Importance Of Radiotherapy Research Articles

The Evolving Role of Artificial Intelligence in Radiotherapy Treatment Planning—A Literature Review

This paper examines the integration of artificial intelligence (AI) in radiotherapy for cancer treatment. The importance of radiotherapy in cancer management and its time-intensive planning process make AI adoption appealing especially with the escalating demand for radiotherapy.This review highlights the efficacy of AI across medical domains, where it surpasses human capabilities in areas such as cardiology and dermatology. Focusing on radiotherapy, the paper details AI's applications in target segmentation, dose optimization, and outcome prediction. It discusses adaptive radiotherapy's benefits and AI's potential to enhance patient outcomes with much improved treatment accuracy. The paper explores ethical concerns, including data privacy and bias, stressing the need for robust guidelines. Educating healthcare professionals and patients about AI's role is crucial as it acknowledges potential job-role changes and concerns about patients' trust in the use of AI.Overall, the integration of AI in radiotherapy holds transformative potential in streamlining processes, improving outcomes, and reducing costs. AI's potential to reduce healthcare costs underscores its significance with impactful change globally. However, successful implementation hinges on addressing ethical and logistical challenges and fostering collaboration among healthcare professionals and patient population data sets for its optimal utilization. Rigorous education, collaborative efforts, and global data sharing will be the compass guiding its' success in radiotherapy and healthcare.

RADT-28. DISRUPTION OF BIOENERGETICS ENHANCES RADIO-SENSITIVITY OF PATIENT-DERIVED GLIOBLASTOMA TUMORSPHERES

Abstract INTRODUCTION Glioblastoma (GBM), the most common primary brain tumor, has been associated with poor prognosis despite various treatment modalities, the surgical resection accompanied by chemotherapy and radiotherapy. Although the importance of radiotherapy is well known, its combination with bioenergetics regulators has not been established in clinical practice. Here, we hypothesized that bioenergetics regulators improve the radio-sensitivity of GBM-tumorspheres (TS). METHODS Gene expression profiles of GBM patient-derived TSs were obtained from microarray. In vitro efficacies of the treatment were evaluated using clonogenic assay, 3D invasion assay, neurosphere-formation assay, and apoptosis-analysis. Protein expression was evaluated by western blot, and immunofluorescence was performed for detection of γH2AX foci. In vivo efficacies were confirmed using a mouse orthotopic-xenograft model. RESULTS GBM TSs with high-radioresistant or low-radioresistant were selected according to expression levels of radiation response associated genes. In order to select the bioenergetics regulators that significantly increased the radiotherapy effect of GBM-TSs, five bioenergetics regulators were combined which are oxidative-phosphorylation (OxPhos) inhibitor (IM156A), aldehyde-dehydrogenase inhibitor (gossypol) + OxPhos inhibitor (phenformin), fatty acid oxidation inhibitor (etomoxir), pentose-phosphate pathway inhibitor (dehydroepiandrosterone; DHEA) and glycolysis inhibitor (2-deoxy-D-glucose; 2DG). Amongst of these five bioenergetics regulators, DHEA and 2DG significantly augmented the therapeutic efficacies of ionizing radiation (IR) by reducing the survival fraction, stemness, and invasiveness in both high-radioresistant and low-radioresistant GBM TSs. IR combined with bioenergetics regulators (DHEA or 2DG) induced DNA damage response and apoptosis in low-radioresistant GBM TSs. In vivo experiments using a mouse orthotopic-xenograft model confirmed the tendency to prolong survival period and reduced the size in tumor after the combined treatment of 2DG with IR in low-radioresistant GBM TS. CONCLUSION These data proposes that the combination of bioenergetics regulators and radiotherapy is more effective than IR monotherapy itself. We expect that this combination regimen can strategically establish as a future treatment practice of GBM.

