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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.)


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.)


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


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


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



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




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




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

CT Vs. MRI

End Result

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 ?

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