Skin Brachytherapy: The Manchester Approach
David Wood Lynsey Hamlett
Acknowledgements• The Brachytherapy Team at The Christie, Manchester
• Special Thanks for the use of slides to:
• Sally Baker, Christie Medical Physics and Engineering• Tony Stanton, Mould room Supervisor (Ret)
Radiation modalities: depth dose
0%
20%
40%
60%
80%
100%
120%
0 10 20 30 40
Dos
e (%
)
Depth (mm)
% Depth Dose for different modalities
40kV Superficial 4cm
6MeV Electrons 10cm
Brachytherapy mould
Brachytherapy• Can position source to precisely cover treatment area• Conformal dose distribution with small effective penumbra• Relative dose at depth can be controlled by adjusting height of source
dwells above skin surface• Due to close source to skin distance, depth dose profile falls off
quickly sparing tissue at depth.• Can account for surface curvature
The Christie NHS Foundation Trust
Evolution
Slides courtesy T. StantonMould Room Supervisor (Ret.)
The Christie NHS Foundation Trust
1905Photograph showing the method of strapping on
small tubes of radium to the skin to treat malignancies.
Metzenbaum, Myron (1905). "Radium: Its value in the treatment of lupus, rodent ulcer, and epithelioma, with reports of cases". International clinics (J.B. Lippincott) 4:14: 21-31.)
The Christie NHS Foundation Trust
1922–1923 at the Institut Curie, Paris
a) Patient before radium treatment, March 1922.b) Patient with radium applicator in the treatment position, February 1923. c) Patient follow-up later in 1923.Br J Radiol. 1998 Dec;71(852):1229-54.The discovery of radium in 1898 by Maria Sklodowska-Curie (1867-1934) and Pierre Curie (1859-1906) with commentary on their life
and times.Mould RF.
http://www.ncbi.nlm.nih.gov/pubmed/10318996http://www.ncbi.nlm.nih.gov/pubmed/?term=Mould%20RF%5BAuthor%5D&cauthor=true&cauthor_uid=10318996
The Christie NHS Foundation Trust
R. F. Mould “A Century of X-Rays and
Radioactivity in Medicine: With Emphasis on Photographic Records of the
Early Years” (1993)
The Manchester System
• Started with Radium sources • Published rules from Paterson-Parker, compiled in
Radium Dosage: The Manchester System (Meredith 1938)• Distribution rules to obtain uniform dose distribution• Tabulated data for calculating treatment time
The Manchester system• Aim is deliver uniform skin surface dose• Regular source positions around circumference of area• For large area need % activity in centre
The Christie NHS Foundation Trust
Birth of the Mould Room
• Radium first used in the early 1900’s
(first used in Manchester 1903)
• Moulds followed very quickly after that
• Mould rooms well established by 1920’s
Treatment depth• Expressed as ‘80% depth’• 100% is the average dose across skin surface• 80% should cover disease plus a 1mm depth margin
Source heightSkin surface (100%)80% depth
The Manchester SystemHeight above skin to place sources determined by the treatment depth required• Governed by the inverse square law• Sources placed higher above skin to achieve greater
relative dose at depthSource height
Separation of 100 and 80%
isodoses5mm 0.6mm
10mm 1.3mm
20mm 2.5mm
10mm source height
Adapted for HDR afterloadingPosition HDR source in
plastic catheters according to distribution rules around circumference and centre
spot if needed
Ensure HDR source height and spacing positioned
accurately
Curved treatment areas• Manchester system ‘can be used’ for curvature less than
½ cylinder
Convex surface results in sources splaying at treatment height
Surface dose profile from centre to periphery
80
85
90
95
100
105
110
0 2.5 5 7.5 10 12.5% S
urfa
ce d
ose
(cGy
)
Dose profile (mm)
Flat geometry
Curved surface
7%13%
Centre Periphery
Chart1
12.512.5
1010
7.57.5
55
2.52.5
00
Flat geometry
Curved surface
