BELdART mailed auditing

The BELdART project was a collaboration between the Nuclear Technology Centre (NuTeC) and the College of Physicians and the Belgian Hospital Physicists Association (BHPA).

The project, supported by the Federal Agency for Nuclear Control (FANC), encompassed a basic audit of each clinical radiation device in all Belgian radiotherapy departments. This basic audit consisted of a dosimetric check of all the photon and electron beams and a check of the most important mechanical parameters. In total 31 centres (representing 208 beams) were audited by the end of the project. The project was worldwide the first large scale dosimetry audit using alanine-EMR-dosimetry.

Within the framework of BELdART, all Belgian centres were offered the possibility to participate in a dosimetry audit without charge. During a period of three years, all radiotherapy centres were visited (about 80 linacs and 230 beams). The BELdART project was a scientific project because it is the first national audit program using alanine-EMR-dosimetry worldwide. The project was financed by the Belgian Federal Agency for Nuclear Control (FANC). The audit results were strictly confidential and were reported anonymously in frequency distribution formats.

Purpose of the audit

The purpose of the audit was to verify the output of external radiotherapy devices in reference and non-reference conditions in an independent way.

• In clinical routine high energy photon beams with and without wedge/ MLC- collimator and electron beams are used. Experimental verification of the dose calculated by the treatment planning system (TPS) is essential to maintain steady quality assurance in radiotherapy.
• In this protocol, the audit team performed a minimal mechanical verification of the LINAC, together with measurements of the absorbed dose to water delivered at a reference depth for a series of experiments covering reference and non-reference conditions, conforming to international audits. The centre calculated the number of monitor units (MU) to irradiate the alanine dosimeters to a requested dose, following the local procedure as it is used in clinical practice for patients.
• The audits encompassed only clinically used radiation beams: all photon beams and one low and one high energy (R₅₀ > 7cm) electron beam.

Materials & methods

The audit encompassed an on-site visitation of one BELdART employee who would perform the verifications with BELdART material, together with the local radiation physicist.

• A mechanical verification encompassed the verification of the dimension of the reference radiation field (10 x 10 cm²) and the verification of the position of the isocenter and laser lines
• The dosimetric verification was performed by measuring the described absorbed dose in water at a predefined depth as stated in the “Procedure instructions”. The alanine dosimeters were delivered packed in a waterproof, air-evacuated sealing. Each holder contained 4 alanine pellets whereby a mark indicated the centre of the 4 pellets. 
• Yearly 4 radiotherapy centres were given the opportunity to simultaneously participate with the BHPA audit using the BHPA ionization chamber.
• Dose to water D_w at the reference point was measured using four alanine dosimeters which were measured at the NuTeC-EMR-Laboratory. The measuring procedure was inspired by and the dosimetry is traceable (water calorimetry) to the German laboratory of Standardization PTB in Braunschweig. Moreover, the alanine response was benchmarked regularly with ionization chamber measurements in the frame of the BHPA-auditing.

Reporting results

• All results were treated with confidence by BELdART. All measurements were internally “validated” before communicating with the participants.
• The relative deviation |δ| ≡ |(D_measured – D_center) x100 / D_center| was classified into four levels with respect to actions to be taken: 

