No abstract available.
Brachytherapy*

No abstract available.
Brachytherapy*

Interventional radiotherapy, also known as brachytherapy, is the use of sealed radioactive sources that directly deliver radiation to the tumor or tumor bed. Its unique dose distribution profile allows for high conformality, making it a very useful modality in the treatment of cancers in the head and neck, where different organs and substructures that serve various but related functions are situated close to each other. In recent years, we have seen several important technological breakthroughs in the field, especially regarding its application in head and neck cancers. These include advances in treatment delivery, dosimetry planning , image guidance , and catheter positioning techniques . These innovations, which often require interdisciplinary interventions, have resulted in enhanced treatment accuracy, and therefore, major clinical advantages in terms of increased local control and decreased toxicity, as well as economic benefits. In order to highlight the differences from old brachytherapy techniques, a more appropriate terminology should perhaps be adopted, to signify these advancements that resulted in new opportunities, approaches and better outcomes – interventional radiotherapy (IRT). Such a change in terminology will not only allow recognition of these advances, but also a meaningful distinction from obsolete techniques and suboptimal outcomes that are associated with traditional brachytherapy. This is very important in increasing awareness among professionals outside the field of radiation oncology. We briefly review these recent advances, the current indications, and future directions for IRT in head-and-neck cancers.
Brachytherapy

Background: Concurrent chemoradiotherapy composed of pelvic external beam radiotherapy (PEBRT) with weekly chemotherapy plus intracavitary brachytherapy (ICBT) remains to be the treatment of choice for locally advanced cervical cancer (LACC). However, some patients are not suitable to have ICBT right after pelvic radiation. Locally, active chemotherapy is being given to these patients until they can undergo the procedure. Objective: The aim of the study was to determine the impact of ICBT in the treatment and survival outcomes of cervical cancer and to compare it with active chemotherapy. Methodology: This was a retrospective study of patients with LACC treated with or without brachytherapy in a single institution from January 2002 to December 2017. Results: The 5-year over-all survival (OS) and 5-year recurrence free survival (RFS) of patients with ICBT were both significantly improved compared to those without ICBT (p=0.001 and p=0.038), respectively. Factors that were significantly correlated with adequate response for brachytherapy were non-squamous cell histology (OR 0.65, CI 0.46- 092, p=0.016), initial tumor size of > 5cm (OR 0.41, CI 0.26-0.65, p=0.001), > 50% decrease in the original tumor size at the middle part of PEBRT (OR 1.83, CI 1.2-2.8, p=0.005), > 3 cycles of chemotherapy as radiosensitizers (OR 2.66, CI 1.79- 3.9, p=0.001), > 45 days duration of PEBRT (OR 0.63, CI 0.41-0.97, p=0.04) and > 2 episodes of anemia during PEBRT (OR 0.67, CI 0.52-0.85, p=0.001). Conclusion Brachytherapy offers significant improvement on tumor control and over-all survival for patients with LACC. Active chemotherapy may offer some benefit in terms of delaying tumor recurrence or progression. However, this did not translate to survival impact if the patient was not able to have brachytherapy at all.
brachytherapy ;

The aim of this study is to introduce the accuracy of Ir-192 source's apparent activity using the well-type chamber and the Farmer-type ionization chamber in the high dose rate brachytherapy. We measured the apparent activity of Ir-192 that each medical center in the country has and the apparent activity of calibration certificate provided by manufacturer is compared with that by our experimental measurement. The number of sources used for the activity comparison was 5. The accuracy of the measured activity was in the range of -2.8% to -1.0% and -2.1% to 0.2% for the Farmer-type chamber system (Jig) and for the well-type, respectively. The maximum difference was within 1.0% for comparison with two calibration's tool. Our results demonstrate that well-type chamber as wall as Farmer-type chamber is a appropriate system as the routine source calibration procedures in HDR brachytherapy. Whenever a new source is installed to use in clinics, by periods, a source calibration should be carried out.
Brachytherapy ; Calibration

No abstract available.
Brachytherapy* ; Stents*

PURPOSE: The dose calculation program for the Buchler type remote afterloading system was developed. This program also can be used to calculate dose for various sealed sources. METHODS AND MATERIALS: We determined the source length and distribution by dividing the program disk to 72 points. The dose rate for the each program disk and source was calculated. The dose rate table for the xy coordinate was established. The dose rate for the interesting points of the patient were calculated by using this table. We also made isodose curve from this calculations. RESULTS: The storage size for the dose rate table were increased.But the calculation of the dose rate for the patient were carried out rapidly. So we could get real time calculation. CONCLUSION: By using this program, we could calculate the dose rate for the various oints of the patient quickly and accurately. This program will be useful for the treatment with various linear sources.
Brachytherapy ; Humans

No abstract available.
Brachytherapy* ; Stents*

We review the evolution of Brachytherapy to interventional radiotherapy and its current and potential roles in HNC management, and the requirements and challenges towards its effective and sustainable implementation in SEA.
Brachytherapy ; Radiotherapy

This work is for the preliminary study for the calibration of an (192)Ir brachytherapy source based on an absorbed dose to water standards. In order to calibrate brachytherapy sources based on absorbed dose to water standards using a clyndirical ionization chamber, the beam quality correction factor kappa(Q,Q0) is needed. In this study kappa(Q,Q0)s were determined by both Monte carlo simulation and semiexperimental methods because of the realistic difficulties to use primary standards to measure an absolute dose at a specified distance. The 5 different serial numbers of the PTW30013 chamber type were selected for this study. While chamber to chamber variations ran up to maximum 4.0% with the generic kappa gen(Q,Q0), the chamber to chamber variations were within a maximum deviation of 0.5% with the individual kappa ind(Q,Q0). The results show why and how important ionization chambers must be calibrated individually for the calibration of (192)Ir brachytherapy sources based on absorbed dose to water standards. We hope that in the near future users will be able to calibrate the brachytherapy sources in terms of an absorbed dose to water, the quantity of interest in the treatment, instead of an air kerma strength just as the calibration in the high energy photon and electron beam.
Brachytherapy ; Calibration ; Electrons ; Water