Dose profile (mm)
% Surface dose (cGy)
95.71
83.41
101.782
89.176
103.432
93.018
102.624
96.498
101.396
95.078
100.828
94.14
Sheet1
R (mm)Dose (cGy)
Flat geometryCurved patient surface
12.5478.55417.05-12.85132170195.7183.41
10508.91445.88-12.3852940599101.78289.176
7.5517.16465.09-10.0684507696103.43293.018
5513.12482.49-5.9693638915102.62496.498
2.5506.98475.39-6.2310150302101.39695.078
centre0504.14470.7-6.6330781132100.82894.14
radial distance from centre (mm)
Flat geometry plan
Dose(cGy)
0504.14
0.5504.3
1504.7
1.5505.31
2506.05
2.5506.98
3507.96
3.5509.12
4510.42
4.5511.78
5513.12
5.5514.39
6515.46
6.5516.37
7516.98
7.5517.16
8516.9
8.5515.98
9514.43
9.5512.1
10508.91
10.5504.8
11499.74
11.5493.66
12486.58
12.5478.55
507.5342307692
Sheet1
Flat geometry
Curved surface
Dose profile (mm)
% Surface dose (cGy)
Sheet2
Sheet3
Array style treatments
• Activate dwells above whole treatment area and with a margin as needed to cover target area
• Adjust dwell weightings to achieve uniform dose distribution across skin surface
• More flexible optimisation• 80% depth doses altered from Manchester system, dependent on
relative weightings within array
system array
Array-style depth doses• Minimal differences seen with different step sizes• Slight differences in depth doses compared with
Manchester System (due to source/dwell weighting arrangement)
The array is positioned at a height using thermoplast bolus material
Optimised weightings• Optimise to give uniform dose to skin surface• Within an individual catheter the dwell weightings are
lowest in the centre• Mimics peripheral loading of classical Manchester System
Dose at depth
Chart1
000
111
222
333
444
555
666
777
888
999
101010
111111
121212
131313
141414
151515
161616
1717
1818
1919
2020
2121
22
23
24
25
26
Source height above skin surface
10mm source height above skin
15mm source height above skin
20mm source height above skin
Depth (mm)
% of skin surface dose
% dose at depth (4cm diameter circle)
1
1
1
0.9259496099
0.9334194024
0.9394250513
0.8593170482
0.8727406861
0.8837268994
0.7986954854
0.8168572482
0.8323921971
0.7437012406
0.7657690889
0.784650924
0.6934390587
0.7185540391
0.7407597536
0.6472694718
0.6750276651
0.6999486653
0.6051924799
0.635005533
0.6622176591
0.5664407213
0.5981187754
0.6273100616
0.5310141962
0.5638140907
0.5947125257
0.4982734365
0.5322759129
0.5644250513
0.4680905487
0.5029509406
0.5361909651
0.4403376391
0.4758391737
0.5097535934
0.4147589206
0.4507561785
0.4853696099
0.3909707124
0.4273330874
0.4622689938
0.369100908
0.4055699004
0.4409650924
0.3487658268
0.3852821837
0.420687885
0.3299654687
0.3662855035
0.3125719401
0.3487642936
0.2963294539
0.3321652527
0.28123801
0.3168572482
0.2671697148
0.302286979
0.2539966748
0.2418467835
0.2303363601
0.219721192
0.2096175982
Sheet1
4cm circle
mmxtrahl
01.000203.90E+00
50.581213.55E+00
100.370223.14E+00
150.254232.81E+00
200.179242.52E+004x4 Brachy array centred on 0,0,0 in x z plane
250.130252.30E+00normalised atsource height above skin surface
300.097262.08E+00xyz-10-15-20depth (mm)-10-15-20
350.073271.90E+000-100-100.1100.1100.00%130.76%168.21%0100.00%100.00%100.00%
400.056281.75E+000-110-94.6594.6594.56%123.64%159.05%194.56%95.00%95.23%
450.043291.61E+000-120-89.6389.6389.54%117.09%150.61%289.54%90.29%90.71%
500.034301.48E+000-130-84.9784.9784.89%111.00%142.78%384.89%85.87%86.44%
550.026311.37E+000-140-80.6280.6280.54%105.32%135.47%480.54%81.69%82.44%
600.021321.27E+000-150-76.5576.5576.47%100.00%128.63%576.47%77.74%78.64%
331.19E+000-160-72.7272.7272.65%95.00%122.20%672.65%74.03%75.08%
341.10E+000-170-69.1269.1269.05%90.29%116.15%769.05%70.52%71.70%
351.02E+000-180-65.7365.7365.66%85.87%110.45%865.66%67.20%68.51%
