Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 1.951
Filtrar
2.
Cancer Radiother ; 24(4): 345-353, 2020 Jul.
Artigo em Francês | MEDLINE | ID: mdl-32360094

RESUMO

Preoperative radiotherapy boosted by chemotherapy is a recommended treatment in locally advanced rectal cancers. This treatment is delivered by three dimensional conformal irradiation, which is usually well tolerated but can induce potential toxicity such as rectitis, cystitis and hematologic adverse effects. Intensity-modulated radiotherapy, widely available nowadays, allows optimization of volume covering and sparing of organs at risk such as bladder and bone marrow. This review presents relevant clinical situations and requirements for a beneficial and safe preoperative irradiation of rectal cancers by intensity-modulated technique. This technique is compared to three-dimensional conformal radiotherapy.


Assuntos
Quimiorradioterapia/métodos , Radioterapia de Intensidade Modulada/métodos , Neoplasias Retais/terapia , Humanos , Órgãos em Risco/efeitos da radiação , Cuidados Pré-Operatórios/métodos , Lesões por Radiação/prevenção & controle , Radioterapia Conformacional/efeitos adversos , Radioterapia Guiada por Imagem/métodos , Neoplasias Retais/cirurgia
3.
Br J Radiol ; 93(1110): 20190692, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32293191

RESUMO

OBJECTIVE: The internal target volume (ITV) strategy generates larger planning target volumes (PTVs) in locally advanced non-small cell lung cancer (LA-NSCLC) than the Mid-position (Mid-p) strategy. We investigated the benefit of the Mid-p strategy regarding PTV reduction and dose to the organs at risk (OARs). METHODS: 44 patients with LA-NSCLC were included in a randomized clinical study to compare ITV and Mid-p strategies. GTV were delineated by a physician on maximum intensity projection images and on Mid-p images from four-dimensional CTs. CTVs were obtained by adding 6 mm uniform margin for microscopic extension. CTV to PTV margins were calculated using the van Herk's recipe for setup and delineation errors. For the Mid-p strategy, the mean target motion amplitude was added as a random error. For both strategies, three-dimensional conformal plans delivering 60-66 Gy to PTV were performed. PTVs, dose-volume parameters for OARs (lung, esophagus, heart, spinal cord) were reported and compared. RESULTS: With the Mid-p strategy, the median of volume reduction was 23.5 cm3 (p = 0.012) and 8.8 cm3 (p = 0.0083) for PTVT and PTVN respectively; the median mean lung dose reduction was 0.51 Gy (p = 0.0057). For 37.1% of the patients, delineation errors led to smaller PTV with the ITV strategy than with the Mid-p strategy. CONCLUSION: PTV and mean lung dose were significantly reduced using the Mid-p strategy. Delineation uncertainty can unfavorably impact the advantage. ADVANCES IN KNOWLEDGE: To the best of our knowledge, this is the first dosimetric comparison study between ITV and Mid-p strategies for LA-NSCLC.


Assuntos
Carcinoma Pulmonar de Células não Pequenas/radioterapia , Neoplasias Pulmonares/radioterapia , Movimentos dos Órgãos , Respiração , Idoso , Plexo Braquial/diagnóstico por imagem , Plexo Braquial/efeitos da radiação , Carcinoma Pulmonar de Células não Pequenas/diagnóstico por imagem , Carcinoma Pulmonar de Células não Pequenas/patologia , Esôfago/diagnóstico por imagem , Esôfago/efeitos da radiação , Tomografia Computadorizada Quadridimensional , Coração/diagnóstico por imagem , Coração/efeitos da radiação , Humanos , Pulmão/diagnóstico por imagem , Pulmão/efeitos da radiação , Neoplasias Pulmonares/diagnóstico por imagem , Neoplasias Pulmonares/patologia , Órgãos em Risco/diagnóstico por imagem , Órgãos em Risco/efeitos da radiação , Estudos Prospectivos , Lesões por Radiação/prevenção & controle , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador , Radioterapia Conformacional/métodos , Medula Espinal/diagnóstico por imagem , Medula Espinal/efeitos da radiação , Carga Tumoral
4.
Br J Radiol ; 93(1110): 20190351, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32233939

RESUMO

OBJECTIVE: Our study aimed to compare regional node coverage and doses to the organ at risk (OAR) using conventional technique (CT) vs "AMAROS" (AT) vs intensity-modulated radiation therapy (IMRT) techniques in patients receiving regional nodal irradiation (RNI) for breast cancer (BC). METHODS: We included 30 consecutive patients with BC who received RNI including axillary nodes. Two independent and blinded dosimetric RNI plans were generated for all patients. For target volume coverage, we analyzed the V95%, the D95%, the mean and the minimal dose within the nodal station. For hotspots within nodal target volume, we used the V105%, the V108% and the maximal doses. For OAR, lung V20, mean lung and heart doses, the maximal dose to the brachial plexus and the axillary-lateral thoracic vessel junction region were compared between the three techniques. RESULTS: Target volume coverage and hotspots: Mean V95% in stations I, II, III and IV were 35.8% and 75% respectively with CV, 22.59 and 59.9% respectively with AT technique and 45.58 and 99.6% respectively with IMRT with statistically significant differences (p < 0.001). Mean V105% (cc) in axillary and supraclavicular stations were 21.3 and 6.4 respectively with CV, 1.2 and 0.02 respectively with AT technique and 0.5 and 0.4 respectively with IMRT with statistically significant differences (p < 0.001)..OARs: The mean ipsilateral lung V20 was 16.9%, 16.4 and 13.3% with CT, AT and IMRT respectively. The mean heart dose (Gy) was 0.3, 0.2 and 0.2 with CT, AT and IMRT respectively. The maximal dose to the plexus brachial (Gy) was 50.3, 46.3 and 47.3 with CT, AT and IMRT respectively. The maximal dose to the axillary-lateral thoracic vessel junction (Gy) was 52.3, 47.3 and 47.6 with CT, AT and IMRT respectively. The differences were statistically significant for all OAR (p < 0.001). CONCLUSION: AT is a valuable technique for RNI including axilla in patients with limited sentinel lymph node biopsy involvement without additional axillary lymph node dissection since it decreases hotspots in the target volume and lowers the radiation exposure of the OAR. For more advanced tumors or patients who did not respond to primary systemic therapy, CT or IMRT should be considered because of their better coverage of the potentially residual nodal disease. IMRT combines several advantages of offering high conformal plans, limited hotspots and protection of main OAR. The clinical impact of these dosimetric differences need to be addressed. ADVANCES IN KNOWLEDGE: This study is to our knowledge the first to compare conventional three-dimensional and IMRT techniques for regional nodal irradiation for each nodal station in breast cancer in a context of increasing utilization of axillary irradiation.


