Vision :IMC aspires to be a leader in applied medical sciences, health care education and research.

Dr. Mohammed EMAMPh.D., Paris-Sud 11 University

RAD 481

Radiotherapy Physics and Equipment

Lecture’s Title: Introduction

Radiological Sciences Department

Lecture Outline

WHAT IS RADIOTHERAPY AND

HOW DOES IT WORK?

Mission: IMC is committed to develop highly qualified and competent graduates able to provide leadership and excellence in

services to meet the health needs of the nation and the global community through wide range programs, nationally competitive

faculty, state-of-the art infrastructure, research applications, and a diverse environment with enriched engagements.

Introduction

• What is radiotherapy?• How does radiotherapy work?• When is radiotherapy used?• What side effects and complications are

associated with the use of radiotherapy?• What are the different types of radiotherapy?

What is radiotherapy?

• The medical use of ionizing radiation in the

treatment of malignant cancers.

• May be used as curative, neo-adjuvant, adjuvant

or palliative treatment.

• Frequently used in combination with other

treatment strategies.

• Types:

External Beam Radiotherapy

(EBRT)

Brachytherapy

How does radiotherapy work?

• DNA damage to cancer cells

• Direct damage

• Indirect damage (via free radical formation)

• Targeted therapy due to differences between

healthy and malignant cells.

• Major limitation

• Hypoxia

How is radiotherapy given?

• Before treatment: CT and

simulation.

• 2D beams using linear

accelerator machines from

several angles.

• Aimed at tumour and

sometimes the draining

lymph node.

• Facilitated by MRI and PET scanning.

• Dose (measured in Gy) Fractionated.

• Typical dose 2Gy fractions 5 times a week

over a 6-7 week period.

How is radiotherapy given?

WHEN IS RADIOTHERAPY

USED AND WHAT ARE ITS

BENEFITS?

• Pre-operative RT• Locally advanced disease – operable.

• Rarely used.

• Post-operative RT• Patients with T3 and T4 tumours.

• ≥4 positive axillary lymph nodes.

• Residual disease.

When is radiotherapy used?

• Post-operative:

• Minimal tumour bulk following surgery.

• Minimal effect on wound healing.

• No delay of surgery.

• Decreases local recurrence from 10-40%

(according to extent of surgery) to

WHAT ARE RADIOTHERAPY

BENEFITS?

What are Radiotherapy Benefits?

• To reduce the risk of local recurrence followingcarcinoma of the breast – 40%.

• To treat patients with Ductal Carcinoma ofhigh grade.

• To treat Mastectomy patients with large,high grade, multifocal tumours involving 4or more lymph nodes.

• Adjuvant:

• Following Breast-Conserving

Surgery (BCS) or Mastectomy

• Radical:

• Primary incision not

possible

• Neo-Adjuvant:

• Large fungating lesions

• Palliative:

• Metastatic disease

When is radiotherapy used?

• Palliative RT

• Treatment of symptomatic manifestations.

• Improves quality of life.

• Used to treat distant metastases – brain, bone,

soft tissues.

• Effective, convenient, cost-effective with tolerable

side effects.

• Can be administered following four cycles of

chemotherapy.

When is radiotherapy used?

WHAT ARE THE SIDE EFFECTS

OF RADIOTHERAPY?

Side Effects

• Acute:

• Nausea and vomiting

• Skin desquamation

• Late:

• Fibrosis

• Alopecia

• Lymphoedema

• Pneumonitis

• Cancer

• Cardiac problems

Late Effect: Radiation Vascular Disease

• Intimal thickening of arteries and arterioles

• Dilatation of capillaries and venules

• Substantial reduction of the capillary vascular

bed

• Ischaemia

• Fibrosis

Practical problems

• Potential prolongation of a treatment schedule

(Monday-Friday, 3-4 weeks).

• Radiotherapy planning.

• Post-operative radiotherapy may have an

adverse effect on reconstruction.

WHAT ARE THE DIFFERENT

TYPES OF RADIOTHERAPY?

External Beam

Radiotherapy

(EBRT)

Internal

Radiotherapy

(Brachytherapy)

External Beam Radiotherapy

• Linear accelerators are the most common source

• Conventional radiotherapy

• Conformal radiotherapy

• Intensity-modulated radiotherapy (IMRT)

Internal Radiotherapy (Brachytherapy)

• Radiation source is placed inside or next to the area requiring

treatment

• Radiation is delivered through catheters or a mammosite

balloon device which remains in place for the duration of

treatment

• Can be given after the whole breast has been treated using

EBRT, providing a ‘boost’

• Can be used as the sole method of radiotherapy after surgery

• Limited evidence of clinical advantage

Conclusion

• Radiotherapy remains a key tool in the treatment of

breast cancer and in reducing the incidence of

recurrence.

• Whilst side effects of nausea, vomiting and skin

erythema are common, new techniques are

reducing toxicity.

• As research in this field progresses, radiotherapy

will undoubtedly continue to improve.

References• Sainsbury, JRC; Anderson, TJ; Morgan, DAL. ABC of breast diseases: Breast

cancer. BMJ. 2000; 321: 745.

• Early Breast Cancer Trial Collaborative Group. The Effects of radiotherapy and

surgery in early breast cancer: an overview of the randomised trials. N. Engl. J. Med.

1995; 333: 1444-44.

• Kurtz JM. Radiotherapy for early breast cancer: was a comprehensive overview

of trials needed? Lancet. Vol 355: No 9217, 2000; 1739-1740.

• Fisher B. Bauer M. Margolese R. et al. Five year results of a randomised clinical

trial comparing total mastectomy and segmental mastectomy with or without radiation

in the treatment of breast cancer. N.Eng. J. Med. 1985; 312: 665-73.

Thank you

Floor is open for Questions and Discussion