369.59E-010-190-62.5362.5362.47%81.69%105.07%962.47%64.09%65.50%
378.87E-010-200-59.5159.5159.45%77.74%100.00%1059.45%61.14%62.66%
388.31E-010-210-56.6756.6756.61%74.03%95.23%1156.61%58.37%59.99%
397.78E-010-220-53.9853.9853.93%70.52%90.71%1253.93%55.74%57.45%
407.29E-010-230-51.4451.4451.39%67.20%86.44%1351.39%53.26%55.05%
416.84E-010-240-49.0649.0649.01%64.09%82.44%1449.01%50.92%52.76%
426.44E-010-250-46.846.846.75%61.14%78.64%1546.75%48.71%50.63%
436.04E-010-260-44.6844.6844.64%58.37%75.08%1644.64%46.64%48.58%
445.67E-010-270-42.6742.6742.63%55.74%71.70%1742.63%44.66%
455.34E-010-280-40.7740.7740.73%53.26%68.51%1840.73%42.80%
465.01E-010-290-38.9838.9838.94%50.92%65.50%1938.94%41.02%
474.75E-010-300-37.2937.2937.25%48.71%62.66%2037.25%39.36%
484.48E-010-310-35.735.735.66%46.64%59.99%2135.66%37.77%
494.23E-010-320-34.1934.1934.16%44.66%57.45%2234.16%
504.01E-010-330-32.7632.7632.73%42.80%55.05%2332.73%
513.78E-010-340-31.431.431.37%41.02%52.76%2431.37%
523.56E-010-350-30.1330.1330.10%39.36%50.63%2530.10%
533.38E-010-360-28.9128.9128.88%37.77%48.58%2628.88%
543.17E-01
553.00E-01
562.84E-01
572.71E-01
582.55E-01
592.43E-01
602.33E-01
612.19E-01
622.07E-01
631.97E-01
641.87E-01
651.78E-01
661.69E-01
671.61E-01
681.53E-01
691.46E-01
701.39E-01
711.32E-01
721.27E-01
731.18E-01
741.13E-01
751.08E-01
761.04E-01
779.99E-02
789.45E-02
799.00E-02
808.55E-02
Sheet1
10mm source height above skin
15mm source height above skin
20mm source height above skin
Sheet2
Sheet3
freiberg 7mm 4cm diameter
4cm circle
mmxtrahl
01.000203.90E+00
50.581213.55E+00
100.370223.14E+00
150.254232.81E+00
200.179242.52E+004x4 Brachy array centred on 0,0,0 in x z plane
250.130252.30E+00normalised atsource height above skin surface
300.097262.08E+00xyz-10-15-20depth (mm)-10-15-20
350.073271.90E+00-61-30-147.94189.21%272.85%379.72%0100.00%100.00%100.00%
400.056281.75E+00-61-40-133.17170.32%245.61%341.81%192.59%93.34%93.94%
450.043291.61E+00-61-50-120.29153.84%221.86%308.75%285.93%87.27%88.37%
500.034301.48E+00-61-60-109.38139.89%201.73%280.75%379.87%81.69%83.24%
550.026311.37E+00-61-70-100.01127.91%184.45%256.70%474.37%76.58%78.47%
600.021321.27E+00-61-80-91.83117.44%169.37%235.70%569.34%71.86%74.08%
331.19E+00-61-90-84.62108.22%156.07%217.20%664.73%67.50%69.99%
341.10E+00-61-100-78.19100.00%144.21%200.69%760.52%63.50%66.22%
351.02E+00-61-110-72.492.59%133.53%185.83%856.64%59.81%62.73%
369.59E-01-61-120-67.1985.93%123.92%172.46%953.10%56.38%59.47%
378.87E-01-61-130-62.4579.87%115.18%160.29%1049.83%53.23%56.44%
388.31E-01-61-140-58.1574.37%107.25%149.26%1146.81%50.30%53.62%
397.78E-01-61-150-54.2269.34%100.00%139.17%1244.03%47.58%50.98%
407.29E-01-61-160-50.6164.73%93.34%129.90%1341.48%45.08%48.54%
416.84E-01-61-170-47.3260.52%87.27%121.46%1439.10%42.73%46.23%
426.44E-01-61-180-44.2956.64%81.69%113.68%1536.91%40.56%44.10%
436.04E-01-61-190-41.5253.10%76.58%106.57%1634.88%38.53%42.07%
445.67E-01-61-200-38.9649.83%71.86%100.00%1733.00%36.63%40.20%
455.34E-01-61-210-36.646.81%67.50%93.94%1831.26%34.88%38.42%
465.01E-01-61-220-34.4344.03%63.50%88.37%1929.63%33.22%36.76%
474.75E-01-61-230-32.4341.48%59.81%83.24%2028.12%31.69%35.19%
484.48E-01-61-240-30.5739.10%56.38%78.47%2126.72%30.23%33.70%
494.23E-01-61-250-28.8636.91%53.23%74.08%2225.40%28.88%32.32%
504.01E-01-61-260-27.2734.88%50.30%69.99%2324.18%27.61%31.01%
513.78E-01-61-270-25.833.00%47.58%66.22%2423.03%26.41%29.77%
523.56E-01-61-280-24.4431.26%45.08%62.73%2521.97%25.29%28.62%
533.38E-01-61-290-23.1729.63%42.73%59.47%2620.96%24.22%27.52%
543.17E-01-61-300-21.9928.12%40.56%56.44%20.03%23.22%26.46%
553.00E-01-61-310-20.8926.72%38.53%53.62%19.15%22.28%25.49%
562.84E-01-61-320-19.8625.40%36.63%50.98%18.31%21.39%24.54%
572.71E-01-61-330-18.9124.18%34.88%48.54%17.53%20.56%23.67%
