A computational study of combination HIFU-chemotherapy as a potential means of overcoming cancer drug resistance.

The application of local hyperthermia, particularly in conjunction with other treatment strategies (like chemotherapy and radiotherapy) has been known to be a useful means of enhancing tumor treatment outcomes. However, to our knowledge, there has been no mathematical model designed to capture the impact of the combination of hyperthermia and chemotherapies on tumor growth and control. In this study, we propose a nonlinear Partial Differential Equation (PDE) model which describes the tumor response to chemotherapy, and use the model to study the effects of hyperthermia on the response of prototypical tumor to the generic chemotherapeutic agent. Ultrasound energy is delivered to the tumor through High Intensity Focused Ultrasound (HIFU), as a noninvasive technique to elevate the tumor temperature in a controlled manner. The proposed tumor growth model is coupled with the nonlinear density dependent Westervelt and Penne's bio-heat equations, used to calculate the net delivered energy and temperature of the tumor and its surrounding normal tissue. The tumor is assumed to be composed of two species: drug-sensitive and drug-resistant. The central assumption underlying our model is that the drug-resistant species is converted to a drug-sensitive type when the tumor temperature is elevated above a certain threshold temperature. The "in silico" results obtained, confirm that hyperthermia can result in less aggressive tumor development and emphasize the importance of designing an optimized thermal dose strategy. Furthermore, our results suggest that increasing the length of the on/off cycle of the transducer is an efficient approach to treatment scheduling in the sense of optimizing tumor eradication.

Uso de ultrassom e laser na descontaminação do sistema de canais radiculares: revisão de literatura / Use of ultrasound and laser in root canal decontamination: literature review

O maior obstáculo para o sucesso do tratamento endodôntico é a eliminação da microbiota instalada. A instrumentação mecânica, bem como as substâncias químicas auxiliares, é utilizada para eliminação dessa microbiota. Além das soluções irrigantes, outras técnicas complementares, como a agitação ultrassônica passiva (PUI) e o laser, estão sendo utilizadas para otimizar a eliminação dos microrganismos. Desse modo, o presente estudo objetivou o levantamento bibliográfico de diferentes tipos de agitação dos irrigantes no tratamento endodôntico. A PUI tem sido sugerida como um meio para melhorar o desbridamento do canal. Já o laser tem sido utilizado por apresentar vantagens terapêuticas ao tratamento. Todas as técnicas citadas para melhorar a limpeza dos canais radiculares mostraram alguma melhora. A técnica mais empregada ainda é a agitação ultrassônica, por apresentar eficiência e praticidade no procedimento. Pôde-se concluir que a diminuição da microbiota é mais eficiente quando se utiliza uma maior concentração da solução irrigadora, independentemente da agitação final de escolha.

Effects of therapeutic ultrasound and electrical stimulation program on pain, trunk muscle strength, disability, walking performance, quality of life, and depression in patients with low back pain: a randomized-controlled trial.

The aim of this trial is to investigate and compare the effects of electrical stimulation (ES) program and ultrasound (US) therapy on pain, disability, trunk muscle strength, walking performance, spinal mobility, quality of life (QOL), and depression in the patients with chronic low back pain (CLBP). A total of 59 patients with definite CLBP were enrolled in this study. These patients were randomized into three groups. Group 1 (n = 20) was given an ES program and exercises. Group 2 (n = 19) was given an US treatment and exercises. Group 3 (n = 20) was accepted as the control group and was given only exercises. All of the programs were performed 3 days a week, for 6 weeks. The patients were evaluated according to pain, disability, walking performance, endurance, mobility, QOL, depression. The trunk muscle strength was measured with a hand-held dynamometer. All of the groups showed stastically significant improvements in pain, disability, muscle strength, endurance, walking performance, mobility, sub-scores of SF 36, and depression when compared with their initial status. The intergroup comparison showed significant difference in physical function, energy and social function sub-groups of SF-36, VAS pain, extensor muscle strength, between three groups. This difference was statistically significant in the groups 1 and 2 compared to the control group. There was also no significant difference between the groups 1 and 2. We observed that US treatment and ES treatment were effective in improving pain, isometric extensor muscle strength, and QOL in patients with CLBP.

