21 research outputs found
Implementation of an intraoperative electron radiotherapy in vivo dosimetry program
Background:
Intraoperative electron radiotherapy (IOERT) is a highly selective radiotherapy technique which aims
to treat restricted anatomic volumes during oncological surgery and is now the subject of intense re-evaluation. In
vivo dosimetry has been recommended for IOERT and has been identified as a risk-reduction intervention in the
context of an IOERT risk analysis. Despite reports of fruitful experiences, information about in vivo dosimetry in
intraoperative radiotherapy is somewhat scarce. Therefore, the aim of this paper is to report our experience in
developing a program of in vivo dosimetry for IOERT, from both multidisciplinary and practical approaches, in a
consistent patient series. We also report several current weaknesses.
Methods:
Reinforced TN-502RDM-H mobile metal oxide semico
nductor field effect tran
sistors (MOSFETs) and
Gafchromic MD-55-2 films were used as a redundant in vivo treatment verification system with an Elekta
Precise fixed linear accelerator for calibrations and tre
atments. In vivo dosimetry was performed in 45 patients
in cases involving primary tumors or relapses. The m
ost frequent primary tumors were breast (37 %) and
colorectal (29 %), and local recurrences among relapses was 83 %. We made 50 attempts to measure with
MOSFETs and 48 attempts to measure with films in th
e treatment zones. The surgical team placed both
detectors with supervision from the radiation oncologist and following their instructions.
Results:
The program was considered an overall success by the different professionals involved. The absorbed doses
measured with MOSFETs and films were 93.8 ± 6.7 % and 97.9 ± 9.0 % (mean ±
SD
) respectively using a scale in which
90 % is the prescribed dose and 100 % is the maximum absorbed dose delivered by the beam. However, in 10 % of
cases we experienced dosimetric problems due to detector misalignment, a situation which might be avoided with
additional checks. The useful MOSFET lifetime length and the film sterilization procedure should also be controlled.
Conclusions:
It is feasible to establish an in vivo dosimetry program for a wide set of locations treated with
IOERT using a multidisciplinary approach according to the skills of the professionals present and the detectors
used; oncological surgeons
’
commitment is key to success in this context. Films are more unstable and show
higher uncertainty than MOSFETs but are cheaper and
are useful and convenient if real-time treatment
monitoring is not necessary.This work was supported by grants IPT-300000-2010-3 and PI11/01659 from
the Spanish Government and ERDF funds
Practical issues regarding angular and energy response in in vivo intraoperative electron radiotherapy dosimetry
AimTo estimate angular response deviation of MOSFETs in the realm of intraoperative electron radiotherapy (IOERT), review their energy dependence, and propose unambiguous names for detector rotations.BackgroundMOSFETs have been used in IOERT. Movement of the detector, namely rotations, can spoil results.Materials and methodsWe propose yaw, pitch, and roll to name the three possible rotations in space, as these unequivocally name aircraft rotations. Reinforced mobile MOSFETs (model TN-502RDM-H) and an Elekta Precise linear accelerator were used. Two detectors were placed in air for the angular response study and the whole set of five detectors was calibrated as usual to evaluate energy dependence.ResultsThe maximum readout was obtained with a roll of 90° and 4[[ce:hsp sp="0.25"/]]MeV. With regard to pitch movement, a substantial drop in readout was achieved at 90°. Significant overresponse was measured at 315° with 4[[ce:hsp sp="0.25"/]]MeV and at 45° with 15[[ce:hsp sp="0.25"/]]MeV. Energy response is not different for the following groups of energies: 4, 6, and 9[[ce:hsp sp="0.25"/]]MeV; and 12[[ce:hsp sp="0.25"/]]MeV, 15[[ce:hsp sp="0.25"/]]MeV, and 18[[ce:hsp sp="0.25"/]]MeV.ConclusionsOur proposal to name MOSFET rotations solves the problem of defining sensor orientations. Angular response could explain lower than expected results when the tip of the detector is lifted due to inadvertent movements. MOSFETs energy response is independent of several energies and differs by a maximum of 3.4% when dependent. This can limit dosimetry errors and makes it possible to calibrate the detectors only once for each group of energies, which saves time and optimizes lifespan of MOSFETs
Control del dolor postoperatorio en hemorroidectomía ambulatoria mediante infusión endovenosa continua domiciliaria
