Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 21
Filtrar
1.
Eur Radiol ; 2020 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-33211140

RESUMO

OBJECTIVE: Assessing the advantage of x-ray dark-field contrast over x-ray transmission contrast in radiography for the detection of developing radiation-induced lung damage in mice. METHODS: Two groups of female C57BL/6 mice (irradiated and control) were imaged obtaining both contrasts monthly for 28 weeks post irradiation. Six mice received 20 Gy of irradiation to the entire right lung sparing the left lung. The control group of six mice was not irradiated. A total of 88 radiographs of both contrasts were evaluated for both groups based on average values for two regions of interest, covering (irradiated) right lung and healthy left lung. The ratio of these average values, R, was distinguished between healthy and damaged lungs for both contrasts. The time-point when deviations of R from healthy lung exceeded 3σ was determined and compared among contrasts. The Wilcoxon-Mann-Whitney test was used to test against the null hypothesis that there is no difference between both groups. A selection of 32 radiographs was assessed by radiologists. Sensitivity and specificity were determined in order to compare the diagnostic potential of both contrasts. Inter-reader and intra-reader accuracy were rated with Cohen's kappa. RESULTS: Radiation-induced morphological changes of lung tissue caused deviations from the control group that were measured on average 10 weeks earlier with x-ray dark-field contrast than with x-ray transmission contrast. Sensitivity, specificity, and accuracy doubled using dark-field radiography. CONCLUSION: X-ray dark-field radiography detects morphological changes of lung tissue associated with radiation-induced damage earlier than transmission radiography in a pre-clinical mouse model. KEY POINTS: • Significant deviations from healthy lung due to irradiation were measured after 16 weeks with x-ray dark-field radiography (p = 0.004). • Significant deviations occur on average 10 weeks earlier for x-ray dark-field radiography in comparison to x-ray transmission radiography. • Sensitivity and specificity doubled when using x-ray dark-field radiography instead of x-ray transmission radiography.

2.
Radiat Oncol ; 15(1): 253, 2020 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-33138837

RESUMO

BACKGROUND: The ESCALOX trial was designed as a multicenter, randomized prospective dose escalation study for head and neck cancer. Therefore, feasibility of treatment planning via different treatment planning systems (TPS) and radiotherapy (RT) techniques is essential. We hypothesized the comparability of dose distributions for simultaneous integrated boost (SIB) volumes respecting the constraints by different TPS and RT techniques. METHODS: CT data sets of the first six patients (all male, mean age: 61.3 years) of the pre-study (up to 77 Gy) were used for comparison of IMRT, VMAT, and helical tomotherapy (HT). Oropharynx was the primary tumor location. Normalization of the three step SIB (77 Gy, 70 Gy, 56 Gy) was D95% = 77 Gy. Coverage (CVF), healthy tissue conformity index (HTCI), conformation number (CN), and dose homogeneity (HI) were compared for PTVs and conformation index (COIN) for parotids. RESULTS: All RT techniques achieved good coverage. For SIB77Gy, CVF was best for IMRT and VMAT, HT achieved highest CN followed by VMAT and IMRT. HT reached good HTCI value, and HI compared to both other techniques. For SIB70Gy, CVF was best by IMRT. HTCI favored HT, consequently CN as well. HI was slightly better for HT. For SIB56Gy, CVF resulted comparably. Conformity favors VMAT as seen by HTCI and CN. Dmean of ipsilateral and contralateral parotids favor HT. CONCLUSION: Different TPS for dose escalation reliably achieved high plan quality. Despite the very good results of HT planning for coverage, conformity, and homogeneity, the TPS also achieved acceptable results for IMRT and VMAT. Trial registration ClinicalTrials.gov Identifier: NCT01212354, EudraCT-No.: 2010-021139-15. ARO: ARO 14-01.

3.
Strahlenther Onkol ; 196(12): 1103-1115, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32748147

RESUMO

BACKGROUND AND PURPOSE: Radiotherapy (RT) is persistently gaining significance in the treatment of pediatric tumors. However, individual features of a growing body and multifocal stages complicate this approach. Tomotherapy offers advantages in the treatment of anatomically complex tumors with low risks of side effects. Here we report on toxicity incidence and outcome of tomotherapy with a focus on multitarget RT (mtRT). MATERIALS AND METHODS: From 2008 to 2017, 38 children diagnosed with sarcoma were treated with tomotherapy. The median age was 15 years (6-19 years). Toxicity was graded according to the Common Terminology Criteria for Adverse Events v.4.03 and classified into symptoms during RT, acutely (0-6 months) and late (>6 months) after RT, and long-term sideeffects (>24 months). RESULTS: The main histologies were Ewing sarcoma (n = 23 [61%]) and alveolar rhabdomyosarcoma (n = 5 [13%]). RT was performed with a median total dose of 54 Gy (40.5-66.0 Gy) and a single dose of 2 Gy (1.80-2.27 Gy). Twenty patients (53%) received mtRT. Median follow-up was 29.7 months (95% confidence interval 15.3-48.2 months) with a 5-year survival of 55.2% (±9.5%). The 5­year survival rate of patients with mtRT (n = 20) was 37.1 ± 13.2%, while patients who received single-target RT (n = 18) had a 5-year survival rate of 75 ± 10.8%. Severe toxicities (grade 3 and 4) emerged in 14 patients (70%) with mtRT and 7 patients (39%) with single-target RT. Two non-hematological grade 4 toxicities occurred during RT: one mucositis and one radiodermatitis. After mtRT 5 patients had grade 3 toxicities acute and after single-target RT 4 patients. One patient had acute non-hematological grade 4 toxicities (gastritis, pericarditis, and pericardial effusion) after mtRT. Severe late effects of RT occurred in 2 patients after mtRT and in none of the single-target RT patients. No severe long-term side effects appeared. CONCLUSION: Our results showed acceptable levels of acute and late toxicities, considering the highly advanced diseases and multimodal treatment. Hence, tomotherapy is a feasible treatment method for young patients with anatomically complex tumors or multiple targets. Especially mtRT is a promising and innovative treatment approach for pediatric sarcomas, delivering unexpectedly high survival rates for patients with multifocal Ewing sarcomas in this study, whereby the limited number of patients should invariably be considered in the interpretation.

