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acrylic dual wedge
LCW-200P with XRV Scintillator Camera Phantom

The LCW-200 is an acrylic (PMMA) dual wedge that can be used to measure Proton beam and X-ray depth-dose relationships. It was designed to quickly provide accurate proximal edge measurements of an ion beam’s Bragg peak penetration range. The height of 212 mm allows proton beam equivalent penetration depths in water of up to 235 mm to be directly captured and measured.

The chevron wedges overlap so that measurements on the edge of one range can be duplicated at the beginning of the next. The wedge angle of 45 degrees enables symmetrical measurements to be made on each side of the center line and averaged for greater precision.

The 100 × 70 mm footprint allows the LCW-200 to be mounted securely above the scintillator of the XRV. The LCW-200P has wider chevrons (24 mm) and is recommended for the XRV-2000 Falcon, XRV-3000 Eagle, and XRV-4000. Mounting hardware firmly locks the LCW above the XRV target so that measurements can be easily made at any angle by rotating the phantom in its gantry cradle.

The acrylic (PMMA) composition of the LCW-200 has a water equivalent density of 1.17 for direct measurements of Bragg peak Proton depths up to 235 mm. More energetic beams can be accommodated by padding the bottom surface with additional acrylic or tissue equivalent plastic. The patent pending design may be enhanced with additional chevrons, so please contact us for custom configurations.

Features and Benefits:

  • Fast Bragg peak measurement of water equivalent Proton beam range up to 235 mm
  • 212 mm tall
  • Acrylic (PMMA) composition
  • Regular 100 × 70 mm and plus-size 100 × 140 mm footprints
  • Accuracy better than 0.5 mm
  • Measures Proton and X-ray beam depth-dose relationships
  • Mounting hardware available for XRV-2000/3000/4000
  • Easy handling for use at all gantry angles
  • Compatible with film
  • Automated image analysis and software measurement
  • 35 energy layer Excel analysis template provided
Standard dimensions total 200 millimeters tall by 100 millimeters wide by 70 millimeters deep. Six chevron wedges are set at a 45-degree angle, and the peak of each chevron is 20 millimeters below the next.
LCW-200 Dimension Diagram

treatment room laser alignment

LCW-200P with the XRV-4000 Scintillator Camera Phantom

The LCW-200P acrylic (PMMA) dual wedge has 24 mm thick chevrons yielding an overall footprint of 100 × 140 mm.

WinLVS BeamWorks Strata processing beams

Automated Capture and Measurement within WinLVS

The WinLVS capture software has a built-in scripting language that facilitates automatic real-time capture of the multi-energy even-dose delivery pattern needed for Bragg peak measurements.

After each layer has been delivered, WinLVS merges the captured PBS image streaks to form complete radiographs. Once the 35 layers of the plan have been delivered, the Bragg peak regions on the radiographs are isolated and measured with the CSV formatted data being output to file. This CSV file can then be imported into an Excel template where the Bragg peak penetration depths are calculated.


LCW-200P Chevron PBS Proton Beam Bragg Peak Data Summary

Average Chevron Bragg Penetration Depth (mm) vs. Proton Beam Energy (MeV)
line graph

