicators are also used nowadays in cervical cancer brachytherapy.Methods and materials
100 CT datasets of cervical cancer patients (stage IB2 – IIIB) receiving HDR application (50 tandem-ovoid and 50 tandem-ring) were studied. Brachytherapy was delivered using a CT-MRI compatible tandem-ovoid (50 patients) and a tandem-ring applicator (50 patients). DVHs were calculated and D2cc was recorded for the bladder and rectum and compared with the corresponding ICRU point doses. The point B dose, the treated volume, high dose volume and the treatment time were recorded and compared for the two applicators.Results
The mean D2cc of the bladder with TR applicator was 6.746 Gy. TO applicator delivered a mean D2cc of 7.160 Gy to the bladder. The mean ICRU bladder points were 5.60 and 5.63 Gy for TR and TO applicator, respectively. The mean D2cc of the rectum was 4.04 Gy and 4.79 Gy for TR and TO applicators, respectively. The corresponding ICRU point doses were 5.10 Gy and 5.66 Gy, respectively.Conclusions
The results indicate that the OAR doses assessed by DVH criteria were higher than ICRU point doses for the bladder with both tandem-ovoid and tandem-ring applicators whereas DVH based dose was lower than ICRU dose for the rectum. The point B dose, the treated volume and high dose volume was found to be slightly higher with the tandem-ovoid applicator. The mean D2cc dose for the bladder and rectum was lower with tandem-ring applicators. The clinical implication of the above dosimetric differences needs to be evaluated further. 相似文献3.
Roger Cai Xiang Soh Guan Heng Tay Wen Siang Lew James Cheow Lei Lee 《Reports of Practical Oncology and Radiotherapy》2018,23(5):413-424
Aim
To identifying depth dose differences between the two versions of the algorithms using AIP CT of a 4D dataset.Background
Motion due to respiration may challenge dose prediction of dose calculation algorithms during treatment planning.Materials and methods
The two versions of depth dose calculation algorithms, namely, Anisotropic Analytical Algorithm (AAA) version 10.0 (AAAv10.0), AAA version 13.6 (AAAv13.6) and Acuros XB dose calculation (AXB) algorithm version 10.0 (AXBv10.0), AXB version 13.6 (AXBv13.6), were compared against a full MC simulated 6X photon beam using QUASAR respiratory motion phantom with a moving chest wall. To simulate the moving chest wall, a 4 cm thick wax mould was attached to the lung insert of the phantom. Depth doses along the central axis were compared in the anterior and lateral beam direction for field sizes 2 × 2 cm2, 4 × 4 cm2 and 10 × 10 cm2.Results
For the lateral beam direction, the moving chest wall highlighted differences of up to 105% for AAAv10.0 and 40% for AXBv10.0 from MC calculations in the surface and buildup doses. AAAv13.6 and AXBv13.6 agrees with MC predictions to within 10% at similar depth. For anterior beam doses, dose differences predicted for both versions of AAA and AXB algorithm were within 7% and results were consistent with static heterogeneous studies.Conclusions
The presence of the moving chest wall was capable of identifying depth dose differences between the two versions of the algorithms. These differences could not be identified in the static chest wall as shown in the anterior beam depth dose calculations. 相似文献4.
Adela Poitevin-Chacón Jessica Chávez-Nogueda Rubí Ramos Prudencio Alejandro Calvo Fernández Alejandro Rodríguez Laguna Jesús Linares Julio César Martínez 《Reports of Practical Oncology and Radiotherapy》2018,23(2):91-96
Aim
To evaluate the dose distribution to the left anterior descending (LAD) coronary artery in patients treated with postoperative three-dimensional conformal radiotherapy (3DCRT).Background
Postoperative radiotherapy may increase the risk of heart disease, particularly in patients with left-sided breast cancer. Clinical data on doses to the LAD are limited.Materials and methods
Retrospective study of 14 patients who underwent postoperative 3DCRT for left breast cancer in 2014. All data were retrieved from medical records. Means, medians, ranges, and percentages were calculated.Results
The mean dose to the LAD in patients with V25 < 1% was 0.12 cGy. Dmean, Dmax and V25 to the heart were, respectively, 3.7 Gy (range, 0.9–4.18), 40.3 Gy (9.28–62.9), and 1.59 cGy. The mean Dmean and Dmax values in the sample were 9.71 Gy and 33.2 Gy, respectively. The maximum dose to the LAD (D2%) ranged from 3.66 to 53.01 Gy. Due to the spacing of the CT slices (5 mm), it was not possible to completely contour the entire artery. The mean dose to the heart (3.3 Gy) was considered acceptable.Conclusions
The maximum dose to the LAD was as high as 53 Gy, suggesting an increased risk of cardiac morbidity. This study underscores the value of contouring the LAD and the value of the breath hold technique to reduce maximum cardiac doses. Smaller CT cuts (2.5 mm) can improve contouring. Larger studies with long-term follow up are needed to determine the radiation tolerance dose for the LAD. 相似文献5.