4.
BMC Cancer ; 20(1): 501, 2020 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-32487151

RESUMO

BACKGROUND: The aim of our study was to assess the feasibility and oncologic outcomes in patients treated with spinal (SI) or craniospinal irradiation (CSI) in patients with leptomeningeal metastases (LM) and to suggest a prognostic score as to which patients are most likely to benefit from this treatment. METHODS: Nineteen patients treated with CSI at our institution were eligible for the study. Demographic data, primary tumor characteristics, outcome and toxicity were assessed retrospectively. The extent of extra-CNS disease was defined by staging CT-scans before the initiation of CSI. Based on outcome parameters a prognostic score was developed for stratification based on patient performance status and tumor staging. RESULTS: Median follow-up and overall survival (OS) for the whole group was 3.4 months (range 0.5-61.5 months). The median overall survival (OS) for patients with LM from breast cancer was 4.7 months and from NSCLC 3.3 months. The median OS was 7.3 months, 3.3 months and 1.5 months for patients with 0, 1 and 2 risk factors according to the proposed prognostic score (KPS < 70 and the presence of extra-CNS disease) respectively. Nonhematologic toxicities were mild. CONCLUSION: CSI demonstrated clinically meaningful survival that is comparable to the reported outcome of intrathecal chemotherapy. A simple scoring system could be used to better select patients for treatment with CSI in this palliative setting. In our opinion, the feasibility of performing CSI with modern radiotherapy techniques with better sparing of healthy tissue gives a further rationale for its use also in the palliative setting.

5.
Radiat Oncol ; 14(1): 135, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31370876

RESUMO

PURPOSE/OBJECTIVE(S): Along with breast-conserving surgery (BCS), adjuvant radiotherapy (RT) of patients with early breast cancer plays a crucial role in the oncologic treatment concept. Conventionally, irradiation is carried out with the aid of tangentially arranged fields. However, more modern and more complex radiation techniques such as IMRT (intensity-modulated radio therapy) are used more frequently, as they improve dose conformity and homogeneity and, in some cases, achieve better protection of adjacent risk factors. The use of this technique has implications for the incidental- and thus unintended- irradiation of adjacent loco regional lymph drainage in axillary lymph node levels I-III and internal mammary lymph nodes (IMLNs). A comparison of a homogeneous "real-life" patient collective, treated with helical tomotherapy (TT), patients treated with 3D conformal RT conventional tangentially arranged fields (3DCRT) and deep inspiration breath hold (3DCRT-DIBH), was conducted. MATERIALS/METHODS: This study included 90 treatment plans after BCS, irradiated in our clinic from January 2012 to August 2016 with TT (n = 30) and 3D-CRT (n = 30), 3DCRT DIBH (n = 30). PTVs were contoured at different time points by different radiation oncologists (> 7). TT was performed with a total dose of 50.4 Gy and a single dose of 1.8 Gy with a simultaneous integrated boost (SIB) to the tumor cavity (TT group). Patients irradiated with 3DCRT/3DCRT DIBH received 50 Gy à 2 Gy and a sequential boost. Contouring of lymph drainage routes was performed retrospectively according to RTOG guidelines. RESULTS: Average doses (DMean) in axillary lymph node Level I/Level II/Level III were 31.6 Gy/8.43 Gy/2.38 Gy for TT, 24.0 Gy/11.2 Gy/3.97 Gy for 3DCRT and 24.7 Gy/13.3 Gy/5.59 Gy for 3DCRT-DIBH patients. Internal mammary lymph nodes (IMLNs) Dmean were 27.8 Gy (TT), 13.5 Gy (3DCRT), and 18.7 Gy (3DCRT-DIBH). Comparing TT to 3DCRT-DIBH dose varied significantly in all axillary lymph node levels and the IMLNs. Comparing TT to 3DCRT significant dose difference in Level I and IMLNs was observed. CONCLUSION: Dose applied to locoregional lymph drainage pathways varies comparing tomotherapy plans to conventional tangentially arranged fields. Studies are warranted whether dose variations influence loco-regional spread and must have implications for target volume definition guidelines.


Assuntos
Neoplasias da Mama/radioterapia , Linfonodos/efeitos da radiação , Órgãos em Risco/efeitos da radiação , Lesões por Radiação/prevenção & controle , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia Adjuvante/normas , Radioterapia Conformacional/normas , Suspensão da Respiração , Feminino , Humanos , Pessoa de Meia-Idade , Prognóstico , Dosagem Radioterapêutica , Radioterapia Conformacional/métodos , Radioterapia de Intensidade Modulada , Estudos Retrospectivos
6.
Radiat Oncol J ; 37(2): 127-133, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31137087

RESUMO

PURPOSE: The aim of this study was to identify volume changes and dose variations of rectum and bladder during radiation therapy in prostate cancer (PC) patients. MATERIALS AND METHODS: We analyzed 20 patients with PC treated with helical tomotherapy. Daily image guidance was performed. We re-contoured the entire bladder and rectum including its contents as well as the organ walls on megavoltage computed tomography once a week. Dose variations were analyzed by means of Dmedian, Dmean, Dmax, V10 to V75, as well as the organs at risk (OAR) volume. Further, we investigated the correlation between volume changes and changes in Dmean of OAR. RESULTS: During treatment, the rectal volume ranged from 62% to 223% of its initial volume, the bladder volume from 22% to 375%. The average Dmean ranged from 87% to 118% for the rectum and 58% to 160% for the bladder. The Pearson correlation coefficients between volume changes and corresponding changes in Dmean were -0.82 for the bladder and 0.52 for the rectum. The comparison of the dose wall histogram (DWH) and the dose volume histogram (DVH) showed that the DVH underestimates the percentage of the rectal and bladder volume exposed to the high dose region. CONCLUSION: Relevant variations in the volume of OAR and corresponding dose variations can be observed. For the bladder, an increase in the volume generally leads to lower doses; for the rectum, the correlation is weaker. Having demonstrated remarkable differences in the dose distribution of the DWH and the DVH, the use of DWHs should be considered.

7.
Radiat Oncol ; 14(1): 2, 2019 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-30626408

RESUMO

BACKGROUND: Advanced radiotherapy (RT) techniques allow normal tissue to be spared in patients with extremity soft tissue sarcoma (STS). This work aims to evaluate toxicity and outcome after neoadjuvant image-guided radiotherapy (IGRT) as helical intensity modulated radiotherapy (IMRT) with reduced margins based on MRI-based target definition in patients with STS. METHODS: Between 2010 to 2014, 41 patients with extremity STS were treated with IGRT delivered as helical IMRT on a tomotherapy machine. The tumor site was in the upper extremity in 6 patients (15%) and lower extremity in 35 patients (85%). Reduced margins of 2.5 cm in longitudinal direction and 1.0 cm in axial direction were used to expand the MRI-defined gross tumor volume, including peritumoral edema, to the clinical target volume. An additional margin of 5 mm was added to receive the planning target volume. The full total dose of 50 Gy in 2 Gy fractions was sucessfully applied in 40 patients. Two patients received chemotherapy instead of surgery due to systemic progression. All patients were included into a strict follow-up program and were seen interdisciplinarily by the Departments of Orthopaedic Surgery and Radiation Oncology. RESULTS: Thirty eight patients that received total RT total dose and subsequent resection were analyzed for outcome. After a median follow-up of 38.5 months cumulative OS, local PFS and systemic PFS at 2 years were determined at 78.2, 85.2 and 54.5%, respectively. Two of 6 local recurrences were proximal marginal misses. Negative resection margins were achieved in 84% of patients. The rate of major wound complications was comparable to previous IMRT studies with 36.8%. RT was overall tolerable with low toxicity rates. CONCLUSIONS: IMRT-IGRT offers neoadjuvant treatment for extremity STS with reduced safety margins and thus low toxicity rates. Wound complication rates were comparable to previously reported frequencies. Two reported marginal misses suggest a word of caution for reduction of longitudinal safety margins.


Assuntos
Extremidades/efeitos da radiação , Terapia Neoadjuvante/métodos , Recidiva Local de Neoplasia/radioterapia , Radioterapia Guiada por Imagem/métodos , Radioterapia de Intensidade Modulada/métodos , Sarcoma/radioterapia , Adulto , Idoso , Idoso de 80 Anos ou mais , Extremidades/patologia , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/patologia , Prognóstico , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia Adjuvante , Sarcoma/patologia , Taxa de Sobrevida , Adulto Jovem
8.
Strahlenther Onkol ; 195(6): 475-481, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30523417

RESUMO

BACKGROUND: The goal of this study was to investigate if daily dose recalculations are necessary or if less time-consuming approaches can be used to identify dose differences to the planned dose in patients with head and neck cancers (H&N). METHODS: For 12 H&N patients treated with helical tomotherapy, daily dose calculations were performed retrospectively. Four different summation doses (SuDo) were calculated: DayDo (daily dose calculation), MVCTx2, MVCTx5, and MVCTx10 (dose calculations every second, fifth, and tenth fraction). Dose recalculations were depicted on the last contoured mega voltage CT (MVCT). The DayDo was compared to the planned dose and to the less time-consuming SuDo scenarios. The doses were assessed for the planning target volume (PTV) and the organs at risk (OARs): mandible (mand), spinal cord (SC), spinal cord +5 mm (SC+5 mm), parotid glands (PG). RESULTS: The ipsilateral PG, contralateral PG, and PTV volume decreased by -22.5% (range: -34.8 to 5.2%), -19.5% (-31.5 to 15.8%), and -2.6% (-16.7 to 0.2%), respectively. There was a significant median mean dose (Dmean) dose difference for DayDo compared to the planned dose for PG total of 1.9 Gy (-3.3 to 7.3 Gy). But less time-consuming SuDo compared to DayDo showed statistically significant but not clinically relevant (<2%) dose differences for several organs. Hence the small dose difference to the gold standard (DayDo), we recommend dose recalculations every fifth MVCT in order to identify the occurrence of dose differences compared to the planned dose. CONCLUSION: Daily dose calculations are the most precise to assess dose differences between actual and planned dose. Dose recalculations on every fifth MVCT (i. e., weekly control CTs) are an applicable and time-saving way of identifying patients with significant dose differences compared to the planned dose.


Assuntos
Neoplasias Otorrinolaringológicas/radioterapia , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia Guiada por Imagem/métodos , Radioterapia de Intensidade Modulada/métodos , Tomografia Computadorizada por Raios X/métodos , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Órgãos em Risco/efeitos da radiação , Fatores de Tempo
9.
Z Med Phys ; 28(4): 303-309, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29858132

RESUMO

The aim of this study was to investigate a single crystal diamond detector, the microDiamond detector from PTW (PTW-Freiburg, Freiburg, Germany), concerning the particular requirements in the set-up and energy range used in small animal radiotherapy (RT) research (around 220kV). We tested it to find out the minimal required pre-irradiation dose, the dose linearity, dose rate dependency and the angular response as well as usability in the small animal radiation research platform, SARRP (Xstrahl Ltd., Camberley, UK). For a stable signal in the range of energies used in the study, we found a required pre-irradiation dose of 10Gy. The dose linearity and dose rate dependence measurements showed a very good performance of the microDiamond detector. Regarding the effect of angular dependency, the variation of the response signal is less than 0.5% within the first 15° of the polar angle. In the azimuthal angle, however, there are differences in detector response up to 20%, depending on the range of energies used in the study. In addition, we compared the detector to a radiosensitive film for a profile measurement of a 5×5mm2 irradiation field. Both methods showed a good accordance with the field size, however, the film has a steeper dose gradient in the penumbra region but also a higher noise than the microDiamond detector. We demonstrated that the microDiamond detector is a useful measurement tool for small animal RT research due to its small size. Nevertheless, it seems to be very important to verify the response of the detector in the given set-up and energy range.


Assuntos
Dosímetros de Radiação , Radiometria/instrumentação , Radiometria/métodos , Diamante , Raios X
10.
Radiat Oncol ; 13(1): 31, 2018 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-29471879

RESUMO

BACKGROUND: Tumor-Treating Fields (TTFields) are a novel treatment strategy for glioblastoma (GBM) that is approved for the use concomitantly to adjuvant chemotherapy. Preclinical data suggest a synergistic interaction of TTFields and radiotherapy (RT). However, the dosimetric uncertainties caused by the highly dense arrays have led to caution of applying the TTF setup during RT. METHODS: In a RW3 slab phantom we compared the MV- and kV-CT based planned dose with the measured dose. VMAT-plans were optimized on MV-CTs of an Alderson head phantom without TTF arrays and then re-calculated on the same phantom equipped with TTF arrays. Dose at organs at risk (OAR) and target volumes (PTVs) were compared. RESULTS: Measurements at a depth of 2, 3 and 4 cm of a RW 3 slab phantom show an attenuation due to TTField arrays of 3.4, 3.7 and 2.7% respectively. This was in-line with calculated attenuations based on MV-CT (1.2, 2.5 and 2.5%) but not with the attenuation expected from kV-CT based calculations (7.1, 8.2 and 8.6%). Consecutive MV-CT based VMAT planning and re-calculation reveals, that the conformity and homogeneity are not affected by the presence of TTField arrays. The dose at organs at risk (OAR) can show increases or decreases by < 0.5 Gy, which should be considered especially in cases next to the scull base. CONCLUSION: MV-CT based dose calculation results in reliable dose distributions also in the presence of TTField arrays. There is a small but clinically not relevant interaction between the TTField arrays and VMAT dose application. Thus, daily replacement of TTField arrays is not necessary in regard to deeply located OARs. RT is feasible, when a VMAT treatment plan is optimized to an array free planning CT. As the biologic effect of a concomitant treatment especially on OARs is currently unknown, a concomitant treatment should be performed only within clinical trials.


Assuntos
Terapia por Estimulação Elétrica/métodos , Glioblastoma/radioterapia , Imagens de Fantasmas , Planejamento da Radioterapia Assistida por Computador/métodos , Planejamento da Radioterapia Assistida por Computador/normas , Transdutores , Terapia por Estimulação Elétrica/instrumentação , Humanos , Órgãos em Risco/efeitos da radiação , Dosagem Radioterapêutica
11.
Radiat Oncol ; 12(1): 45, 2017 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-28249612

RESUMO

BACKGROUND: Standard of care primary treatment of carcinoma of locally advanced squamous cell head and neck cancer (LAHNSCC) consists of platinum-based concomitant chemo-irradiation. Despite progress in the treatment of LAHNSCC using modern radiotherapy techniques the outcome remains still poor. Using IMRT with SIB the escalation of total dose to the GTV is possible with the aim to improve clinical outcome. This study tests the hypothesis if radiation dose escalation to the GTV improves 2-year-LRC and -OS after concomitant chemo-irradiation. METHODS: The ESCALOX trial is a prospective randomized phase III study using cisplatin chemo-irradiation and the SIB-IMRT concept in patients with LAHNSCC of the oral cavity, oropharynx or hypopharynx to escalate the total dose to the GTV up to 80.5 Gy. Chemotherapy is planned either in the 1st and 5th week (cisplatin 20 mg/m2/d d 1-5 and d 29-33) or weekly (cisplatin 40 mg/m2/d) during RT. RT is delivered as SIB with total doses of 80.5 Gy/70.0 Gy/56.0 Gy with 2.3 Gy/2.0 Gy and 1.6 Gy in the experimental arm and in the control arm with 70.0 Gy/56.0 Gy with 2.0 Gy and 1.6 Gy. A pre-study with dose escalation up to 77.0 Gy/70.0 Gy/56.0 Gy with 2.2 Gy/2.0 Gy and 1.6 Gy is demanded by the German federal office of radiation protection (BfS). In the translational part of the trial 100 of the randomised patients will be investigated by 18-F-FMiso-PET-CT for the presence and behaviour of tumor hypoxia twice in the week before treatment start. DISCUSSION: The primary endpoint of the pre-study is acute radiation induced toxicity. Primary endpoint of the main trial is 2-year-LRC. By using the dose escalation up to 80.5 Gy to the GTV of the primary tumor and lymph nodes > 2 cm a LRC benefit of 15% at 2 years should be expected. The ESCALOX trial is supported by Deutsche Forschungsgemeinschaft (DFG); Grant No.: MO-363/4-1. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT 01212354 , EudraCT-No.: 2010-021139-15.


Assuntos
Carcinoma de Células Escamosas/radioterapia , Neoplasias de Cabeça e Pescoço/radioterapia , Recidiva Local de Neoplasia/prevenção & controle , Hipóxia Tumoral , Adolescente , Adulto , Idoso , Carcinoma de Células Escamosas/tratamento farmacológico , Carcinoma de Células Escamosas/patologia , Quimiorradioterapia , Feminino , Seguimentos , Neoplasias de Cabeça e Pescoço/tratamento farmacológico , Neoplasias de Cabeça e Pescoço/patologia , Humanos , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Prognóstico , Estudos Prospectivos , Dosagem Radioterapêutica , Taxa de Sobrevida , Adulto Jovem
12.
J Neurooncol ; 127(3): 597-606, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-26852221

RESUMO

In this retrospective evaluation, we correlated radiation dose parameters with occurrence of optical radiation-induced toxicities. 213 meningioma patients received radiation between 2000 and 2013. Radiation dose and clinical data were extracted from planning systems and patients' files. The range of follow-up period was 2-159 months (median 75 months). Median age of patients was 60 years (range 23-86). There were 163 female and 50 male patients. In 140 cases, at least one of the neuro-optic structures (optic nerves and chiasm) was inside the irradiated target volumes. We found 15 dry eye (7 %) and 24 cataract (11.2 %) cases. Median dose to affected lachrymal glands was 1.47 Gy and median dose to affected lenses was 1.05 Gy. Age and blood cholesterol level in patients with cataract were significantly higher. Patients with dry eye were significantly older. Only two patients with visual problems attributable to radiation treatment were seen. They did not have any risk factors. Maximum and median delivered doses to neuro-optic structures were not higher than 57.30 and 54.60 Gy respectively. Low percentages of cases with radiation induced high grade optic toxicities show that modern treatment techniques and doses are safe. In very few patients with optic side effects, doses to organs at risk were higher than the defined constraint doses. This observation leads to the problem of additional risk factors coming into play. The role of risk factors and safety of higher radiation doses in high grade meningiomas should be investigated in more comprehensive studies.


Assuntos
Neoplasias Meníngeas/radioterapia , Meningioma/radioterapia , Doenças do Nervo Óptico/etiologia , Nervo Óptico/efeitos da radiação , Lesões por Radiação/etiologia , Radioterapia/efeitos adversos , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Seguimentos , Humanos , Masculino , Neoplasias Meníngeas/patologia , Meningioma/patologia , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Doenças do Nervo Óptico/diagnóstico , Prognóstico , Lesões por Radiação/diagnóstico , Dosagem Radioterapêutica , Estudos Retrospectivos , Adulto Jovem
13.
Front Oncol ; 5: 262, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26640777

RESUMO

While neutron therapy was a highly topical subject in the 70s and 80s, today there are only a few remaining facilities offering fast neutron therapy (FNT). Nevertheless, up to today more than 30,000 patients were treated with neutron therapy. For some indications like salivary gland tumors and malignant melanoma, there is clinical evidence that the addition of FNT leads to superior local control compared to photon treatment alone. FNT was available in Munich from 1985 until 2000 at the Reactor Neutron Therapy (RENT) facility. Patient treatment continued at the new research reactor FRM II in 2007 under improved treatment conditions, and today it can still be offered to selected patients as an individual treatment option. As there is a growing interest in high-linear energy transfer (LET) therapy with new hadron therapy centers emerging around the globe, the clinical data generated by neutron therapy might help to develop biologically driven treatment planning algorithms. Also FNT might experience its resurgence as a combinational partner of modern immunotherapies.

14.
BMC Cancer ; 15: 904, 2015 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-26573139

RESUMO

BACKGROUND: The aim of the trial is to demonstrate that with the use of modern IMRT/IGRT and reduction of safety margins postoperative wound complications can be reduced. METHODS/ DESIGN: The trial is designed as a prospective, monocentric clinical phase II trial. The treatment is performed with helical IMRT on the Tomotherapy HiArt System© or with RapidArc© IMRT as available. All treatments are performed with 6 MV photons and daily online CT-based IGRT. A dose of 50 Gy in 2 Gy single fractions (5 fractions per week) is prescribed. Restaging including MRI of the primary tumor site as well as CT of the thorax/abdomen is planned 4 weeks after RT. PET-examinations or any other imaging can be performed as required clinically. In cases of R1 resection, brachytherapy is anticipated in the 2nd postoperative week. Brachytherapy catheters are implanted into the tumor bed depending on the size and location of the lesion. Surgery is planned 5-6 weeks after completion of neoadjuvant RT. All patients are seen for a first follow-up visit 2 weeks after wound healing is completed, thereafter every 3 months during the first 2 years. The endpoints of the study are evaluated in detail during the first (2 weeks) and second (3 months) follow-up. Functional outcome and QOL are documented prior to treatment and at year 1 and 2. Treatment response and efficacy will be scored according to the RECIST 1.1 criteria. A total patient number of 50 with an expected 20% rate of wound complications were calculated for the study, which translates into a 95% confidence interval of 10.0-33.7% for wound complication rate in a binomial distribution. DISCUSSION: The present study protocol prospectively evaluates the use of IMRT/IGRT for neoadjuvant RT in patients with soft tissue sarcomas of the extremity with the primary endpoint wound complications, which is the major concern with this treatment sequence. Besides complications rates, local control rates and survival rates, as well as QOL, functional outcome and treatment response parameters (imaging and pathology) are part of the protocol. The data of the present PREMISS study will enhance the current literature and support the hypothesis that neoadjuvant RT with IMRT/IGRT offers an excellent risk-benefit ratio in this patient population. TRIAL REGISTRATION: NCT01552239.


Assuntos
Terapia Neoadjuvante/métodos , Radioterapia de Intensidade Modulada/métodos , Sarcoma/radioterapia , Neoplasias de Tecidos Moles/radioterapia , Adulto , Braquiterapia/métodos , Relação Dose-Resposta à Radiação , Extremidades , Feminino , Humanos , Masculino , Recidiva Local de Neoplasia/radioterapia , Estudos Prospectivos , Radioterapia Adjuvante/métodos , Sarcoma/patologia , Sarcoma/cirurgia , Neoplasias de Tecidos Moles/patologia , Neoplasias de Tecidos Moles/cirurgia , Taxa de Sobrevida
15.
Phys Med ; 31(3): 266-72, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25724350

RESUMO

PURPOSE: To investigate the influence of interfractional changes on the delivered dose of intensity modulated proton (IMPT) and photon plans (IMXT). METHODS AND MATERIALS: Five postoperative head and neck cancer patients, previously treated with tomotherapy at our institute, were analyzed. The planning study is based on megavoltage (MV) control images. For each patient one IMPT plan and one IMXT plan were generated on the first MV-CT and recalculated on weekly control MV-CTs in the actual treatment position. Dose criteria for evaluation were coverage and conformity of the planning target volume (PTV), as well as mean dose to parotids and maximum dose to spinal cord. RESULTS: Considerable dosimetric changes were observed for IMPT and IMXT plans. Proton plans showed a more pronounced increase of maximum dose and decrease of minimum dose with local underdosage occurring even in the center of the PTV (worst IMPT vs. IMXT coverage: 66.7% vs. 85.0%). The doses to organs at risk (OARs) increased during the treatment period. However, the OAR doses of IMPT stayed below corresponding IMXT values at any time. For both modalities treatment plans did not necessarily worsen monotonically throughout the treatment. CONCLUSIONS: Although absolute differences between planned and reconstructed doses were larger in IMPT plans, doses to OARs were higher in IMXT plans. Tumor coverage was more stable in IMXT plans; IMPT dose distributions indicated a high risk for local underdosage during the treatment course.


Assuntos
Fracionamento da Dose de Radiação , Neoplasias de Cabeça e Pescoço/radioterapia , Fótons/uso terapêutico , Terapia com Prótons , Radioterapia de Intensidade Modulada/métodos , Humanos , Órgãos em Risco/efeitos da radiação , Fótons/efeitos adversos , Prótons/efeitos adversos , Planejamento da Radioterapia Assistida por Computador , Radioterapia de Intensidade Modulada/efeitos adversos , Estudos Retrospectivos
16.
Strahlenther Onkol ; 190(8): 722-6, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24756138

RESUMO

AIM: The goal of this study was to assess the impact of different setup approaches in image-guided radiotherapy (IMRT) of the prostatic gland. METHODS: In all, 28 patients with prostate cancer were enrolled in this study. After the placement of an endorectal balloon, the planning target volume (PTV) was treated to a dose of 70 Gy in 35 fractions. A simultaneously integrated boost (SIB) of 76 Gy (2.17 Gy per fraction and per day) was delivered to a smaller target volume. All patients underwent daily prostate-aligned IGRT by megavoltage CT (MVCT). Retrospectively, three different setup approaches were evaluated by comparison to the prostate alignment: setup by skin alignment, endorectal balloon alignment, and automatic registration by bones. RESULTS: A total of 2,940 setup deviations were analyzed in 980 fractions. Compared to prostate alignment, skin mark alignment was associated with substantial displacements, which were ≥ 8 mm in 13%, 5%, and 44% of all fractions in the lateral, longitudinal, and vertical directions, respectively. Endorectal balloon alignment yielded displacements ≥ 8 mm in 3%, 19%, and 1% of all setups; and ≥ 3 mm in 27%, 58%, and 18% of all fractions, respectively. For bone matching, the values were 1%, 1%, and 2% and 3%, 11%, and 34%, respectively. CONCLUSION: For prostate radiotherapy, setup by skin marks alone is inappropriate for patient positioning due to the fact that, during almost half of the fractions, parts of the prostate would not be targeted successfully with an 8-mm safety margin. Bone matching performs better but not sufficiently for safety margins ≤ 3 mm. Endorectal balloon matching can be combined with bone alignment to increase accuracy in the vertical direction when prostate-based setup is not available. Daily prostate alignment remains the gold standard for high-precision radiotherapy with small safety margins.


Assuntos
Neoplasias da Próstata/radioterapia , Radioterapia Guiada por Imagem/métodos , Artefatos , Fracionamento da Dose de Radiação , Marcadores Fiduciais , Humanos , Masculino , Posicionamento do Paciente/métodos , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia de Alta Energia/métodos , Radioterapia de Intensidade Modulada/métodos
17.
Oncol Lett ; 6(5): 1470-1474, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24179543

RESUMO

Head and neck cancers that are associated with high-risk factors have a poor prognosis. In such patients, post-operative radiochemotherapy is mandatory. The present study describes the case of a 71-year-old high-risk head and neck cancer patient who was not able to tolerate the supine position for the radiotherapy setup. A lateral immobilization with a head mask and a vacuum cushion was performed. The patient underwent daily computed tomography (CT)-guided radiation therapy [image-guided radiation therapy (IGRT)]. At nine months post-radiotherapy, the patient had no xerostomia and no swallowing dysfunction. However, the patient suffered a local recurrence and succumbed due to bleeding of the tumor a number of weeks after the recurrence. A recalculation of the actual delivered dose, taking the daily delivered dose into account, was performed. The recurrence occurred within the high-dose region. In selected cases of patients with head and neck cancers who are unable to tolerate the supine position, lateral positioning and high precision treatment is possible using daily IGRT.

18.
Int J Radiat Oncol Biol Phys ; 84(1): 283-8, 2012 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-22417803

RESUMO

PURPOSE: To quantify the actual delivered dose to the cervical spinal cord with different image-guided radiotherapy (IGRT) approaches during head and neck (HN) cancer helical tomotherapy. METHODS AND MATERIALS: Twenty HN patients (HNpts) treated with bilateral nodal irradiation were analyzed. Daily megavoltage computed tomography MVCT) scans were performed for setup purposes. The maximum dose on the planning CT scan (plan-Dmax) and the magnitude and localization of the actual delivered Dmax (a-Dmax) were analyzed for four scenarios: daily image-guided radiotherapy (dIGRT), twice weekly IGRT (2×WkIGRT), once weekly IGRT (1×WkIGRT), and no IGRT at all (non-IGRT). The spinal cord was recontoured on 236 MVCTs for each scenario (total, 944 fractions), and the delivered dose was recalculated for each fraction (fx) separately. RESULTS: Fifty-one percent of the analyzed fx for dIGRT, 56% of the analyzed fx for the 2×WkIGRT, 62% of the analyzed fx for the 1×WkIGRT, and 63% of the analyzed fx for the non-IGRT scenarios received a higher a-Dmax than the plan-Dmax. The median increase of dose in these fx was 3.3% more for dIGRT, 5.8% more for 2×WkIGRT, 10.0% more for 1×WkIGRT, and 9.5% more for non-IGRT than the plan-Dmax. The median spinal cord volumes receiving a higher dose than the plan-Dmax were 0.02 cm³ for dIGRT, 0.11 cm³ for 2×WkIGRT, 0.31 cm³ for 1×WkIGRT, and 0.22 cm³ for non-IGRT. Differences between the dIGRT and all other scenarios were statistically significant (p < 0.05). CONCLUSIONS: Compared to the Dmax of the initial plan, daily IGRT had the smallest increase in dose. Furthermore, daily IGRT had the lowest proportion of fractions and the smallest volumes affected by a dose that was higher than the planned dose. For patients treated with doses close to the tolerance dose of the spinal cord, we recommend daily IGRT. For all other cases, twice weekly IGRT is sufficient.