• Validated results were communicated to the local radiation physicist and the responsible radiation oncologist. Results “out of tolerance level” were discussed within the BELdART team, together with the local radiation physicist. All findings were treated in strict confidence by the BELdART team.
• The results of the audit were meant to be an independent verification of the beam output and "treatment'" quality and could not replace a beam calibration as performed by a qualified radiation physicist. THE RESULTS SHOULD NEVER BE CONSIDERED AS A CERTIFICATE FOR THE QUALITY OF A RADIOTHERAPY TREATMENT.
• Depending on the results the following actions were undertaken:
  • All observed deviations are “within tolerance level”: a detailed overview of the results will be sent to the radiation physicist and the responsible radiation oncologist of the centre.
  • At least one observed deviation is “out of tolerance”, but all deviations are smaller than the “alarm level”: the centre is informed about the “out of tolerance level” with the request to organize a second test. All results “within tolerance” are communicated.
    • If all results of the second test are within the tolerance level, all results will be mailed, and the cause of the deviation should be communicated, as well as the actions to avoid the problem in the future.
    • If the second test is not finished, the deviation “out of tolerance” is considered to be confirmed by the first measurement. The results will be communicated to the radiation physicist and the responsible radiation oncologist.
    • If the second test confirms the deviation out of tolerance: results are mailed to the radiation physicist and the responsible radiation oncologist with confirmation of the observed deviation. The BELdART team will contact the radiation physicist to discuss the case.
  • At least one observed deviation is at “alarm level”: same procedure as described above, but prior to mailing the results, the BELdART team contacts the local radiation physicist and announces a significant deviation and organizes a second test.
  • If the second test confirms the large deviation, both results will be sent to inform the radiation physicist and the responsible radiation oncologist of the centre so that they can take action.

Final project status

The following map shows the locations of the clinics that were audited:

BELdART-2 (2013-2015) was the continuation of the BELdART-1 project. It encompassed mailed audits for advanced and dynamic radiotherapy techniques (e.g. IMRT, VMAT, Tomotherapy). The audit consisted of 2 parts:

1) Control of basic dosimetry in a water tank using alanine positioned with a 3D printed holder

2) End-to-end verification of plans delivered on an EasyCube phantom (LAP GmbH Laser Applikationen)

BELdART-2 used a combination of alanine-EPR-dosimetry and radiochromic film dosimetry. 

The project was supported by the College of Medicine-radiotherapy and FOD Healthcare and financed by Het Kankerplan/Plan Cancer. Within the framework of BELdART-2, all Belgian centres were offered the possibility to participate to the dosimetry audit without charge. 

Results

EPR basic tests

The dose difference between planned and alanine doses was within 3% for all the centres for 10x10 cm² fields. For wedges fields where the field is corrected for the output of the day, the dose difference was within 2%.

Falling within the 2% criterion were 88.4% of the centres for the reference dose, 100% at 8 cm depth, 92.9% for 20 cm depth and 94.9% for SSD85. All the other centres were within 3% for these tests.

For 2x10 cm² fields, 79.0% of the centers were within 2% and 89.5% within 3%. All the centres were within 5%. The uncertainty was 1% (k=1).

EPR in the EasyCube phantom

Film results

We evaluated the films with gamma analysis (global) with 3%/3mm criterion and 10% threshold. 3% of the films had a passing rate <90%. 27% of the films had a passing rate between 95%-98% and 70% had a passing rate >98%.

BeldART-SRS encompasses mailed audits for intracranial Stereotactic Radiosurgery (SRS) in Belgium. The project is financed by Het Kankerplan/Plan Cancer and monitored by the College of Medicine-radiotherapy and FOD Healthcare. All Belgian centres are offered the possibility to participate to the dosimetry audit without charge.

The audit consists of 2 parts:

1) Control of basic dosimetry in a water tank using alanine positioned with a 3D printed holder.

2) End-to-end verification of plans delivered on a STEEV Stereotactic End-to-End Verification Phantom (CIRS Inc.)

BELdART uses a combination of alanine-EPR-dosimetry and radiochromic film dosimetry. 2 sets of structures in DICOM format are delivered to the participating clinic. 1 larger structure which is analysed with GAFchromic^TM EBT-XD films and alanine detectors and 1 smaller structure which is analysed with EBT-XD film detectors only.

Results (2017-2024)

EPR basic tests

The figure above shows the results for 68 beams. The results are corrected for the output of the day. The difference between the measured and planned doses for the output in reference conditions is < 3% for all beams, except for 1 case for the small field test. 90 % of the beams are within 2 % for the tests with a 10x10 cm² field.

For the small fields, 79 % of the beams are within 2 % The uncertainty on the measurements is 1% (k=1).

EPR in the SRS phantom

The figure above shows the results for 57 beams for the alanine pellet placed in the middle of the larger PTV. 56 beams are delivered using a frameless technique, and 1 beam with a framed technique.

