Narrow Results

Tests have been performed on the high sensitive (HS) GAFChromic film to evaluate its densitometric response to external X-rays (photon beam). Several 2 cm by 2 cm pieces of HS and MD-55-2 GAFChromic films were prepared and irradiated for sensitivity comparison, and X-rays energy dependence study. The optical densities of three irradiated pieces of HS film were measured as a function of time to establish the time taken for the optical density to stabilize. The densitometric sensitivity curves comparison showed that the HS film is twice as sensitive as its predecessor, MD-55-2, more spatially uniform and dosimetric measurements can be made with high precision. Its sensitivity is independent of 6 MV and 15 MV X-ray beam energies and its optical density is stable after about 36 hours post-irradiation time.

Treatment planning for external beams radiotherapy for patients with metallic hip prosthesis is often difficult, in particular with regards to the contouring process, in case of poor CT imaging. This may result in inaccurate dosimetry for the femoral bone and regions next to it. In this work an alternative method to obtain more accurate prosthetic contourings, based on photogrammetry, was developed. More precisely, the process of 3D modeling of a femoral prosthetic component and the conversion to DICOM was developed, plus the effective employment in a treatment planning system was evaluated. Validation of the obtained model was performed by comparing several cross sections against experimental measurements. Comparison resulted in very low deviations, showing good accuracy of the photogrammetry technique, despite the high asymmetry of the object. The tests conducted in a research TPS indicate that models obtained with the proposed method are able to provide additional information in order to better characterize such prosthetic implants.

The overall survival (OS) prediction for nonsmall cell lung carcinoma (NSCLC) patients of clinical IIIA-N2 stage undergone various treatments was investigated through a refined Taylor series expansion algorithm. The model was created according to a population-based study in Taiwan. The proposed prediction algorithm is based on the well-known hit and target model adopted for analyzing the cell death from the microscopic viewpoint. It also implies the application of the Taylor series expansion to the population-based survey dataset. In the proposed algorithm, the basic degradation of a patient’s health is represented via a specific function comprising a single exponential term exp($-\alpha t$). The refined algorithm successfully predicted NSCLC IIIA-N2 patients’ OS rate. A total of 127,301 patients were collected from 2010 to 2017. Then, 2655 patients were recognized as effective events and classified into eight classes according to various medical treatments, namely surgical operation, radiotherapy, and chemotherapy. For each class of patients, the average life was evaluated, according to Taylor’s expansion algorithm, and the average derived life range spread from 3.51 to 7.81 years. An index of life gain with specific treatment was defined according to the Taguchi optimization analysis. The life gains provided by the surgical operation, chemotherapy, and radiotherapy were 2.74, 1.18, and 0.48 years. The surgical operation was the most beneficial treatment, which is in concert with recommendations of European experts. A similar finding was also reflected in four out of eight classes, which included the surgical operation in the treatment plans of most Taiwanese hospitals.

Patients treated with radiation therapy (RT) for head and neck cancer are exposed during the course of several weeks of treatment (6–7 weeks) to several physiological processes that can induce inter-fraction deformation of the parotid salivary glands (PGs). Gland morphing tends to make them move towards the high dose region of the dose distribution. As a consequence, parotids may be irradiated more than initially planned, leading to increased toxicity. We implemented a biomechanical model of the parotid morphing process that can serve as the basis to optimize adaptive RT protocols, leading to further reductions of dose to these structures. Raystation$\text{®}$ hybrid deformation algorithms and 3DSlicer$\text{®}$ tools were employed to obtain a mesh representation of PG anatomy and deformation from CT-series of eight patients treated with highly modulated radiotherapy (Tomotherapy$\text{®}$). The biomechanical model was computationally implemented with the finite element software COMSOL$\text{®}$ multiphysics. Gland tissue was modeled as a linear elastic material with a Poisson ratio of 0.49 and a density value of 1 g/cm³. A radial force field was introduced to mimic parotid shrinkage due to radiation exposure. Fixed constraints were placed taking into account the anatomical barrier effect of parotid-surrounding structures (mandible) during the shrinkage process. The implemented biomechanical model was able to predict PG morphing with a mean volume difference of 1.36% [0.9–2.0] % between real and modeled deformed anatomy for the first half of treatment and 1.5% [0.8–2.1]% for the second half of treatment. Prediction of geometric overlap of observed versus simulated geometry as quantified using DICE was acceptable for the first half of the treatment but still unsatisfactory for the second half. Adding model components taking into account other elements that define PG morphing (facial geometry changes due to general weight loss and — in patients with significant macroscopic tumor load - local tumor volume loss) may accurately predict parotid morphing and thus permit further optimization of frequency and timing of off-line ART protocols in patients undergoing radiotherapy for head and neck cancer. This may result in a further reduction of treatment toxicity and these approaches are becoming even more important as the use of particle therapy with its increased dosimetric sensitivity towards geometric changes of the patient is slowly increasing.