A national study of the availability and use of electrophysical agents by Australian physiotherapists.

Electrophysical agents (EPAs) are a core part of physiotherapy practice and entry level education. With the increase in the number of EPAs over time, their availability and use in contemporary physiotherapy practice is an important consideration when determining entry level curricula. Thus, the aim of the study was to ascertain the current availability and usage of EPAs in Australian physiotherapy practice. A purpose-designed questionnaire was mailed to all registered physiotherapists in Australia. A response rate of 27% was obtained (n=3,538). Nonresponder analyses indicated that the results were representative of the total population of Australian physiotherapists. Over 70% of respondents had access to ultrasound, cold packs/ice, heat packs, electrical stimulation for sensory stimulation, and interferential therapy. Two main groups of EPAs were used relatively frequently. The first group was used daily or monthly by 60% of respondents (ultrasound, hot packs, and cold packs/ice), and a second group (electromyographic and pressure biofeedback, interferential therapy, and electrical stimulation for sensory stimulation) was used on a daily or monthly basis by between 30% and 45% of the sample. A group of EPAs, including ultraviolet light, microwave, and shortwave diathermy, was not used by over 90% of the sample. The study has provided contemporary national data on EPA availability and use in Australia.

Use of medical technologies in rehabilitation medicine settings in Israel: results of the TECHNO-R 2005 survey.

BACKGROUND: With the development of computer technology and the high-tech electronic industry over the past 30 years, the technological age is flourishing. New technologies are continually being introduced, and questions regarding the economic viability of these technologies need to be addressed. OBJECTIVES: To identify the medical technologies currently in use in different rehabilitation medicine settings in Israel. METHODS: The TECHNO-R 2005 survey was conducted in two phases. Beginning in 2004, the first survey used a questionnaire with open questions relating to the different technologies in clinical use, including questions on their purpose, who operates the device (technician, physiotherapist, occupational therapist, physician, etc.), and a description of the treated patients. This questionnaire was sent to 31 rehabilitation medicine facilities in Israel. Due to difficulties in comprehension of the term "technology," a second revised standardized questionnaire with closed-ended questions specifying diverse technologies was introduced in 2005. The responder had to mark from a list of 15 different medical technologies which were in use in his or her facility, as well as their purpose, who operates the device, and a description of the treated patients. RESULTS: Transcutaneous electrical nerve stimulation, the TILT bed, continuous passive movement, and therapeutic ultrasound were the most widely used technologies in rehabilitation medicine facilities. Monitoring of the sitting position in the wheelchair, at the bottom of the list, was found to be the least used technology (with 15.4% occurrence). Most of the technologies are used primarily for treatment purposes and to a lesser degree for diagnosis and research. CONCLUSIONS: Our study poses a fundamental semantic and conceptual question regarding what kind of technologies are or should be part of the standard equipment of any accredited rehabilitation medicine facility for assessment, treatment and/or research. For this purpose, additional data are needed.

A survey of orthopaedic traumatologists concerning the use of bone growth stimulators.

The purpose of the study was to determine the attitudes of members of the Orthopaedic Trauma Association (OTA) concerning the use and efficacy of bone growth stimulators. A questionnaire regarding bone growth stimulators was sent to the active members of the OTA. Descriptive statistics was performed using frequencies and percentages. All analyses were performed using Stata for Linux, version 8.0 (Intercooled Stata, Stata Corporation; College Station, TX). A response rate of 43% was obtained. Respondents indicated that they only occasionally used bone stimulators for the treatment of acute fractures and stress fractures. A majority of respondents have utilized stimulators for the treatment of delayed unions and nonunions. It was concluded that many members of the OTA utilize bone stimulators for delayed unions and nonunions, but not routinely for the treatment of acute fractures or stress fractures.