Assuntos
Neoplasias da Mama/radioterapia , Irradiação Linfática/métodos , Órgãos em Risco/efeitos da radiação , Radioterapia de Intensidade Modulada/métodos , Biópsia de Linfonodo Sentinela , Adulto , Idoso , Idoso de 80 Anos ou mais , Análise de Variância , Axila/irrigação sanguínea , Vasos Sanguíneos/efeitos da radiação , Plexo Braquial/efeitos da radiação , Feminino , Coração/efeitos da radiação , Humanos , Pulmão/efeitos da radiação , Pessoa de Meia-Idade , Dosagem Radioterapêutica , Tórax/irrigação sanguínea , Adulto Jovem
5.
Bull Cancer ; 107(5): 565-573, 2020 May.
Artigo em Francês | MEDLINE | ID: mdl-32245602

RESUMO

Modern high-precision radiotherapy techniques have recently incorporated the notion of anatomical variations of the patient during treatment and have tried to adapt the treatment planning to them. Adaptive radiotherapy for nasopharyngeal tumors is starting to prove its benefit nowadays. His interest is constantly being evaluated. The variations encountered during the treatment are both geometric and dosimetric. They are represented by a reduction in the macroscopic tumors volume, a change in its position and a consequent dosimetric impact. The changes also concern organs at risk with a reduction of glandular structure volumes, and a different position which increases their doses. Delivered doses to noble structures (brainstem and spinal cord) may also increase. However, difficulties are encountered in its realization. There is a problem to perfectly reproduce the patient position during the second acquisition, which impacts the fusion quality between the two CT scans. This generates an imprecision in the definition of the same treatment isocentre on the second scanner. Also, there is a difficulty in accumulated doses calculation. The indication of adaptive radiotherapy remains a subject of controversy. It should be proposed for a subgroup of patients who could benefit from this new strategy. We present here an update on the state of the art of adaptive radiotherapy for nasopharyngeal cancer.


Assuntos
Carcinoma Nasofaríngeo/radioterapia , Neoplasias Nasofaríngeas/radioterapia , Tronco Encefálico/efeitos da radiação , Humanos , Carcinoma Nasofaríngeo/diagnóstico por imagem , Carcinoma Nasofaríngeo/patologia , Neoplasias Nasofaríngeas/diagnóstico por imagem , Neoplasias Nasofaríngeas/patologia , Pescoço/anatomia & histologia , Órgãos em Risco/efeitos da radiação , Posicionamento do Paciente , Radioterapia/métodos , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador , Medula Espinal/efeitos da radiação , Carga Tumoral/efeitos da radiação , Perda de Peso
6.
Cancer Radiother ; 24(3): 206-214, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32171674

RESUMO

PURPOSE: The aim of this study was to extensively describe the epidemiological, clinical and therapeutic outcomes of adolescents and young adults (AYA) population with classical Hodgkin Lymphoma (cHL). Then, a comparison between AYAs and adults and between the subgroups of AYAs treated with the same adult protocol was accomplished to further inform on optimal therapy approach of choice for adolescent patients. MATERIAL AND METHODS: In this mono-centric, retrospective study, we reviewed the medical records. We analyzed 112 consecutive North Tunisian patients, including 66 AYAs (15 to 39 years) and 46 adults (≥40years) affected by cHL treated from 2000 to 2015 at Salah Azaiez Institute. Then, we performed a comparative analysis between AYA and 46 adult patients and a subgroup analysis between adolescents and young adults. All patients were treated according to the national protocol for HL, edited by the Tunisian Society of Hematology. The treatment included chemotherapy and involved-field radiotherapy (RT) at a dose of 20 or 30 Grays (Gy) for responders and 36Gy for non-responders. RESULTS: AYA patients presented with adverse features with nodular sclerosis subtype (p=3.88×10-02) and mediastinal mass involvement (p=9.40×10-04). At a median follow-up of 51 and 32 months for AYAs and adults, respectively, no statistical difference in terms of 3 and 5-years overall survival (OS) and event-free survival (EFS) was shown. Using the Kaplan-Meier method, in AYAs, the ABVD regimen has an impact on 3-years EFS (p=4.63×10-02). The 36Gy RT was associated with the best 3-years EFS (p=9.24×10-03). Besides, AYA patients with advanced-stage had the worst 3-years OS (76%) (p=2.41×10-02). Although the adolescents and young adults shared similar clinical presentation, we noted that the adolescent group had the worst 3-years EFS (48%), but the best 3-years OS (91%). We identified 15% of primary refractory patients and a rate of toxicity of 5.3% in AYA. CONCLUSION: The treatment approach used is well tolerated by adult patients. However, the AYA patients and particularly adolescent subgroup had more advanced disease at diagnosis and should be treated more intensively in dedicated units. RT dose<36Gy and ABVD chemotherapy were associated with lower EFS in this population.


