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The Ruber International Hospital has boosted the most diversified and modern usage of ionizing radiations in the therapeutic area, giving the more complete resources among the Spanish hospitals in this matter and, leading the highly professional multidisciplinary teams. From January 2008 it has the most modern devices for this target: The Fifth Generation Gamma Knife or PERFEXION.

Aware of the healthcare technology of these radiant energy applications, it has moved towards the most accurate application as possible in the lesions to be treated. It has obtained the more precise devices currently available for the most advanced radiotherapy treatments: two CLINAC IX lineal accelerators with OBI system for volumetric image-guided and RAPIDARC and 600 C/D technology from the company Varian with 1000 lines portal imaging. Both have a Millennium 120 leaves multileaf with modulated intensity modules, the Gamma Knife PERFEXION from Elekta and the robotic CYBERKNIFE from the company Accuray for radiosurgical treatments in any part of the body.

In order to supplement these purposes, it is supported by the Imaging Department provided with excellent display systems (three MRIs, one of them of 3 Teslas, helical CT, Digital Angiography and a cutting-edge PET/CT system). Gamma Knife is connected to these devices by two planning GammaPlan equipments. It enables an excellent definition, as anatomic as functional, of the injuries and an appropriate analysis of the treatment results (follow-up) in the context of a hospital organization making possible to undertake the procedure with the maximum warranties for the patient.
We just are going to describe the radiosurgical intracranial procedure in only one session performed by the Gamma Knife (stereotactic intracranial radiosurgery) in the called Gamma Unit of the Ruber International Hospital. We are also doing a brief profile of our experience since 1993 with such procedure.


Arterio-venous malformations AVM

This procedure completes prior embolizations of malformations in many cases, and thus, we cooperate with some groups of the most prestigious interventionional neuroradiologists of the country. It is also feasible the treatment by radiosurgery of patients previously operated and who still show some malformation remains. Finally, we have accomplished a second session of radiosurgery to those patients who, after more than four years are still presenting a part of malformation.
The risk of complications is related to the administered irradiation dosage, the size of the malformation and the situation of his brain. By complications we mean a new neurological symptom undergone by the patient from the treatment to the malformation closing. In our centre we assume a theoretic risk of a 5% of cases and in 6 years practising, it has not exceeded the 2%. We should underline that treatments especially sensitive due to the malformation situation in the encephalon stem, have been performed with the GK without any problems obliterating all the abnormalities placed in this area without a new neurological symptomatology.
Currently, from the 746 cases treated, the closing is observed, in 3-4 years after surgery, in a 70% of AVM which volume do not exceed 3cc. In all other cases, the success rate goes from 60% in 3 cc – 5cc AVM and the 45% for the 5-12 cc group (and 25% in bigger than 12 cc.)
Previous image to radiosurgery treatment (1999) Volume: 16,7 cc.

Check out at six years (2005): Full closing and without disorders in the remaining brain parenchyma.


Until 2010, 932 patients have been treated of meningioma. The 70% of them was located in the skull base, being in these cases the radiosurgery with GK the first chosen treatment. As a whole the 43% of cases have been previously operated. In 98% of cases follow-up of 4 years average, there has not been observed any tumor development with a volume reduction of the 70% of cases. It has been observed that a 2.4% of cases provisional treatment with steroids have been required. It is highlighted the lack of complications related to new presence of cranial nerves and a previously present increasingly deficit in cranial nerves only in a 4.5%.
Another preferable indication is for cases of multiple brain meningioma in which radiosurgery with GK can be the only therapeutic option. We have treated 81 patients with meningiomas requiring more than one treatment due to the appearance of new distant meningiomas of the ones already treated (159 treatments in total). Most of these cases had been already operated. It is been noticed that the imaging local control was of 94’6% of which volume was decreasing in a 50% of the cases. From the clinical point of view it has been achieved a stabilization of a 78% (average follow-up of 38.2 months). There have been 8 cases with clinical development without morphologic changes and 7 cases of clinical development due to new meningiomas appearance.

Neurinomas (Schwannoma of the vestibular nerve)

689 patients with neurinomas in the acoustic nerve have been treated until 2010, with many diverse volumes, intracanalicular neurinomas included (22% intracanaliculars).
The growth control, stabilization or reduction has been reached in a 96% of patients. In a 68% of the cases it has been observed a significant reduction between a 10-100%.

