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Alberta Radiosurgery Centre
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Treatment Procedure

Once the referral, rounds, and consultation process has been completed, the patient will attend ARC for treatment. If the treatment is fractionated, the planning process will occur over a few days prior to the patient commencing treatment. If the treatment is to be delivered in a single fraction, the planning and treatment occur on the same day. Prior to receiving treatment, the patient will need to have a creatinine and CBC 90 days before, due to the use of contrast for the CT scan. At the time of consultation, the patient may be prescribed steroids and/or anti-seizure medication. Patients will be advised when to begin the steroids and/or anti-seizure medication prior to treatment.

photo Step 1 - Application of the head frame or face mask

At the beginning of treatment, a metal head frame is placed on the patient's head. The head frame is designed to restrain the head during treatment and to hold reference markers in a fixed position in relation to the tumour. The frame is attached to the patient's head using 4 pins that penetrate through the skin into the skull. The metal frame feels heavy and tight, but this is necessary to ensure adequate immobilization. The patient will be given a topical anesthetic prior to the injection of anesthesia into the scalp. Patients complain of a stinging sensation similar to that of a wasp's sting until the anesthetic takes effect within a few minutes. If needed, anesthetic will be re-administered later in the day.

For fractionated treatments, a face mask is employed instead of the metal head frame. Each face mask is individually custom-made for each patient. Constructing the face mask is completely painless and requires no anesthesia. The patient will lie on a custom-made body cushion, patterned to each patient's exact body shape to ensure accurate positioning during treatment. This does not interfere with breathing or restrict the patient in any way. The body cushion does not require any hardware, attachments, incisions or painful procedures.

Step 2 - Diagnostic imaging

photo After the head frame or face mask is secured, the localization box is attached to the frame and the patient is taken to the CT Simulator. The patient is situated in a treatment position based on conventional skin marks and wall lasers while a CT scan is performed using IV contrast dye. If the patient has an AVM, an angiogram may be required on the procedure day with the head frame in place. The diagnostic information is fused using the Novalis Body workstation, providing images that show the actual position of the patient.


Step 3 - Image transfer, planning and quality assurance

After imaging is complete, the localization box is removed. At this point, Novalis software automatically calculates the Digitally Reconstructed Radiograph (DRR) corresponding to the data acquired by CT. The resulting DDR is used in verifying the patient position and making adjustments to ensure the patient position is accurate at the time of treatment. The treatment couch then moves automatically to shift the patient in correct 3D location ensuring a perfect set-up. The automatic fusion works for bony structures as well as implanted markers (where appropriate) and is important mainly for frameless treatments.

Once the customized treatment plan is completed, a series of carefully controlled quality checks using precise Novalis instruments are done on the LINAC in order to ensure the shaped radiation beams will be guided precisely to the defined target position.

photo Step 4 - Treatment

To begin treatment, the patient is taken to the treatment room and positioned on a specially designed firm couch. Next, the head frame or mask is secured to the table so the patient's head will not move during the procedure.

During treatment, the patient does not feel any sensations. The machine makes some noises while the treatment is being administered due to the generation of the radiation beam and accelerator movement. The patient is in the room by themselves during treatment, but is monitored closely using closed circuit TV monitors and intercom systems.

Once treatment begins, Novalis will move around the head, delivering the prescribed dose of radiation. The treatment takes about 30-45 minutes.

Step 5 - Post Treatment

photo Once treatment is complete, the head frame is removed. Patients are recommended to apply antibiotic ointment to the pin sites 3 times/day for a few days following the procedure. If the patient experiences headaches, they can use pain medication i.e. Tylenol, though headaches generally subside in 48 hours. Fatigue is common for 2-3 weeks after the procedure. A Radiation Oncologist and neurosurgeon is on call should any problems occur the night following the procedure and the ARC nurse will call the patient the following day to check for any post treatment headaches, seizures, changes in levels of consciousness or bleeding at pin sites. Patients will be counseled on medication use as appropriate.


Step 6 - Follow Up

Malignant Brain Tumours

The ARC nurse will call the patient 10 days post procedure, and patients should be seen 4-6 weeks post treatment by their referring physician. The patient will be seen 3 months post treatment by ARC physicians with another MRI performed prior to this appointment. Referring physician will provide ongoing follow-up.

Non Malignant Tumours

The ARC nurse will call the patient 10 days post procedure. Patients will be seen 3 months post treatment by an ARC physician with another MRI performed prior to this appointment. Ongoing follow-up will be provided by the ARC neurosurgeons and usually the patients' referring physician (especially if living outside of Calgary).

AVM's

The ARC nurse will call the patient 10 days post procedure. Patients will be seen 6-12 months post treatment by the ARC neurosurgeons and will be sent for MRI prior to this appointment. Ongoing follow-up will be provided by the ARC neurosurgeons and the patient's referring neurosurgeon and communication will be maintained over the time course of the expected AVM obliteration.

As malignant tumour patients cannot all be followed by the ARC, outcomes and ongoing follow up information will be requested of the referring physician who provides ongoing care to the patient.

 

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