Red+Group+QA

=Daily Simulator QA:=


 * __Procedures:__**

The goal of a CT-simulation QA program is to verify safe and accurate operation of the CT-simulation process as a whole. The QA program design should include tests which will assure perfect target and critical structure localization, and accurate placement of treatment beams (with respect to a volumetric CT-scan of a patient). For accurate patient treatment planning, the CT-scanner must provide high quality images, with geometrical and spatial integrity, and with a known CT number ~Hounsfield Unit (HU) to electron density relationship. The CT-scanner QA program should include tests to confirm that all three of the above conditions are met. The primary areas of focus for the CT-simulation QA program should be the imaging performance and geometric accuracy of the CT-scanner. The geometric accuracy and utility of the CT-simulation software, accuracy and image quality of DRRs, and accuracy and integrity of information transfer, between the various treatment planning and treatment delivery systems.1

The daily simulator QA starts with a tube warm up, followed by the fast calibration. A tube warm up brings the tube up to a safe and tolerable operating temperature to prevent unnecessary wear on tube components. Fast calibration adjusts the collimator, gantry balance, and ensures that the mylar window in the bore is clean. If it is dirty a warning is given to clean it.
 * Tube warm up**

The lasers are checked using a tabletop box phantom. This phantom is aligned to the external LAP lasers and a scan is performed to verify the distance the tabletop travels at the beginning of scans. The distance between the external and internal points is 500 mm. The scan tests to ensure that the table is actually moving 500 mm when asked to. Using a virtual simulation software system (Advantage Work station) the isocenter is moved to a BB located on the phantom. The isocenter coordinates are then sent to the lasers in the room which moves in the anterior, posterior and lateral directions. The superior and inferior movements are controlled by the therapist performing QA. Also on the laser phantom there are two fiducial markers spaced 50 mm apart from the center. This verifies that the LAP lasers are correctly represented the isocenter set on the CT scan.
 * LAP Laser system check **

Once the initial checks have been done, a water phantom with a diameter of 30 cm from the manufacture is attached to the table. A scan is taken in 3mm slices through the whole phantom to check the images for noise and uniformity ( the consistency of the scan and radiation emitted from the tube). Within the phantom there are several region's of interest (ROI's) made up of varying electron density- made to represent variations with a patient. Measuring CT Houndsfield Units at different ROI's allows the evaluation of the mean and standard deviation of HU's in the specified area. The CT numbers are then measured at the center, at the water hole, and at the Teflon pin, and compared to known values. The tolerance for the CT number accuracy and uniformity are ±5 HU. The diameter of the imaged phantom is also measured in the x and y directions to confirm spatial integrity. Acceptable limits are ± 1 mm.
 * Water phantom**

Philips Brilliance Big Bore CT Sim- available at: []
 * __Types of equipment__:**

LAP Lasers: 2mm Water ROI: 3.5 +/- 4 HU Teflon ROI: 920 +/- 50 HU Nylon (center ROI) 14000 +/- 1000 Ct number: 2.3 +/- 4 HU CT uniformity: 0.3 +/- 4 HU CT noise: 3.7 +/- 0.4 HU Low contrast: 4.5 +/- 1.2 HU
 * __Tolerances (expected)__:**2

//Image 1: Philips Brilliance Big Bore CT//
 * __Images:__**

//Image 2: Philips Brilliance water Phantom//

//Image 3: Philips Brilliance phantom attached to table//

//Image 4: CT number check using the Philips body phantom //

 //Image 5: Philips Brilliance Big Bore CT service call//

__References:__ 1. Mutic S, Palta JR, Butker EK, et al. Quality assurance for computed-tomography simulators and the computed-simulation process: Report of AAPM Radiation Therapy Committee Task Group 66. College Park, MD: American Association of Physicists in Medicine; 2003. 2. Brilliance CT Big Bore Configuration. Technical Reference Guide. 2010.