Verification procedures for patient-specific quality assurance (QA) in advanced radiotherapy are laborious and time-consuming. Moreover, it has been shown that these procedures cannot detect some inaccuracies for some particular complex cases due to tissue inhomogeneity and highly modulated plans. Secondary dose calculation verification of radiotherapy plans is an important aspect in patient-specific QA. A suitably optimized software, RadCalc equipped with 3D Monte Carlo Module (MC), was used to dosimetrically verify radiotherapy treatment plans where the measured dose distributions can be inaccurate due to the TPS dose calculation algorithm and/or treatment unit delivery uncertainties. MC Models were built using specific commissioning measurements and then the Additional Radiation to Light Field Offset parameter (Dosimetric Leaf Gap parameter) was tuned to achieve the best dose comparison agreement with phantom patient-specific QA measurements. The results showed a good agreement between the TPS and the simulations. RadCalc MC also allows to better estimate the plan doses in lung cancer patients and to detect the presence of possible inaccuracies due to tissue inhomogeneity, which is not estimable with a homogeneous phantoms.

Incidence: Nasopharyngeal cancer (NPC) is a rare disease in Caucasians and is commonly WHO Type 1 (squamous cell carcinoma) histology. NPC is endemic in southern China (the Guangdong Province), Hong Kong and Taiwan, and is usually WHO Type 3 (undifferentiated) histology. These differing patient cohorts and different staging systems have hampered the rate of progress in optimizing the management of NPC patients.

Changing demographics: Melbourne's population demographics have changed significantly since 1985. Our NPC population currently bridges the endemic and non-endemic populations.

Treatment: There have been major improvements in radiation therapy techniques. The optimal conformal radiation technique(s) to be used if IMRT is not available is discussed. Concurrent chemotherapy and radiation therapy (chemoradiation) is the current standard of treatment in NPC. The role of additional sequential chemotherapy is controversial. A randomized trial comparing induction chemotherapy and chemoradiation versus chemoradiation alone would be very informative.

Nasopharyngeal carcinoma (NPC) is endemic in southern China and Southeast Asia. It is distinctly different from other head and neck cancers in terms of etiology, clinical behavior and response to treatment. There have been marked improvements in treatment outcome in the past decades, partly the result of early presentation and diagnosis, and partly the result of improvements in treatment. Radiotherapy is the standard treatment for NPC, its success depending on accurate delineation of target volume, determination of optimal radiation dose, and the means to deliver the desired radiation dose to this target volume. The advent of cross-sectional imaging of CT and MR has allowed more accurate delineation of tumor extent. The recent advent of intensity-modulated radiotherapy (IMRT), as a means of 3D conformal radiotherapy, allows conforming high radiation dose to target volume, and at the same time conforming low radiation dose to sensitive structures. For the more advanced cases, adding chemotherapy can in theory partly help through sensitizing tumor cells to radiotherapy, and partly through direct effect on the occult micro-metastases. Randomized prospective controlled trials of concurrent chemoradiotherapy had demonstrated benefits in terms of improving relapse-free and overall survival; studies using neoadjuvant or adjuvant chemotherapy had not been able to demonstrate such benefits.