A tomographic reconstruction algorithm for cross-sectional imaging of IMRT beams from six projections

Objective. Patient-specific Quality Assurance (QA) measurements are of key importance in radiotherapy for safe and efficient treatment delivery and allow early detection of clinically relevant errors. Such QA processes remain challenging to implement for complex Intensity Modulated Radiation Therapy (IMRT) radiotherapy fields delivered using a multileaf collimator (MLC) which often feature small open segments and raise QA issues similar to those encountered in small field dosimetry. Recently, detectors based on long scintillating fibers have been proposed to measure a few parallel projections of the irradiation field with good performance for small field dosimetry. The purpose of this work is to develop and validate a novel approach to reconstruct MLC-shaped small irradiation fields from six projections. Approach. The proposed field reconstruction method uses a limited number of geometric parameters to model the irradiation field. These parameters are iteratively estimated with a steepest descent algorithm. The reconstruction method was first validated on simulated data. Real data were measured with a water-equivalent slab phantom equipped with a detector made of 6 scintillating-fiber ribbons placed at 1 m from the source. A radiochromic film was used to acquire a reference measurement of a first dose distribution in the slab phantom at the same source-to-detector distance and the treatment planning system (TPS) provided the reference for another dose distribution. In addition, simulated errors introduced on the delivered dose, field location and field shape were used to evaluate the ability of the proposed method to efficiently identify a deviation between the planned and delivered treatments. Main results. For a first small IMRT segment, 3%/3 mm, 2%/2 mm and 2%/1 mm gamma analysis conducted between the reconstructed dose distribution and the dose measured with radiochromic film exhibited pass rates of 100%, 99.9% and 95.7%, respectively. For a second and smaller IMRT segment, the same gamma analysis performed between the reconstructed dose distribution and the reference provided by the TPS showed pass rates of 100%, 99.4% and 92.6% for the 3%/3 mm, 2%/2 mm and 2%/1 mm gamma criteria, respectively. Gamma analysis of the simulated treatment delivery errors showed the ability of the reconstruction algorithm to detect a 3% deviation between the planned and delivered doses, as well as shifts lower than 7 mm and 3 mm when considering an individual leaf and a whole field shift, respectively. Significance. The proposed method allows accurate tomographic reconstruction of IMRT segments by processing projections measured with six scintillating-fiber ribbons and is suitable for water-equivalent real-time small IMRT segments QA.

Challenges in Treatment and the Importance of Radiotherapy in a Synchronous Endometrial and Breast Cancer

Abstract We report the case of a 69-year-old-female with synchronous endometrial and breast cancer. The imaging and pathology results confirmed the diagnosis. The patient underwent surgery and chemotherapy for endometrial cancer, and surgery followed by external beam radiotherapy for breast cancer. The patient’s clinical condition and imaging showed a favorable evolution after 2 months of follow-up.

Benefits of radiotherapy for patients with solitary plasmacytoma or multiple myeloma

Treatment options for patients with solitary plasmacytoma (SP) or multiple myeloma (MM) should be discussed in an interdisciplinary context. This systematic review focuses on the importance of radiotherapy in MM and SP. Summary of local radio-oncological treatment options for patients with SP and MM. Based on asystematic literature search, the current evidence on the topic was analyzed and summarized. Patients with SP should be primarily treated with radiotherapy with or without surgery. Irradiation concepts may vary depending on risk factors and manifestation (solitary bone plasmacytoma vs. solitary extramedullary plasmacytoma). Although local control rates are high after radiotherapy, progression to multiple myeloma frequently occurs. In patients with MM, radiation is mainly used in palliative settings for pain relief, prevention of fractures or in patients who suffer from neurological symptoms due to spinal cord compression. Irradiation dose and fractionation should be selected based on treatment indication and general condition of the patient. Although most patients receive systemic treatment at initial diagnosis, approximately 40% of patients with MM will require radiation during the course of their disease. While radiation is mainly used for palliation in patients with MM, it represents the primary and curative treatment option in patients with SP.

Prolongation of radiotherapy duration is associated with inferior overall survival in patients with pediatric medulloblastoma and central nervous system primitive neuroectodermal tumors.