82 % of the beams have a dose difference of <3% than the planned dose. In 3 beams, the difference is > 5 %. The uncertainty on the measurements is 1% (k=1).

Film results

The figure above shows the film results for 57 beams. 1 film was placed through the centre of the large target, where the alanine pellet was also placed, and another film was placed through the small target. 56 beams are delivered using a frameless technique, and 1 beam is delivered using a framed technique.

We evaluated the films using gamma analysis with a 5%/1mm criteria (global) and 30 % threshold. 94 % of the beams have a passing rate higher than 95 %. For 3 beams, the passing rate is < 90 %. 

BeldART-SBRT encompasses mailed audits for extracranial Stereotactic Body Radiation Therapy (SBRT) in Belgium. The project is financed by Het Kankerplan/Plan Cancer and monitored by the College of Medicine-radiotherapy and FOD Healthcare. All Belgian centres are offered the possibility to participate to the dosimetry audit without charge.

The audit consists of 2 parts:

1) Control of basic dosimetry in a water tank using alanine positioned with a 3D printed holder.

 2) End-to-end verification of plans delivered on a Virtual Water™ IMRT Dose Verification Phantom (Standard Imaging, Inc.)

BELdART uses a combination of alanine-EPR-dosimetry and radiochromic film dosimetry. 1 set of structures in DICOM format is delivered to the participating clinic. An alanine pellet and a piece of GAFCHROMIC^TM EBT-XD film are placed through the target.

Results (2017-2024)

EPR basic tests

The figure above shows the results for 39 beams. The results are corrected for the output of the day. The difference between the measured and planned doses for the output in reference conditions is < 3% for all beams, except for 2 cases for the small field test. 92 % of the beams are within 2 % for the tests with a 10x10 cm² field.

For the small fields, 74 % of the beams are within 2 % The uncertainty on the measurements is 1% (k=1).

EPR in the lung phantom

The figure above shows the results for 32 beams for the alanine pellet placed in the middle of the target. 87 % of the beams have a dose difference <3% than the planned dose. In 4 beams, the difference is > 5 %. The uncertainty on the measurements is 1% (k=1).

Film results

The figure above shows the results for 32 beams. 1 film was placed through the target on top of the alanine pellets, and 1 film was placed on top of the lungs. We evaluated the films using gamma analysis with criteria 5%/1mm 10 % threshold with global normalisation for the film through the target and 3%/2mm 10 % threshold with global normalisation for the film on top of the lungs.

For the film through the target, 95 % of the beams have a passing rate > 95 %. For the film on top of the lungs,  81 % of the beams have a passing rate > 95 %. 4 beams have a passing rate < 90 %.

We perform internal QA on each day of the alanine read-out. This test is part of the regular methodology of the read-out for the BELdART audits and is used to make sure that the spectrometer is performing normally on the day of the read-out. The calibration set received from PTB consists of alanine pellets irradiated at 10 different dose levels in a water phantom with a 60Co beam. The actual calibration of the spectrometer is performed with the alanine receiving 0 and 25 Gy. For QA purposes, alanine pellets for two more dose levels in the region of the expected dose, 7.5 and 15 Gy in this case, are read and compared with their certified doses. Each set consisted of four alanine pellets irradiated uniformly. The readings on that day are repeated if the QA pellets measure more than 1 % deviation from the given dose by PTB. The uncertainty on the read-out was 1 % (k=1).

External QA

Our team also performs external QA. Our alanine/EPR dosimetry system was validated by comparing our readings with a known dose given by VSL. Three sets of sealed alanine pellets were irradiated on May 12, 2025, at VSL using the BELdART custom-designed alanine holder in water in a ⁶⁰Co-beam. The results are shown below.

Yalvac B, Reulens N and Reniers B. Early results of a remote dosimetry audit program for lung stereotactic body radiation therapy. Phys Imaging Radiat Oncol 2024;29;100544. 

