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Bolus and megavoltage irradiation of the intact breast
CORRESPONDENCE had popliteal stenoses which had thrombosed. Following thrombectomy, per-operative angiography revealed that this was complicated by severe disease compromising their subpopliteal run-off and in one a thrombosed femoro-popliteal bypass of saphenous vein which was also complicated by poor run-off. We feel that 'surgical angioplasty' is an important adjunct and complements rather than replaces conventional radiological PTA and that this very valuable technique will gain widespread acceptance in Britain as it has already in Europe and the USA. We feel that with the different work practices in Britain, the availability of this technique to the vascular surgeon serves to strengthen rather than detract from the close liaison which exists between surgeons and radiologists. P. O'BYRNE C. BLAKENEY R. HAM J. MURFITT
The London Hospital Whitechapel London E1 1BB
Vinten UT-LiF-7 ultra-thin TLDs of 6 mm in diameter and of 0.02 mm thickness were used. All TLDs were calibrated before use, and subsequent readings corrected using individual calibration factors. The standard TLDs were sandwiched between two strips of micropore tape and then applied to the scar; ultra-thin TLDs were packaged in cling film before application, in order to avoid damage during removal from the tape. The number of TLDs used was determined by the length of the scar. Prior to use, the TLDs were irradiated in tissue equivalent medium using the proposed packaging arrangements; this confirmed that the packaging did not significantly affect the measurements. Results using the standard TLDs did not differ substantially from those using the ultra-thin ones.
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McMillan, PJ., Collin, J. & Fletcher, EWL (1988). Intraoperative transluminal balloon dilatation permits simpler safer reconstructive surgery. Clinical Radiology, 39, 91-93.
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SIR - In Dr A. K. Tucker's letter published in Volume 39, no. 1, January 1988, she states that at the present time the only established training programme in existence in the UK is that of the Symposium Mammographican workshops. May we draw attention to the fact that this is not an entirely accurate statement. Intensive teaching in mammography screening is carried on at courses both at the Edinburgh Screening Clinic and at the Jarvis Screening Clinic in Guildford. Furthermore, in the near future, training will become available at the other designated training centres, namely Nottingham, King's College, London and Manchester.
Jarvis Screening Centre Stoughton Road Guildford, Surrey GU1 1LT
SIR - - I realise that both Guildford and Edinburgh are now running programmes for teaching breast screening. Nottingham starts on 29 February 1988 and Manchester and King's are still anxiously awaited. I did however, say in my letter, established programmes and unfortunately there was some delay between the writing of the latter and publication, which would partly account for the misinterpretation. Also, by established, I was thinking in terms of programmes which had been running for 2 or 3 years. I am well aware of the great effort which goes into establishing teaching programmes and the importance of teaching, and refresher courses cannot be underestimated.
Department of Radiology St Bartholomew's Hospital West Smithfield, London EC1 7BE
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References
J. L. PRICE A. E. KIRKPATRICK
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Fig. 1 . 0 , with bolus; O_),without bolus. Figure 1 shows that skin sparing even in the absence of bolus is considerably less than would be expected, due to the opposing field effect; this was true for both large and small breasts. The classic build up curve does not apply and is misleading in this situation. Addition of bolus would only serve to enhance dose in the region, beyond the quasi-threshold dose for severe late effects proposed by Harris et al. (1979). We hope that these data will further discourage a practice which lacks scientific foundation. J. STAPLES P. WALDOCK*
Division of Radiation Oncology The University of lowa Hospitals and Clinics lowa City, 1A52242 USA *Department of Radiotherapy and Oncology The Ipswich Hospital, Anglesea Road Wing Ipswich, Suffolk 1P1 3PY
Acknowledgements. We thank Mr T. Mott and Dr C. R. Wiltshire for their support in this study. References
BOLUS AND MEGAVOLTAGE IRRADIATION OF THE INTACT BREAST
S m - The excellent paper by Read et al. (1987) illustrates that the use of bolus to the surgical scar during megavoltage irradiation of the intact breast persists, despite evidence that the most superficial millimetres of skin spared by such radiation are at little risk of tumour recurrence (Harris et al., 1979). We present the following data in urging that the practice br~ discontinued, and to suggest that anxieties related to skin sparing may be exaggerated. Following lumpectomy or wide excision, nine patients with a wide range of breast sizes had surface doses measured with thermoluminescent dosimetry (TLD), both with and without bolus (as our treatment policy in Ipswich at the time was to apply bolus to the scar for alternative treatments). All patients were treated using a 5 MV linear accelerator with a build up curve reaching Dmax at 1.3 cm, and a surface dose of 25.7% as measured using a thinwindowed ionisafion chamber in tissue equivalent medium. All tumour doses were prescribed to the 90% isodose line on computer plans normalised to 100%. Initially, Vinten D-LiF-N-0.4 TLDs of diameter 12.7 mm and of 0.4 mm thickness, and subsequently,
Harris, JR, Levene, MB, Svensson G & Hellmann, S (1979). Analysis of cosmetic results following primary radiation therapy for stages I and II carcinoma of the breast. International Journal of Oncology Biology & Physics, 5, 257-261. Read, PE, Ash, DV, Thorogood, J & Benson, E A (1987). Short term morbidity and cosmesis following lumpectomy and radical radiotherapy for operable breast cancer. Clinical Radiology, 38, 371-373.