In 11 cases a later surgery had to be performed, although in five cases there was no lesion gain but a placement of a ventricular shunt was needed.
In an 18% of patients with preserved audition, we have observed a decrease to a 30% in the threshold of perception of audition frequencies after 18 and 24 months of treatment. Later they have not experienced major decrease.

The observed complications are:
Permanent facial paralysis 0%Facial transitory Pyrexias/hemyspasmous lower than 1% Trigeminal disorder (10% of hypaesthesia) it appears again in a 5%.
Case 1. Neurinoma of acoustic neurinoma (VIII par) previous MRI to the treatment and control after 3 years:

Case 2. Neurinoma of acoustic (VIII par). No candidate patient to surgery.
1997. Previous image to radiosurgery treatment Volume (22 cc) (above).
2005. Eight years after (below):

Hypophysis adenomas

There are two purposes in the hypophysis adenomas treatment: to prevent its development in order to avoid the damage in peripheral structures, mainly in the optical tract, and in adenoma cases which are excessively secreting hormones, to decrease or stop this secretion to control clinical problems aroused from it (Nelson syndrome, acromegaly, hyperprolactinemia).
The planning and performance of the radiosurgery in these cases implies a special care for nearness to optical tracts. Our team is the only one in the country using these MRI techniques called “rapid perfusion” enabling to precisely identify tumors which are producing hormones inside the hypophysis. The images obtained with these techniques are melted with the other ones, including those images acquired specially to intensify the optical nerves and chiasm. Thus, we have highly improved the results with producing hormone adenomas, keeping a great safety and accuracy.
After treating 207 cases (116 of them were non-producing adenomas), we have not observed damages in any patient’s optical tracts after radiosurgery. The development control regarding the tumoral volume is of a 100% of cases, with a 70% in which the volume has been reduced in a 10-100%. Significant reductions of hormonal rates in 50% of treated adenomas producing cases have been reached. This percentage of improvement on the hormonal overproduction is bigger is all the cases of secreting of Cushing syndrome (ACTH secretion) and hyperprolactinemia, where the improvement ranges between 80-60% of cases.
The initial results are published (Martinez, R., Bravo, G., Burzaco, J. & Rey, G. (1998) Pituitary tumors and gamma knife surgery. Clinical experience with more than 2 years of follow-up. Stereotactic and Functional Neurosurgery, 70, 110-118).
Hypophysis macroadenoma planning.

Other benign tumors

Glomus yugulare tumors (chemodectomas). It is a group of tumors which full surgical resection is really complex in addition to present a significant toxicity at a cranial nerves low level. Until now 34 cases have been treated in our Unit, obtaining in all of them the volume control of the injury, with a volume reduction between 10 to 60% in the 66% of them. Only in two cases a clinic worsening has happened, which means a greater loss of hearing of that they were already presenting at the moment of the treatment. The other patients remain stables and in a 30% of them the clinic they had before has shown improvements.
Craniopharyngiomas. These are benign tumors related with the hypothalamic region and near the optic tracts. Often they present an associated-cystic compound somewhat responsible of the patient symptoms. Up to now, we have treated 35 craniopharyngiomata in our Unit, most of them already operated. In both cases, and due to the size of the cyst, a drain of it has been performed through sterotaxy and later on through irradiation in the solid part. It is a rapid and comfortable procedure and both treatments, drainage and irradiation, can be done on the same day or in consecutive days. It has not been detected any growth from the treatment, although four of them needed a later drainage of the cyst due to its enlargement in any moment of the follow-up. In a 54% of cases has been a significant lesion size reduction (between 10-80%). In addition, a visual clinic improvement has been obtained in half of the patients with visual disorders existent before the treatment and there have not been side effects associated to the radiosurgery.
Glomus yugulare tumors (chemodectomas). Glomus yugular previous to radiosurgery:

Glomus yugulare six years after radiosurgery:

Glomus yugulare nine years after radiosurgery:

Radiosurgery represents an essential advance in the treatment of brain metastasis, up to its arrival only could be operated and an external beam radiation fraction therapy was applied. Currently the survival of these patients has increased thanks to the high dose rate radiation and focused of the radiosurgery.
Inside radiosurgery, metastasis has been the indication that has more quickly grown in the last years. In a recent publication of the Gamma Knife Users’ Society collecting the experience of 210 units of the 267 that existed in the world in 2008, more than 185.000 cases had been treated with this equipment.
In our case the number of patients treated of metastasis is of 585 of the 4926 treated patients since August 1993 to May 2010.
Nevertheless, any publication on metastasis must show the studies including metastasis from the type of origin tumor and then classify the results by size, number of metastasis, degree of disease control, age, general health state of the patient.
Thus, the more striking publications may contain a short number of patients if the tumor is rare or if it assembles some particular conditions as, for example, a publication of 29 patients with metastasis of unknown origin which only a 1% of more than the 2500 treated patients of metastasis in the University of Pittsburgh from 1990 to 2007.