=Monthly Simulator QA:=

__ **Procedures**: __

Quality assurance (QA) for computed tomography (CT) simulators are performed to ensure the proper functionality of the system and for the safety of the patients. The physicist is responsible for “the implementation, performance, and periodic review of the CT simulation QA program.”1 The physicists at our institution performs a monthly QA on our Philips Brilliance CT simulator. However, depending on the facility, the dosimetrist may be responsible for performing certain QA tasks assigned by the physicist. The monthly QA involves mainly testing for proper mechanical alignments and the integrity of the scanned images consisting of 6 separate tests. All collected data are recorded on the CT monthly QA form as well as an indication of a pass or fail result, the physicist’s initials and the date the test was performed.

TEST 1: Table Vertical and Longitudinal Motion PURPOSE: To verify that the vertical and longitudinal table motion according to the digital indicators are accurate and reproducible. DEVICE: Stainless steel ruler <span style="font-family: Arial,Helvetica,sans-serif;">PROCEDURE: A stainless steel ruler is placed longitudinally on the tabletop. The table is moved in and out of the gantry and the distance traveled in one direction is measured by using the laser projection on the ruler and compared to the table indicator. This test is repeated for the vertical motion with the ruler positioned in the vertical position. The measurement recorded by the ruler and the one shown on the table indicator is recorded and compared. Both setups have a tolerance of ±1 mm over the range of table motion.

<span style="font-family: Arial,Helvetica,sans-serif;">TEST 2: Laser tracking <span style="font-family: Arial,Helvetica,sans-serif;">PURPOSE: To verify that the external laser motion is accurate and reproducible. <span style="font-family: Arial,Helvetica,sans-serif;">DEVICE: Stainless steel ruler, Laser QA device, LAP laser PDA <span style="font-family: Arial,Helvetica,sans-serif;">PROCEDURE: The lateral and sagittal lasers are aligned with the ‘laser QA device’. See Figure 1. The vertical laser is then positioned at 0.0 mm. The sagittal laser is then aligned to three known peg positions on the laser QA device with the following positions: left (125.9), central (1 mm) and right pegs (-124.1 mm). Readings on the laser PDA are recorded. The laser positions for the upward and downward movement of the table were tested by placing the vertical ruler on the table and moving the laser up and down by 10cm as indicated by the ruler. Readings on the laser PDA are recorded. Laser PDA readings are compared to the pegs dimensions. These positions have an allowable tolerance of ±2 mm.

<span style="font-family: Arial,Helvetica,sans-serif;">TEST 3: Alignment of external lasers with table motion <span style="font-family: Arial,Helvetica,sans-serif;">PURPOSE: To verify that the external lasers are parallel to the table motion. <span style="font-family: Arial,Helvetica,sans-serif;">DEVICE: Two small rulers <span style="font-family: Arial,Helvetica,sans-serif;">PROCEDURE: The table is positioned in the middle of the vertical range of motion indicated by the known 150mm vertical position reading on the display. Two small rulers are placed on the table at the zero position and aligned orthogonal to the axial and sagittal planes. (See Figure 2) The table is then moved up and down over the full range of the table motion. The maximum longitudinal (z) and lateral (x) deviation from the center is recorded. Next, one of the rulers are positioned in the vertical direction and the other orthogonal to the vertical plane. The table is moved in and out over the full range of motion and the maximum vertical (y) and lateral (x) deviation from the center are recorded. This test has a tolerance of ±2 mm.

<span style="font-family: Arial,Helvetica,sans-serif;">TEST 4: Alignment of external lasers with imaging plane <span style="font-family: Arial,Helvetica,sans-serif;">PURPOSE: To verify that external lasers are parallel and orthogonal with the scan plane and intersect in the center of the scan plane. <span style="font-family: Arial,Helvetica,sans-serif;">DEVICE: Laser QA device, boxes, BBs <span style="font-family: Arial,Helvetica,sans-serif;">PROCEDURE: A custom made box of 40 cm in height is placed on the table. Two fiducial markers are placed at the top and at the bottom of the box aligned to the vertical laser. An axial CT scan is taken with specifications of 16×0.75 mm collimator, 0.75 mm contiguous slice width, 600 mm FOV. If the two fiducial markers appear on the same plane, this confirms that the vertical laser is parallel to the scan plane and gantry tilt is negligible. Next the laser QA device previously used in Test 2 is placed at the H2-H3 table position. It is then aligned to the external lasers. The longitudinal table position is set to zero by pressing the button at the gantry control panel. Two fiducial markers are placed on the table positioned about 50cm apart longitudinally along the sagittal laser projection. A helical CT scan is taken of the two fiducial markers with 8×3 mm collimator at 5mm slice width. If the two fiducial markers have the same vertical/lateral position in the image, this confirms that the sagittal laser is orthogonal to the scan plane. Lastly, a helical CT scan is taken enclosing the three pegs of the laser QA device (~3 cm length), with 16×0.75 mm collimator at 0.8mm scan width. The longitudinal coordinates of the three pegs should be within ±2 mm from the known dimension of -500mm. This indicates that the transverse laser is parallel to the scan plane and accurately spaced from the scan plane. If the position of the central peg is at zero, this confirms that the vertical/horizontal lasers intersect in the center of the scan plane.

