TSG ASHA 3D BT Treatment Planning System (RTPS) is computer software based electronic system that is used to simulate the application of radiation to a patient for a proposed radiotherapy treatment in order to pre-evaluate the total curative and harmful effects. It provides estimates of absorbed dose distribution in the patient using mathematical algorithms. A qualified person uses the information of absorbed dose distributions in planning a course of radiotherapy.

Safety concerns of the patient are due to inaccuracies in the input data, limitations of algorithms, errors in treatment planning process, and improper use of output data should the resulting data be used for treatment purposes. For protection against occurrence of such safety hazards, the ASHA RTPS has been tested for compliance with International Electrotechnical Commission Standard IEC 62083 on requirement for the safety of RTPS.

ASHA RTPS employs many types of input data, calculation algorithms and provides outputs in many forms. It follows ICRU recommendations on terminology and presentation of information to the user. Accompanying documents created by the system provide information for the user to make informed choices during the treatment planning process.

Brachytherapy Planning Functions
Supports Image guided planning functions. Radiation dose is visualized on orthogonal radiograph images of the patient volume of interest, as well as on CT / MRI images. Supports planning based on Ir-192, Cs-137, Co-60 and I-125 sources in linear or seed form. Additional sources like Pd-103 and Cf-252 are also supported by addition of isotope data in the library. Both long and short half-life sources are supported. Compatible with popular remote Afterloading units. User friendly image guided patient registration and storage, archival and retrieval of patient data. Functions and features implemented in the software are guided by ICRU recommendations. Customized pre-planning and optimization function to be available shortly. Please inquire for details.

Patient Data
Patient data is acquired from orthogonal radiographs of the volume of interest and CT/MRI images through a film scanner (flat bed A3 size scanner is used). Radiographs may be taken as orthogonal, semi-orthogonal or variable angle in flexible orientations with controlled geometry. DICOM images of radiographs are acquired directly from simulator equipment through a computer network or media exchange. Phantom application data is generated by software function.

CT Image
Supports Image guided planning functions. Radiation dose is visualized on patient images in 2D/3D. Brachytherapy plan consisting of source data and anatomical points of interest is registered with the CT/MRI image data set of teletherapy plan.

Applications
Applicators for HDR / MDR / LDR. Including manual applicators for Cs-137 and Ir-192 application are supported. Applications for Intracavitory / Interstitial / Intraluminal / Surface Moulds may be planned. Specific support for Manchester loading for intracavitory and Paris system for initerstitial applications is provided. Source activity is in Air Kerma Rate as per ICRU. Activity may also be specified in mCi or in MgRaEq, in which case, software coverts source activity to Air Kema Rate for dose calculations. Source activity decay correction is automatically computed and applied by the software. Applicator path and position of active sources are localized on the scanned radiograph image. Number of channels in the applicator and number of dwell positions within a channel are flexible. Applicator data stored in the library is used for planning the application. Points of interest are localized and displayed on the radiographs. Upto 45 points may be localized from the radiographs. Some of these points may be marked as prescription points. Average of dose these prescription points is used for dwell time computation. Additional points on the surface of the target volume and structures of interest are localized on the CT / MRI images, and transferred to the radiographic view of brachytherapy application. These are large numbers of points, and dose to these points is computed and displayed for evaluation. Template applicators are supported. Templates are maintained in the source library. User can create template for standardized treatments. Applicators with variable dwell time assigned to each source, different source strength for each source, and choice to make dwell position active / inactive are supported. Actual application data may be interactively edited by using a mouse cursor.

Dose Calculations
Linear source dose calculation algorithm is employed for planning with linear sources. Tissue absorption corrections to dose are computed with Meisberger polynomials or by employing user provided data. Geometric and dose point optimization is available for applicators supporting variable dwell time for each dwell position of the source in a channel. Dose calculation with shielded applicators is supported with sector shielding data. Dose is calculated with a variable grid size and displayed with a resolution of one mm or better. Radiobiological evaluation of dose using LQ model with user specified parameters for acute and late reactions, and TDF model of radiobiological dose evaluation is also supported.

Prescription
Choice of normalization methods is supported based on the type of application, such as basel dose or dose at Point “A”.

Dose Display. Dose is displayed on radiograph images (for AP and Lateral), CT/MRI images (for transverse) and in empty space (for any other orientation) as isodose lines with annotations as absolute dose. Planer view of any orientation may be selected for dose display. Source and applicator is displayed on top of radiograph image. Point dose, point coordinates, name of structure containing the point, density at the point, and distance from an arbitrary fixed point is automatically displayed at the mouse cursor position. Multiple views may be displayed with flexible sizing and positioning of each view on the screen. Centimeter scale is appended to the two edges of each view plane. DVH graphs for each structure, both integral and differential, is displayed / printed. DVH data is also available in MS Excel worksheet. Dose component in the DVH analysis may be absolute dose or radiobiological effective dose based on LQ model.

Output
Isodose plots in life size or film size. Transverse images are scaled. Complete prescription details in a computer file as DICOM RT objects.