Nasopharyngeal Cancer is a radiosensitive disease. About 60% of all patients are cured with radiotherapy alone, and this figure is likely to increase with the use of chemotherapy. The use of Intensity Modulated Radiotherapy (IMRT) will improve local control and reduce the morbidity of irradiation. Salvage surgery is used for local and regional relapses, but the use of radiosurgery may result in comparable outcomes. In the metastatic setting, the use of new molecules involved in signaling pathways and the use of immunotherapy strategies are being investigated.

Objective: A randomized trial was performed to evaluate the contribution of gan lu fu zheng soup with chemotherapy plus radiotherapy (CT/RT) in the patients with histologically proven nasopharyngeal carcinoma with local metastasis to lymph nodes. Methods: Sixty-eight patients with nasopharyngeal carcinoma were treated either with gan lu fu zheng soup alongside with chemotherapy and radiotherapy (TCM/CT/RT group) or with chemotherapy and radiotherapy (CT/RT group) alone. All patients in the two groups were treated with a uniform definitive-intent radiation therapy and chemotherapy, while those patients in the TCM/CT/RT group were treated with extra gan lu fu zheng soup. Results: From 1999 to 2002, 68 patients (38 in TCM/CT/RT, 30 in CT/RT group) were enrolled and eligible. The rates of complete resolution of nasopharyngeal tumors in the treatment group and the control group were respectively, 94.7% and 90%; the rates of complete resolution of cervical lymph node metastases were respectively, 92.1% and 83%; the resolution rates of nasopharyngeal foci examined by CT were respectively, 73.6% and 63.3%; and the total survival rates of one year were respectively, 100.0% and 96.7% (P > 0.05). Changes in clinical symptoms: the total amelioration rates of the two groups were respectively, 97.4% and 76.7%; changes in life quality: the amelioration rates of the two groups were respectively, 89.5% and 66.7%; toxic and side reactions: in comparison with the control group, the treatment group were also distinctly relieved from leukopenia, nausea and vomiting, toxic and side reaction of oral mucosa. Through statistic analysis, the differences are of significances (P < 0.05). Conclusions: Treating nasopharyngeal carcinoma with gan lu fu zheng soup in combination with radiotherapy and chemotherapy is helpful to increase the rates of tumor resolution and complete resolution, to protect immunocompetence of organism, to promote the amelioration of clinical symptoms, to alleviate the toxic and side reaction of radiotherapy and chemotherapy, to increase life quality and prolong survival time, which provides an effective auxiliary means for the treatment of nasopharyngeal carcinoma.

Stomach cancer is still a leading cause of cancer-related deaths in the Asia-Pacific region. The risk factors are well known. However, the clinical symptoms are very nonspecific. Indeed, most of the stomach cancers are diagnosed at a late stage in most countries outside Japan. This contributes to the overall poor survival rate. Surgery remains the main modality for curative treatment. However, there are controversies over the extent of surgical resection. For locally advanced and metastatic disease, other nonsurgical modalities play an increasing role. Future efforts to improve the outcome of the disease should therefore focus on early detection.

As ²¹³Bi, a spontaneous alpha-emitting radioisotope, and ¹⁰B, a neutron-activated source of alpha particles, have been found to be potential tools in the treatment of cancer patients, a novel bismuth porphyrin, bearing both boron atoms and a strap with a hanging carboxylic group, was synthesized.

A comparative study of bismuth complexation by various porphyrins which differ according to the structural scaffold – either picket(s) or strap(s) – that deliver the carboxylic acid groups close to the metal, has been performed. Unlike strapped porphyrins, and although more flexible, the picket ligands do not lead to more stable bismuth complexes.