<span style="font-family: Arial,Helvetica,sans-serif;">TEST 5: Orientation of tabletop with respect to imaging plane <span style="font-family: Arial,Helvetica,sans-serif;">PURPOSE: To verify that the tabletop is leveled and orthogonal with respect to the imaging plane <span style="font-family: Arial,Helvetica,sans-serif;">DEVICE: Laser QA device <span style="font-family: Arial,Helvetica,sans-serif;">PROCEDURE: The laser QA device is placed at the foot of the table at positions F3-F4. A CT scan is taken and using the scanner cursor tool, the location of the central cross (See Figure 3) is measured and compared to the central cross location from the image with the laser QA device at the gantry side of the table at position H2-H3. The x and y coordinates of the gantry side and at the foot of the table should all be ±2 mm to be within tolerance.

<span style="font-family: Arial,Helvetica,sans-serif;">TEST 6: Image performance <span style="font-family: Arial,Helvetica,sans-serif;">PURPOSE: To verify spatial integrity, CT number accuracy and uniformity. <span style="font-family: Arial,Helvetica,sans-serif;">DEVICE: Philips phantom <span style="font-family: Arial,Helvetica,sans-serif;">PROCEDURE: In this test, a Philips phantom is aligned to the external lasers and then an axial scan of the phantom is taken. The diameter of the phantom in both the x and y directions is measured and compared to the known diameter of 30cm to verify the spatial integrity. The diameter measured should be within the tolerance for spatial integrity of ±1 mm. Using the same scan from the previous test, the mean CT numbers are measured for a 1cm2 region at the center and at four locations in the periphery of the Nylon body to confirm uniformity. The tolerance for CT number uniformity is ±5 HU. The area profile for the water hole, nylon body, and Teflon pin is then measured and should be within 0±4HU, 100±15HU and 920±50HU, respectively.

__** Images: **__

//Figure 1: Laser QA Device//

//Figure 2: Test 3 Ruler Setup//

//Figure 3: Test 5 Central Cross Measurement//

//Figure 4: Test 5 Central Cross Measurement//

__**<span style="font-family: Arial,Helvetica,sans-serif; font-size: 110%;">Reference: **__
 * 1) <span style="font-family: Arial,Helvetica,sans-serif;">Mutic S, Palta JR, Butker EK, et al. //Quality assurance for computed-tomography simulators and the computed-simulation process: Report of AAPM Radiation Therapy Committee Task Group 66//. College Park, MD: American Association of Physicists in Medicine; 2003.

=SRS QA:=

__**Procedures:**__

A Winston-Lutz test is completed each day a patient is treated with SRS. The Winston-Lutz test is done to ensure isocentric accuracy. The Winston-Lutz phantom contains a sphere, made of stainless steel. This is attached to the end of the treatment table and secured by pulling down on the locking rod. The sphere is lined up using the gantry rotated to four different angles: 180 degrees, 270 degrees, 0 degrees and 90 degrees. FIne adjustments may be made using the X, Y, and Z knobs located on the phantom. Once the sphere is lined up to the gantry, the room lasers are then adjusted (the lasers are used because that is what the imaging system ExacTrac uses). Film is attached to the EPID. A field size of 1.2 x 1.2 is set and the sphere is imaged at 180, 270, 0 and 90 degrees on the gantry with the couch at 0. Than the couch is set at 0, 90 and 270 degrees and the sphere is imaged again with the gantry at 0 and 180 degrees. The sphere is measured and should be <1 mm in diameter.