The effect of combined therapy (ultrasound and interferential current) on pain and sleep in fibromyalgia.

Multidisciplinary treatment has proven to be the best therapeutic option to fibromyalgia (FM) and physiotherapy has an important role in this approach. Considering the controversial results of electrotherapy in this condition, the aim of this study was to assess the effects of combined therapy with pulsed ultrasound and interferential current (CTPI) on pain and sleep in FM. Seventeen patients fulfilling FM criteria were divided into two groups, CTPI and SHAM, and submitted to pain and sleep evaluations. Pain was evaluated by body map (BM) of the painful areas; quantification of pain intensity by visual analog scale (VAS); tender point (TP) count and tenderness threshold (TT). Sleep was assessed by inventory and polysomnography (PSG). After 12 sessions of CTPI or SHAM procedure, patients were evaluated by the same initial protocol. After treatment, CTPI group showed, before and after sleep, subjective improvement of pain in terms of number (BM) and intensity (VAS) of painful areas (P<0.001, both); as well as objective improvement, with decrease in TP count and increase in TT (P<0.001, both). Subjective sleep improvements observed after CTPI treatment included decrease in morning fatigue and in non-refreshing sleep complaint (P<0.001, both). Objectively, PSG in this group showed decrease in sleep latency (P<0.001) and in the percentage of stage 1 (P<0.001), increase in the percentage of slow wave sleep (P<0.001) and in sleep cycle count (P<0.001). Decrease in arousal index (P<0.001), number of sleep stage changes (P<0.05) and wake time after sleep onset (P<0.05), were also observed and no difference regarding pain or sleep parameters were verified after SHAM procedure. This study shows that CTPI can be an effective therapeutic approach for pain and sleep manifestations in FM.

Calibration and electrical safety status of therapeutic ultrasound used by chiropractic physicians.

BACKGROUND: Ultrasound therapy is a commonly used therapeutic modality within the chiropractic profession. Previous calibration studies of ultrasound units within the physical therapy communities in Scotland and Canada have shown that approximately two thirds of units tested did not conform to minimum calibration standards. Similar failure rates may exist in the chiropractic profession and need to be addressed. OBJECTIVE: To determine whether ultrasound machines used by chiropractic physicians met established calibration and electrical safety standards, and to assess frequency of ultrasound therapy use. DESIGN: This cross-sectional study tested 45 ultrasound units for ultrasonic output and electrical safety. Additionally, we asked the doctors to complete a short survey relating to education, usage, and maintenance of their ultrasound equipment. RESULTS: Of the 45 machines tested, 44% failed either calibration or electrical safety inspection. Failure rate was age dependent (P < or =.05). Only 2 of the 45 machines tested had been safety checked within the last year. CONCLUSIONS: A large percentage of ultrasound machines in chiropractic physicians' offices deliver too much or too little dosage to the patient. Electrical safety inspections also revealed a significant failure rate. Chiropractic physicians must become more aware of the requirement for yearly calibration and safety inspections, and understand that failure to maintain their equipment could result in loss of therapeutic effectiveness and pose a threat to the safety of their patients and staff.

The use of therapeutic ultrasound by physical therapists in Dutch primary health care.

BACKGROUND AND PURPOSE: The purposes of this study were to describe the use of ultrasound by Dutch physical therapists and to address the question of whether this use is what would be considered correct. SUBJECTS AND METHODS: Physical therapists in the Dutch primary health care system gathered data on 17,201 patients, addressing reasons for referral, treatment goals (in terms of impairments and disabilities), and physical therapy interventions. Patients treated with ultrasound (n = 3,959) were compared with a reference group of patients who were not treated with ultrasound (n = 13,242). RESULTS: Physical therapists applied ultrasound for soft tissue injuries of recent onset, mainly aiming to reduce pain and swelling. Ultrasound was used in all phases of treatment and was not restricted to the first 3 weeks of treatment. Ultrasound was combined relatively infrequently with exercise and relatively frequently with massage. CONCLUSION AND DISCUSSION: Regarding the indications for referral and treatment goals chosen, the actual use of ultrasound corresponds to assumptions about expected use. The timing of its application and the combination with other forms of therapy do not correspond in all aspects to the assumptions made.