Vaandering, A., Roels, S., Yalvaç, B., Reulens, N., Reniers, B., Vanhoutte, F., Remouchamps, V., Lievens, Y., & Weytjens, R. (2023). Favouring quality improvement initiatives: the experience of the Belgian College of Radiation Oncology. Precision Cancer Medicine. https://pcm.amegroups.com/article/view/7502

Yalvac, B., Reulens, N., Schroeyers, W., Schreurs, S., & Reniers, B. (2021). BELdART: Belgian dosimetry audits in radiotherapy. Physica Medica, 92, S188-S189. https://doi.org/10.1016/s1120-1797(22)00404-5

B. Yalvac, N. Reulens B. Reniers, "Results of the national remote lung SBRT audits after 1 year", Symposium of the Belgian Hospital Physicists Association, April 2021

Reniers, B., Yalvac, B., & Reulens, N. (2020). SP-0394: Audits for SBRT. Radiotherapy and Oncology, 152. https://doi.org/10.1016/s0167-8140(21)00418-7

Yalvac, B., & Reniers, B. (2020). PO-1783: A method for performing film dosimetry as part of a postal audit service by a recalibration process. Radiotherapy and Oncology, 152. https://doi.org/10.1016/s0167-8140(21)01801-6

B. Yalvac, B. Reniers, "A method for performing film dosimetry as part of a mailed audit service using a recalibration process", Symposium of the Belgian Hospital Physicists Association, February 2020

B. Yalvac, N. Reulens, B. Reniers, "BELdART-SBRT: a national mailed audit program for Lung SBRT", Symposium of the Belgian Hospital Physicists Association, February 2020 

Yalvac, B., Reulens, N., Schroeyers, W., Schreurs, S., & Reniers, B. (2019). BELdART: A Belgian dosimetry audit programme in radiotherapy based on alanine/EPR and radiochromic film dosimetry (1011-2669). https://www-pub.iaea.org/MTCD/Publications/PDF/Newsletters/ssdl-70.pdf

B. Yalvac, N. Reulens, B. Reniers, "Results of external audits for basic and complex dosimetry for photon and electron beams from Oct 2016", Symposium of the Belgian Hospital Physicists Association", February 2019 

B. Yalvac, N. Reulens, B. Reniers, "BELdART-SRS: First results of the Belgian national audits in intracranial stereotaxy", Symposium of the Belgian Hospital Physicists Association, February 2018 

B. Yalvac, W. Schroeyers, N. Reulens, S. Schreurs, B. Reniers, "BELdART-3 a national mailed audit program for Stereotaxy", Symposium of the Belgian Hospital Physicists Association, February 2017  

Fonseca, Gabriel P.; Podesta, Mark; Bellezzo, Murillo; Van den Bosch, Michiel R.; Lutgens, Ludy; Vanneste, Ben G. L.; Voncken, Robert; Van Limbergen, Evert J.; Reniers, Brigitte & Verhaegen, Frank (2017) Online pretreatment verification of high-dose rate brachytherapy using an imaging panel.
In: PHYSICS IN MEDICINE AND BIOLOGY, 62(13), p. 5440-5461.

B. Reniers, W. Schroeyers, N. Reulens, S. Schreurs, "BELdART-2 a national mailed audit program for complex radiation therapy techniques: final results.", Symposium of the Belgian Hospital Physicists Association, February 2016

Ebert, Martin A.; Dhal, Bipina; Prunster, Janelle; McLaren, Sally; Zeps, Nikolajs; House, Michael; Reniers, Brigitte; Verhaegen, Frank; Corica, Tammy; Saunders, Christobel & Joseph, David J. (2016) Theoretical versus Ex Vivo Assessment of Radiation Damage Repair: An Investigation in Normal Breast Tissue.
In: RADIATION RESEARCH, 185 (4), p. 393-401. 

Reniers, Brigitte; Janssens, Gerrit; de Xivry, J. Orban; Landry, G. & Verhaegen, F. (2016) Dose distribution for gynecological brachytherapy with dose accumulation between insertions: Feasibility study.
In: BRACHYTHERAPY, 15(4), p. 504-513. 