Ryszard Dąbrowski Izabela Drozdyk Paweł Kukołowicz 《Reports of Practical Oncology and Radiotherapy》2018,23(2):114-120
Aim
To investigate the influence of several factors on the accuracy of dose measurements and feasibility of application of small Gafchromic detectors for postal audit.Background
Our experience showed that precision of dose measurements with small pieces of Gafchromic films may be significantly improved.Materials and methods
Gafchromic films with dimensions of 1 × 1, 2 × 2 and 3 × 3 cm2 were exposed to 6 MV X-rays at dose levels of 50 cGy-210 cGy. The single- and multichannel methods (MM) were used for dose measurements. Detectors were scanned with an Epson V750PRO flatbed colour scanner. For 1 × 1 and larger detector sizes, separate calibration curves were established. The influence of the following factors was investigated: the heterogeneity of Gafchromic detectors group for single- and MM, ambient thermal detector conditions, the dose delivered on the measurement accuracy, application of two separate calibration curves for the smallest and larger pieces of films.Results
The MM improves significantly the precision of dose measurement. The uncertainty attributed to detector active layer differences and scanner instabilities was about 1 cGy (1 StDev) regardless of dose and detector size. The ambient temperature of the environment in which films were stored after irradiation influenced the dose reading. Significant difference of transmission for detectors sized 1 × 1 and 2 × 2cm2 was observed. The maximal difference between applied dose and dose reading performed was 1.1%.Conclusions
The MM with a scaling protocol leads to a very high precision of dose measurements. The ambient thermal detector environment causes significant changes of measured signal. The detector size has relevant impact on dose reading. 相似文献6.
Elham Hosseinzadeh Nooshin Banaee Hassan Ali Nedaie 《Reports of Practical Oncology and Radiotherapy》2018,23(1):39-46
Aim
The aim of this study is to calculate neutron contamination at the presence of circular cones irradiating by 18 MV photons using Monte Carlo code.Background
Small photon fields are one of the most useful methods in radiotherapy. One of the techniques for shaping small photon beams is applying circular cones made of lead. Using this method in high energy photon due to neutron contamination is a crucial issue.Materials and methods
Initially, Varian linac producing 18 MV photons was simulated and after validating the code, various circular cones were also simulated. Then, the number of neutrons, neutron equivalent dose and absorbed dose per Gy of photon dose were calculated along the central axis.Results
Number of neutrons per Gy of photon dose had their maximum value at depth of 2 cm and these values for 5, 10, 15, 20 and 30 mm circular cones were 9.02, 7.76, 7.61, 6.02 and 5.08 (n cm?2 Gy?1), respectively. Neutron equivalent doses per Gy of photon dose had their maximum at the surface of the phantom and these values for mentioned collimators were 1.48, 1.33, 1.31, 1.12 and 1.08 (mSv Gy?1), respectively. Neutron absorbed doses had their maximum at the surface of the phantom and these values for mentioned collimators sizes were 103.74, 99.71, 95.77, 81.46 and 78.20 (μGy/Gy), respectively.Conclusions
As the field size gets smaller, number of neutrons, equivalent and absorbed dose per Gy of photon increase. Also, neutron equivalent dose and absorbed dose are maximum at the surface of phantom and then these values will be decreased. 相似文献7.