Assuntos
Doença de Hodgkin/terapia , Adolescente , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Bleomicina/administração & dosagem , Ciclofosfamida/administração & dosagem , Dacarbazina/administração & dosagem , Intervalo Livre de Doença , Doxorrubicina/administração & dosagem , Etoposídeo/administração & dosagem , Feminino , Doença de Hodgkin/epidemiologia , Doença de Hodgkin/mortalidade , Doença de Hodgkin/patologia , Humanos , Estimativa de Kaplan-Meier , Masculino , Mecloretamina/administração & dosagem , Neoplasias do Mediastino/patologia , Pessoa de Meia-Idade , Órgãos em Risco/efeitos da radiação , Prednisona/administração & dosagem , Procarbazina/administração & dosagem , Dosagem Radioterapêutica , Recidiva , Estudos Retrospectivos , Resultado do Tratamento , Tunísia/epidemiologia , Vimblastina/administração & dosagem , Vincristina/administração & dosagem , Adulto Jovem
7.
Cancer Radiother ; 24(3): 247-257, 2020 Jun.
Artigo em Francês | MEDLINE | ID: mdl-32220563

RESUMO

In radiotherapy, the dose prescription is currently based on discretized dose-effects records that do not take into fully account for the complexity of the patient-dose-response relationship. Their predictive performance on both anti-tumour efficacy and toxicity can be optimized by integrating radiobiological models. It is with this in mind that the calculation models TCP (Tumor Control Probability) and NTCP (Normal Tissue Complication Probability) have been developed. Their construction involves several important steps that are necessary and important to understand. The first step is based on radiobiological models allowing to calculate according to more or less complexity the rate of surviving cells after irradiation. Two additional steps are required to convert the physical dose into an equivalent biological dose, in particular a 2Gy equivalent biological dose (EQD2): first to take into account the effect of the fractionation of the dose for both the target volume and the organs at risk; second to convert an heterogeneous dose to an organ into an homogeneous dose having the same effect (Niemierko generalized equivalent uniform dose (gEUD)). Finally, the process of predicting clinical effects based on radiobiological models transform doses into tumour control (TCP) or toxicity (NTCP) probabilities using parameters that reflect the radiobiological characteristics of the tissues in question. The use of these models in current practice is still limited, but since the radiotherapy softwares increasingly integrate them, it is important to know the principle and limits of application of these models.


Assuntos
Sobrevivência Celular/efeitos da radiação , Modelos Biológicos , Radiobiologia , Relação Dose-Resposta à Radiação , Humanos , Órgãos em Risco/efeitos da radiação , Probabilidade , Dosagem Radioterapêutica , Eficiência Biológica Relativa
8.
Cancer Radiother ; 24(2): 88-92, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32156457

RESUMO

PURPOSE: The optimal dose in esophageal cancer patients treated with definitive chemoradiation (CRT) remains debated. We herein report on the dosimetric results, treatment-related toxicities and long-term outcomes of escalated dose up to 60Gy delivered with intensity-modulated radiotherapy (IMRT). MATERIALS AND METHODS: All consecutive patients that received a definitive CRT>50Gy for an unresectable esophageal carcinoma between 2010 and 2015 were retrospectively evaluated for this study. Methodology included data base search, delayed toxicity grading, statistical testing including frequency analysis and survival analysis. RESULTS: A total of 51 patients were irradiated for a squamous cell carcinoma (86.3%) or an adenocarcinoma (13.7%). The median age at diagnosis was 62 years. Seven patients were simultaneously irradiated for another synchronous primary tumor. Forty-six patients (90.2%) received concurrent platin-based chemotherapy. The median prescribed doses were 60Gy (54-66) and 48Gy (44.8-56) delivered in 30 (27-35) fractions to the high and the low risks PTV respectively. The mean dose delivered to the lungs was 11.4Gy (IC 95%: 4.8-19.8), the median volumes receiving up to 20Gy (V20) and 30Gy (V30) were 13.5% (3.0-46.0) and 4.6% (0.7-19.8) respectively. The mean dose delivered to the heart was 13.9Gy (IC 95%:0.3-31.3) with a median V40 of 3.3% (0.0-25.0). One treatment-related death occurred within days after RT completion (neutropenic aplasia). After a median follow-up of 2.7 years (95% CI: 1.9-4.3), the 2-year overall survival, disease free survival and loco-regional control rates were 53.6%, 42.0% and 72.8% respectively. Delayed treatment related-toxicities ≤grade 3 occurred among 25 patients (62.5%) mostly esophageal stricture (79.2%). CONCLUSION: We demonstrated in this study that dose escalation using IMRT in combination with platin-based chemotherapy as a definitive treatment for esophageal carcinoma is safe and results in higher loco-regional and control survival when compared to previously reported data.


Assuntos
Adenocarcinoma/terapia , Carcinoma de Células Escamosas/terapia , Quimiorradioterapia/métodos , Neoplasias Esofágicas/terapia , Tolerância a Radiação , Radioterapia de Intensidade Modulada/métodos , Adenocarcinoma/mortalidade , Adenocarcinoma/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Carcinoma de Células Escamosas/mortalidade , Carcinoma de Células Escamosas/patologia , Quimiorradioterapia/efeitos adversos , Intervalo Livre de Doença , Fracionamento da Dose de Radiação , Neoplasias Esofágicas/mortalidade , Neoplasias Esofágicas/patologia , Estenose Esofágica/etiologia , Feminino , Fluoruracila/administração & dosagem , Coração/efeitos da radiação , Humanos , Leucovorina/administração & dosagem , Pulmão/efeitos da radiação , Masculino , Pessoa de Meia-Idade , Compostos Organoplatínicos/administração & dosagem , Órgãos em Risco/efeitos da radiação , Radioterapia de Intensidade Modulada/efeitos adversos , Estudos Retrospectivos , Fatores de Tempo , Resultado do Tratamento
9.
Br J Radiol ; 93(1107): 20190807, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32003574