Introduction: Moderate to severe postoperative pain is still a problem in outpatient surgery, since it causes patient flow problems and delays the discharge of patients, being one of the major causes of re-hospitalization and hence a relevant quality indicator of these Units. The use of home invasive analgesic techniques, in all their regimes, can be effective for the management of postoperative pain in these surgical procedures and allow them to be included in outpatient surgery programs. Objectives: The aim of our study was to determine the feasibility and safety of the use of elastomeric continuous perfusion pumps for the administration of home continuous endovenous analgesia, as well as to assess analgesic effectiveness and degree of satisfaction of patients undergoing outpatient hemorrhoidectomy. Material and methods: We conducted a simple prospective study in 61 patients. After the surgical procedure was performed under multimodal analgesia, an elastomeric endovenous pump operating at 5 ml.h-1 with 16,000 mg of metamizol, 500 mg of tramadol and 16 mg of ondansetron in a 275 ml reservoir was used. At home, the Home Care Unit checked the perfusion system and the endovenous access, detected side effects and events attributable to the system and withdrew the system prematurely during the first 48 hours of postoperative. Results: Just 1 out of 61 patients of the study (1.63%) had severe pain during the first day of postoperative, compared to 81.96% of patients that did not have pain at day 1, 95% at day 2 and 98.35% at day 3. The 9,83% of patients required rescue therapy with tramadol and 20 patients reported side effects attributable to analgesics. There were two cases of early withdrawal of the infusion system because of intolerance to tramadol. A 91.8% of patients reported a high degree of satisfaction with the infusion system and the procedure. Conclusion: Our study has shown the feasibility and safety of the use of endovenous elastomeric infusion pumps as a method of postoperative analgesia that allow to manage cases of moderate or severe pain after outpatient surgical procedures. However, further studies are required to compare this technique with conventional analgesic techniques, as well as with different infusion regimes.Introducción: El dolor postoperatorio moderado-severo sigue siendo un problema en cirugía ambulatoria, ya que provoca problemas de flujo de pacientes, retrasando el alta de los pacientes, siendo uno de los principales motivos de reingreso en los hospitales, y por tanto un importante indicador de calidad de estas Unidades. El empleo de técnicas analgésicas invasivas domiciliarias, en todos sus regímenes, puede controlar el dolor postoperatorio en estas intervenciones y permitir incluirlas en los programas de cirugía ambulatoria. Objetivos: El objetivo de nuestro estudio es valorar la viabilidad y la seguridad de la utilización de bombas de perfusión continua elastoméricas para la administración de analgesia endovenosa continua domiciliaria, a la vez que valorar la eficacia analgésica y el grado de satisfacción de los pacientes intervenidos de hemorroidectomía en régimen ambulatorio. Material y métodos: Estudio prospectivo simple en 61 pacientes. Una vez intervenidos bajo estrategia de analgesia multimodal, se les coloca una bomba elastomérica endovenosa a 5 ml.h-1 con 16.000 mg de metamizol, 500 mg de tramadol y 16 mg de ondansetrón en un reservorio de 275 ml. En el domicilio, la Unidad de Atención Domiciliaria realiza revisiones de la integridad del sistema infusor y de la vía endovenosa, detección de efectos secundarios e incidentes atribuibles al sistema y retiradas precoces durante las 48 horas del postoperatorio. Resultados: De los 61 pacientes, sólo se registra un caso (1,63%) de dolor severo durante el primer día del postoperatorio. Un 81,96% de los pacientes no tienen dolor durante el primer día, 95% el segundo y 98,35% el tercer día. Un 9,83% de los pacientes precisan rescate con tramadol. Veinte pacientes presentan efectos secundarios atribuibles a los analgésicos. Dos casos de retirada precoz del sistema infusor por intolerancia al tramadol. En un 91,8% de los pacientes se mostró un alto grado de satisfacción con el sistema infusor y el procedimiento. Conclusión: Nuestro estudio demuestra la viabilidad y seguridad de la utilización de infusores elastoméricos endovenosos como método de analgesia postoperatoria, que permiten controlar los casos de dolor moderado a severo en procedimientos aplicados a la cirugía ambulatoria. Sin embargo se necesitan más estudios comparativos con técnicas analgésicas convencionales, así como con diferentes regímenes de infusión
The Usefulness of Adaptative Radiotherapy in Prostate Cancer: How, When, and Who?