Erratum Ultrasound in the Follow-up of Spinally Injured Patients. Clinical
Radiology, 39, 356. Correspondence. We apologise for an error in the letter by Morcos and Thomas. The sentence 'We have logistic difficulty in moving these patients within the X-ray department' should have read 'We have no logistic difficulty in moving these patients within the X-ray department'.
The London Hospital Whitechapel London E1 1BB
Vinten UT-LiF-7 ultra-thin TLDs of 6 mm in diameter and of 0.02 mm thickness were used. All TLDs were calibrated before use, and subsequent readings corrected using individual calibration factors. The standard TLDs were sandwiched between two strips of micropore tape and then applied to the scar; ultra-thin TLDs were packaged in cling film before application, in order to avoid damage during removal from the tape. The number of TLDs used was determined by the length of the scar. Prior to use, the TLDs were irradiated in tissue equivalent medium using the proposed packaging arrangements; this confirmed that the packaging did not significantly affect the measurements. Results using the standard TLDs did not differ substantially from those using the ultra-thin ones.
O3 CO O 2D
B
0.8
t
:
T
~
~
{ r
r
;
~
l
:
4~
E
McMillan, PJ., Collin, J. & Fletcher, EWL (1988). Intraoperative transluminal balloon dilatation permits simpler safer reconstructive surgery. Clinical Radiology, 39, 91-93.
x
E
SIR - In Dr A. K. Tucker's letter published in Volume 39, no. 1, January 1988, she states that at the present time the only established training programme in existence in the UK is that of the Symposium Mammographican workshops. May we draw attention to the fact that this is not an entirely accurate statement. Intensive teaching in mammography screening is carried on at courses both at the Edinburgh Screening Clinic and at the Jarvis Screening Clinic in Guildford. Furthermore, in the near future, training will become available at the other designated training centres, namely Nottingham, King's College, London and Manchester.
Jarvis Screening Centre Stoughton Road Guildford, Surrey GU1 1LT
SIR - - I realise that both Guildford and Edinburgh are now running programmes for teaching breast screening. Nottingham starts on 29 February 1988 and Manchester and King's are still anxiously awaited. I did however, say in my letter, established programmes and unfortunately there was some delay between the writing of the latter and publication, which would partly account for the misinterpretation. Also, by established, I was thinking in terms of programmes which had been running for 2 or 3 years. I am well aware of the great effort which goes into establishing teaching programmes and the importance of teaching, and refresher courses cannot be underestimated.
Department of Radiology St Bartholomew's Hospital West Smithfield, London EC1 7BE
0.6
o O
POPULATION SCREENING BY MAMMOGRAPHY
A . K . TUCKER
10 t,t
O
References
J. L. PRICE A. E. KIRKPATRICK
465
0.4
.=__ 5O
O
0.2
¢7" I
I
I
1
2
3
I
I
I
4 5 6 Patient n u m b e r
i
I
I
7
8
9
Fig. 1 . 0 , with bolus; O_),without bolus. Figure 1 shows that skin sparing even in the absence of bolus is considerably less than would be expected, due to the opposing field effect; this was true for both large and small breasts. The classic build up curve does not apply and is misleading in this situation. Addition of bolus would only serve to enhance dose in the region, beyond the quasi-threshold dose for severe late effects proposed by Harris et al. (1979). We hope that these data will further discourage a practice which lacks scientific foundation. J. STAPLES P. WALDOCK*
Division of Radiation Oncology The University of lowa Hospitals and Clinics lowa City, 1A52242 USA *Department of Radiotherapy and Oncology The Ipswich Hospital, Anglesea Road Wing Ipswich, Suffolk 1P1 3PY
Acknowledgements. We thank Mr T. Mott and Dr C. R. Wiltshire for their support in this study. References
BOLUS AND MEGAVOLTAGE IRRADIATION OF THE INTACT BREAST
S m - The excellent paper by Read et al. (1987) illustrates that the use of bolus to the surgical scar during megavoltage irradiation of the intact breast persists, despite evidence that the most superficial millimetres of skin spared by such radiation are at little risk of tumour recurrence (Harris et al., 1979). We present the following data in urging that the practice br~ discontinued, and to suggest that anxieties related to skin sparing may be exaggerated. Following lumpectomy or wide excision, nine patients with a wide range of breast sizes had surface doses measured with thermoluminescent dosimetry (TLD), both with and without bolus (as our treatment policy in Ipswich at the time was to apply bolus to the scar for alternative treatments). All patients were treated using a 5 MV linear accelerator with a build up curve reaching Dmax at 1.3 cm, and a surface dose of 25.7% as measured using a thinwindowed ionisafion chamber in tissue equivalent medium. All tumour doses were prescribed to the 90% isodose line on computer plans normalised to 100%. Initially, Vinten D-LiF-N-0.4 TLDs of diameter 12.7 mm and of 0.4 mm thickness, and subsequently,
Harris, JR, Levene, MB, Svensson G & Hellmann, S (1979). Analysis of cosmetic results following primary radiation therapy for stages I and II carcinoma of the breast. International Journal of Oncology Biology & Physics, 5, 257-261. Read, PE, Ash, DV, Thorogood, J & Benson, E A (1987). Short term morbidity and cosmesis following lumpectomy and radical radiotherapy for operable breast cancer. Clinical Radiology, 38, 371-373.
Erratum Ultrasound in the Follow-up of Spinally Injured Patients. Clinical
Radiology, 39, 356. Correspondence. We apologise for an error in the letter by Morcos and Thomas. The sentence 'We have logistic difficulty in moving these patients within the X-ray department' should have read 'We have no logistic difficulty in moving these patients within the X-ray department'.