Daisuke Kawahara Shuichi Ozawa Akito Saito Tomoki Kimura Tatsuhiko Suzuki Masato Tsuneda Sodai Tanaka Kazunari Hioki Takeo Nakashima Yoshimi Ohno Yuji Murakami Yasushi Nagata 《Reports of Practical Oncology and Radiotherapy》2018,23(1):50-56
Aim
Lipiodol was used for stereotactic body radiotherapy combining trans arterial chemoembolization. Lipiodol used for tumour seeking in trans arterial chemoembolization remains in stereotactic body radiation therapy. In our previous study, we reported the dose enhancement effect in Lipiodol with 10× flattening-filter-free (FFF). The objective of our study was to evaluate the dose enhancement and energy spectrum of photons and electrons due to the Lipiodol depth with flattened (FF) and FFF beams.Methods
FF and FFF for 6 MV beams from TrueBeam were used in this study. The Lipiodol (3 × 3 × 3 cm3) was located at depths of 1, 3, 5, 10, 20, and 30 cm in water. The dose enhancement factor (DEF) and the energy fluence were obtained by Monte Carlo calculations of the particle and heavy ion transport code system (PHITS).Results
The DEFs at the centre of Lipiodol with the FF beam were 6.8, 7.3, 7.6, 7.2, 6.1, and 5.7% and those with the FFF beam were 20.6, 22.0, 21.9, 20.0, 12.3, and 12.1% at depths of 1, 3, 5, 10, 20, and 30 cm, respectively, where Lipiodol was located in water. Moreover, spectrum results showed that more low-energy photons and electrons were present at shallow depth where Lipiodol was located in water. The variation in the low-energy spectrum due to the depth of the Lipiodol position was more explicit with the FFF beam than that with the FF beam.Conclusions
The current study revealed variations in the DEF and energy spectrum due to the depth of the Lipiodol position with the FF and FFF beams. Although the FF beam could reduce the effect of energy dependence due to the depth of the Lipiodol position, the dose enhancement was overall small. To cause a large dose enhancement, the FFF beam with the distance of the patient surface to Lipiodol within 10 cm should be used. 相似文献8.
9.
Use of lignocellulosic wastes of pecan (Carya illinoinensis) in the cultivation of Ganoderma lucidum
María Virginia Ozcariz-Fermoselle Raúl Fraile-Fabero Tomás Girbés-Juan Oscar Arce-Cervantes Juan Andrés Oria de Rueda-Salgueiro Anabela Marisa Azul 《Revista iberoamericana de micología》2018,35(2):103-109
Background
The wastes of pecan nut (Carya illinoinensis (Wangenh.) K. Koch) production are increasing worldwide and have high concentrations of tannins and phenols.Aims
To study the biodegradation of lignocellulosic wastes of pecan used as solid substrate for the cultivation of the white-rot fungus Ganoderma lucidum (Curtis) P. Karst.Methods
Six formulations of pecan wastes were used as solid substrate: pecan shells (PS100), pecan pericarp (PP100), pecan wood-chips (PB100), and the combinations PS50 + PP50, PB50 + PS50 and PB50 + PP50. The substrates were inoculated with a wild strain of G. lucidum collected in the Iberian Peninsula. The biodegradation capability of G. lucidum was estimated by using the mycelial growth rate, the biological efficiency, the production and the dry biological efficiency.Results
Notably, all solid substrates were suitable for G. lucidum growth and mushroom yield. The best performance in mushroom yield was obtained with PB100 (55.4% BE), followed by PB50 + PP50 (31.7% BE) and PB50 + PS50 (25.4% BE). The mushroom yield in the substrates containing pecan wood-chips (PB) was significantly higher.Conclusions
Our study is leading the way in attempting the cultivation of G. lucidum on lignocellulosic pecan waste. These results show an environmentally friendly alternative that increases the benefits for the global pecan industry, especially in rural areas, and transforms biomass into mushrooms with nutraceutical properties and biotechnological applications. 相似文献10.