The aim of this study was to develop a deformable image registration (DIR)-based offline ART protocol capable of identifying significant dosimetric changes in the first treatment fractions to determine when adaptive replanning is needed. A total of 240 images (24 planning CT (pCT) and 216 kilovoltage cone-beam CT (CBCT)) were prospectively acquired from 24 patients with prostate adenocarcinoma during the first three weeks of their treatment (76 Gy in 38 fractions). This set of images was used to plan a hypofractionated virtual treatment (57.3 Gy in 15 fractions); correlation with the DIR of pCT and each CBCT allowed to translate planned doses to each CBCT, and finally mapped back to the pCT to compare with those actually administered. In 37.5% of patients, doses administered in 50% of the rectum (D50) would have exceeded the dose limitation to 50% of the rectum (R50). We first observed a significant variation of the planned rectal volume in the CBCTs of fractions 1, 3, and 5. Then, we found a significant relationship between the D50 accumulated in fractions 1, 3, and 5 and the lack of compliance with the R50. Finally, we found that a D50 variation rate [100 × (administered D50 − planned D50/planned D50)] > 1% in fraction three can reliably identify variations in administered doses that will lead to exceeding rectal dose constraint
Failure mode and effect analysis oriented to risk-reduction interventions in intraoperative electron radiation therapy: The specific impact of patient transportation, automation, and treatment planning availability
Background and purpose: Industrial companies use failure mode and effect analysis (FMEA) to improve quality. Our objective was to describe an FMEA and subsequent interventions for an automated intraoperative electron radiotherapy (IOERT) procedure with computed tomography simulation, pre-planning, and a fixed conventional linear accelerator.
Material and methods: A process map, an FMEA, and a fault tree analysis are reported. The equipment considered
was the radiance treatment planning system (TPS), the Elekta Precise linac, and TN-502RDM-H metal–oxide-semiconductor-field-effect transistor in vivo dosimeters. Computerized order-entry and treatment-automation were also analyzed.
Results: Fifty-seven potential modes and effects were identified and classified into ‘treatment cancellation’ and ‘delivering an unintended dose’. They were graded from ‘inconvenience’ or ‘suboptimal treatment’ to ‘total cancellation’ or ‘potentially wrong’ or ‘very wrong administered dose’, although these
latter effects were never experienced. Risk priority numbers (RPNs) ranged from 3 to 324 and totaled 4804. After interventions such as double checking, interlocking,
automation, and structural changes the final total RPN was reduced to 1320.
Conclusions: FMEA is crucial for prioritizing risk-reduction interventions. In a semi-surgical procedure like IOERT double checking has the potential to reduce risk and improve quality. Interlocks and automation should also be implemented to increase the safety of the procedure
The Impact of Frailty Screening on Radiation Treatment Modification
Background: Care overburden makes it difficult to perform comprehensive geriatric assessments (CGAs) in oncology settings. We analyzed if screening tools modified radiotherapy in oncogeriatric patients. Methods: Patients ≥ 65 years, irradiated between December 2020 and March 2021 at the Hospital Provincial de Castellón, completed the frailty G8 and estimated survival Charlson questionnaires. The cohort was stratified between G8 score ≤ 14 (fragile) or >14 (robust); the cutoff point for the Charlson index was established at five. Results: Of 161 patients; 69.4% were male, the median age was 75 years (range 65–91), and the prevailing performance status (PS) was 0–1 (83.1%). Overall, 28.7% of the cohort were frail based on G8 scores, while the estimated survival at 10 years was 2.25% based on the Charlson test. The treatment administered changed up to 21% after frailty analysis. The therapies prescribed were 5.8 times more likely to be modified in frail patients based on the G8 test. In addition, patients ≥ 85 years (p = 0.01), a PS ≥ 2 (p = 0.008), and limited mobility (p = 0.024) were also associated with a potential change. Conclusions: CGAs remain the optimal assessment tool in oncogeriatry. However, we found that the G8 fragility screening test, which is easier to integrate into patient consultations, is a reliable and efficient aid to rapid decision making
Failure mode and effect analysis oriented to risk-reduction interventions in intraoperative electron radiation therapy: The specific impact of patient transportation, automation, and treatment planning availability
Background and purpose: Industrial companies use failure mode and effect analysis (FMEA) to improve quality. Our objective was to describe an FMEA and subsequent interventions for an automated intraoperative electron radiotherapy (IOERT) procedure with computed tomography simulation, pre-planning, and a fixed conventional linear accelerator.