Using cones to treat SRS utilizes an addition step. This method includes the BrainLab Collimator Mount. Slide the BrainLab Collimator Mount onto the collimator housing on the accelerator. Tighten the two knobs to secure it in place. Mount BrainLab's 30 mm conical collimator to the collimator mount and secure it in place by screwing on the ring. Ensure that it is tight and the cone is flush against the Collimator Mount. The EPID is used to image at a vertical distance of 70 cm from isocenter. MV images are acquired at 8 different angle arrangements (4 require room entry to preform couch kicks).

An analysis can be done using a "Simplify" database. This database will generate a report of the SRS QA. It should be confirmed that the average total shift in mm is < 1 mm.

**Daily QA-**

 * Warm-up
 * Door interlock
 * Emergency off
 * Video monitor
 * Radiation monitor

**QA done weekly, or before a patient is treated-**

 * Couch release
 * Helmet microswitches
 * Helmet trunions
 * Automatic positioning system

Daily QA-

 * Linac output
 * Voltages and currents
 * Robot perch position
 * Safety interlocks
 * Test coincidence of treatment beam with imaging center (AQA)


 * __Types of equipment__**:
 * BrainLAB Winston-Lutz phantom
 * Gamma Knife []
 * Cyberknife []

__**Tolerances (expected):**__
 * isocenter accuracy: <1mm

__**Images:**__

//Image 1: The setup from two different views for a Winston-Lutz test with the sphere (simulated target ball) at the isocenter.1//

//Image 2: Images taken of sphere showing <1mm diameter//

//Image 3: Gamma Knife// //Image 4: Gamma Knife with Focusing Helmet// //Image 5: Focusing Helmets for the Gamma Knife// //Image 6: Cyberknife//

__**References:**__

1. Zheng C, Wang Z, Ma J, et al. Six degrees of freedom image guidance for frameless intracranial radiosurgery with kilovoltage ConeBeam CT. //J of Nucl Med and Radiat Ther//. 2010; 1(101). doi:10.4172/2155-9619.1000101. 2. Shepard D. Gamma Knife and Cyberknife: physics and quality assurance. Available at: []. Accessed October 25, 2012.

=**Brachytherapy:**=

__**Procedures:**__

**__ High Dose Rate (HDR) DAILY __**

 * Emergency Procedures -** verify that emergency procedures are printed out and readily available at HDR treatment console


 * Video Monitor -** verify that video monitors are functioning properly and that you can see clearly into the HDR suite


 * Door Radiation Sign -** verify that there are yellow "Caution Radioactive Material" and "Caution High Radiation Area" signs on HDR suite door


 * Console Activity** - verify the following in Ocentra software:
 * Print Pre-treatment report
 * Verify date and time on report and HDR console computer
 * Verify source activity listed on Pre-treatment report with source decay printout


 * Distance Measuring Ruler** - connect distance measuring ruler to HDR unit


 * Emergency Container** - check that emergency containers are available, empty, and located close to HDR afterloader


 * Unit Emergency Stop** - verify the following:
 * Hit emergency stop button on HDR unit
 * See that "Emergency stop ACTIVE" interlock has tripped in Ocentra software and HDR control console
 * Turn reset key on console and check "Emergency stop INACTIVE" indicator


 * Room Emergency Stop -** verify the following:
 * Hit emergency stop button located just inside suite door
 * See that "Emergency stop ACTIVE" interlock has tripped in Ocentra Software and HDR control console
 * Turn reset key on console and check "Emergency stop INACTIVE" indicator


 * Door Interlock -** verify the following:
 * While suite door is open, see that "Door OPEN" interlock has tipped in Ocentra software
 * Close suite door, check "Door CLOSED" indicator


 * Interrupt Button** - Run QA plan by turning console key to "Operation". Verify the following:
 * Run dummy cable, press "Interupt" button on cosole (source should retract)