Assuntos
Irradiação Linfática/métodos , Neoplasias Nasofaríngeas/radioterapia , Radioterapia Guiada por Imagem/métodos , Radioterapia de Intensidade Modulada/métodos , Medula Espinal/efeitos da radiação , Tomografia Computadorizada por Raios X/métodos , Neoplasias Tonsilares/radioterapia , Fracionamento da Dose de Radiação , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Pescoço , Planejamento da Radioterapia Assistida por Computador , Erros de Configuração em Radioterapia , Medula Espinal/diagnóstico por imagem , Fatores de Tempo , Incerteza
19.
J Appl Clin Med Phys ; 12(4): 3596, 2011 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-22089018

RESUMO

Intensity-modulated radiation therapy (IMRT) requires more beam-on time than normal open field treatment. Consequently, the machines wear out and need more spare parts. A helical tomotherapy treatment unit needs a periodical tungsten target replacement, which is a time consuming event. To be able to predict the next replacement would be quite valuable. We observed unexpected variations towards the end of the target lifetime in the performed pretreatment measurements for patient plan verification. Thus, we retrospectively analyze the measurements of our quality assurance program. The time dependence of the quotient of two simultaneous dose measurements at different depths within a phantom for a fixed open field irradiation is evaluated. We also assess the time-dependent changes of an IMRT plan measurement and of a relative depth dose curve measurement. Additionally, we performed a Monte Carlo simulation with Geant4 to understand the physical reasons for the measured values. Our measurements show that the dose at a specified depth compared to the dose in shallower regions of the phantom declines towards the end of the target lifetime. This reproducible effect can be due to the lowering of the mean energy of the X-ray spectrum. These results are supported by the measurements of the IMRT plan, as well as the study of the relative depth dose curve. Furthermore, the simulation is consistent with these findings since it provides a possible explanation for the reduction of the mean energy for thinner targets. It could be due to the lowering of low energy photon self-absorption in a worn out and therefore thinner target. We state a threshold value for our measurement at which a target replacement should be initiated. Measurements to observe a change in the energy are good predictors of the need for a target replacement. However, since all results support the softening of the spectrum hypothesis, all depth-dependent setups are viable for analyzing the deterioration of the tungsten target. The suggested measurements and criteria to replace the target can be very helpful for every user of a TomoTherapy machine.


Assuntos
Radioterapia de Intensidade Modulada/métodos , Humanos , Método de Monte Carlo , Garantia da Qualidade dos Cuidados de Saúde , Dosagem Radioterapêutica
20.
Int J Radiat Oncol Biol Phys ; 77(4): 1266-73, 2010 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-20350787

RESUMO

PURPOSE: To assess the impact of interfractional variations of shape and setup uncertainties on the dose to the parotid glands (PGs) in head-and-neck cancer intensity-modulated radiotherapy and image-guided radiotherapy (IGRT). METHODS AND MATERIALS: Two scenarios were analyzed retrospectively for 10 head-and-neck cancer patients, treated with helical TomoTherapy (TomoTherapy Inc., Madison, WI): the IGRT scenario and the non-IGRT scenario. The initial dose-volume histograms derived from the planning computed tomography (PCT) scan and 120 recalculated dose-volume histograms of the PGs of each scenario and of corresponding fractions were compared. Setup errors, cumulative median doses (CMDs) for 6 fractions, overall volumes of the PGs, and volumes that received less than 1 Gy or more than 1.6 Gy per fraction were analyzed. RESULTS: The mean decrease in the PG volume was 0.13 cm(3)/d. There was a significantly higher CMD than initially predicted (mean increase for 6 fractions, 1.13 Gy for IGRT and 0.96 Gy for non-IGRT). The volume that received less than 1 Gy per fraction decreased (mean difference to PCT, 1.36 cm(3) for IGRT [p = 0.003] and 1.35 cm(3) for non-IGRT [p = 0.003]) and the volume that received more than 1.6 Gy per fraction increased with increasing fraction number (mean difference to PCT, 1.14 cm(3) for IGRT [p = 0.01] and 1.16 cm(3) for non-IGRT [p = 0.006]). There was no statistically significant difference between the two scenarios (CMD, p = 0.095; volume that received <1 Gy per fraction, p = 0.896; and volume that received >1.6 Gy per fraction, p = 0.855). CONCLUSIONS: In the analyzed group the actual delivered dose to the PGs does not differ significantly between an IGRT and a non-IGRT approach. However, IGRT in head-and-neck cancer intensity-modulated radiotherapy is strongly recommended to improve patient setup.


Assuntos
Neoplasias de Cabeça e Pescoço/radioterapia , Glândula Parótida/efeitos da radiação , Radioterapia de Intensidade Modulada/métodos , Adulto , Idoso , Fracionamento da Dose de Radiação , Feminino , Neoplasias de Cabeça e Pescoço/diagnóstico por imagem , Humanos , Masculino , Pessoa de Meia-Idade , Neoplasias Nasofaríngeas/radioterapia , Neoplasias Palatinas/radioterapia , Glândula Parótida/diagnóstico por imagem , Doses de Radiação , Radiografia , Estudos Retrospectivos , Neoplasias Tonsilares/radioterapia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...