RESUMO

After years of lethargy, studies on two non-conventional microstructures in time and space of the beams used in radiation therapy are enjoying a huge revival. The first effect called "FLASH" is based on very high dose-rate irradiation (pulse amplitude ≥106 Gy/s), short beam-on times (≤100 ms) and large single doses (≥10 Gy) as experimental parameters established so far to give biological and potential clinical effects. The second effect relies on the use of arrays of minibeams (e.g., 0.5-1 mm, spaced 1-3.5 mm). Both approaches have been shown to protect healthy tissues as an endpoint that must be clearly specified and could be combined with each other (e.g., minibeams under FLASH conditions). FLASH depends on the presence of oxygen and could proceed from the chemistry of peroxyradicals and a reduced incidence on DNA and membrane damage. Minibeams action could be based on abscopal effects, cell signalling and/or migration of cells between "valleys and hills" present in the non-uniform irradiation field as well as faster repair of vascular damage. Both effects are expected to maintain intact the tumour control probability and might even preserve antitumoural immunological reactions. FLASH in vivo experiments involving Zebrafish, mice, pig and cats have been done with electron beams, while minibeams are an intermediate approach between X-GRID and synchrotron X-ray microbeams radiation. Both have an excellent rationale to converge and be applied with proton beams, combining focusing properties and high dose rates in the beam path of pencil beams, and the inherent advantage of a controlled limited range. A first treatment with electron FLASH (cutaneous lymphoma) has recently been achieved, but clinical trials have neither been presented for FLASH with protons, nor under the minibeam conditions. Better understanding of physical, chemical and biological mechanisms of both effects is essential to optimize the technical developments and devise clinical trials.


Assuntos
Tratamentos com Preservação do Órgão/métodos , Terapia com Prótons/métodos , Animais , Gatos , Proliferação de Células , Dano ao DNA , Reparo do DNA , Fracionamento da Dose de Radiação , Linfoma Cutâneo de Células T/radioterapia , Camundongos , Órgãos em Risco/efeitos da radiação , Oxigênio , Consumo de Oxigênio , Lesões por Radiação/prevenção & controle , Tolerância a Radiação , Radiometria/métodos , Neoplasias Cutâneas/radioterapia , Análise Espaço-Temporal , Suínos , Peixe-Zebra
10.
Int J Radiat Oncol Biol Phys ; 106(3): 604-611, 2020 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-32014151

RESUMO

PURPOSE: Steep dose falloff outside of tumors is a hallmark of stereotactic radiosurgery (SRS) and radiation therapy (SRT). Dose gradient index (DGI) quantifies the dose drop off. Tables of DGIs versus target volumes have been published for body sites, but none is available for brain. This study recommends guidelines for DGIs for brain SRS/SRT treatments based on clinical CyberKnife (CK) cases. METHODS AND MATERIALS: Four hundred ninety-five plans for patients with central nervous system tumors treated with CK at our institution between March 2015 and May 2018 were analyzed. The CK treatment planning system MultiPlan was used for planning. SRS/SRT plans were stratified into 6 groups by tumor size (Group I [0-1 cm3], II [1.0-3.0 cm3], III [3.0-5.0 cm3], IV [5.0-10.0 cm3], V [10.0-15.0 cm3], and VI [15.0-40.0 cm3]). Ideal and minimally acceptable DGIs were determined for each size group. To evaluate the effect of target shape on DGI criteria, the plans were divided into 4 target shape groups: (1) homogeneous shape (circular), (2) adjacent to radiosensitive organs at risk (adjacent), (3) irregularly shaped (irregular), and (4) multiple target plans (multilesion). The mean for each target size group was defined as the ideal DGI. Minimally acceptable DGI criteria are specified to reject the lowest 10% of cases. RESULTS: The minimal acceptable DGIs were 83 (Group I), 72 (II), 65 (III), 58 (IV), 52 (V), and 35 (VI). The ideal DGI is designated to evaluate SRS/SRT plans for homogeneous circular lesions, whereas minimal DGI is chosen to assess the plans for irregular, adjacent to organs at risk, and multilesions. SRS/SRT plans with higher DGI values are correlated with lower irradiated normal tissue volumes. CONCLUSIONS: This study provides a table of DGIs for brain SRS/SRT treatments as a tool for assessing the quality of intracranial SRS/SRT plans. DGI guidelines support SRS/SRT planning that results in lower risk of radionecrosis.


Assuntos
Neoplasias Encefálicas/radioterapia , Órgãos em Risco/efeitos da radiação , Radiocirurgia/métodos , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia Conformacional/métodos , Neoplasias Encefálicas/diagnóstico por imagem , Guias como Assunto , Humanos , Órgãos em Risco/diagnóstico por imagem , Tolerância a Radiação , Radiocirurgia/efeitos adversos , Dosagem Radioterapêutica , Radioterapia Conformacional/efeitos adversos , Espalhamento de Radiação
11.
Int J Radiat Oncol Biol Phys ; 106(5): 1052-1062, 2020 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-32007365

RESUMO

PURPOSE: The aim of this study was to investigate the influence of brachytherapy technique and applicator type on target dose, isodose surface volumes, and organ-at-risk (OAR) dose. METHODS AND MATERIALS: Nine hundred two patients treated with tandem/ovoids (T&O) (n = 299) and tandem/ring (T&R) (n = 603) applicators from 16 EMBRACE centers were analyzed. Patients received external beam radiation therapy and magnetic resonance imaging guided brachytherapy with dose prescription according to departmental practice. Centers were divided into 4 groups, according to applicator/technique: Ovoids and ring centers treating mainly with the intracavitary (IC) technique and ovoids and ring centers treating routinely with the intracavitary/interstitial (IC/IS) technique. V85Gy EQD210, CTVHR D90% (EQD210), and bladder, rectum, sigmoid, and vaginal 5-mm lateral-point doses (EQD23) were evaluated among center groups. Differences between T&O and T&R were tested with multivariable analysis. RESULTS: For similar point A doses, mean CTVHR D90% was 3.3 Gy higher and V85Gy was 23% lower for ring-IC compared with ovoids-IC centers (at median target volumes). Mean bladder/rectum doses (D2cm3 and ICRU-point) were 3.2 to 7.7 Gy smaller and vaginal 5-mm lateral-point was 19.6 Gy higher for ring-IC centers. Routine use of IC/IS technique resulted in increased target dose, whereas V85Gy was stable (T&R) or decreased (T&O); reduced bladder and rectum D2cm3 and bladder ICRU-point by 3.5 to 5.0 Gy for ovoids centers; and similar OAR doses for ring centers. CTVHR D90% was 2.8 Gy higher, bladder D2cm3 4.3 Gy lower, rectovaginal ICRU-point 4.8 Gy lower, and vagina 5-mm lateral-point 22.4 Gy higher for ring-IC/IS versus ovoids-IC/IS centers. The P values were <.002 for all comparisons. Equivalently, significant differences were derived from the multivariable analysis. CONCLUSIONS: T&R-IC applicators have better target dose and dose conformity than T&O-IC in this representative patient cohort. IC applicators fail to cover large target volumes, whereas routine application of IC/IS improves target and OAR dose considerably. Patients treated with T&R show a more favorable therapeutic ratio when evaluating target, bladder/rectum doses, and V85Gy. A comprehensive view on technique/applicators should furthermore include practical considerations and clinical outcome.


Assuntos
Braquiterapia/instrumentação , Estudos Observacionais como Assunto , Neoplasias do Colo do Útero/radioterapia , Braquiterapia/efeitos adversos , Feminino , Humanos , Pessoa de Meia-Idade , Órgãos em Risco/efeitos da radiação , Dosagem Radioterapêutica
12.
Clin Nucl Med ; 45(4): 288-291, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32049721

RESUMO

PURPOSE: Lu-PSMA inhibitor peptide receptor radioligand therapy (RLT) is playing an increasing role in metastatic castration-resistant prostate cancer. We aimed to estimate the absorbed radiation doses for critical organs (eg, kidneys, parotid glands, submandibular glands, and lacrimal glands) of patients treated with 4 to 6 cycles by Lu-PSMA inhibitor RLT, retrospectively, and to evaluate the findings extensively in order to determine the critical organ radiation-absorbed limitations and the number of prospective RLT. MATERIALS AND METHODS: A total of 51 cycles Lu-PSMA inhibitor RLT in 10 patients was analyzed. Therapies have been applied in 4 to 6 cycles with 8 to 10 weeks' intervals. Dosimetric estimates of kidneys, parotid glands, submandibular glands, and lacrimal glands have been calculated based on MIRD scheme pamphlet no. 16. Regions of interest were drawn with GE Xeleris Functional Imaging Workstation. OLINDA/EXM 1.1 simulation software was used to calculate radiation-absorbed doses. RESULTS: Mean radiation-absorbed doses were 0.70 ± 0.24 Gy/GBq for kidneys, 1.34 ± 0.78 Gy/GBq for parotid glands, 0.94 ± 0.45 Gy/GBq for submandibular glands, and 2.28 ± 1.29 Gy/GBq for lacrimal glands. CONCLUSIONS: Due to the critical target organ risks and the optimal therapy doses, patient-specific dosimetry is a deterministic factor in radionuclide therapy. Even when the absorbed kidney doses were above the ICRP critical dose limits in patients who had 4 to 6 cycles of therapy, mortality due to nephrotoxicity has not been observed. Mild increased tolerated radiation dose is acceptable for the patient groups with very low survival rate.


Assuntos
Dipeptídeos/uso terapêutico , Compostos Heterocíclicos com 1 Anel/uso terapêutico , Órgãos em Risco/efeitos da radiação , Neoplasias de Próstata Resistentes à Castração/radioterapia , Doses de Radiação , Compostos Radiofarmacêuticos/uso terapêutico , Idoso , Humanos , Masculino , Pessoa de Meia-Idade , Metástase Neoplásica , Neoplasias de Próstata Resistentes à Castração/patologia , Dosagem Radioterapêutica
13.
AJR Am J Roentgenol ; 214(5): 1131-1136, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32097032

RESUMO

OBJECTIVE. The purposes of this study were to determine organ and effective doses and to estimate the risk of exposure-induced cancer death (REID) associated with coronary CT angiography (CCTA) examinations. SUBJECTS AND METHODS. CCTA examinations were performed in three stages: calcium score, monitoring, and cardiac phases for all patients. Effective dose was calculated using two methods. The first was based on the scanner-derived dose-length product, and the second entailed use of an organ and effective dose calculator software application. Organ doses were calculated on the basis of the tissue weighting factors of International Commission on Radiation Protection report 103. REID values were assessed with a cancer risk estimator software application. RESULTS. The study included 185 patients (95 men, 90 women). For women, breast doses were high at 52.04 ± 14.08 mGy. The mean effective dose in the women was greater than that in the men (24.05 vs 16.30 mSv, p < 0.05). The mean REID values in patients undergoing CCTA with a 64-MDCT scanner were 13.4 per 10,000 men (1 in 746) and 19.6 per 10,000 women (1 in 508). The REID values were considerably higher for the younger women. CONCLUSION. The results of this study will help referring physicians justify requesting CCTA examinations by considering their benefits for diagnosis on the one hand and awareness of the risk of radiation-induced cancer on the other. In the case of CCTA scans that are properly justified by clinical indication, patients and physicians should not be concerned about the radiation risks.


Assuntos
Angiografia por Tomografia Computadorizada , Angiografia Coronária , Neoplasias Induzidas por Radiação/mortalidade , Doses de Radiação , Adulto , Idoso , Idoso de 80 Anos ou mais , Algoritmos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Órgãos em Risco/efeitos da radiação , Fatores de Risco , Software
14.
Br J Radiol ; 93(1108): 20190792, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31939310

RESUMO

OBJECTIVES: To evaluate the feasibility and optimal restricted angle of the complete-directional-complete block (CDCB) technique in helical tomotherapy (HT) by including regional nodal irradiation (RNI) with the internal mammary node (IMN) in left-sided breast cancer. METHODS: Ten left-sided breast cancer patients treated with 50 Gy in 25 fractions were compared with five-field intensity-modulated radiation therapy (5F-IMRT) and six types of HT plans. In the HT plans, complete block (CB), organ-based directional block (OBDB) and CDCB with different restricted angles were used. RESULTS: The conformity index (CI) between the CDCB0,10,15,20 and 5F-IMRT groups was similar. Compared to CB, OBDB and 5F-IMRT, CDCB20 resulted in a decreased ipsilateral mean lung dose. The low-dose region (V5) of the ipsilateral lung in OBDB (84.0%) was the highest among all techniques (p < 0.001). The mean dose of the heart in CB was significantly reduced (by 11.5-22.4%) compared with other techniques. The V30 of the heart in CDCB20 (1.9%) was significantly lower than that of CB, OBDB and 5F-IMRT. Compared to the mean dose of the left anterior descending (LAD) artery of 5F-IMRT (27.0 Gy), CDCB0, CDCB10, CDCB15, CDCB20 and OBDB reduced the mean dose effectively by 31.7%, 38.3%, 39.6%, 42.0 and 56.2%, respectively. Considering the parameters of the organs-at-risk (OARs), CDCB10,15,20 had higher expectative values than the other techniques (p = 0.01). CONCLUSIONS: HT with the CDCB technique is feasible for treating left-sided breast cancer patients. The CDCB10-20 techniques not only achieved similar planning target volume coverage, homogeneity and dose conformity but also allowed better sparing of the heart and bilateral lungs. ADVANCES IN KNOWLEDGE: For left-sided breast cancer patients whose RNI field includes the IMN, heart avoidance is an important issue. The CDCB technique achieved good PTV coverage, homogeneity and dose conformity and allowed better sparing of the mean dose of the lung, the LAD artery, and the heart and reduced the V30 of the heart.


Assuntos
Coração/efeitos da radiação , Pulmão/efeitos da radiação , Irradiação Linfática/métodos , Órgãos em Risco/efeitos da radiação , Lesões por Radiação/prevenção & controle , Radioterapia de Intensidade Modulada/métodos , Neoplasias Unilaterais da Mama/radioterapia , Fracionamento da Dose de Radiação , Estudos de Viabilidade , Feminino , Humanos , Órgãos em Risco/diagnóstico por imagem , Planejamento da Radioterapia Assistida por Computador/métodos , Neoplasias Unilaterais da Mama/diagnóstico por imagem
15.
Br J Radiol ; 93(1108): 20190577, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31944823

RESUMO

OBJECTIVE: It has been established that survival and toxicity outcomes in some cancer types could be influenced by haemoglobin (Hb) levels. This study aims to determine if pre-treatment Hb is associated with late toxicity or survival outcomes in prostate cancer. METHODS: Data from one Phase III randomised controlled trial and one single arm translational trial were analysed. Patients had localized prostate cancer and received ≥70 Gy radiotherapy and neo-adjuvant androgen deprivation between 1997 and 2013. RESULTS: 302 males were included. Median follow-up was 6.8 years for toxicity and 10.3 years for survival outcomes. Patients with Hb below the reference range were more likely to experience Grade 2-3 late gastrointestinal toxicity than patients with Hb within the range (p = 0.050). Neither late genitourinary toxicity, erectile function toxicity, prostate-specific antigen relapse free survival nor overall survival of patients were statistically significantly different between groups. CONCLUSION: Anaemia in prostate cancer is found in the minority of patients and is usually mild. Prostate cancer patients undergoing radiotherapy with low Hb were more likely to experience Grade 2-3 late gastrointestinal toxicity. ADVANCES IN KNOWLEDGE: This study is one of the first in the published literature to investigate the role of Hb in prostate cancer toxicity and survival. We have found an association between Hb below the reference range and late GI toxicity. Consideration should be given to further investigating patients with iron deficiency anaemia to guide management options and outrule underlying GI pathology before proceeding with radiotherapy treatment.


Assuntos
Anemia/sangue , Hemoglobina A/análise , Órgãos em Risco/efeitos da radiação , Neoplasias da Próstata/mortalidade , Neoplasias da Próstata/radioterapia , Idoso , Idoso de 80 Anos ou mais , Antagonistas de Androgênios/uso terapêutico , Trato Gastrointestinal/efeitos da radiação , Hormônio Liberador de Gonadotropina/agonistas , Humanos , Masculino , Pessoa de Meia-Idade , Terapia Neoadjuvante , Ereção Peniana , Antígeno Prostático Específico/sangue , Neoplasias da Próstata/sangue , Neoplasias da Próstata/tratamento farmacológico , Valores de Referência , Estudos Retrospectivos
16.
Br J Radiol ; 93(1108): 20190789, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31971829