 * Console Emergency Stop** - run "30 seconds" QA plan in Oncentra. Verify the following:
 * Once source is out and a few seconds have passed, press the emergency stop buttom on the HDR console (source should retract)
 * See that "Emergency ACTIVE" interlock has tripped in Ocentra software
 * Once source is fully retracted and interlock has been tripped, turn reset key on the HDR console


 * Audio Check** - verify the clicking sound of the interlock clearing through the audio monitor system


 * Prime Alerts** - Ready a stop watch. Press start button on HDR console, verify the following:
 * When source is out of the safe and the gold crank has stopped turning, start the stop watch
 * While radiation treatment time runs out, check that prime alerts are working inside the suite (via video camera) and outside the suite


 * Source Positioning Indicator** - verify that the souce position indicator is on during treatment


 * Timer Accuracy** - once source begins to be withdrawn, stop the stop watch. Verify that the time on the watch closely matches the time that was remaining on the radiation treatment plan


 * Source Positioning** - In Ocentra software, verify the following:
 * Enter a known treatment distance that the source should travel, press start on the treatment console
 * Once the source has run, been retracted and prime alerts stop flashing, enter HDR suite with portable survey meter
 * Check that the end of the position indicator in the distance measuring ruler is 2mm above the chosen treatment distance (2mm offset accounts for the 4mm source length


 * Final Reading** - Take a reading with the portable survey meter near the HDR unit. Record the reading.

//Image 1: QA done before the treatment of a patient//

**__ High Dose Rate (HDR) MONTHLY __**

 * Emergency Equipment Readiness**- the following should be present:
 * Emergency Kit
 * Emergency Container
 * Emergency Procedures
 * Flashlight/Battery check- ensure in working condition


 * Equipment Readiness**- the following should be present:
 * Operator's Manual
 * Survey Meter/Battery check- Do battery check and ensure registering radiation when positioned on the surface of the afterloader
 * Printer- must have paper
 * Stopwatch


 * Safety Checks**- the following should be functional:
 * Audio/Visual Communications System- ensure the video monitor and audio is working properly
 * Key Interlock Test (prior and during treatment)- if key not turned to proper position on afterloader, the key image on the console should be red (cannot extend source), if key turned to the off position during treatment, source should retract immediately
 * PrimAlert (AC power On&Off)- red light should blink when source is out (radiation is present)
 * Unit UPS Check- unplug the afterloader while source is out to ensure backup battery will power the afterloader until treatment is complete
 * Emergency Stop- ensure the emergency stop buttons are functioning. There are 3 button locations: afterloader, console and independent. When pushed, the emergency stop button should retract the source into the afterloader immediately.
 * Catheter Misconnect Test- test to ensure the afterloader does not extend source when a catheter is not properly connected. The light should be RED on the afterloader showing the wrong connection. (When connected properly, light will be GREEN)
 * Display Panel- ensure the panel is displaying correct operation
 * Afterloader and Console Indicator Lights- lights should blink when source is out and treatment is in progress
 * Door Interlock- test to ensure when the "open door" button is activated, the source is immediately retracted into the afterloader.


 * Mechanical Checks-** the following should be correct:
 * Radiographic Marker Alignment Test- use radiographic film to test the source size and position. Tape radiochromic film to table and tape catheter on top of the film. Mark the tip of the catheter on the film for a landmark point. Send out the source to planned positions, some 1 cm apart and some 2 cm apart. The tip of the source should be 1cm from the mark made on the film. This can be physically measured.

//Image 1: Radiochromic film illustrating source positions//


 * Timer Accuracy/Linearity
 * Correct Date/Time in computer
 * Position Verification Test (PVT)- ensure the source travels to the correct planned positions in the catheter, 80 and 140 cm, the ranges used for treatment
 * Brachy Check in Brachyvision

__**Types of equipment:**__

Standard Imaging website:
 * [|www.standardimaging.com/products.php?id=6]

__**Tolerances (expected):**__

Tolerance=Present
 * Emergency Equipment Readiness**:

Tolerance=Present
 * Equipment Readiness**:

Tolerance=Functional
 * Safety Checks**:

Tolerance=Correct
 * Mechanical Checks**:
 * Position Verification Test: Tolerance=1mm
 * Radiographic Marker Alignment Test: Tolerance=1mm

__**Images:**__



//Image 2: IVB 1000 well chamber//

__**References:**__

=Conventional Simulator:=

__**Procedures:**__

The purpose of the daily QA is to ensure that the unit is both functional and accurate prior to patient use focusing on mainly the mechanical aspects of the device. Whereas the monthly quality assurance will analyze each specific feature of the machine both mechanical and imaging this takes more time and attention. The time frame for each procedure should be 10 to 15 minutes for the daily QA and 1 to 2 hours for the monthly.

