This document reviews techniques for total skin electron beam (TSEB) therapy. It discusses the equipment needed, including a linear accelerator capable of producing large, uniform electron fields at an extended source-to-skin distance. The Stanford technique is described as delivering radiation using six dual electron fields while the patient rotates, allowing treatment in a small room. High dose rates of 2500-3000 cGy/min are recommended to reduce treatment time. Dose prescription for TSEB therapy typically involves delivering 27-40 Gy over 9 weeks at 4 days per week.

1. Clinical implementation of total skin electron
beam (TSEB) therapy: A review of the relevant
literature
Presented by: Sehrish Inam
Trainee Medical Physicist
Date : May13,2014

2. Contents
◦ Abstract
◦ Introduction
◦ Equipment requirement
◦ Physical requirement
◦ Single scattered electron beam therapy
◦ Other techniques of skin therapy
◦ Stanford technique
◦ Dose rates
◦ Setup problems
◦ Dose prescription
◦ Dosimetric setup
◦ Dosimetric problems
◦ Clinically acceptance objectives
◦ Conclusion

3. Abstract:
Total skin electron beam therapy has been in medical service since
the middle of the last century in order to confront rare skin
malignancies. Since then various techniques have been developed,
all aiming at better clinical results in conjunction with less post-irradiation
complications. In this article every available technique is
presented in addition to physical parameters of technique
establishment and common dose fractionation. This study also
revealed the preference of the majority of institutes the last 20
years in “six dual field technique” at a high dose rate, which is a safe
and effective treatment.

4. Introduction
•Total skin electron beam is treatment modality for
 T-cell lymphoma
Mycosis
 Fungoides
Kaposi sarcoma
Low penetration electron beam
Linear accelerator capable of producing large 200 cm 80
cm uniform fields with extended SSD.

5. Equipment Requirement
 Linear accelerator that can be modified in order to
deliver a homogeneous electron field at a large
distance from its source (2-7 m).
 Beam degrader which ensures superficial beam
penetration into tissue.
 Large treatment room for large SSD.
 ventilation that removes O3 produced by electron
air interactions .
 Auxiliary equipment for the proper and repeatable
positioning.
 Dosimetry equipments.
 Shielding to avoid sensitivity (eyes & nails)

6. Physical requirements
3steps of dosimetric checks
1. Physical specification of field dimensions, nominal
SSD, electron beam energies, field at treatment plane
and dose distributions, dose rate and photon
contamination.
2. Dose distribution and rate for dose from electrons
and photons.
3. Clinical aspects that arises dose prescription, dose
fractionation, boost fields for underdosed areas,
shielding design

7. Single scattered horizontal beam
 Requires a linear accelerator that can provide a
homogenous electron field at an SSD of 700 cm.
 Energy degrader for beam flattening patient is
irradiated in standing position.
 Requires a large treatment room

8. Other techniques of skin therapy
Static large
electron
fields with
patient in
standing
position.
Static electron
field, rotated
the standing
patient over
360˚.
Static
electron field
with patient
translated in
lying position

9. Stanford technique
 Developed in 1973 at Stanford university
 Patient rotates in 60˚ steps standing at
treatment positions
 Beam energy and shape modulators are used.
 Easily achievable in small treatment rooms.
 2 central axes of beam pointing outward
patient’s body ,so x-ray contamination can be
avoided

10. Stanford technique

11. Stanford technique
 Six dual field techniques or Stanford technique

12. Stanford technique
 Six dual field technique

13. Dose rates
 High dose rate 2500-3000 cGy/min at dmax .
 Daily treatment time reduced to 9.5min to
15min.
 HDR is a treatment modality in mycosis
fungodis with good results and less time
consuming

14. Setup problems
 Room size
 Ventilation of ozone
 Skin sensitivity
 Eye nail shielding

15. Dose prescription
 27Gy – 40Gy(mean dose 35-36Gy) at HDR in an
average of 9weeks,4 days per week.
 HDR provides low toxicity ,better tolerance &
reduces treatment time.
 For under dosed areas boost fields of 4-26Gy
are prescribed.
 For vertex of scalp angled lead reflector is
provided.

16. Dosimetric setup
 Dosimeter (TLDs, ionization chambers,
gafchromic films)
 Solid water phantom or anthromorphic
phantom.
 Scanning and evaluation of gafchromic
by Epson10000xl

17. Dosimetric problems
 On extended SSD;
Combination of partial beams in order to
create a large field that cover patient
dimensions.
 Beam energy degrdading, because lowest
energy provided in electron mode is 6MeV.
 Thickness of degrader can vary from 3mm
to 18mm.
 If air volume is not sufficient use acraylic
sheet for secondary scattering.

18. Clinically acceptance objectives
 +5% of dose at dmax in a phantom on the central ray
for atleast 80% of the nominal field area.
 In Stanford technique dose homogeneity varies from 4%
to 10%.
 Prefer dosimetry by gafchromic.

19. Conclusion
 Total skin electron beam irradiation is an effective
treatment for various skin malignancies.
 Toxicity can be reduced by HDR & appropriate shielding.
 All techniques require linear accelerator with electron
mode & large SSD.
 Dosimetric technique should be carried out to ensure
treatment quality.
 Prescribed doses differ according to personalized
patient needs and treatment schedules.
 36-40 Gy dose delivered in 4 days per week for 9
weeks at HDR.