Measurements of peripheral dose for multileaf collimator based linear accelerator

BackgroundIn radiation therapy, peripheral dose (PD), or the dose outside the geometrical boundaries of the radiation field, is of clinical importance when anatomical structures such as foetus in pregnant women, gonads, and lenses of the eye, with low dose tolerances are involved. Even a small percentage of the total treatment dose might cause injury in such cases. The sources of peripheral dose are leakage from the treatment unit, scatter from the secondary collimators and beam modifiers such as wedges and blocks, and internal scatter originating in the patient.AimTo determine the peripheral dose (PD) for multileaf collimator (MLC) based linear accelerator in water equivalent slab phantom for open and wedged fields.Materials/MethodsPD measurements were carried out for 6 and 15 MV photons using a 0.4cc parallel plate chamber in the slab phantom. Measurements were performed for different field sizes at different depths (Dmax, 5 cm and 10 cm) and up to a maximum distance of 30 cm beyond the field edges. PD was measured using wedge filters also. PD was further computed using a three-dimensional treatment planning system (3D TPS).ResultsFor 6 MV photon beams, the maximum PD for open beams at 5 cm distance from the field edge was 3.42% and the minimum PD at 20 cm distance was 0.11%. For 15 MV, the maximum PD for open beam at 5 cm distance was 3.07% and the minimum PD was 0.14%. For wedge filters, the maximum PD measured at 5 cm distance for 6 and 15 MV photons were 5.56% (60° Wedge) and 5.03% (45° wedge). The TPS PD values showed minimal variation from the measured values.ConclusionsThe PD due to MLC and beam modifiers would definitely be helpful to assess the doses received by the relevant critical structures outside the treatment field

Role of Palliative Radiotherapy in Brain Metastases

Background: Brain metastases are a common manifestation of systemic cancer and exceed primary brain tumors in number and are a significant cause of neurologic problems. They affect 20-40% of all cancer patients. Aggressive management of brain metastases is effective in both symptom palliation and prolonging the life. Radiotherapy has a major role to play in the management of brain metastases. AIM: The aim of the study was to know the outcome of palliative radiotherapy in symptomatic brain metastases in terms of improvement in their performance status. Materials and Methods: This is a retrospective study of 63 patients diagnosed to have brain metastases and treated with palliative whole brain radiotherapy to a dose of 30 Gy in 10 fractions over two weeks between June 1998 and June 2007. Diagnosis was done in most of the cases with computed tomography scan and in a few with magnetic resonance imaging. Improvement in presenting symptoms has been assessed in terms of improvement in their performance status by using the ECOG scale. Results: Fifty-four patients completed the planned treatment. Eight patients received concurrent Temozolamide; 88% of patients had symptom relief at one month follow-up; 39/54 patients had a follow-up of just one to three months. Hence survival could not be assessed in this study. Conclusion: External beam radiotherapy in the dose of 30 Gy over two weeks achieved good palliation in terms improvement in their performance status in 88% of patients. Addition of concurrent and adjuvant Timozolamide may improve the results

Design and Application of Microfluidic Capture Device for Physical–Magnetic Isolation of MCF-7 Circulating Tumor Cells

Circulating tumor cells (CTCs) are a type of cancer cell that spreads from the main tumor to the bloodstream, and they are often the most important among the various entities that can be isolated from the blood. For the diagnosis of cancer, conventional biopsies are often invasive and unreliable, whereas a liquid biopsy, which isolates the affected item from blood or lymph fluid, is a less invasive and effective diagnostic technique. Microfluidic technologies offer a suitable channel for conducting liquid biopsies, and this technology is utilized to extract CTCs in a microfluidic chip by physical and bio-affinity-based techniques. This effort uses functionalized magnetic nanoparticles (MNPs) in a unique microfluidic chip to collect CTCs using a hybrid (physical and bio-affinity-based/guided magnetic) capturing approach with a high capture rate. Accordingly, folic acid-functionalized Fe3O4 nanoparticles have been used to capture MCF-7 (breast cancer) CTCs with capture efficiencies reaching up to 95% at a 10 µL/min flow rate. Moreover, studies have been conducted to support this claim, including simulation and biomimetic investigations

Effects of yoga on symptom management in breast cancer patients: A randomized controlled trial

Objectives: This study compares the effects of an integrated yoga program with brief supportive therapy on distressful symptoms in breast cancer outpatients undergoing adjuvant radiotherapy. Materials and Methods: Eighty-eight stage II and III breast cancer outpatients were randomly assigned to receive yoga (n = 44) or brief supportive therapy (n = 44) prior to their radiotherapy treatment. Intervention consisted of yoga sessions lasting 60 min daily while the control group was imparted supportive therapy once in 10 days during the course of their adjuvant radiotherapy. Assessments included Rotterdam Symptom Check List and European Organization for Research in the Treatment of Cancer-Quality of Life (EORTC QoL C30) symptom scale. Assessments were done at baseline and after 6 weeks of radiotherapy treatment. Results: A GLM repeated-measures ANOVA showed a significant decrease in psychological distress (P = 0.01), fatigue (P = 0.007), insomnia (P = 0.001), and appetite loss (P = 0.002) over time in the yoga group as compared to controls. There was significant improvement in the activity level (P = 0.02) in the yoga group as compared to controls. There was a significant positive correlation between physical and psychological distress and fatigue, nausea and vomiting, pain, dyspnea, insomnia, appetite loss, and constipation. There was a significant negative correlation between the activity level and fatigue, nausea and vomiting, pain, dyspnea, insomnia, and appetite loss. Conclusion: The results suggest beneficial effects with yoga intervention in managing cancer- and treatment-related symptoms in breast cancer patients

Regional collaboration to improve quality of radiation therapy in Asia

In Asia, several challenges hinder the delivery of high-quality cancer treatment, especially radiation therapy (RT). Many Asian countries face large-scale shortage of RT centres and treatment machines. Additionally, there is also a significant technological gap, with many RT centres in Asia still using outdated technology. There is an urgent need to improve radiation treatment quality in Asia. The Federation of Asian Organizations for Radiation Oncology (FARO) was set up to foster regional collaboration, which we believe can help to identify and solve some of these issues collectively. This report describes the background and rationale of starting FARO, and puts forth some of the early achievements of the group, including fact-finding and educational activities. Finally, we discuss future possibilities, including strategic proposals that may benefit the RT community and our patients in Asia