__**Daily qa procedures:**__
 * Move table from rest positon to 00
 * Raise table so that FAD (Field Axis Distance) readout is 100cm
 * Set couch top to100cm using ODI light.
 * With tape measure record actual distance
 * Set delineator wires to 10x10 then place graph paper with defined 10x10 square on table. Record results from both digital read out and measurements from graph paper.
 * Set laser test tool on table and align with room lasers and cross hairs from simulator head. Rotate gantry to 900, 2700 and 1800 to check cross hairs on tool and note alignment of sagittal and axial room lasers.
 * __Tolerances:__**
 * ODI +/- 1mm
 * Field size +/-0.2cm
 * Room lasers +/- 2mm

__**Monthly qa:**__ __**Mechanical checks:**__
 * FAD readout accuracy
 * Digital readout mechanical readout
 * <span style="font-family: 'Calibri','sans-serif'; font-size: 15px;">Optical distance indicator (ODI)
 * Measured field size
 * Digital readout
 * Gantry, collimator angle indicators
 * Gantry angles (180,270,360,90)
 * collimator angles (90,180,270)


 * [[image:uwlmedicaldosimetry2012/sim 007.jpg width="560" height="451" align="left" caption="Gantry angle check vs readout"]][[image:uwlmedicaldosimetry2012/sim 002.jpg width="603" height="450" caption="Comparison of digital readout vs. mechanical measurement. "]]


 * Cross-hair centering


 * Light vs. radiation congruence (60kVp with 24mAs) 100SFD




 * Couch position (absolute and relative positions)
 * Longitudinal
 * Lateral
 * Vertical
 * angle
 * Room lasers
 * Rt transvers overhead sagittal
 * Rt coronal overhead transverse
 * Lt transvers sagittal
 * Lt coronal
 * Review field service reports
 * Review daily QA log book documentation.


 * __Safety interlock checks:__**
 * Emergency collision avoidance
 * Touch guard (touch during rotation)
 * Collimator head (touch during rotation)
 * Flat panel (touch during rotation)
 * Door (open during “beam on”)


 * DTI distortion check
 * 1) Set table to 100.0cm
 * 2) Set flat panel image detector to 165cm or (153cm or 140cm)
 * 3) Place DTI test tool on table and align cross hairs to cross hairs on device
 * 4) Set
 * 5) field size to 15x15 with delineator wires.
 * 6) gantry angle to 1800
 * 7) collimator angle to 1800
 * 8) move image detector to center chamber position
 * 9) fluoro, ABS 1 and take fluoro image
 * 10) Once image has been taken, in Simplicity use measurement tool for distance between tow dots of the 10x10 and 5x5 square pattern and record results. Magnification factor should be determined at this stage to be used later.
 * 11) print images to paper
 * 12) save images and print to KODAK
 * 13) on film measure field size defined by wires after demagnification


 * __Types of equipment:__**
 * 1) metric ruler
 * 2) graph paper
 * 3) level
 * 4) DTI test tool
 * 5) Laser alingment cube
 * __Tolerances (expected):__**
 * Digital read out vs. mechanical +/- 1mm
 * Optical distance indicator (ODI) +/-2mm
 * Gantry/ Collimator angle measured vs. readout +/- 0.5 degree
 * Cross hair centering +/-2mm
 * Light/ Radiation congruence +/- 2mm or +/-1%
 * Couch position vs. measured +/-2mm
 * Room lasers +/-2mm
 * Collision avoidance = functional
 * DTI tool vs. film +/-2mm
 * __Images:__**

//Image 1: Conventional Simulator//



//Image 2: Varian Ximatron// References: