Virtual Wedge of Siemens

The use of wedge filters in radiotherapy to produce dose gradients across the beam profile is widespread.

Traditionally this is done using physical wedges made of metallic material shaped in such a way so as to produce graduated attenuation across the radiation beam.

Controlling the movement of one of the collimator jaws and the delivered dose rate throughout irradiation can produce similar beam profiles.

The Siemens Virtual Wedge™ uses this philosophy to replace physical wedge filters.

Reference:

Behavior of the Siemens Virtual Wedge™ following an interruption to beam delivery. N. D. Richmond* and C. P. Walker

Brachytherapy : overview

Brachytherapy is a method of cancer treatment in which we put directly the radiation source into tumor volumn. Then these radiation sources will kill the cancer cells.

Some types of volume in oncology

The volume of patient interested in the oncology is the region that we considered in the therapy. There are some types of volume in oncology.

1. PTV. PTV - Planning Tumor Volume (GTV <= CTV <= PTV). That is the region of tumor that we make a plan of therapy.
2. CTV. CTV - Clinical Tumor Volume (GTV <= CTV <= PTV). That is the region of tumor that is detected in clinic.
3. GTV. GTV - Gross Tumor Volume (GTV <= CTV <= PTV). That is the real (approximating) region of tumor of the patient.
4. Treated Volume. That is the region that we isolate for treatment.
5. Irradiated Volume. That is the region that we are irradiated. In this region, we need an enough dose to destroy the tumor.
6. Organ. That is the region representing organs of patient. This region is so sensible with the radiation. We need an minimal dose of radiation on this region.

Normalement, each computer-aided therapy software  supports all these volumns. Because, they are basic volumes considered in the oncology.

Some main steps for creating a treating plan in oncology

Some main steps for creating a treating plan in oncology.

Some software provides some different steps for constitute a treating plan. In this article, I will mention some principal steps:

Construction of patient profile.
The information of the patient is stored in a patient information server. Each software want to use a patient profile, it connects to the server and get the expected profile. In each patient profile, we attach each model. Each model contains the basic information about the patient and CT or MR, etc image serie.