RESUMO

OBJECTIVE: Prostate stereotactic ablative radiotherapy (SABR) delivers large doses using a fast dose rate. This amplifies the effect geometric uncertainties have on normal tissue dose. The aim of this study was to determine whether the treatment dose-volume histogram (DVH) agrees with the planned dose to organs at risk (OAR). METHODS: 41 low-intermediate risk prostate cancer patients were treated with SABR using a linac based technique. Dose prescribed was 35 Gy in five fractions delivered on alternate days, planned using volumetric modulated arc therapy (VMAT) with 10X flattening filter free (FFF). On treatment, prostate was matched to fiducial markers on cone beam CT (CBCT). OAR were retrospectively delineated on 205 pre-treatment CBCT images. Daily CBCT contours were overlaid on the planning CT for dosimetric analysis. Verification plan used to evaluate the daily DVH for each structure. The daily doses received by OAR were recorded using the D%. RESULTS: The median rectum and bladder volumes at planning were 67.1 cm3 (interquartile range 56.4-78.2) and 164.4 cm3 (interquartile range 120.3-213.4) respectively. There was no statistically significant difference in median rectal volume at each of the five treatment scans compared to the planning scan (p = 0.99). This was also the case for median bladder volume (p = 0.79). The median dose received by rectum and bladder at each fraction was higher than planned, at the majority of dose levels. For rectum the increase ranged from 0.78-1.64Gy and for bladder 0.14-1.07Gy. The percentage of patients failing for rectum D35% < 18 Gy (p = 0.016), D10% < 28 Gy (p = 0.004), D5% < 32 Gy (p = 0.0001), D1% < 35 Gy (p = 0.0001) and bladder D1% < 35 Gy (p = 0.001) at treatment were all statistically significant. CONCLUSION: In this cohort of prostate SABR patients, we estimate the OAR treatment DVH was higher than planned. This was due to rectal and bladder organ variation. ADVANCES IN KNOWLEDGE: OAR variation in prostate SABR using a FFF technique, may cause the treatment DVH to be higher than planned.


Assuntos
Órgãos em Risco/efeitos da radiação , Neoplasias da Próstata/radioterapia , Radiocirurgia/métodos , Radioterapia de Intensidade Modulada/métodos , Reto/efeitos da radiação , Bexiga Urinária/efeitos da radiação , Idoso , Fracionamento da Dose de Radiação , Humanos , Masculino , Próstata , Radiometria , Planejamento da Radioterapia Assistida por Computador/métodos , Reto/diagnóstico por imagem , Estudos Retrospectivos , Bexiga Urinária/diagnóstico por imagem
17.
Br J Radiol ; 93(1107): 20190845, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31904261

RESUMO

OBJECTIVES: The purpose of this study is to investigate the dosimetric effect and clinical impact of delivering a focal radiotherapy boost dose to multiparametric MRI (mp-MRI)-defined dominant intraprostatic lesions (DILs) in prostate cancer using proton therapy. METHODS: We retrospectively investigated 36 patients with pre-treatment mp-MRI and CT images who were treated using pencil beam scanning (PBS) proton radiation therapy to the whole prostate. DILs were contoured on co-registered mp-MRIs. Simultaneous integrated boost (SIB) plans using intensity-modulated proton therapy (IMPT) were created based on conventional whole-prostate-irradiation for each patient and optimized with additional DIL coverage goals and urethral constraints. DIL dose coverage and organ-at-risk (OAR) sparing were compared between conventional and SIB plans. Tumor control probability (TCP) and normal tissue complication probability (NTCP) were estimated to evaluate the clinical impact of the SIB plans. RESULTS: Optimized SIB plans significantly escalated the dose to DILs while meeting OAR constraints. SIB plans were able to achieve 125, 150 and 175% of prescription dose coverage in 74, 54 and 17% of 36 patients, respectively. This was modeled to result in an increase in DIL TCP by 7.3-13.3% depending on α/ß and DIL risk level. CONCLUSION: The proposed mp-MRI-guided DIL boost using proton radiation therapy is feasible without violating OAR constraints and demonstrates a potential clinical benefit by improving DIL TCP. This retrospective study suggested the use of IMPT-based DIL SIB may represent a strategy to improve tumor control. ADVANCES IN KNOWLEDGE: This study investigated the planning of mp-MRI-guided DIL boost in prostate proton radiation therapy and estimated its clinical impact with respect to TCP and NTCP.


Assuntos
Imageamento por Ressonância Magnética Multiparamétrica , Neoplasias da Próstata/diagnóstico por imagem , Neoplasias da Próstata/radioterapia , Terapia com Prótons/métodos , Reirradiação/métodos , Idoso , Idoso de 80 Anos ou mais , Fracionamento da Dose de Radiação , Humanos , Masculino , Pessoa de Meia-Idade , Tratamentos com Preservação do Órgão/métodos , Órgãos em Risco/diagnóstico por imagem , Órgãos em Risco/efeitos da radiação , Próstata/diagnóstico por imagem , Próstata/efeitos da radiação , Neoplasias da Próstata/patologia , Lesões por Radiação/prevenção & controle , Dosagem Radioterapêutica , Estudos Retrospectivos , Tomografia Computadorizada por Raios X , Uretra/diagnóstico por imagem
18.
Br J Radiol ; 93(1107): 20190955, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31971818

RESUMO

Patients with squamous cell carcinoma of the oropharynx are generally treated with (chemo) radiation. Patients with oropharyngeal cancer have better survival than patients with squamous cell carcinoma of other head and neck subsites, especially when related to human papillomavirus. However, radiotherapy results in a substantial percentage of survivors suffering from significant treatment-related side-effects. Late radiation-induced side-effects are mostly irreversible and may even be progressive, and particularly xerostomia and dysphagia affect health-related quality of life. As the risk of radiation-induced side-effects highly depends on dose to healthy normal tissues, prevention of radiation-induced xerostomia and dysphagia and subsequent improvement of health-relatedquality of life can be obtained by applying proton therapy, which offers the opportunity to reduce the dose to both the salivary glands and anatomic structures involved in swallowing.This review describes the results of the first cohort studies demonstrating that proton therapy results in lower dose levels in multiple organs at risk, which translates into reduced acute toxicity (i.e. up to 3 months after radiotherapy), while preserving tumour control. Next to reducing mucositis, tube feeding, xerostomia and distortion of the sense of taste, protons can improve general well-being by decreasing fatigue and nausea. Proton therapy results in decreased rates of tube feeding dependency and severe weight loss up to 1 year after radiotherapy, and may decrease the risk of radionecrosis of the mandible. Also, the model-based approach for selecting patients for proton therapy in the Netherlands is described in this review and future perspectives are discussed.