Neuroblastoma (NB) is one of the most common extracranial malignancies in children, accounting for 7–8% of childhood malignancies. As one of the main treatments for NB, radiotherapy is limited by various factors in clinics, such as the hypoxia microenvironment in tumor and serious side effects. Herein, we synthesized a kind of nanoscale coordination polymer denoted as Hf@DAP nanoparticles composed of hafnium ion (Hf${}^{4+})$ and 2,6-diaminopimelic acid (DAP), one of bacterial derivatives. From the image of transmission electron microscope (TEM), nanoparticles had uniform dispersion. Furthermore, the hydrodynamic diameter measured by dynamic light scattering method was about 190 nm. In this structure, the Hf${}^{4+}$ can enhance radiotherapy by effectively enhancing the function of X-ray, and the DAP was a biocompatible ligand for fabricating the nanoscale coordination nanoparticles. Furthermore, Hf@DAP nanoparticles were stable in various mediums and exhibited favorable biocompatibility in various cell lines in vitro. Cell viabilities were tested by cell counting kit (CCK-8) in vitro. There was no obvious cytotoxicity to normal cells, including NIH3T3, RAW264.7, and HUVECs, after incubation with Hf@DAP nanoparticles, indicating biocompatibilities of Hf@DAP nanoparticles. Additionally, a significantly enhanced radiotherapy effect was observed in the N2a cells, a kind of NB cell line, pretreated with Hf@DAP nanoparticles in vitro. The in vivo tumor growth was obviously inhibited in the mice with the combined therapy of Hf@DAP nanoparticles and X-ray, compared with PBS group, Hf@DAP group, and X-ray group. Furthermore, the survival time of the mice in the combined group was significantly prolonged, compared with PBS group. In addition, tissues structures of main organs, such as the lung, liver, spleen, and kidney in these mice, were ordered without the influence of Hf@DAP nanoparticles. Thus, this work proposed a potential radio-sensitizer for further clinical radiotherapy with limited side effects and high efficiency.

The world's first hospital-based proton treatment center opened at Loma Linda University Medical Center in 1990, following two decades of development. Patients' needs were the driving force behind its conception, development, and execution; the primary needs were delivery of effective conformal doses of ionizing radiation and avoidance of normal tissue to the maximum extent possible. The facility includes a proton synchrotron and delivery system developed in collaboration with physicists and engineers at Fermi National Accelerator Laboratory and from other high-energy-physics laboratories worldwide. The system, operated and maintained by Loma Linda personnel, was designed to be safe, reliable, flexible in utilization, efficient in use, and upgradeable to meet demands of changing patient needs and advances in technology. Since the facility opened, nearly 14,000 adults and children have been treated for a wide range of cancers and other diseases. Ongoing research is expanding the applications of proton therapy, while reducing costs.

The history and technology of medical linacs are reviewed, focusing on machine requirements for radiotherapy. Configurations used in modern machines are described and operational aspects of a gantry-style linac system are illustrated with reference to the state of the art. Aspects of structure design, modeling and testing are discussed.

Background: Primary broad ligament epithelial malignancies are rare occurrence. Hence, the treatment options are uncertain. Therefore, an accurate diagnosis is warranted to manage this condition.

Case report: We present a 61-year-old female with abdominal distension associated with significant weight loss for six months. A computed tomography (CT) scan of the abdomen and pelvis revealed a pelvic mass measuring 10.7 × 14.6 × 13.5 cm with omental caking.

Result: An exploratory laparotomy and tumour debulking was performed. Histological examination revealed moderately differentiated endometrioid carcinoma of the broad ligament stage IC and an endometrioid carcinoma of endometrium, stage 1A. She received external beam radiotherapy; brachytherapy followed by adjuvant chemotherapy with a 6 monthly surveillance. Currently, she is healthy with no recurrence at 24 months postoperatively.

Conclusion: The rarity of primary broad ligament endometrioid carcinoma may incline clinicians to suspect more common malignancies such as ovarian. However, with an accurate diagnosis, the treatment will allow a better prognosis to the patient.