Naoki Kinoshita Hiroshi Oguchi Toshiki Adachi Hiroki Shioura Hirohiko Kimura 《Reports of Practical Oncology and Radiotherapy》2018,23(3):199-206
Background
Uncertainty in the calibration of high-energy radiation sources is dependent on user and equipment type.Aim
We evaluated the uncertainty in the positioning of a cylindrical chamber at a reference depth for reference dosimetry of high-energy photon beams and the resulting uncertainty in the chamber readings for 6- and 10-MV photon beams. The aim was to investigate major contributions to the positioning uncertainty to reduce the uncertainty in calibration for external photon beam radiotherapy.Materials and methods
The following phantoms were used: DoseView 1D, WP1D, 1D SCANNER, and QWP-07 as one-dimensional (1D) phantoms for a vertical-beam geometry; GRI-7632 as a phantom for a fixed waterproofing sleeve; and PTW type 41023 and QWP-04 as 1D phantoms for a horizontal-beam geometry. The uncertainties were analyzed as per the Guide to the Expression of Uncertainty in Measurement.Results
The positioning and resultant uncertainties in chamber readings ranged from 0.22 to 0.35 mm and 0.12–0.25%, respectively, among the phantoms (using a coverage factor k = 1 in both cases). The major contributions to positioning uncertainty are: definition of the origin for phantoms among users for the 1D phantoms for a vertical-beam geometry, water level adjustment among users for the phantom for a fixed waterproofing sleeve, phantom window deformation, and non-water material of the window for the 1D phantoms for a horizontal-beam geometry.Conclusion
The positioning and resultant uncertainties in chamber readings exhibited minor differences among the seven phantoms. The major components of these uncertainties differed among the phantom types investigated. 相似文献11.
Claudio Farías-Valenzuela Cristian Pérez-Luco Rodrigo Ramírez-Campillo Cristian Álvarez Mauricio Castro-Sepúlveda 《Revista espa?ola de geriatría y gerontología》2018,53(3):141-144
Background
Handgrip strength (HS) and peak oxygen consumption (Vo2peak) are powerful predictors of cardiovascular risk, although it is unknown which of the two variables is the better predictor.Aim
The objective of the following study was to relate HS and Vo2peak to cardiovascular risk markers in older Chilean women.Methods
Physically active adult women (n = 51; age, 69 ± 4.7 years) participated in this study. The HS and Vo2peak were evaluated and related to the anthropometric variables of body mass, body mass index (BMI), waist circumference (WC), hip circumference (HC), waist ratio (WR), and waist height ratio (WHR), as well as with the cardiovascular variables systolic (SBP) and diastolic (DBP) and cardiac recovery in one minute (RHR1). A multilinear regression model was used for the analysis of the associated variables (P < .05).Results
The cardiovascular risk markers associated (P < .05) with the handgrip strength of the dominant limb (HSDL) were body mass, BMI, WR, and WHR. The handgrip strength of the non-dominant limb (HSNDL) was associated with body mass. Vo2peak was associated with body mass, BMI, HC and RHR1. The multilinear regression model showed a value of r = 0.43 in HSDL, r = 0.39 in HSNDL and r = 0.69 in peak Vo2.Conclusion
Although HS and Vo2peak were related to cardiovascular risk markers, Vo2peak offers greater associative power with these cardiovascular risk factors. 相似文献12.
Sweta Bandanatham Janaki Manur Gururajachar Mohan Kumar Somashekar 《Reports of Practical Oncology and Radiotherapy》2018,23(2):69-74
Aim
This prospective study aims to assess the compliance with bladder protocol and the correlation with enteritis during pelvic radiation.Background
Bladder protocol is routinely used for patients undergoing pelvic radiation to reduce radiation enteritis. It is very difficult to maintain constant volume especially in the last two weeks due to radiation enteritis and cystitis.Materials and methods
Histologically proven 35 cervical cancer patients treated with concurrent chemoradiation in a tertiary care center were the subjects of this prospective study. Following CT simulation and after every fraction, patients were asked to void urine in a calibrated urine container and the volume was documented. Patients were assessed for the highest grade of radiation enteritis weekly as per common toxicity criteria. The mean voided urine volume was correlated with the radiation enteritis.Results
The mean urine volume at planning CT scan was 295.85 ± 300 ml (SD) with a range of 75–650. At the end of treatment, it was reduced to 233.14 ± 250 ml (range 50–400 ml), a reduction by 21% (p < 0.001). The maximum grade of enteritis was grade I (11%), II (11.4%), III (3–29%) in week 1,2 and 3–5, respectively with a p value of <0.001. A mean urine volume of 230 ml was associated with grade III enteritis in the third week.Conclusions
Urine output volume measured using a calibrated container is a simple, efficient and practical method to monitor bladder distension thereby reducing enteritis in cervical cancer patients treated with concurrent chemoradiation. 相似文献13.