582.55E-01-61-340-18.0123.03%33.22%46.23%16.79%19.77%22.82%
592.43E-01-61-350-17.1821.97%31.69%44.10%16.10%19.02%22.00%
602.33E-01-61-360-16.3920.96%30.23%42.07%15.45%18.31%21.25%
612.19E-01-61-370-15.6620.03%28.88%40.20%14.84%17.63%20.51%
622.07E-01-61-380-14.9719.15%27.61%38.42%14.26%17.00%19.82%
631.97E-01-61-390-14.3218.31%26.41%36.76%13.71%16.40%19.17%
641.87E-01-61-400-13.7117.53%25.29%35.19%13.19%15.81%18.53%
651.78E-01-61-410-13.1316.79%24.22%33.70%12.70%15.27%17.94%
661.69E-01-61-420-12.5916.10%23.22%32.32%12.23%14.74%17.35%
671.61E-01-61-430-12.0815.45%22.28%31.01%11.79%14.24%16.81%
681.53E-01-61-440-11.614.84%21.39%29.77%11.37%13.78%
691.46E-01-61-450-11.1514.26%20.56%28.62%10.96%13.32%
701.39E-01-61-460-10.7213.71%19.77%27.52%10.59%12.89%
711.32E-01-61-470-10.3113.19%19.02%26.46%10.22%12.47%
721.27E-01-61-480-9.9312.70%18.31%25.49%9.87%12.08%
731.18E-01-61-490-9.5612.23%17.63%24.54%9.55%
741.13E-01-61-500-9.2211.79%17.00%23.67%9.23%
751.08E-01-61-510-8.8911.37%16.40%22.82%8.94%
761.04E-01-61-520-8.5710.96%15.81%22.00%8.65%
779.99E-02-61-530-8.2810.59%15.27%21.25%8.38%
789.45E-02-61-540-7.9910.22%14.74%20.51%
799.00E-02-61-550-7.729.87%14.24%19.82%
808.55E-02-61-560-7.479.55%13.78%19.17%
-61-570-7.229.23%13.32%18.53%
-61-580-6.998.94%12.89%17.94%
-61-590-6.768.65%12.47%17.35%
-61-600-6.558.38%12.08%16.81%
freiberg 7mm 4cm diameter
10mm source height above skin
15mm source height above skin
20mm source height above skin
Depth (mm)
% of skin surface dose
% dose at depth
• Since the 80’s: 4000 – 4500cGy in 8# with HDR• Sometimes dose is reduced to 3750cGy (poorly perfused
areas)• Prescribed to skin surface as per classical Manchester
System for skin with manual sources• Treated bi-daily with at least a 6 hour gap• 8# delivered over 4/5 days
• Treatment times ~10 mins per # depending on area, treatment height and age of source (range 2 – 60 mins)
Treatment prescription and delivery
PlanningPatient attends Clinic, depth of lesion determined with ultrasound
Treatment area outlined with radio-opaque wire/blue tack Guide wires threaded through treatment catheters show source
path
CT scan with patient in Mould
Oncentra planning Aim= 100% to skin surface and 80% at specified treatment depth (planning time approx 1 to 2 hrs)
Treatment is usually carried out as an outpatient 1 week after CT
Marking the treatment area• A thin wire is taped to the inside of the shell underneath
the clinician’s target outline• Easy to mark out target area on planning system
5 steps to Oncentra Planning…
1.Rind2. Catheters3. Points4. Activation5. Optimisation
1. Rind
2. Catheter Reconstruction
3. Add Normalisation Points
4. Activation and Prescription
5. Optimisation
Finger
Pinna
CT Vs. MRI
End Result
The Christie NHS Foundation Trust
Any Questions ?
Slide Number 1AcknowledgementsSlide Number 3BrachytherapyEvolutionSlide Number 6 1905 �Photograph showing the method of strapping on small tubes of radium to the skin to treat malignancies.1922–1923 at the Institut Curie, ParisSlide Number 9The Manchester System�The Manchester systemBirth of the Mould Room Treatment depthThe Manchester System��Adapted for HDR afterloading��Curved treatment areasSurface dose profile from centre to peripheryArray style treatmentsArray-style depth dosesOptimised weightingsSlide Number 21Slide Number 22PlanningMarking the treatment area5 steps to Oncentra Planning…��1.Rind�2. Catheters�3. Points�4. Activation�5. Optimisation1. Rind2. Catheter Reconstruction3. Add Normalisation Points4. Activation and Prescription5. OptimisationFingerPinnaSlide Number 33Slide Number 34CT Vs. MRISlide Number 36Slide Number 37Slide Number 38End Result Slide Number 40Slide Number 41Slide Number 42Slide Number 43��Any Questions ?