Int. J. Radiat Oncol Biol Phys. 2010 Jan 5.
Radiosurgery for Brain Metastases from Unknown Primary Cancers. Niranjan et al.
Department of Neurological Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania
The current debate resides in search the role of radiosurgery against or jointly to other techniques used until now as are surgery and holocraneal radiation therapy. Each case must be carefully studied by a multidisciplinar team composed by surgeons and oncologic radiotherapists who determine if the patient can be benefited from this technique.
The rate of complications is another point to be considered on choosing the treatment technique. This parameter depends on the location of the injury and its size.

Other malignant tumors

It is a very heterogeneous group of tumors from a glial origin and potentially malignant. The much circumscribed location of these tumors and its biological characteristics make them very sensitive to radiosurgery with GK. In these cases, the location with MRI is really important, including perfusion that lets to identify the exact areas to where the tumor is spreading out.
In this group, we have treated 3 xanthoastrocytomas in childhood (study to be published), one of them multiple, with response consisting of a volume reduction between a 50% and a 80%. 14 pilocytic astrocytomas with a reduction in 10 cases (between 20%-60%) have been also treated, one case has not been developed and a patient has died for tumoral progression. Other 10 microcystic astrocytomas have been treated with a considered response in a reduction of 50% and fading in all the cases. Finally, we have treated three II grade oligodendrogliomas with response in the three cases, consisting in a 20%-40% volume reduction.
Chordomas: Since starting treatments through radiosurgery with GK, these tumors were forwarded to a treatment with heavy particles accelerator. Today we rely on a series of 12 treated cases (study pending to be published) with a reduction of 2 years in 6 of them (between a 10% and a 50%) and lack of progression in 2 patients, other case had a disease development and died. Evidenced complications have not been observed in any other case.

Trigeminal neuralgias

The use of treatments with radiosurgery for functional disorders is enjoying an extremely rapid growth. Several clinical trials are being carried out by diverse users groups of GK. Only in our centre as a routinely clinical procedure radiosurgery is applied for treating the neuralgia of trigeminal nerve and of some causative lesions of epileptic seizures, having begun recently to perform treatments for chronic irritative pain (cingulotomies).

Up to now (2010), this treatment has been applied to a total of 267 patients (33 of them twice). 217 treatments have been a typical trigeminal neuralgia. This type of neuralgia treatment by radiosurgery is done applying radiation beams to the nerve in its cisternal tracking (between its brain stem and the Gasser node). It is a very comfortable therapy for the patient although the results are at long term (after 3-9 months) collected. However, a 16% of the patients show an immediate response; from the first day of treatment they do not evidence pain again.
Overall, a 76% of patients have a complete pain loss and a 40% of them do not need to take medicines to remain asymptomatics. The toxicity is the appearance of some grade of hypesthesia (decrease sensitivity in the affected side of the face) in a 20% of patients.
There is a facial pain clinical setting (atypical facial pain) of different characteristics from the typical neuralgia and that entails a more difficult control with a worse response to medical and surgical treatments. We have dealt with 83 cases and its response has been positive, whilst rather lesser than the typical neuralgia: a third of patients remain without pain after the procedure. The side effects are alike.
We also have treated a total of 10 patients with neuralgia due to the multiple sclerosis disorders with successful results: 43% of cases with pain control and disorders in sensitivity similar to the other groups.
Additionally to this pathology we have treated 8 patients (10 treatments) of cluster cephalea and 3 patients who show an “irritative” facial pain.
The use of treatments with radiosurgery for functional disorders is enjoying an extremely rapid growth. Several clinical trials are being carried out by diverse users groups of GK. Only in our centre as a routinely clinical procedure radiosurgery is applied for treating the neuralgia of trigeminal nerve and of some causative lesions of epileptic seizures, having begun recently to perform treatments for chronic irritative pain (cingulotomies).
The Unit works jointly coordinated with the Epylepsy Hospital Unit for these cases studying and assessing all the patients setting together the indications. The follow-up is also combined.
Up to the present we have treated and followed up 11 cases of patients with secondary epileptic seizures to temporary mesial sclerosis. Only one of them, with few months of follow-up, remains in a similar situation to the previous one. The remaining has significantly improved with a reduction in number and intensity of the seizures. Seizures have not recurred in three patients: One from the day of treatment and, in the other two cases seizures disappeared at 12 and 17 months. As a side effect, in two cases an important brain edema has been watched at 9 months after radiosurgery, what has required a corticoids treatment and, later, he has improved. The edema has appeared in two of three patients who are currently without seizures.
The data collected in the mesial sclerosis are included in a European cooperative study and the preliminary results are similar to the brought ones in previous series (significant number of seizures reduction after a year from radiosurgery taking the same medication).
6 cases of epileptic and/or gelastic seizures (unmotivated laugh) have been also treated and followed in patients with hypothalamic hamartomas. Two of them are invariable and four have improved their seizures as well as the aggressive behaviour, remaining two patients without any seizure from a month after treatment. No toxicity has been related to the treatment.
– Tremor.
– Obsessive-compulsive disorders (OCD).
– Treatments-refractory anorexia.
– Treatments-refractory bipolar disorder.
Planning of a case of temporary mesial epilepsy.


Dr. Martínez Álvarez, Roberto Team leader
Más información

  • Licenciado en Medicina y Cirugía  por la Facultad de Medicina de la Universidad Autónoma de Madrid, 1978. – Tesis Doctoral  en el año 1985.
  • Medico residente en la Especialidad  de Neurocirugía  entre  1979-1984.
  • Neurocirujano de la Clínica Puerta de Hierro de Madrid entre  1985-1989.
  • Neurocirujano de la Unidad de Radiocirugía del Hosp. Ruber Internacional de Madrid desde 1993. Jefe de la Unidad de Neurocirugía Funcional y Radiocirugía del Hosp. Ruber Internacional desde 2005.
  • Miembro de 15 sociedades médicas nacionales e internacional.
  • Académico  Correspondiente de la Academia de Medicina de Asturias, España.
  • Consultor de la compañía Elekta desde el año 2011.
  • Profesor Honorario de la Facultad Autónoma de Medicina de Madrid.
  • 180 trabajos publicados en revistas nacionales y extranjeras.
  • 230 presentaciones en congresos nacionales e internacionales.
  • Ponente Invitado a 100 congresos nacionales e internacionales.
  • Editor de 3 libros publicados.
  • Autor de 22 capítulos en diversos libros publicados entre  1988 y 2015.
  • Premio Fabrikan otorgado por la International Stereotactic and Radiosurgery Society en 2105.

How is the treatment with radiosurgery?

It is fundamental to know when and in which conditions can be applied radiosurgery.
Overall, this technique is used to deliver radiations in brain areas at volumes of 0.3 cc to 10 cc. Assuming that an equal effectiveness is not guaranteed, it is possible to overcome this figure to the 30 cc.

Radiosurgical procedure

The procedure must spare specific main areas of the brain, near to the area to deliver radiation in just one surgical performance.
– The stereotactic frame-based.
The radiosurgical procedure with Gamma Knife (GK) starts by a complete information to the patient and the informed consent filling.
The patient is hospitalized receiving the suitable medication. The next step is the placement of the stereotactic head frame (picture), the head frame is strongly fixed to the skull by pins, and local anaesthesia will be required. This is the only way for keeping the precise position of the patient, required by a unique session of radiosurgery.

-Lesion situation.
Next, the patient is moved to the imaging department. There a MRI is always done in sterotaxic conditions, so that in any image are marks able to identify the position of any point regarding the reference frame attached to the patient. The required sequence or sequences are used and a contrast is injected according to the process to be treated.
A key element to conduct the test in such conditions is the usage of the Leksell stereotactic frame and the use of attaching devices of aluminium and titanium.
By the MRI a better settlement to locate utmost lesions to deal with, and the risking structures. A CT in stereotactic conditions has had to be used only if there is device produced by a metallic object. CT is also used to merging MRI images if there the misgiving of, due to air-bone interfaces, could exist a non-valuable defect for the previously mentioned controlling method.
If it is an arterial venous malformation a digital angiography is also part of the protocol in stereotactic conditions with defect correction.
The images coming from all these procedures are transferred by our local network to the planning system (neither printing nor film digitalizing is required and therefore, stages of possible vagueness are avoided.)

-The planning.
A multidisciplinary team formed by neuroradiologists, neurosurgeons, oncologic radiotherapists and radiophisicists, determine the situation and the white limits, the critical organs; they set the treatment strategy and decide the dosages that will be administered.