y = 0.0232x1.7592
R2 = 0.9999

LCW-200P/XRV-4000 Data from two deliveries of the same 35 layer even-dose diagnostic plan starting at 189 MeV and ranging downwards to 121 MeV:
 Delivery A Data (BPD = Bragg peak Penetration Depth) 
LayerPlan Layer Energy (MeV)Post Snout Energy (MeV) ChangeChevron BPD (mm)ChangeMathematical BPD (mm)ChangeDelta BPD (mm)(Absolute value)Delivery B Delta BPD (mm)BPD Difference between Delivery A and B (mm)
1189187.2 229.209 230.5681 1.3590831.3590831.2199750.139108
2187.1185.3-1.9225.5437-3.6653226.465-4.103120.9212630.9212630.7804380.140824
3185.2183.4-1.9221.1806-4.36309222.3937-4.071261.2130981.2130981.0722810.140816
4183.3181.5-1.9217.66-3.52064218.3544-4.039320.6944180.6944180.8370440.142626
5181.4179.6-1.9213.8899-3.77006214.3471-4.00730.4571760.4571760.3858490.071327
6179.5177.7-1.9210.2054-3.68455210.3719-3.97520.1665230.1665230.3803640.213841
7177.5175.7-2206.2218-3.98356206.2223-4.149660.0004210.0004210.0716230.071201
8175.6173.8-1.9202.3213-3.90055202.3132-3.90906-0.008080.0080840.0075660.000518
9173.6171.8-2198.47-3.85133198.2334-4.07985-0.23660.23660.3081720.071572
10171.6169.8-2194.271-4.19894194.1895-4.0439-0.081560.0815560.063160.018397
11169.6167.8-2190.2904-3.98058190.1816-4.00785-0.108830.1088280.1085940.000233
12167.6165.8-2186.2387-4.05175186.2099-3.9717-0.028780.0287810.028810.000029
13165.6163.8-2182.3415-3.89721182.2744-3.93545-0.067020.0670230.0683090.001286
14163.5161.7-2.1178.203-4.13849178.1814-4.09309-0.021620.0216210.2699230.248302
15161.5159.7-2174.3163-3.88672174.3206-3.86080.0043030.0043030.0699780.065675
16159.9158.1-1.6171.2277-3.08857171.2583-3.06230.0305650.0305650.1022610.071697
17158.3156.5-1.6168.4256-2.80212168.2194-3.03884-0.206150.2061480.1345750.071574
18156.7154.9-1.6165.1103-3.31526165.2041-3.015310.0938070.0938070.1289880.035181
19155.1153.3-1.6162.4706-2.63967162.2124-2.99173-0.258250.2582510.1841270.074124
20153.5151.7-1.6159.3777-3.0929159.2443-2.96808-0.133430.1334340.0603790.073055
21151.9150.1-1.6156.6548-2.72291156.2999-2.94438-0.35490.3549010.2805480.074354
22150.3148.5-1.6153.4399-3.21493153.3793-2.92062-0.060590.0605940.0876390.027045
23148.1146.3-2.2149.8192-3.62067149.4024-3.97694-0.416860.416860.3429560.073904
24146.2144.4-1.9146.0767-3.7425146.0041-3.39826-0.072620.072620.0029410.069679
25143.6141.8-2.6141.6569-4.41986141.4087-4.59542-0.248180.2481760.0986410.149536
26141.4139.6-2.2137.6217-4.03518137.5699-3.83876-0.051760.0517580.0504770.001281
27139.1137.3-2.3133.5789-4.04278133.6056-3.964370.0266530.0266530.0270150.000362
28136.8135-2.3129.7561-3.82282129.6914-3.9142-0.064730.0647340.0117530.05298
29134.4132.6-2.4125.7952-3.96095125.6607-4.03068-0.134470.1344680.0953650.039103
30132.1130.3-2.3121.5329-4.26226121.8496-3.811060.3167330.3167330.3166230.00011
31129.7127.9-2.4117.5707-3.96217117.927-3.922590.3563110.3563110.356140.000171
32127.2125.4-2.5113.7647-3.80602113.9001-4.026950.1353760.1353760.2121730.076797
33124.8123-2.4109.7267-4.03804110.0912-3.80890.3645180.3645180.2879150.076603
34122.3120.5-2.5106.0684-3.6583106.1832-3.907960.1148570.1148570.1149990.000141
35121119.2-1.3103.5541-2.51426104.1752-2.007990.6211260.6211260.6209160.00021
 Average-3.92091 Average0.2694480.26250.065533
 Standard. Deviation.0.224626 Standard. Deviation.0.3314760.301521 
 Max.1.3590831.219975 
 Min.0.0004210.002941 
Total Depth: 125.6549 mm
Average Layer Depth: 3.695733 mm