The importance of radiotherapy (RT) duration in medulloblastoma in the modern era of chemotherapy has not been well elucidated. The aim of this study was to determine the impact of RT treatment duration on overall survival (OS) in pediatric medulloblastoma and cenral nervous system neuroectodermal tumors (PNETs). The National Cancer Database (NCDB) was queried to identify patients with newly diagnosed medulloblastoma and CNS PNETs diagnosed between 2004 and 2014. Patients were excluded if they had extraneural metastasis, did not receive standard craniospinal irradiation dose, had a nonstandard total dose outside of 54 or 55.8 Gy, did not receive adjuvant chemotherapy, or if the RT duration was outside of the expected range of 37 to 80 days. The Kaplan-Meier estimator was used to estimate the association between RT duration (≤45 days or >45 days) and OS. Multivariate Cox regression was used to assess other confounders of OS. Six-hundred twenty-five patients met inclusion criteria, of which 181 were assigned to the "RT long" (>45 days) cohort (29.0%) and 444 (71.0%) to the "RT short" group (≤45 days). The five-year OS for the "RT short" compared with "RT long" cohort was 82.2% versus 70.9%, respectively (log-rank, P < 0.0037). For average risk patients, the five-year OS was 84.6% versus 86.4% for "RT short" and "RT long," respectively (log-rank, P = 0.40). However, for high-risk patients, five-year OS was 77.7% versus 51.0% (log-rank, P < 0.0001) in the "RT short" and "RT long" cohorts. For patients with high-risk medulloblastoma and CNS PNETs, RT duration >45 days was associated with inferior OS.

Delivered dose quantification in prostate radiotherapy using online 3D cine imaging and treatment log files on a combined 1.5T magnetic resonance imaging and linear accelerator system.

Monitoring the intrafraction motion and its impact on the planned dose distribution is of crucial importance in radiotherapy. In this work we quantify the delivered dose for the first prostate patients treated on a combined 1.5T Magnetic Resonance Imaging (MRI) and linear accelerator system in our clinic based on online 3D cine-MR and treatment log files. A prostate intrafraction motion trace was obtained with a soft-tissue based rigid registration method with six degrees of freedom from 3D cine-MR dynamics with a temporal resolution of 8.5-16.9s. For each fraction, all dynamics were also registered to the daily MR image used during the online treatment planning, enabling the mapping to this reference point. Moreover, each fraction's treatment log file was used to extract the timestamped machine parameters during delivery and assign it to the appropriate dynamic volume. These partial plans to dynamic volume combinations were calculated and summed to yield the delivered fraction dose. The planned and delivered dose distributions were compared among all patients for a total of 100 fractions. The clinical target volume underwent on average a decrease of 2.2%±2.9% in terms of D99% coverage while bladder V62Gy was increased by 1.6%±2.3% and rectum V62Gy decreased by 0.2%±2.2%. The first MR-linac dose reconstruction results based on prostate tracking from intrafraction 3D cine-MR and treatment log files are presented. Such a pipeline is essential for online adaptation especially as we progress to MRI-guided extremely hypofractionated treatments.

Evaluating Magnetic Resonance Spectroscopy as a Tool for Monitoring Therapeutic Response of Whole Brain Radiotherapy in a Mouse Model for Breast-to-Brain Metastasis.

Brain metastases are the most common intracranial tumor in adults and are associated with poor patient prognosis and median survival of only a few months. Treatment options for brain metastasis patients remain limited and largely depend on surgical resection, radio- and/or chemotherapy. The development and pre-clinical testing of novel therapeutic strategies require reliable experimental models and diagnostic tools that closely mimic technologies that are used in the clinic and reflect histopathological and biochemical changes that distinguish tumor progression from therapeutic response. In this study, we sought to test the applicability of magnetic resonance (MR) spectroscopy in combination with MR imaging to closely monitor therapeutic efficacy in a breast-to-brain metastasis model. Given the importance of radiotherapy as the standard of care for the majority of brain metastases patients, we chose to monitor the post-irradiation response by magnetic resonance spectroscopy (MRS) in combination with MR imaging (MRI) using a 7 Tesla small animal scanner. Radiation was applied as whole brain radiotherapy (WBRT) using the image-guided Small Animal Radiation Research Platform (SARRP). Here we describe alterations in different metabolites, including creatine and N-acetylaspartate, that are characteristic for brain metastases progression and lactate, which indicates hypoxia, while choline levels remained stable. Radiotherapy resulted in normalization of metabolite levels indicating tumor stasis or regression in response to treatment. Our data indicate that the use of MR spectroscopy in addition to MRI represents a valuable tool to closely monitor not only volumetrical but also metabolic changes during tumor progression and to evaluate therapeutic efficacy of intervention strategies. Adapting the analytical technology in brain metastasis models to those used in clinical settings will increase the translational significance of experimental evaluation and thus contribute to the advancement of pre-clinical assessment of novel therapeutic strategies to improve treatment options for brain metastases patients.

Monte Carlo Simulation of the Oxygen Effect in DNA Damage Induction by Ionizing Radiation

DNA damage induced by ionizing radiation exposure is enhanced in the presence of oxygen (the "oxygen effect"). Despite its practical importance in radiotherapy, the oxygen effect has largely been excluded from models that predict DNA damage from radiation tracks. A Monte Carlo-based algorithm was developed in MATLAB software to predict DNA damage from physical and chemical tracks through a cell nucleus simulated in Geant4-DNA, taking into account the effects of cellular oxygenation (pO2) on DNA radical chemistry processes. An initial spatial distribution of DNA base and sugar radicals was determined by spatially clustering direct events (that deposited at least 10.79 eV) and hydroxyl radical (•OH) interactions. The oxygen effect was modeled by increasing the efficiency with which sugar radicals from direct-type effects were converted to strand breaks from 0.6 to 1, the efficiency with which sugar radicals from the indirect effect were converted to strand breaks from 0.28 to 1 and the efficiency of base-to-sugar radical transfer from •OH-mediated base radicals from 0 to 0.03 with increasing pO2 from 0 to 760 mmHg. The DNA damage induction algorithm was applied to tracks from electrons, protons and alphas with LET values from 0.2 to 150 keV/μm under different pO2 conditions. The oxygen enhancement ratio for double-strand break induction was 3.0 for low-LET radiation up to approximately 15 keV/μm, after which it gradually decreased to a value of 1.3 at 150 keV/μm. These values were consistent with a range of experimental data published in the literature. The DNA damage yields were verified using experimental data in the literature and results from other theoretical models. The spatial clustering approach developed in this work has low memory requirements and may be suitable for particle tracking simulations with a large number of cells.

A study on slab-wooden dust-slab phantom for the development of thorax phantom

Introduction: The determination of accurate dose distribution is an issue of fundamental importance in radiotherapy, especially with regard to the fact that the human body is a heterogeneous medium. Therefore, the present study aimed to analyze the density and isodose depth profiles of 6 MV beam in a SP34 slab-wooden dust (pine)-SP34 slab (SWS) heterogeneous phantom. Materials and Methods: The density of SP34 slab, wooden dust of pine, and thoracic region of 10 patients were calculated using computed tomography (CT) images. The depths of isodose lines were measured for 6 MV beam on the CT images of the chest, SP34 slab phantom, and SWS phantom. Dose calculation was performed at the depths of 2, 13, and 21 cm in both phantoms. Furthermore, patient-specific quality assurance (QA) was implemented using both phantoms. Results: The mean densities of the lung, SP34 slabs, and wooden dust were 0.29, 0.99, and 0.27 gm/cc respectively. The mean depths of different isodose lines in the SWS phantom were found to be equivalent to those in actual patients. Furthermore, the percentage variation between the planned and measured doses was higher in the SWS phantom as compared to that in the SP34 phantom. Furthermore, the percentage variation between the planned and measured doses in patient-specific QA was higher in the SWS phantom as compared to that in the SP34 phantom. Conclusion: As the findings indicated, the density and isodose depth profiles of the SWS phantom were equivalent to those of the actual thoracic region of human.

EP-1388: Clinical features of bone metastases and their importance for radiotherapy

EP-1388: Clinical features of bone metastases and their importance for radiotherapy

The importance of radiotherapy on diffuse large B cell lymphoma treatment: a current review.

Diffuse large B cell lymphoma is recognized as a heterogeneous group of hematological malignancies; two main subtypes germinal center B and activated B cells are well defined although 15% of patients remain with unclassifiable disease. R-CHOP treatment has proven to provide very effective results in limited or advanced stage of the disease. However, treatment solely involving R-CHOP submits the patient to possible chemotherapy-induced toxicities, which may be avoided with the use of radiotherapy. Patients with early stage localized disease or who are particularly unresponsive to chemotherapy may be more suitable for mixed modality treatment with R-CHOP and consolidative radiotherapy. Although radiotherapy is being slowly phased out by other treatment strategies including chemotherapy and therapeutic drugs, it is still a highly important method of treatment. The different forms of radiotherapy can be used alongside these "new-age" treatment strategies to further improve prognostic outcomes and overall survival rates. The establishment of radiotherapy as a treatment strategy provides a highly beneficial prognostic advantage in early stage, localized disease.

Radiotherapy for brain metastases: are we getting better?

Brain metastases are the most common malignant adult CNS tumor. The blood brain barrier (BBB) prevents many drugs from achieving therapeutic concentrations in the central nervous system (CNS), leaving the brain as a potential sanctuary site of disease and underscoring the importance of radiotherapy. Neurons, glial cells and vascular endothelium are prone to radiation-induced damage. Efforts have been made to reduce radiation-induced toxicity and increase efficacy (Stereotactic radio-surgery - SRS, advanced radiation-techniques that allow decreasing the dose to the hippocampi, while intensifying the radiation dose to large brain metastases or administering neuroprotective or radiation sensitizing agents during whole brain radiotherapy -WBRT in order to increase the therapeutic ratio). Surgery, radiotherapy and new pharmacological agents may become advantages for specific patient subgroups or in specific disease stages. Choosing how to treat brain metastases, must take into consideration patients and disease parameters (the primary tumor, age and performance status, systemic and brain tumor burden), and the potential risks and benefits of a treatment tool emphasising QOL considerations. Which modality to apply and when, is often a matter of local practice and treatment availability since level I evidence is lacking. The technology behind WBRT, FSR and SRS has substantially advanced over the previous decade, however only formal clinical trials will allow a definite answer to the question - are we getting better?

Study on systematic health education for patients with nasopharyngeal carcinoma undergone radiotherapy

Objective To explore the application effect of systematic health education in patients with nasopharyngeal carcinoma undergone radiotherapy.Methods Eighty-three patients with nasopharyngeal carcinoma from the Department of Oncology,Affiliated Hospital of Guangdong Medical College from January 2009 to January 2011 were randomly divided into two groups:the control group (41 patients) and the observational group (42 patients).The control group received routine health education,while the observational group received systematic health education with a health education guidebook throughout the treatment period.Questionnaire on the radiotherapy knowledge was used on the 10th day during radiation treatment to evaluate patients' mastering of the knowledge and their satisfaction with medical personnel.Results 98％ patients in the observational group knew the aetiological agent of nasopharyngeal carcinoma,95％ of them knew the importance of radiotherapy,95％ patients knew the secondary reaction of radiotherapy and matters need attention,98％knew the dietary instruction and 98％ knew the discharge guidance,all of which were higher than those in control group (76％,78％,80％,78％,78％,respectively).The differences were statistically significant (x2 =8.742,5.332,4.260,7.499,7.499,respectively; P ＜ 0.05).In observational group,the incidence rate of mucous membrane of mouth reaction was 35.7％,radiodermatitis accounted for 35％,mucous membrane of nasopharynx accounted for 30.9％,jaw joint functional disorder accounted for 38％,all of which were lower than those in the control group (73.1％,70.7％,65.8％,75.6％,respectively).The differences were statistically significant (Hc =10.266,10.173,8.772,10.414,respectively; P ＜ 0.05).The satisfaction with medical personnel in observational group was 95％,was higher than that in the control group (80％),and the difference were statistically significant (x2 =4.26,P ＜ 0.05).Conclusions Systematic health education can increase the nasopharyngeal carcinoma patients' knowledge about radiotherapy,reduce the incidence rates of adverse reactions,improve their satisfaction with the nursing,and promote good communication between patients and nurses. Key words: Health education; Nasopharyngeal carcinoma; Radiotherapy; Therpy effect

Abstract P4-11-01: Cardiovascular Effects of Postmastectomy Irradiation Evident after 15 Years. Results from the South Sweden Breast Cancer Group's Randomised Studies SBII:1 with 25 Years of Follow-Up of Pre-and Postmenopausal Women with Stage II Breast Cancer