Avinash H. Udayashankar Shibina Noorjahan Nirmala Srikantia K. Ravindra Babu Sandeep Muzumder 《Reports of Practical Oncology and Radiotherapy》2018,23(4):233-241
Aim
To identify the most reproducible technique of patient positioning and immobilization during pelvic radiotherapy.Background
Radiotherapy plays an important role in the treatment of pelvic malignancies. Errors in positioning of patient are an integral component of treatment. The present study compares two methods of immobilization with no immobilization with an aim of identifying the most reproducible method.Materials and methods
65 consecutive patients receiving pelvic external beam radiotherapy were retrospectively analyzed. 30, 21 and 14 patients were treated with no-immobilization with a leg separator, whole body vacuum bag cushion (VBC) and six point aquaplast immobilization system, respectively. The systematic error, random error and the planning target volume (PTV) margins were calculated for all the three techniques and statistically analyzed.Results
The systematic errors were the highest in the VBC and random errors were the highest in the aquaplast group. Both systematic and random errors were the lowest in patients treated with no-immobilization. 3D Systematic error (mm, mean ± 1SD) was 4.31 ± 3.84, 3.39 ± 1.71 and 2.42 ± 0.97 for VBC, aquaplast and no-immobilization, respectively. 3D random error (mm, 1SD) was 2.96, 3.59 and 1.39 for VBC, aquaplast and no-immobilization, respectively. The differences were statistically significant between all the three groups. The calculated PTV margins were the smallest for the no-immobilization technique with 4.56, 4.69 and 4.59 mm, respectively, in x, y and z axes, respectively.Conclusions
Among the three techniques, no-immobilization technique with leg separator was the most reproducible technique with the smallest PTV margins. For obvious reasons, this technique is the least time consuming and most economically viable in developing countries. 相似文献14.
Cristina Buiza Javier Yanguas Amaia Zulaica Iván Antón Enrique Arriola Alvaro García 《Revista espa?ola de geriatría y gerontología》2018,53(4):208-212
Introduction
Adaptation and validation to the Basque language of tests to assess advanced cognitive impairment is a not covered need for Basque-speaking people. The present work shows the validation of the Basque version of the Severe Mini Mental State Examination (SMMSE).Material and methods
A total of 109 people with advanced dementia (MEC < 15) took part in the validation study, and were classified as GDS 5-7 on the Geriatric Depression Scale (GDS). All participants were Spanish-Basque bilingual.Results
It was shown that SMMSE-eus has a high internal consistency (alpha = 0.92), a good test-retest reliability (r = 0.88; P < .01), and a high inter-rater reliability (CCI = 0.99; P < .00) for the overall score, as well as for each item.Conclusions
Both the high internal consistency and inter-rater reliability, and to a lesser extent, test-retest reliability, made the SMMSE-eus a valid test for the brief assessment of cognitive status in people with advanced dementia in Basque-speaking people. For this reason, the SMMSE-eus is a usable and reliable alternative for assessing Basque-speaking people in their mother-tongue, or preferred language. 相似文献15.
