New advances in Radiotherapy: Radiosurgery, IMRT, IGRT

The practice of stem cell transplantation can be autologous (where the patient is their own donor) or allogeneic (where someone else is the donor – either a sibling or a registry, unrelated donor). Stem cell transplants are mostly performed for malignant blood conditions (e.g. Leukemia, Myeloma, Lymphoma etc) or for bone marrow failure syndromes. The transplant of marrow stem cells allows higher (myeloablative) doses of chemotherapy to be given and in some transplants (from an allogeneic donor) allows a "clean" marrow and new immune system to replace the diseased marrow.

What is Stereotactic Radiosurgery?

Stereotactic Radiosurgery (SRS) and Stereotactic Irradiation refer to radiation treatment in which a large radiation dose is delivered very precisely to a lesion in anything from one to 25 treatment fractions. Stereotactic irradiation is performed worldwide as an alternative to surgical removal of brain lesions such as arteriovenous malformations (AVM’s), acoustic neuromas, solitary or multiple brain metastases, gliomas, pituitary microadenomas, astrocytomas and others. Stereotactic irradiation treatment is specifically indicated when lesions are near critical brain structures, making them difficult to reach with invasive surgery techniques without damaging normal, healthy brain structures. The treatment procedure is typically performed on an out-patient basis. No surgical incision is required and therefore radiosurgery and stereotactic radiotherapy (irradiation) avoids the complications, substantial recovery times, and costs associated with open brain surgery.

Stereotactic irradiation is a very attractive alternative to the emotional and physical trauma associated with major, high-risk surgery.

Stereotactic irradiation is a very attractive alternative to the emotional and physical trauma associated with major, high-risk surgery.

What is Intensity Modulated Radiotherapy (IMRT)

Radiation beams in conventional external radiation therapy and three dimensional conformal radiotherapy (3D-CRT) can be shaped by customised blocks or multileaf collimators, but the intensity or fluency of the radiation beam has traditionally been uniform within the treated region. By adjusting the beam-intensity across the field, another dimension to treatment delivery can be provided to permit even more conformal dose distributions. This treatment delivery is known as intensity-modulated radiation therapy, or IMRT. In IMRT, the intensity of the radiation exposure in one portion of the field is modified depending on whether tumor or critical normal structures are present in the beam pathway. Hence, the beam is divided into multiple beamlets, which are the essence of IMRT. When the beamlet hits sensitive normal tissues such as the spinal cord or parotid glands, the intensity is lowered, and when the beamlet hits tumor, the intensity is higher. By dividing the radiation beam into multiple slices, the beam-intensity in any slice can be varied either by computer-controlled multileaf collimation or physical compensators during the radiation exposure. While the radiation source, or linear accelerator gantry head, moves around the patient, both the shape of the beam and the intensity of the beam slices (lighter shades representing higher radiation intensity) are varied to avoid the organ at risk while treating the tumor. This results in highly conformal distributions of radiation dose, even around concave tumor volumes.

What is Image Guided Radiation Therapy (IGRT)

Image-guided radiation therapy is conformal radiation treatment guided by imaging equipment, such as CT, ultrasound or stereoscopic X-rays, taken in the treatment room just before the patient is given the radiation treatment. IGRT allows radiation to be delivered to tumors with more precision than was traditionally possible. One of the challenges encountered when radiation is delivered to a tumor is that the tumor can move based on the patient's day-to-day position on the treatment table (as well as from breathing). IGRT allows the physician to better deliver the radiation dose directly to the cancer by using a variety of automated and tracking systems.

Clinicians obtain daily high-resolution imagery to pinpoint tumor sites, adjust patient positioning when necessary, and complete a treatment, all within the standard treatment time period. By Imaging the tumor daily, we can detect movement in normal structures or changes in tumor location or size which permits the physician to precisely locate the tumor while the patient is in the treatment position. This minimizes the volume of healthy tissue exposed to radiation during treatment, yet allows the delivery of higher doses of radiation to the tumor volume.

Dr Alberts, Bouwer & Jordaan Inc.

The Alberts, Bouwer & Jordaan practices and clinics are spread across Gauteng and the North West Province and offer the most advanced treatment methods available worldwide. We pride ourselves in our quality and the standard of care given by our doctors, nurses and support staff who treat all our patients with professionalism, compassion and understanding, providing the most effective treatments and therapy.

After hours contact details:

Radiotel: +27 (0)12 333-6000

(for all practices except Klerksdorp)

PO Box 12555, Hatfield, 0028

Download documents:

Manual in terms of section 51 PAIA ACT [1]
Manual in terms of section 51 PAIA ABJ [2]