Fonseca, Gabriel P.; Viana, Rodrigo S. S.; Podesta, Mark; Rubo, Rodrigo A.; de Sales, Camila P.; RENIERS, Brigitte; Yoriyaz, Helio & Verhaegen, Frank (2015) HDR Ir-192 source speed measurements using a high speed video camera.
In: MEDICAL PHYSICS, 42 (1), p. 412-415.

Adolfsson, Emelie; White, Shane; Landry, Guillaume; Lund, Eva; Gustafsson, Hakan; Verhaegen, Frank; RENIERS, Brigitte; Tedgren, Asa Carlsson & Carlsson, Gudrun Alm (2015) Measurement of absorbed dose to water around an electronic brachytherapy source. Comparison of two dosimetry systems: lithium formate EPR dosimeters and radiochromic EBT2 film.
In: PHYSICS IN MEDICINE AND BIOLOGY, 60 (9), p. 3869-3882.

Trani, Daniela; RENIERS, Brigitte; Persoon, Lucas; Podesta, Mark; Nalbantov, Georgi; Leijenaar, Ralph T. H.; Granzier, Marlies; Yaromina, Ala; Dubois, Ludwig; Verhaegen, Frank & Lambin, Philippe (2015) What Level of Accuracy Is Achievable for Preclinical Dose Painting Studies on a Clinical Irradiation Platform?.
In: RADIATION RESEARCH, 183 (5), p. 501-510.

Fonseca, Gabriel Paiva; Tedgren, Asa Carlsson; RENIERS, Brigitte; Nilsson, Josef; Persson, Maria; Yoriyaz, Helio & Verhaegen, Frank (2015) Dose specification for Ir-192 high dose rate brachytherapy in terms of dose-to-water-in-medium and dose-to-medium-in-medium.
In: PHYSICS IN MEDICINE AND BIOLOGY, 60 (11), p. 4565-4579.

Trani, Daniela; Yaromina, Ala; Dubois, Ludwig; Granzier, Marlies; Peeters, Sarah G. J. A.; Biemans, Rianne; Nalbantov, Georgi; Lieuwes, Natasja; Reniers, Brigitte; Troost, Esther E. G. C.; Verhaegen, Frank & Lambin, Philippe (2015) Preclinical Assessment of Efficacy of Radiation Dose Painting Based on Intratumoral FDG-PET Uptake.
In: CLINICAL CANCER RESEARCH, 21 (24), p. 5511-5518.

B. Reniers, W. Schroeyers, N. Reulens, S. Schreurs, "BELdART-2 a national mailed audit program for complex radiation therapy techniques: 2 years-results.", Symposium of the Belgian Hospital Physicists Association, February 2015

B. Reniers, W. schroeyers, N. Reulens, S. Schreurs, "PO-0928: Development of a national audit program for dynamic therapy.", Radiotherapy and Oncology, Volume 111, Supplement 1, 2014, Pages S117-S118

Fonseca, Gabriel Paiva; Landry, Guillaume; White, Shane; D'Amours, Michel; Yoriyaz, Helio; Beaulieu, Luc; RENIERS, Brigitte & Verhaegen, Frank (2014) The use of tetrahedral mesh geometries in Monte Carlo simulation of applicator based brachytherapy dose distributions.
In: PHYSICS IN MEDICINE AND BIOLOGY, 59 (19), p. 5921-5935.

Fonseca, Gabriel P.; RENIERS, Brigitte; Landry, Guillaume; White, Shane; Bellezzo, Murillo; Antunes, Paula C.G.; de Sales, Camila P.; Welteman, Eduardo; Yoriyaz, Helio & Verhaegen, Frank (2014) A medical image-based graphical platform-Features, applications and relevance for brachytherapy.
In: BRACHYTHERAPY, 13 (6), p. 632-639.

B. Reniers, W. schroeyers, N. Reulens, S. Schreurs, "Development of a national audit program for dynamic therapy." , Symposium of the Belgian Hospital Physicists Association, February 2014

B. Reniers, W. schroeyers, N. Reulens, S. Schreurs, "Development of an auditing program for intensity modulated radiotherapy", Physica Medica, Volume 29, Supplement 1, June 2013, Page e8

S. Lelie, W. Schroeyers, B. Reniers, S Schreurs, "EP-1159: BELdART-2: a national IMRT audit", Radiotherapy and Oncology, Volume 106, Supplement 2, March 2013, Page S438

S. Lelie, W. Schroeyers, B. Reniers, S Schreurs "BELdART-2: Moving towards safer radiotherapy", BHPA symposium, Mechelen, Belgium February 2013

B. Schaeken, R. Cuypers, J. Goossens, D. Van den Weyngaert, D. Verellen, 
"Experimental determination of the energy response of alanine in the high dose-rate 192Ir spectrum",
Phys. Med. Biol.  56:6625-6634, 2011.

Schaeken, R. Cuypers, W. Schroeyers, F. Sergent, S. Vynckier, A. Rijnders, D. Verellen, H. Janssens, S. Schreurs
"Quality assurance audit for photon and electron beams (BELdART): how good we're doing?",
B, Proc. Annual. Symp. Bel. Hosp. Physicist Ass., Charleroi, 2011. (Download  Presentation)

B. Schaeken, R. Cuypers, S. Lelie, W. Schroeyers, S. Schreurs, H. Janssens, D. Verellen,
"Implementation of alanine/EPR as transfer dosimetry system in a radiotherapy audit programme in Belgium",
Radiother. Oncol. 99:94-96, 2011.

B. De Ost, B. Schaeken, E. Sterpin, S. Vynckier, D. Van den Weyngaert,
"Reference dosimetry for tomotherapy: practical implementation and multi-centre validation",
Med. Phys. Accepted, 2011.

B. Schaeken, S. Lelie, R. Cuypers, W. Schroeyers, F. Sergent, S. Vynckier, A. Rijnders , D. Verellen, H. Janssens, S. Schreurs,
“BELdART: Implementation of a quality assurance audit for photon beams based on alanine/ EMR dosimetry: methodology and first results”,
Proc. Ann. Symp. Belgian Hosp. Physicist Ass., p31, Brussel, 2010.

T. Lennertz, B. Schaeken, S. Lelie, B. Bogdanov, E. Bressers, D. Verellen, S. Schreurs,
“Validation of LiFo films for dosimetry in breast conservative treatment”,
Proc. Ann. Symp. Belgian Hosp. Physicist Ass., p42, Brussel, 2010. (Download Presentation)

B. De Ost, B. Schaeken, D. Van den Weyngaert,
“Reference dosimetry for tomotherapy : practical implementation and validation”,
Proc. TomoTherapy Users Meeting, p.52, Marbella, 2010.

B. De Ost, B. Schaeken, D. Van den Weyngaert,
“Validation of the reference dosimetry in water for static and helical tomotherapy”,
Radiother.  Oncol. 96 (S1):S466, 2010.

S. Lelie, T. Lennertz, B. Schaeken, B. Bogdanov, E. Bressers, S. Schreurs, W. Schroeyers, D. Verellen,
“LiFo-film dosimeters in skin dose measurements”,
Proc. IAEA Int. Symp. On Standards, Applications and Quality Assurance in Medical Radiation Dosimetry (IDOS), Vienna, 2010.

B. Schaeken, S. Lelie, P. Meijnders, D. Van den Weyngaert, H. Janssens, D. Verellen,
“EPR dosimetry applied to the verification of a total body irradiation protocol and treatment planning dose calculation using a humanoid phantom”,
Med. Phys. 37:6292-99, 2010.