Hidekazu Tanaka Takahiro Yamaguchi Kae Hachiya Kazuhiro Miwa Jun Shinoda Masahide Hayashi Shinichi Ogawa Hironori Nishibori Satoshi Goshima Masayuki Matsuo 《Reports of Practical Oncology and Radiotherapy》2018,23(3):215-219
Aim
To define the optimal margin on MRI scans in the re-radiation planning of recurrent glioblastoma using methionine positron emission tomography (MET-PET).Background
It would be very useful if the optimal margin on MRI to cover the uptake area on MET-PET is known.Materials and Methods
CT, MRI, and MET-PET were performed separately over the course of 2 weeks. Among the MRI scans, we used the contrast-enhanced T1-weighted images (Gd-MRI) and T2-weighted images (T2-MRI). The Gd-MRI-based clinical target volume (CTV) (CTV-Gd) and the T2-MRI-based CTV (CTV-T2) were defined as the contrast-enhanced area on Gd-MRI and the high intensity area on T2-MRI, respectively. We defined CTV x mm (x = 5, 10, 15, 20) as x mm outside the CTV. MET-PET-based CTV (CTV-MPET) was defined as the area of accumulation of MET-PET. We calculated the sensitivity and specificity of CTV-Gd and CTV-T2 following comparison with CTV-MPET, which served as the gold standard in this study.Results
The sensitivity of CTV-T2 5 mm (98%) was significantly higher than CTV-T2 (87%), and there was no significant difference in the sensitivity between CTV-T2 5 mm and CTV T2 10, 15, or 20 mm. The sensitivity of CTV-Gd 20 mm (97%) was lower than that of CTV-T2 5 mm (98%).Conclusions
A margin of at least 5 mm around the high intensity area on T2-MRI is necessary in the target volume delineation of recurrent glioblastoma for the coverage of MET-PET findings in re-radiation therapy planning. 相似文献16.
Oriol Turró Garriga Sílvia Farrés Costa Albert Pérez Terré Pau Batlle Amat 《Revista espa?ola de geriatría y gerontología》2018,53(4):196-201
Introduction
The care of dependent persons is arduous, and requires time, energy, and physical effort on the part of caregivers. Personal characteristics, such as the sense of coherence (SOC), can influence the perceived burden and care giving.Objective
To determine the impact of SOC on the perceived burden and to determine if these characteristics are associated with adherence to a psycho-educational program for informal caregivers.Material and method
Prospective observational study of caregivers of dependent persons participating in the ‘School of Caregivers’, a psycho-educational program for family and paid caregivers. An analysis was made of the SOC-13 items and the results of the Zarit Burden Interview. The relationship between the SOC and the adherence to the program (≥ 50% sessions) was also analysed.Results
The study included 96 participants, with 71.9% family carers. The higher burden was associated with a lower SOC meaningfulness factor (β = –0.388; P = .002), and to be a relative vs. paid carer (β = –0.300; P = .010). Just over half (52.1%) of carers completed 50% or more sessions, and in the case of the relatives, this adherence increased by higher SOC (OR: 1.1, P = .034), and lower burden (OR: 0.95, P = .032). The lack of adherence of paid caregivers was not associated with any of the analysed variables.Conclusions
The sense of coherence and mainly the meaning, is a characteristic to take into account for the adaptation of interventions in caregivers and provide them with greater equity working more on the people who need it the most (lower SOC and greater burden). 相似文献17.
Hidekazu Tanaka Takahiro Yamaguchi Kae Hachiya Shingo Kamei Satoshi Ishihara Masahide Hayashi Shinichi Ogawa Hironori Nishibori Satoshi Goshima Masayuki Matsuo 《Reports of Practical Oncology and Radiotherapy》2018,23(1):28-33
Aim
This study aimed to evaluate the treatment result of intensity-modulated radiation therapy (IMRT) in a large number of Japanese patients with prostate cancer.Background
A total of 1091 patients with localized prostate cancer were recruited between March 2006 and July 2014. The patients were stratified into low- (n = 205 [18.8%]), intermediate- (n = 450 [41.2%]), high- (n = 345 [31.6%]), and very high-risk (n = 91 [8.3%]) groups according to the National Comprehensive Cancer Network classification. All patients were irradiated via IMRT at a dose of 74–78 Gy with or without androgen-deprivation therapy. The mean follow-up period was 50 months (range, 2–120 months).Results
The biochemical failure-free rate (BFFR), the clinical failure-free rate, and the overall survival rate at the 5-year follow-up for all patients was 91.3%, 96.2%, and 99.1%, respectively. In univariate analysis, the prostate-specific antigen (PSA) levels (≤20 vs. >20 ng/ml) were significantly correlated with BFFR. A trend toward higher BFFR was noted in patients with a Gleason score (GS) of ≤7 than in patients with GS ≥8. In multivariate analysis, only PSA (≤20 vs. >20 ng/ml) was significantly correlated with BFFR. The cumulative incidence rate of gastrointestinal and genitourinary toxicity (≥grade 2) at the 5-year follow-up was 11.4% and 4.3%, respectively.Conclusions
The findings of this study indicate that IMRT is well tolerated and is associated with both good long-term tumor control and excellent outcomes in patients with localized prostate cancer. 相似文献18.
