Differences

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--- planning:userguide:tutorials:fraction_group [2017/05/08 21:17] – kerhart
+++ planning:userguide:tutorials:fraction_group [2021/07/29 18:28] (current) – external edit 127.0.0.1
@@ Line 1: / Line 1: @@
-====== Fraction Groups ======
+====== PBS Fraction Groups ======
 Defining //Fraction Groups// is the first step in the PBS Optimization process within Astroid. Most commonly, a fraction group is simply an arrangement of beams that will be used in a typical daily treatment fraction. The Fraction Group contains some basic group information, as well as Fraction Group level constraints and collections of //Beam Sets// and //Constraints// for each target of the fraction group. The //Beam Set// and various //Constraint// levels are key concepts within Astroid that allow for high levels of control over the Astroid PBS Optimization engine. Further details of these critical items are provided below and additionally, examples of some common cases and how fraction groups, targets, and beam sets can be constructed to meet the clinical needs of various clinical cases can be found in the [[planning:userguide:walkthroughs:prostate_plan|Prostate Plan Walkthrough]].
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   * **Prescription**: Prescription that the //Fraction Group// implements; note that only targets containing dose statements from this Prescription will be available when selecting the Target for the Fraction Group
   * **Number of Fractions**: The total number of fractions to be delivered for this //Fraction Group//; this is very important as it will determine the appropriate Monitor Units for the individual beams
   * **Type**: The delivery approach that will be used for the beams in the Fraction Group. Options for this include SFO, IMPT, and Advanced. If either SFO or IMPT are selected the Fraction Group user interface will remain in "Simple Mode", whereas selecting Advanced as the type will switch the interface to the "Advanced Mode"
 {{ :planning:userguide:tutorials:fraction_groups_types.png?650 |}}
@@ Line 17: / Line 17: @@
 Single Field Optimized treatments are created using this type option. Simply select //SFO// from the //Type// drop down and then add any number of beams and constraints. Each constraint will be equally divided among each beam during optimization. For example, if three beams are included in the Fraction Group and a PTV min constraint of 60 Gy(RBE) is added, then each beam will be individually set to have a constraint of 20 Gy(RBE) (60/3) when running the optimization.
+<WRAP center round info 60%>
+**Note:** A fraction group with only one beamset and a single beam will always be considered to be an SFO fraction group.
+</WRAP>
 ==== IMPT ====
 Intensity Modulated Proton Therapy treatments are created using this type option. Simply select //IMPT// from the //Type// drop down and then add any number of beams and constraints. These constraints will be applied to the collective (total) dose from all beams in the Fraction Group. Using the same example as the SFO section, if three beams are included and a PTV min constraint of 60 Gy(RBE) is added, then the total dose from the three beams must be above 60 at all points within the PTV, however, no restrictions are placed per beam, so that each beam is free to give any portion of the 60 Gy(RBE) dose. This allows for maximum flexibility in sculpting dose to the target, but generally at the expense of increased sensitivity to motion and patient positioning uncertainty.
+{{ :planning:userguide:tutorials:fraction_groups_simple_1.png?300 |}}
 ===== Advanced Type Fraction Groups =====
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     *  In other words, the Constraint dose is divided by the number of Beam Sets for the Target, so that both SFO and IMPT can be achieved
-=== Beam Sets ===
+==== Beam Sets ====
 The //Beam Set// is the lowest level unit for the Astroid PBS Optimizer and proper arrangement of the beams within a beam set allows for both Single Field Optimized (SFO) and Intensity Modulated Proton Therapy (IMPT) fields to be included within the same fraction. A careful review of the Beam Set Level (BSL) Constraints described above, should reveal how to properly arrange beams within Beam Sets to achieve a desired type of treatment. Since BSL Constraints are equally split and are then applied individually to each Beam Set, SFUD beams can easily be achieved by placing each beam in its own Beam Set. Conversely, IMPT beams are created when multiple beams are included within a single Beam Set. Further details of these two cases are presented below, as this will provide the information necessary to allow users to construct complex constraint relationships, which is the purpose of the Advance type UI.
-== SFO Beams ==
+==== SFO Beams ====
 Single Field Optimized treatment beams are produced by including each beam in a separate Beam Set. This is best understood by example. Suppose a target is intended to receive 20 Gy (2 Gy per day for 10 fractions) from a two beam Fraction Group using a SFO approach. This is achieved by specifying a min dose of 18 Gy and a max dose of 22 Gy using Beam Set Level Constraints. Now two beam sets are created, each containing a single beam, as shown below. Since the BSL constraints are split between the beam sets, this actually tells the optimizer that each beam must provide a min dose of 9 Gy and a max dose of 11 Gy (1/2 of the BSG constraint doses). Therefore, each individual beam will be providing coverage to the entire target as is expected for a SFO approach.
 {{ :planning:userguide:tutorials:fraction_group_sfo.png?200 | SFO Beam Sets}}
-== IMPT Beams ==
+==== IMPT Beams ====
 Intensity Modulated Proton Therapy treatment beams are produced by including all desired beams in a single Beam Set. This is again best understood by example. Suppose a target is intended to receive 20 Gy (2 Gy per day for 10 fractions) from a two beam Fraction Group using an IMPT approach. This is achieved by specifying a min dose of 18 Gy and a max dose of 22 Gy using Beam Set Level Constraints. Now one Beam Set is created, containing both beams, as shown below. Since there is only Beam Set, the BSL constraints will be applied to the combined dose from the two beams. Therefore, there are no guarantees regarding the uniformity of dose from either beam and instead there is simply the guarantee that the combined dose from the two beams meets the given constraints, thereby producing an IMPT treatment approach.
@@ Line 53: / Line 61: @@
 ===== Working with Fraction Groups =====
-  - Select the Create New Fraction Group button {{ :planning:userguide:tutorials:fx_group_create_new.png?300 |}}
+  - Select the Create New Fraction Group button
   - In the newly opened block the planner will:
     * Choose the color the fraction will be denoted in