B. Schaeken, S. Lelie, R. Cuypers, W. Schroeyers, F. Sergent, S. Vynckier, A. Rijnders, D. Verellen, H. Janssens, S. Schreurs,
"BELdART: Implementation of a quality assurance audit for photon and electron beams based on alanine/ EMR dosimetry",
Proc. IAEA Int. Symp. On Standards, Applications and Quality Assurance in Medical Radiation Dosimetry (IDOS), Vienna, 2010. (Download  Abstract)

B. Schaeken, W. Schroeyers, B. De Ost, S. Lelie, D. Verellen, S. Schreurs, H. Janssens,
“A new facility dedicated to EPR-dosimetry in Belgium”,
Proc. Ann. Symp. Belgian Hosp. Physicist Ass., Kortrijk, 2009. (Download Poster)

B. Schaeken, S. Lelie, R. Cuypers, W. Schroeyers, F. Sergent, S. Vynckier, A. Rijnders, D. Verellen, H. Janssens, S. Schreurs,
“BELdART: Implementation of an audit program for photon beams in radiotherapy based on alanine/ EMR dosimetry: first results”,
Conf. on Modern Radiotherapy-patient protection, Versailles, 2009. (Download Poster)

B. De Ost, B. Schaeken, D. Van Gestel, J. Goossens, D. Van den Weyngaert,
“Accuracy of dose calculations for sinus ethmoidalis patients treated with helical tomotherapy”,
Radiother.  Oncol. (1), 2008.

B. Schaeken, D. Van den Weyngaert, H. Janssens, D. Verellen,
“Quality Assurance for IMRT in Belgium: verification of the integral delivered dose with alanine-ESR dosimetry”,
Med. Phys. 35(6):2761, 2008.

Frederik Verbeek, Gudrun koppen, Bob Schaeken, Luc Verschaeve,
"Automated detection of irradiated food with the comet assay",
Rad. Prot. Dosim. 128:421-26, 2008.

M. Duchateau, D. Verellen, B. Schaeken,
“The evaluation of two different IMRT treatment delivery systems, Helical tomotherapy and step_shoot IMRT: an alanine dosimetric verification”
Proc. Ann. Symp. Belgian Hosp. Physicist Ass., 45-145, Gent, 2006.

B. Schaeken, B. De Ost, D. Van Gestel, D. Van den Weyngaert,
“Estimating a confidence limit for the integral evaluation of IMRT treatments for head & neck tumors”
Proc. Ann. Symp. Belgian Hosp. Physicist Ass., 53-124, Gent, 2006.

B. De Ost, B. Schaeken, D. Van Gestel, A. Coelmont, D. Van den Weyngaert,
“Copy to phantom a tool and a toy”,
Proc. Ann. Symp. Belgian. Hosp. Physicist Ass., 47-124, Gent, 2006.

S. Duane, H. Palmans, P. Sharpe, M. Tomsej, B. Schaeken, S. Vynkier,
“Absolute and relative dosimetry in tomotherapy using alanine and ion chambers”
Proc. Ann. Symp. Belgian Hosp. Physicist Ass. 78-124, Gent, 2006.

S. Duane, D. Nicholas, H. Palmans, B. Schaeken, J. Sephton, P. Sharpe, R. Thomas, M. Tomsej, K. Tournel, D. Verellen, S. Vynckier,
“Reference dosimetry for Tomotherapy using alanine and ion chambers”
Book of abstracts, Biennial Radiotherapy physics meeting, Institute of  Physics and Engineering in Medicine, Norwich, UK, 2006.

B. Schaeken, B. De Ost, D. Van Gestel, H. Janssens, D. Van den Weyngaert,
“Verification of the integral delivered dose for IMRT treatments in the head & neck region with alanine/ESR dosimetry”,
Proceedings of the 216th PTB seminar "Alanine Dosimetry for Clinical Applications" , May 2006, Braunschweig.  PTB-Bericht, PTB-DOS-51, ISBN 3-86509-526-7 (Download Paper)

S. Duane, D. Nicholas, H. Palmans, B. Schaeken, J. Sephton, P. Sharpe, R. Thomas, M. Tomsej, K. Tournel, D. Verellen, S. Vynckier, 
“Alanine and ion chamber dosimetry in helical tomotherapy”,
Radiother.  Oncol. 81(S1):S45, 2006.

B. Schaeken, B. De Ost, D. Van Gestel, P. Meijnders, I. Jacobs, C. Goor, S. Vanderkam, A. Coelmont, D. Van den Weyngaert,
“Alanine dosimetry in dose verification for IMRT”,
Radiother.  Oncol. Vol 81(S1):S365, 2006.