Material and methods: A process map, an FMEA, and a fault tree analysis are reported. The equipment considered
was the radiance treatment planning system (TPS), the Elekta Precise linac, and TN-502RDM-H metal–oxide-semiconductor-field-effect transistor in vivo dosimeters. Computerized order-entry and treatment-automation were also analyzed.
Results: Fifty-seven potential modes and effects were identified and classified into ‘treatment cancellation’ and ‘delivering an unintended dose’. They were graded from ‘inconvenience’ or ‘suboptimal treatment’ to ‘total cancellation’ or ‘potentially wrong’ or ‘very wrong administered dose’, although these
latter effects were never experienced. Risk priority numbers (RPNs) ranged from 3 to 324 and totaled 4804. After interventions such as double checking, interlocking,
automation, and structural changes the final total RPN was reduced to 1320.
Conclusions: FMEA is crucial for prioritizing risk-reduction interventions. In a semi-surgical procedure like IOERT double checking has the potential to reduce risk and improve quality. Interlocks and automation should also be implemented to increase the safety of the procedure
Fractionated stereotactic radiotherapy plus bevacizumab after response to bevacizumab plus irinotecan as a rescue treatment for high-grade gliomas
AimTo evaluate the possibility of implementing a new scheme of rescue treatment after relapse or progression of high-grade glioma (HGG) treated at the first-line with bevacizumab and irinotecan (BVZ+CPT11), evaluating the response and toxicity of associating BVZ and fractionated stereotactic radiotherapy (BVZ+FSRT).Materials and methodsWe retrospectively analysed data from 59 patients with relapse of HGG. Nine patients with HGG relapse after treatment using the Stupp protocol that were treated with BVZ+CPT11 for progression between July 2007 and August 2012, after which the response was assessed according to the Revised Assessment in Neuro-Oncology (RANO) criteria. BVZ was administered at a dose of 10[[ce:hsp sp="0.25"/]]mg/kg and FSRT up to a prescribed dose of 30[[ce:hsp sp="0.25"/]]Gy, 500[[ce:hsp sp="0.25"/]]cGy per fraction, three days a week. The median follow-up was 38 months.ResultsThe treatment was well-tolerated by all patients. The response after nuclear magnetic resonance imaging (MRI) at 3–6 months was progression in two patients, stable disease in four, and three patients had a partial response. The median overall survival (OS) from diagnosis until death or the last control was 36.8 months. The median progression-free survival (PFS) was 10.8 months. The results from tumour sub-group analysis indicated that the PFS was not statistically significant although it seemed that it was higher in grade-III. The OS was higher in grade-III gliomas.ConclusionsThe combination of BVZ+FSRT as a second-line HGG relapse rescue treatment is well-tolerated and seems to offer promising results. We believe that multi-centre prospective studies are needed to determine the long-term efficacy and toxicity of this therapeutic approach
Real-life management of patients with breakthrough cancer pain caused by bone metastases in Spain.
Purpose: We aimed to explore the characteristics, and real-life therapeutic management of patients with breakthrough cancer pain (BTcP) caused by bone metastases in Spain, and to evaluate physicians' opinion of and satisfaction with prescribed BTcP therapy. Participants and methods: For the purposes of this study, an ad-hoc questionnaire was developed consisting of two domains: a) organizational aspects and care standards; b) clinical and treatment variables of bone metastatic BTcP patients. In addition, physicians' satisfaction with their prescribed BTcP therapy was assessed. Specialists collected data from up to five patients receiving treatment for BTcP caused by bone metastasis, all patients gave their consent to participate prior to inclusion. Results: A total of 103 cancer pain specialists (radiation oncologists [38.8%], pain specialists [33.0%], and palliative care (PC) specialists [21.4%]) were polled, and data on 386 BTcP patients with bone metastatic disease were collected. Only 33% of the specialists had implemented specific protocols for BTcP management, and 19.4% had established referral protocols for this group of patients. Half of all participants (50.5%) address quality of life and quality of care in their patients; however, only 27.0% did so from the patient's perspective, as they should do. Most patients had multiple metastases and were prescribed rapid-onset fentanyl preparations (71.2%), followed by immediate-release morphine (9.3%) for the treatment of BTcP. Rapid-onset fentanyl was prescribed more often in PC units (79.0%) than in pain units (75.9%) and radiation oncology units (61.1%) (