The patient goes to the unit where the GK is and he places on the table. With the stereotactic frame the called “helmet” or secondary collimator is attached. Next, he is introduced inside the GK, for some minutes. All this procedure is completely painless. It is very common, according to the size and shape of the lesion, changing the position and size of the secondary collimator. The whole process, in most of the cases, last about half an hour or two hours and it is supervised by a neurosurgeon and a radiation physicist.
The patient is firmly held to the secondary collimator by the robot:
Patient’s positioning system
The patient’s rain area that is going to be irradiated must be placed extremely precisely in the centre of the radiating semi-sphere. The procedure involves the patient placing on a stretcher and holds his/her head to the secondary collimator by a stereotactic head frame.
Usually, the volumes to deliver beam radiation are not spherical. In those cases the patient must be moved so, that all the tumor volume is properly irradiated. The classic method (which sometimes will be necessary to apply) implies to release the patient and place him again manually in his new irradiating position.
The C model includes, as an amazing innovation, a robot (the APS) which safely and accurately moves the patient reducing human mistakes and implying a shorter treatment times and, therefore, a greater comfort for the patient.
On the whole, the movements are so slow that allow several patients snoozing during the treatment.

Gamma Knife

Gamma Knife or Gamma Unit is a highly accurate and reliable device.
The used irradiation system: The GK is, in terms of technology, jointly with the planning system, two most typical elements of the procedure and it requires a shallow description.
The GK has two essential parts:
The irradiation system:
The secondary collimator (left) moves to be fixed to the emptying semi-sphere where the radioactive sources are contained.

Gamma Unit diagram (right) showing the secondary collimator movement (to which the patient is submitted) to the sphere containing the sources.

Patient’s positioning system:

The patient’s brain area that is going to be irradiated must be placed extremely precisely in the centre of the radiating semi-sphere. The procedure involves the patient placing on a stretcher and holds his/her head to the secondary collimator by a stereotactic head frame.
Usually, the volumes to deliver beam radiation are not spherical. In those cases the patient must be moved so, that all the tumor volume is properly irradiated. The classic method (which sometimes will be necessary to apply) implies to release the patient and place him again manually in his new irradiating position.
The C model includes, as an amazing innovation, a robot (the APS) which safely and accurately moves the patient reducing human mistakes and implying a shorter treatment times and, therefore, a greater comfort for the patient.
On the whole, the movements are so slow that allow several patients snoozing during the treatment.
The patient is place inside the semi-sphere, so that the point on which the radiation concentrates matches with the brain area intended to be irradiated.
The rest of the brain supports as much a very small part (and of course tolerable) of the received dosage into the target.
The irradiated area is really tiny and almost spherical, however the shape of inter cerebral lesions often differs significantly to the spherical, so the patient’s position must be modified, in order to irradiate a near area to the above one. Thus, in a set of stages (overall, from 5 to 15) all the lesion size is covered with an extraordinary accuracy in all its volume.
With this system two main advantages are gained: The first one is that inside the lesion may remain small volumes in which the radiation delivery, by the two irradiated areas superposition, increases the desired action. The second one is that the dosage drop outside the lesion tends to become sharper as we use less basic volumes of irradiation.

Our Experience Our experience is reinforced with the one of other groups, which, using the same means, works in the rest of the world.
Average of the treated different pathologies with GK in our hospital.
Since 1993, more than 5.300 (June 2011) treatments from diverse pathologies have been performed with Gamma Knife radiosurgery in our hospital. This technology is applied in other centres, from the most renowned in the world: Karolinska University Hospital (Stockolm), Mayo Clinic, Pitssburg University, Munich, etc. Our results are proven, undoubtedly, with the ones of the series performed in the above mentioned centres through the close contact supported between the diverse Units of Gamma Knife by the personal visits, annual and biannual meetings, carried out in this regard.
The experience of more than 155 GK around the world means more than 200.000 performed treatments from 1986.
In 1993, we performed the first treatments with the second generation device (model B) which, in that moment was the equipment No 43 of the world. In year 2000 this model was changed to model C (our device is the No 11 of the world with this same specifications) improved with the automatic positioning system from April 2001. Finally in 2007, the machinery was completely renewed, the most cutting edge model since the moment (2011) called PERFEXION. It is outstanding its safety for the patient as it is a full automatic procedure and the beam dosage outside the head is lower (from 10 to 100 times lower to other procedures).
For further information please go to site Elekta in the Radiosurgery Spanish Society or click here aquí.