Abstract Background: The importance of radiotherapy for local control after mastectomy and breast conservation surgery is well established with a reduction in loco-regional recurrences by two thirds. In early radiotherapy trials the reduction of loco-regional failures did not result in a reduction of mortality due to increased late non-breast cancer mortality. The 2005 overview of radiotherapy by EBCTCG did however show a significantly improved survival with the addition of radiotherapy. Patients and methods: From 1978 to 1985 1100 patients with breast cancer stage II were included in two randomized trials of radiotherapy and adjuvant systemic treatment, SBII:1 pre (Cyclophosphamide per os one year) and SB II:1 post (Tamoxifen 10 mg x 3 one year). The radiotherapy technique and the outcome of these studies have been published previously (Arwidi Å et al. Acta Radiol Oncol 18:273, 1979, Killander F et al. Eur J Cancer 43:2100, 2007, Killander F et al. The Breast 18:309, 2009). An efficient reduction of loco-regional recurrences but no improvement in survival was reported at 25 years of follow-up. Linkage to the following population based Swedish registries was obtained: 1. National Population Registry 2. National Cause of Death Registry, and 3. Swedish Hospital Discharge Registry. Per protocol treatment was administered to 1044 patients, which form the basis for the analyses. We have included both underlying and contributing causes of death due to heart, cerebrovascular and lung disease. Results: After 15 years a significantly increased cardiac mortality was observed in irradiated patients compared to patients given systemic treatment only, and this effect prevailed at 25 years of follow-up. However not until 15 years after radiotherapy significantly higher cardiovascular mortality was observed. When analysing cerebro-vascular mortality the same pattern was seen. Cumulative incidence of non-breast cancer mortality after postmastectomy radiation in pre-and For lung diseases no increase in mortality was discernible. An interesting observation was that in premenopausal patients cardiovascular and cerebrovascular mortality were less pronounced, and that the latency period was longer than for postmenopausal patients. Analyses of all hospital admissions during follow-up showed neither increased overall morbidity nor increased cardiovascular morbidity. Discussion: The significant cardiovascular side effects of radiation observed with the radiotherapy technique used in these studies underlines the importance of careful dose planning and reduction in the volumes of the heart and large vessels, that are exposed to radiation. Extended follow-up is necessary for detection of these late effects. The longer latency and lower cardiovascular mortality in premenopausal patients may reflect lower sensitivity for radiation of normal tissue compared to postmenopausal women. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P4-11-01.

Optimizing chemotherapy and radiotherapy for anaplastic glioma

The optimum approach for the treatment of rare anaplastic gliomas following surgical resection is uncertain. A recent study has now provided a greater understanding of the heterogeneous tumor biology of these tumors and has emphasized the prognostic importance of chromosome 1p19q deletion, IDH mutation and MGMT promoter methylation. The importance of radiotherapy and chemotherapy for treating these heterogeneous tumors is being elucidated for subgroups of patients.

Indication of Radiotherapy for Women With Cervical Cancer in Rio De Janeiro, Brazil

The objective of this article was to analyze the treatment modalities used at the Brazilian National Cancer Institute, with particular emphasis on the use of radiotherapy (RT) and its indications in invasive cervical cancer, considering the staging and clinical epidemiological characteristics of the population. All cases of primary invasive tumors of the cervix (CID C53) registered at the institute and diagnosed between 1999 and 2004 were selected. The following variables were studied: (1) age, (2) year of diagnosis, (3) level of schooling, (4) race, (5) histopathologic subtype, (6) the staging of the tumor on diagnosis, and (7) the treatment modality initially offered. We analyzed 3509 cases of invasive disease, and 79.7% of them received RT. Based on the final logistic model, it was possible to construct a probabilistic model for the indication of RT in the subgroups formed by the combinations of the 3 highlighted variables (stage, age, and histological type). The likelihood varied from 22.5% in those with epidermoid carcinoma, stage I, younger than 55 years up to 100% in those with locally advanced disease and older than 65 years. These results indicate the importance of RT as a modality of treatment of invasive cervical cancer in Brazil, where a substantial proportion of the diagnoses are made in advanced stages. This set of information regarding this important center may help the long-term strategic planning and the allocation of funds that enable the high demand to be met in an optimized manner.

