Recent developments and best practice in brachytherapy treatment planning

Abstract

Brachytherapy has evolved over many decades, but more recently, there have been significant changes in the way that brachytherapy is used for different treatment sites. This has been due to the development of new, technologically advanced computer planning systems and treatment delivery techniques. Modern, three-dimensional (3D) imaging modalities have been incorporated into treatment planning methods, allowing full 3D dose distributions to be computed. Treatment techniques involving online planning have emerged, allowing dose distributions to be calculated and updated in real time based on the actual clinical situation. In the case of early stage breast cancer treatment, for example, electronic brachytherapy treatment techniques are being used in which the radiation dose is delivered during the same procedure as the surgery. There have also been significant advances in treatment applicator design, which allow the use of modern 3D imaging techniques for planning, and manufacturers have begun to implement new dose calculation algorithms that will correct for applicator shielding and tissue inhomogeneities. This article aims to review the recent developments and best practice in brachytherapy techniques and treatments. It will look at how imaging developments have been incorporated into current brachytherapy treatment and how these developments have played an integral role in the modern brachytherapy era. The planning requirements for different treatments sites are reviewed as well as the future developments of brachytherapy in radiobiology and treatment planning dose calculation. CHANGES AND DEVELOPMENTS IN TREATMENT PLANNING TECHNIQUESWithin the past few decades, there have been some major changes to the way brachytherapy treatments are both planned and delivered, and the introduction of modern, three dimensional (3D) imaging techniques have contributed significantly. In the 1930s, before the advent of planning computers, treatment planning was carried out by simply following a set of rules according to a dosimetry system such as the Manchester system. [1][2][3] This system was originally developed for use with radium sources and provided information, in tabular form, for the dose specification and distribution of sources and was used for many years. An increase in radiation safety awareness in the 1970s and 1980s led to a decline in the use of radium in favour of the relatively newer and safer radioisotopes such as caesium-137 and iridium-192. Over the same period, technological advances in afterloading techniques and the wider implementation of computerized planning using planar radiographic imaging were being implemented in an attempt to verify the applicator or catheter positions and calculate patient-specific dose. Alongside these advances, the need to compare patients' treatments with those from other treatment centres was being recognized as an important scientific standardization of treatment. The International Commission on Radiation Units and Measurements (ICRU) reports 38 and 58, 4,5 details t...

Design and validation of a surgical navigation system for brachytherapy based on mixed reality

“…Next, the tumor target area is delineated, the needles and seeds are arranged, and the radiation dose is calculated. Then, the software will automatically export the database and calculate the depth of the needle and skin …”

“…Then, the software will automatically export the database and calculate the depth of the needle and skin. 32 Step 3: Users perform pattern recognition and registration. The transformation between the medical coordinate system and the HoloLens coordinate system must be performed to calculate and fuse all information onto the patient.…”

Electronic brachytherapy—current status and future directions

“…[3][4][5][6][7][8] The past decade has seen the development of a new form of treatment, termed electronic brachytherapy (EB), 9 and there are now .400 systems worldwide. These miniature X-ray sources, operating at low kilovoltage energies, have many of the advantages of established radiotherapy approaches, but with further benefits of their own ( Table 1).…”

Three‐dimensional‐printed vaginal applicators for electronic brachytherapy of endometrial cancers

“…Postoperative radiation therapy for endometrial cancer includes external radiation therapy and brachytherapy. There has been much evidence reported regarding advantages of brachytherapy over external radiotherapy, including economic feasibility and convenience of radiation protection . Furthermore, because 75% of pelvic relapses are specific to the vaginal region, postoperative vaginal brachytherapy is an appropriate option for the patients …”

“…There has been much evidence reported regarding advantages of brachytherapy over external radiotherapy, including economic feasibility and convenience of radiation protection. 4,5 Furthermore, because 75% of pelvic relapses are specific to the vaginal region, postoperative vaginal brachytherapy is an appropriate option for the patients. 6 Postoperative vaginal brachytherapy is typically performed with radionuclides such as Ir-192 delivered by a high-dose rate (HDR) afterloader.…”