Optimizing ultrasound focus distributions for hyperthermia.

A method is described for generating ultrasound focus patterns for ultrasound hyperthermia treatment planning for steady state and transient hyperthermia. The solution for placement and intensity of ultrasound focus points is based on two types of temperature constraints: 1) equality constraints on the tumor boundary (temperature is held at maximum safe level) and 2) inequality constraints in the tumor interior (in a therapeutic range of temperatures). The method employs a simplex algorithm to solve a series of linear equations which approximate the heating distribution in tissue. Examples are given for field conjugate acoustic lens applicators capable of generating multiple foci simultaneously.

Simulation of bidirectional ultrasound hyperthermia treatments of neck tumours.

The temperature distributions produced in neck tumours by using either a single, scanned transducer (a unidirectional scan) or two separate transducers whose axis are perpendicular (a bidirectional scan) were simulated. The three-dimensional neck model included separate anatomical regions for the normal neck muscle tissue, the tumour, the spinal column and the trachea (no large blood vessels). The effects of variations in the transducer frequency and f number, the tumour size and location, and the normal and tumour blood perfusion rates were studies. The best simulated temperature distributions were produced by bidirectionally scanned, 2 MHz, f number 2.0 ultrasound transducers whose powers were modulated as a function of position. The simulated temperature distributions from such modulated bidirectional scans were significantly better than those of both unidirectional and unmodulated bidirectional scans. The 1-MHz transducers generally produced hot spots at the tissue-spine and/or tissue-trachea interface. The 3-MHz transducers eliminated those deep hot spots but created other hot spots close to the skin surface, and did not adequately heat the deeper regions of the tumour. These results from the simplified computer simulations may be used to guide the construction of improved ultrasound hyperthermia systems for the treatment of neck tumours.

Acoustic power calibrations of cylindrical intracavitary ultrasound hyperthermia applicators.

Preliminary clinical results indicate that some tumors can be heated well utilizing cylindrical ultrasound sources placed in body cavities. In this paper a simple method for measuring the acoustic power from cylindrical intracavitary transducers will be described. The radially propagating acoustic field was converted to a beam with a single propagation direction by a brass reflector, and the radiation force generated by this beam on an absorbing target was measured. The power output of several clinical intracavitary arrays varied significantly between identically shaped transducer elements. The results show that it is important to measure the acoustic power output from each element prior to its clinical use. The radiation force technique is simple and sensitive and can be easily adapted to be used as a routine clinical quality assurance method.

[Use of thermotherapy, ultrasound and laser by practising physiotherapists. Physiotherapists' choice of treatment]. / Praktiserende fysioterapeuters anvendelse af termisk terapi, ultralyd og laser. Fysioterapeuters behandlingsvalg.

The purpose of this examination was to examine the practising physiotherapist's way of treating patients with nine selected diagnoses (fibrosites, osteoarthritis, rheumatoid arthritis, cervical slipped disc, lumbar slipped disc, generalized lumbar/back pain, generalized bursitis, generalized tendinitis, and sprains). In addition, nine different forms of therapy were examined (hot packs, infra-red light, ice packs, short waves, microwaves, diadynamic current, ultrasound, transcutaneous electric nerve stimulation and laser). All in all, 41 clinics with 2,018 treatment confrontations in the examination period, the last week of March 1990, took part in the survey. The majority of therapists were in possession of short wave, hot packs, ultrasound and laser which are also the four forms of therapy most frequently used for treatment. Compared to a Swedish examination from 1979, there is a doubling in ultrasound treatments from 24% to 48%, while the amount of short wave and microwave treatment remained unchanged. There was a remarkable variation in the physiotherapist's choice of therapy in each different diagnosed case. This can be due to the lack of specification of the diagnosis, so that different symptoms, course and stage of illness changed the treatment pattern elected.