To estimate the respiration-induced dosimetric change at beam edge during a beam-on interval of radiotherapy, by the integration of a mathematical model for organ motion and a modeled beam profile. A method is proposed which incorporated the effects of intra-treatment organ motion due to breathing on the dosimetric change for the treatment of liver cancer. The basic algorithm was to assume the motion of infra-abdominal organs was predominantly in the superior-inferior (S-I) direction. The starting phase was defined as the mid-phase at exhale, to reproduce the same situation of computed tomography simulation for liver cancer. The S-I extent of motion was defined as 1.5cm. The period of a breathing cycle was defined as 4.2 seconds. The shape parameter of the respiratory model was defined as 3. The radiation dose of 100 cGy given with the rate of 300 MU/minute was designed for the model analysis. The position at the beam edge as a function of time could be parameterized for a 10cm x 10cm field with a setup of SAD 100cm. The dose profiles of both 6MV and 18MV photons were applied for the dosimetric calculation of the beam-edge point during the dynamic movement in a beam-on time interval of radiotherapy. The point doses at the superior beam edge for 6MV photons and18MV photons during a beam-one interval of 22.8 seconds were 73.5% and 77.2% of the isocenter dose, respectively. The point doses at the inferior beam edge for the two energies were 31.2% and 32.4%, respectively. There were 147-154% dose increase for superior beam edge and 62.4-64.8% dose decrease for inferior beam edge, as compared to the 50% isocenter dose with the static dose distribution. It is simple and feasible to use the mathematical model to estimate the dosimetric change of the intra-abdominal organ motion from respiration. The impact of respiration on the dosimetric difference deserves more attention in the prescription of radiation treatment. Further measurement of the exact organ motion during the real treatment is warranted to optimize the model.

The full scale 3D Anthropometric Digital Model system is a technique combining digital imaging, three-dimensional (3D) image processing and reverse engineering to produce a full-scale solid Anthropometric Digital Model. This paper describes the Anthropometric Digital Model being made and used in radiation treatment. By using computed tomography and optical scanning, the data required for the Anthropometric Digital Model is collected. Through surface reconstruction, a model of the patient skull is made, after which rapid prototyping and rapid tooling is applied to acquire a 1:1 solid model. Thus, without the patient needing to be present, the medical physicist or dosimetrist will be able to design a treatment plan tailored to the patient and to simulate all kinds of situations on the simulator and the linear accelerator for positioning and verification. We expect that the application of Anthropometric Digital Model can reduce the time spent on pretreatment procedures in radiotherapy and enhance the quality of health care for cancer patients.

Accurate planning of radiation therapy entails the definition of treatment volumes and a clear delimitation of normal tissue of which unnecessary exposure should be prevented. The spinal cord is a radiosensitive organ, which should be precisely identified because an overexposure to radiation may lead to undesired complications for the patient such as neuronal dysfunction or paralysis. In this chapter, a knowledge-based approach to identifying the spinal cord in computer tomography images of the thorax is presented. The approach relies on a knowledge-base which consists of a so-called anatomical structures map (ASM) and a task-oriented architecture called the plan solver. The ASM contains a frame-like knowledge representation of the macro-anatomy in the human thorax. The plan solver is responsible for determining the position, orientation and size of the structures of interest to radiation therapy. The plan solver relies on a number of image processing operators. Some are so-called atomic (e.g. thresholding and snakes) whereas others are composite. The whole system has been implemented on a standard workstation. Experimental results performed on 23 patients show that the approach is reliable in spinal cord segmentation.

Purpose: Cancer patients widely use complementary alternative medicines. Although some remedies have been shown to be of benefit, there is also a risk of potentially serious interactions with conventional cancer therapies and diagnostic procedures. The aim of this review is to identify the main factors which might make complementary medicines potentially unsafe in cancer.

Method: Systematic review of potential interactions with chemo- and radiotherapy and review of the purported mechanisms of action.

Results: Four factors were identified. These included the potential modification of the clinical course, interaction with the pharmacodynamics and pharma-cokinetics of conventional therapies and potential alterations of investigations. Complementary immunostimulants may be contraindicated in lymphomas and other cancers in which suppression of the immune system is desired. Phytoestrogens could stimulate growth of hormone sensitive cancer cells. Antioxidants should not be used in chemotherapies whose mechanisms of action rely on cell damage through oxidative stress. Many remedies can interact with the cytochrome P450 system thereby potentially changing plasma levels of conventional medicines. However, in vitro effects or findings from animal studies may not translate into clinically relevant effects. Some remedies may interfere with the membrane transporter proteins thereby contributing to multi-drug resistance. Finally some complementary medicines remedies may interfere with unsealed source radiotherapy or nuclear scans.

Conclusions: Predicting the safety profile of complementary medicines is complex and may depend on personal and genetic factors. In cancer therapy, where the therapeutic margin of chemotherapies is very narrow, potential risks and benefits need to be meticulously evaluated.