Hamid Shafaei Douk Mahmoud Reza Aghamiri Mahdi Ghorbani Bagher Farhood Mohsen Bakhshandeh Hamid Reza Hemmati 《Reports of Practical Oncology and Radiotherapy》2018,23(2):105-113
Aim
The aim of this study is to evaluate the accuracy of the inverse square law (ISL) method for determining location of virtual electron source (SVir) in Siemens Primus linac.Background
So far, different experimental methods have presented for determining virtual and effective electron source location such as Full Width at Half Maximum (FWHM), Multiple Coulomb Scattering (MCS), and Multi Pinhole Camera (MPC) and Inverse Square Law (ISL) methods. Among these methods, Inverse Square Law is the most common used method.Materials and methods
Firstly, Siemens Primus linac was simulated using MCNPX Monte Carlo code. Then, by using dose profiles obtained from the Monte Carlo simulations, the location of SVir was calculated for 5, 7, 8, 10, 12 and 14 MeV electron energies and 10 cm × 10 cm, 15 cm × 15 cm, 20 cm × 20 cm and 25 cm × 25 cm field sizes. Additionally, the location of SVir was obtained by the ISL method for the mentioned electron energies and field sizes. Finally, the values obtained by the ISL method were compared to the values resulted from Monte Carlo simulation.Results
The findings indicate that the calculated SVir values depend on beam energy and field size. For a specific energy, with increase of field size, the distance of SVir increases for most cases. Furthermore, for a special applicator, with increase of electron energy, the distance of SVir increases for most cases. The variation of SVir values versus change of field size in a certain energy is more than the variation of SVir values versus change of electron energy in a certain field size.Conclusion
According to the results, it is concluded that the ISL method can be considered as a good method for calculation of SVir location in higher electron energies (14 MeV). 相似文献19.
Marta Kruszyna-Mochalska 《Reports of Practical Oncology and Radiotherapy》2018,23(5):309-314
Aim
The aim of the work was to catch potential errors with daily EPID measurements of repeatability of the dose distribution during irradiation of IMRT patients.Materials and methods
In the first stage, measurements were made using an anthropomorphic phantom in which the method of collecting data with an EPID device and the possibility of detecting errors in positioning were developed. Next, for 23 patients, the pelvis (P) and head and neck (H&N) regions, images were collected with an EPID device for each IMRT subfield daily and compared to reference images using the gamma method (DTA 3 mm, DD 3%). Finally, the dependencies between treatment plan parameters, pre-verification results and repeatability of collected images were evaluated.Results
The anthropomorphic phantom study has shown what kind of effects we can expect with EPID measured at potential shifts during radiotherapy. For the clinical case, score results were obtained for individual tumor regions as below: (P) 0.786 ± 1.046, (H&N) 0.720 ± 1.552. For most evaluated cases, score values were below 1%: (P) 75.5% and (H&N) 83.9% of analyzed fields. 95% of all evaluated data was with the score below: (P) 2.86% and (H&N) 3.40%. The relationship between the results of the analysis of daily collected images and the results of pre-verification, field size and irradiation time was shown.Conclusions
The EPID-based daily verification can provide extra information about day-to-day repeatability of treatment, without additional dose. 相似文献20.
Daisuke Kawahara Shuichi Ozawa Takeo Nakashima Shintaro Tsuda Yusuke Ochi Takuro Okumura Hirokazu Masuda Kazunari Hioki Tathsuhiko Suzuki Yoshimi Ohno Tomoki Kimura Yuji Murakami Yasushi Nagata 《Reports of Practical Oncology and Radiotherapy》2018,23(2):84-90