S. Duane, H. Palmans, B. Schaeken, J. Septhon, P. Sharpe, R. Thomas, M. Tomsej, K. Toernel, D. Verellen, S. Vynckier.
“Dosimetry audit for Tomotherapy using alanine/EPR,
Med. Phys. Vol 33(6):2093, 2006.

T. Gevaert, F. Desmedt, B. Vanderlinden, B. Schaeken, C. Van Ranst, G. Storme, M. Levivier, S. Simon, D. Verellen. D. Kondziolka (ed):
In vivo estimation of the extracranial doses in stereotactic radiosurgery with the Gamma Knife and Novalis system,
Radiosurgery; 6:36-49 (DOI:10.1159/000093714), Basel, Karger, 2006.

B. Schaeken, T. Wauters, B. De Ost, D. Van Gestel, A. Coelmont, D. Van den Weyngaert
“Alanine dosimetry as a measuring system in QA for step and shoot IMRT
Deutsche Gesellschaft für Medizinische Physik, p234, Leipzig, 2004

B. de Ost, B. Schaeken, T. Wauters, D. Van Gestel, A. Coelmont, D. Van den Weyngaert,
“QA with alanine dosimetry for step and shoot IMRT of head and neck tumors”
Radiother. Oncol., 73(S1), 2004.

R.J.M. Elfrink, I-K kolkman-Deurlo, H.J. kleffens, A. Rijnders, B. Schaeken, T.H.L. Aalbers, W. J.F. Dries, J.L.M. Venselaar, "Quality Control of brachytherapy equipment in The Netherlands and Belgium: current practice and minimum requirements",
Radiother. Oncol. 62:95-102, 2002.

C.G. Soares, S. Vynckier, H.Jrvinen, W.G. Cross, J. Hokkanen, P. Sipil, D. Flyhs, B. Schaeken, F. Moertada, G.A. Bass, T.T. Williams,
“Dosimetry of beta-ray ophtalmic applicators: Comparison of different measuring methods”
Med. Phys., 28(7):1373-84, 2001.

R.J.M. Elfrink, I-K Kolkman-Deurloo, H. J. van Kleffens, A. Rijnders, B. Schaeken, T.H.L. Aalbers, W. J. F. Dries, J. L. M. Venselaar, 
"Determination of the accuracy of implant-reconstruction and dose delivery in brachytherapy in The Netherlands and Belgium",
Radiother. Oncol. 59:297-306, 2001

B. Schaeken, P. Scalliet,
“One Year of Experience with alanine dosimetry in Radiotherapy”
Appl. Radiat. Isot. Vol. 47:1177-82, 1996. (Download Paper)

B. Schaeken, C. Goor, D. Van den Weyngaert, 
“Results of routine measurements of rectal dose with alanine during LDR brachytherapy treatment”,
Radiother. Oncol. 39(1):S28, 1996.

B. Schaeken, C. Goor, D. Van den Weyngaert, 
“Routine measurements of dose to the bladder: still an utopy?”, 
Radiother.  Oncol.,  39(S1):S10, 1996.

B. Schaeken, C. Goor, P. Scalliet,
“EPR / Alanine Dosimetry: just another dose measuring system?”
The European J. of Cancer, 31A, S5:S33, 1995.

B. Schaeken,
“EPR-based dose measurements with alanine in clinical dosimetry”
Radiother. Oncol. 37(S1):S30, 1995.

B. Schaeken, B. De Ost, T. Borbely, P. Scalliet,
“Possibilities of EPR-dosimetry in radiotherapy”
Med. Phys. 21(6) :944, 1994

B. Schaeken, B. De Ost, C. Goor, P. Scalliet, 
"Dosimétrie in vivo par RPE en applications gynécologiques"
Bull. Cancer Radiother., vol. 81(4):469, 1994.

B. Schaeken, P. Scalliet,
“HDR stepping source dosimetry: the EPR approach”,
Radiother.  Oncol. 31(S 1): S22, 1994.