Evaluation of the radiation-sensitizer/protector and/or antioxidant efficiencies using Fricke and PAG dosimeters

In this study, our aim is to assess the potential of Fricke and polyacrylamide gel (PAG) dosimeters to quantitatively evaluate the efficiency of potential radiation sensitizers/protectors and antioxidants. These compounds are of importance in radiotherapy as well as in disease prevention and promotion of health. The basic principle of the Fricke dosimeter is the radiation-induced oxidation of Fe2+ to Fe3+ in an aerated aqueous 0.4 M H2SO4. The production of ferric ions is most sensitive to the radical species produced in the radiolysis of water. Using this method, we observed that cystamine (one of the best of the known radioprotectors) can prevent oxydation of Fe2+ from reactive radiolysis species. However, one obvious disadvantage of the Fricke dosimeter is that it operates under highly acidic conditions (pH 0.46), which may degrade biological compounds. In contrast, the pH of the polyacrylamide gel (PAG) dosimeter is almost neutral, such that degradation of compounds is less probable. A change in R2-dose sensitivity was observed in the presence of radiosensitizers/radioprotectors and antioxidants. The protective effect of Trolox (a well-known antioxidant) and thiourea (a radioprotector) was readily observed using the PAG dosimeter. Incorporation of iodinated radiation sensitizers such as NaI and an iodine contrast agent led to a quantifiable sensitizer enhancement ratio. These studies suggest that the Fricke and the PAG dosimeters have the potential to evaluate the efficiency of radiation sensitizers/protectors and antioxidants.

The importance of radiotherapy in paediatric atypical teratoid rhabdoid tumour of the brain

Summary Background Atypical teratoid rhabdoid tumours (ATRT) are very rare children's cancers. Approximately 200 cases of ATRT located in the central nervous system have been described in the literature up till now. Aim The aim of this report was to analyze the results of treatment of 8 children with these very rare neoplasms of the central nervous system, who were treated according to the Polish Paediatric Brain Tumour Group protocol. Material and Methods Eight children aged from 4 months to 22 years, 5 girls, 3 boys with ATRT of the central nervous system are presented. All children have been operated on and received multidrug chemotherapy; 5 children received radiotherapy as well. In all craniospinal irradiation was applied, in doses of 35 Gy to the whole axis and 55 Gy to tumour boost. Results Five patients died and 3 children are still alive. The progression-free survival of all 8 patients was 3 to 73 months. The overall survival was 5 to 73 months. All living children received radiotherapy. Two of them had total surgical resection and one partial. Conclusions We conclude that radiotherapy prolonged survival in ATRT and should be incorporated in all treatment protocols for patients with this diagnosis.

Chemotherapy for prostate cancer

For many years the benefit of chemotherapy in patients with prostate cancer was thought to be limited to palliation of late-stage disease, and thus this treatment option only became involved in patient care towards the end of the disease process, if at all. However, two landmark phase-III trials with docetaxel-based therapy (TAX 327 and Southwest Oncology Group, SWOG, 9916) have shown a survival benefit for patients with hormone refractory prostate cancer (HRPC) thus prompting a change in patterns of care. With raising interest for chemotherapeutic options and clinical trials for new drugs and new indications (neoadjuvant therapy, adjuvant therapy, increasing PSA levels after local treatment, and hormone sensitive cancer) under way our goal was to review within the context of a multidisciplinary team the available evidence and explore the standard for the medical treatment of prostate cancer outside of clinical trials. We are carefully evaluating the current treatment recommendations based on the available evidence and highlight potential future treatment options but also discuss important clinical topics (treatment until progression versus the advantage of chemo holidays, definition of particular patient subgroups and potential second line options) for which there are no clear cut answers to date. The role and importance of radiotherapy, biphosphonate treatment and the medical management of pain and side effects is also discussed. The multitude of treatment options for patients with advanced prostate cancer clearly asks for a close collaboration between urologists, medical oncologists and radiation therapists.