Assuntos
Carcinoma de Células Escamosas/radioterapia , Transtornos de Deglutição/prevenção & controle , Neoplasias Orofaríngeas/radioterapia , Terapia com Prótons/métodos , Lesões por Radiação/prevenção & controle , Xerostomia/prevenção & controle , Idoso , Transtornos de Deglutição/etiologia , Nutrição Enteral/estatística & dados numéricos , Humanos , Mandíbula/efeitos da radiação , Pessoa de Meia-Idade , Países Baixos , Órgãos em Risco/efeitos da radiação , Qualidade de Vida , Glândulas Salivares/efeitos da radiação , Xerostomia/etiologia
19.
Int J Radiat Oncol Biol Phys ; 106(4): 743-753, 2020 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-31953061

RESUMO

PURPOSE: The purpose of our study was to provide a guide for identification and contouring of upper abdominal organs-at-risk (OARs) in the setting of online magnetic resonance imaging (MRI)-guided radiation treatment planning and delivery. METHODS AND MATERIALS: After a needs assessment survey, it was determined that an upper abdominal MRI-based atlas of normal OARs would be of benefit to radiation oncologists and radiation therapists. An anonymized diagnostic 1.5T MRI from a patient with typical upper abdominal anatomy was used for atlas development. Two MRI sequences were selected for contouring, a T1-weighted gadoxetic acid contrast-enhanced MRI acquired in the hepatobiliary phase and axial fast imaging with balanced steady-state precession. Two additional clinical MRI sequences from commercial online MRI-guided radiation therapy systems were selected for contouring and were included in the final atlas. Contours from each data set were completed and reviewed by radiation oncologists, along with a radiologist who specializes in upper abdominal imaging, to generate a consensus upper abdominal MRI-based OAR atlas. RESULTS: A normal OAR atlas was developed, including recommendations for contouring. The atlas and contouring guidance are described, and high-resolution MRI images and contours are displayed. OARs, such as the bile duct and biliary tree, which may be better seen on MRI than on computed tomography, are highlighted. The full DICOM/DICOM-RT MRI images from both the diagnostic and clinical online MRI-guided radiation therapy systems data sets have been made freely available, for educational purposes, at econtour.org. CONCLUSIONS: This MRI contouring atlas for upper abdominal OARs should provide a useful reference for contouring and education. Its routine use may help to improve uniformity in contouring in radiation oncology planning and OAR dose calculation. Full DICOM/DICOM-RT images are available online and provide a valuable educational resource for upper abdominal MRI-based radiation therapy planning and delivery.


Assuntos
Abdome/diagnóstico por imagem , Abdome/efeitos da radiação , Imagem por Ressonância Magnética , Órgãos em Risco/diagnóstico por imagem , Órgãos em Risco/efeitos da radiação , Radioterapia (Especialidade)/normas , Humanos , Planejamento da Radioterapia Assistida por Computador , Padrões de Referência
20.
Int J Radiat Oncol Biol Phys ; 106(2): 440-448, 2020 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-31928642

RESUMO

PURPOSE: Recent studies suggest that ultrahigh-dose-rate, "FLASH," electron radiation therapy (RT) decreases normal tissue damage while maintaining tumor response compared with conventional dose rate RT. Here, we describe a novel RT apparatus that delivers FLASH proton RT (PRT) using double scattered protons with computed tomography guidance and provide the first report of proton FLASH RT-mediated normal tissue radioprotection. METHODS AND MATERIALS: Absolute dose was measured at multiple depths in solid water and validated against an absolute integral charge measurement using a Faraday cup. Real-time dose rate was obtained using a NaI detector to measure prompt gamma rays. The effect of FLASH versus standard dose rate PRT on tumors and normal tissues was measured using pancreatic flank tumors (MH641905) derived from the KPC autochthonous PanCa model in syngeneic C57BL/6J mice with analysis of fibrosis and stem cell repopulation in small intestine after abdominal irradiation. RESULTS: The double scattering and collimation apparatus was dosimetrically validated with dose rates of 78 ± 9 Gy per second and 0.9 ± 0.08 Gy per second for the FLASH and standard PRT. Whole abdominal FLASH PRT at 15 Gy significantly reduced the loss of proliferating cells in intestinal crypts compared with standard PRT. Studies with local intestinal irradiation at 18 Gy revealed a reduction to near baseline levels of intestinal fibrosis for FLASH-PRT compared with standard PRT. Despite this difference, FLASH-PRT did not demonstrate tumor radioprotection in MH641905 pancreatic cancer flank tumors after 12 or 18 Gy irradiation. CONCLUSIONS: We have designed and dosimetrically validated a FLASH-PRT system with accurate control of beam flux on a millisecond time scale and online monitoring of the integral and dose delivery time structure. Using this system, we found that FLASH-PRT decreases acute cell loss and late fibrosis after whole-abdomen and focal intestinal RT, whereas tumor growth inhibition is preserved between the 2 modalities.


Assuntos
Órgãos em Risco/efeitos da radiação , Terapia com Prótons/instrumentação , Lesões Experimentais por Radiação/prevenção & controle , Proteção Radiológica/instrumentação , Radioterapia Guiada por Imagem/instrumentação , Abdome/efeitos da radiação , Animais , Proliferação de Células/efeitos da radiação , Desenho de Equipamento/métodos , Estudos de Viabilidade , Feminino , Fibrose , Raios gama , Intestino Delgado/patologia , Intestino Delgado/efeitos da radiação , Camundongos , Camundongos Endogâmicos C57BL , Tratamentos com Preservação do Órgão/instrumentação , Tratamentos com Preservação do Órgão/métodos , Órgãos em Risco/patologia , Neoplasias Pancreáticas/radioterapia , Terapia com Prótons/métodos , Proteção Radiológica/métodos , Radiometria/métodos , Radioterapia Guiada por Imagem/métodos , Espalhamento de Radiação , Células-Tronco/efeitos da radiação , Tomografia Computadorizada por Raios X
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA