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Introduction Methods Results Conclusions Online adaptive radiotherapy is well suited for stereotactic ablative radiotherapy (SABR) in pancreatic cancer due to considerable intrafractional tumour motion. This study aimed to assess intrafraction motion and generate adjusted planning target volume (PTV) margins required for online adaptive radiotherapy in pancreatic cancer treatment using abdominal compression on the magnetic resonance linear accelerator (MR‐Linac).Motion monitoring images obtained from 67 fractions for 15 previously treated pancreatic cancer patients were analysed. All patients received SABR (50 Gy in five fractions) on the MR‐Linac using abdominal compression. The analysis included quantification of intrafraction motion, leading to the development of adjusted PTV margins. The dosimetric impact of implementing the adjusted PTV was then evaluated in a cohort of 20 patients.Intrafraction motion indicated an average target displacement of 1–3 mm, resulting in an adjusted PTV margin of 2 mm in the right–left and superior–inferior directions, and 3 mm in the anterior–posterior direction. Plans incorporating these adjusted margins consistently demonstrated improved dose to target volumes, with improvements averaging 1.5 Gy in CTV D99%, 4.9 Gy in PTV D99% and 1.2 Gy in PTV‐high D90%, and better sparing of the organs at risk (OAR).The improved target volume coverage and reduced OAR dose suggest potential for reducing current clinical margins for MR‐Linac treatment. However, it is important to note that decreasing margins may reduce safeguards against geographical misses. Nonetheless, the continued integration of gating systems on MR‐Linacs could provide confidence in adopting reduced margins. [ABSTRACT FROM AUTHOR]

Abstract Colonoscopy is a common procedure for screening of colon cancer. Although complications are rare, recently there have been reports of splenic injury associated with colonoscopy. Its causes are not clear. Herein, we report an 84‐year‐old man who underwent a colonoscopy for an annual routine examination. The colonoscopy was performed with moderate difficulty due to loop formation and took about 50 min. After the examination, he developed syncope, sweating, and abdominal distention with low blood pressure. Plain computed tomography revealed ascites, and the patient was hospitalized with close monitoring. The following day, his hemoglobin level was decreased by about 3.0 g/dL. Contrast‐enhanced computed tomography revealed the splenic injury. The patient was hemodynamically stable and was treated conservatively. Splenic injury is an uncommon complication of colonoscopy; however, it may cause hemodynamic instability. Physicians performing colonoscopies should be aware of this potential complication.

Purpose: Stereotactic body radiotherapy (SBRT) has been firmly established as a treatment choice for patients with oligometastases, as it has demonstrated both safety and efficacy by consistently achieving high rates of local control. Moreover, it offers potential survival benefits for carefully selected patients in real-world clinical settings. Methods: Between January 2008 and May 2020, a total of 149 patients (with 414 liver metastases) received treatment. The Active Breathing Coordinator device was used for 68 patients, while respiratory gating was used for 65 and abdominal compression was used for 16 patients. The most common histological finding was colorectal adenocarcinoma, with 37.6% of patients having three or more metastases, and 18% having two metastases. The prescribed dose ranged from 36 to 60 Gy, delivered in 3–5 fractions. Results: Local control rates at 2 and 3 years were 76.1% and 61.2%, respectively, with no instances of local recurrence after 3 years. Factors negatively impacting local control included colorectal histology, lower prescribed dose, and the occurrence of new liver metastases. The median overall survival from SBRT was 32 months, with the presence of metastases outside the liver and the development of new liver metastases after SBRT affecting survival. The median disease-free survival was 10 months. No substantial differences in both local control and survival were observed between the respiratory motion control techniques employed. Treatment tolerance was excellent, with only one patient experiencing acute grade IV thrombocytopenia and two patients suffering from ≥ grade II chronic toxicity. Conclusion: For radical management of single or multiple liver metastases, SBRT is an effective and well-tolerated treatment option. Regardless of the technology employed, experienced physicians can achieve similarly positive outcomes. However, additional studies are required to elucidate prognostic factors that can facilitate improved patient selection. [ABSTRACT FROM AUTHOR]

Background and purpose: Stereotactic body radiotherapy (SBRT) has emerged as a promising treatment for patients with ventricular tachycardia (VT) who do not respond to standard treatments. However, the management of respiratory motion during treatment remains a challenge. This study aimed to investigate the effect of abdominal compression (AC) on respiratory induced motion in the heart. Materials and methods: A patient cohort of 18 lung cancer patients was utilized, where two four-dimensional computed tomography (4DCT) scans were performed for each patient, one with and one without AC. The patient setup consisted of an AC plate together with a stereotactic body frame. The left coronary artery, the left anterior descending artery, the lateral wall of the left ventricle, the heart apex, the carina, and the right and left diaphragm were delineated in max expiration and max inspiration phases in both 4DCT scans. The center of mass shift from expiration to inspiration phase was determined to assess the AC’s impact on respiratory motion. Results: A significant reduction in motion in the superior-inferior direction was found for all heart structures when AC was used. The median respiratory motion of the heart structures decreased by approximately 1–3 mm with AC in the superior-inferior direction, and approximately 60% of the patients had a motion reduction ≥3 mm in the left ventricle wall. Conclusion: These findings suggest that AC has the potential to improve the motion management of SBRT for VT patients, by reducing the respiratory induced motion in the heart.

Background and purpose: Motion mitigation is of crucial importance in particle therapy (PT) of patients with abdominal tumors to ensure high-precision irradiation. Magnetic resonance imaging (MRI) is an excellent modality for target volume delineation and motion estimation of mobile soft-tissue tumors. Thus, the aims of this study were to develop an MRI- and PT-compatible abdominal compression device, to investigate its effect on pancreas motion reduction, and to evaluate patient tolerability and acceptance. Materials and methods: In a prospective clinical study, 16 patients with abdominal tumors received an individualized polyethylene-based abdominal corset. Pancreas motion was analyzed using time- and phase resolved MRI scans (orthogonal 2D-cine and 4D MRI) with and without compression by the corset. The pancreas was manually segmented in each MRI data set and the population-averaged center-of-mass motion in inferior-superior (IS), anterior-posterior (AP) and left–right (LR) directions was determined. A questionnaire was developed to investigate the level of patient acceptance of the corset, which the patients completed after acquisition of the planning computed tomography (CT) and MRI scans. Results: The corset was found to reduce pancreas motion predominantly in IS direction by on average 47 % − 51 % as found in the 2D-cine and 4D MRI data, respectively, while motion in the AP and LR direction was not significantly reduced. Most patients reported no discomfort when wearing the corset. Conclusion: An MRI- and PT-compatible individualized abdominal corset was presented, which substantially reduced breathing-induced pancreas motion and can be safely applied with no additional discomfort for the patients. The corset has been successfully integrated into our in-house clinical workflow for PT of tumors of the upper abdomen.

Background: Diagnostic imaging is an integral part of the examination of patients with urinary tract pathologies and many imaging modalities are available. Owing to easy accessibility and low cost, radiography used together with ultrasonography as one of the first-step imaging methods in order to visualize the urinary system. Contrast-enhanced radiographic examination of the upper urinary system "intravenous urography" (IVU) can be performed with bolus injection, abdominal compression (with bolus injection) and infusion techniques. The aim of present study was to evaluate the urograms obtained in cats with urinary system complaints, compare the application of the IVU techniques and urogram quality, and interpret their diagnostic efficacy. Materials, Methods & Results: A total of 30 cats (of different age, breed, sex and weight) with urinary system complaint brought to Selcuk University Veterinary Faculty and Balikesir University Veterinary Faculty Surgery Clinics were included in the study. The cats were randomly divided into 3 groups with 10 cats in each group. In these groups, IVU was performed with bolus (Group 1), infusion (Group 2) and abdominal compression with bolus injection (Group 3) techniques. Nonionic monomeric contrast agent iohexol3 (300 mg I/mL, GE Healthcare) at a dose of 800 mg I/kg was administered as an IV bolus injection in the Bolus group; iohexol at a dose of 1200 mg I/kg was diluted in an equal volume of 0.9% NaCl solution and the prepared solution was administered as an IV infusion through the catheter within 10 min in the Infusion group; iohexol at a dose of 800 mg I/kg was administered through the catheter after an elastic compression band was placed around the caudal abdomen to provide compression on the ureters in the bolus injection with abdominal compression group. The contrast agent (iohexol) injection was well tolerated by all cats. None of the cats developed anaphylactoid reactions or anesthesia-related complication. Changes observed in the heart and respiration rates and body temperature during the procedure did not show a statistically significant difference between the groups (P > 0.05). The renal and ureteral opacity scores and groups were compared, there was a significant difference was observed (P < 0.05). Urograms with "1 point" and "2 points" in kidney opacity scores were in the bolus injection group; urograms with "3 points" and "4 points" showed a statistically significant increase in the infusion and abdominal compression groups (P < 0.05). Urograms with "2 points" and "3 points" in ureteral opacity scores did not show a statistically significant difference (P > 0.05). Discussion: Currently, radiological IVU can still be used as a feasible, economical and valuable diagnostic tool with appropriate techniques, contrast agents and dose selection. For this purpose, patient preparation before IVU is very important to increase the interpretation ability of the urograms obtained. Sedation or anesthesia is not required to obtain better urograms. The bolus injection technique would be preferable for evaluating the anatomical position of the kidneys and observing the renal parenchyma. Urograms up to 20 min after the injection in the ventrodorsal (VD) position would be sufficient for proper observation of the nephrography phase. The infusion technique would be preferable for evaluating the collecting system. Urograms up to 20 min following the completion of the infusion in the VD position would be sufficient for proper observation of the pyelography phase and ureters. Urograms should be obtained in the VD and lateral positions for ureteral evaluation. Urograms taken after 5 or 40 min would be sufficient, depending on the ureteral part to be examined. [ABSTRACT FROM AUTHOR]

Background and purpose: Reduction of respiratory tumour motion is important in liver stereotactic body radiation therapy (SBRT) to reduce side effects and improve tumour control probability. We have assessed the distribution of use of voluntary exhale breath hold (EBH), abdominal compression (AC), free breathing gating (gating) and free breathing (FB), and the impact of these on treatment time. Materials and Methods: We assessed all patients treated in a single institution with liver SBRT between September 2017 and September 2021. Data from pre-simulation motion management assessment using fluoroscopic assessment of liver dome position in repeat breath holds, and motion with and without AC, was reviewed to determine liver dome position consistency in EBH and the impact of AC on motion. Treatment time was assessed for all fractions as time from first image acquisition to last treatment beam off. Results: Of 136 patients treated with 145 courses of liver SBRT, 68 % were treated in EBH, 20 % with AC, 7 % in gating and 5 % in FB. AC resulted in motion reduction

Background: Radiotherapy to tumors in the abdomen is challenging because of the significant organ movement and tissue deformation caused by respiration. Purpose: A motion management strategy that integrated ultrasound (US) imaging with abdominal compression was developed and evaluated, where US was used to real‐time monitor organ motion after abdominal compression. Methods: A device that combined a US imaging system and an abdominal compression plate (ACP) was developed. Twenty‐one healthy volunteers were involved to evaluate the motion management efficacy. Each volunteer was immobilized on a flat bench by the device. Abdominal US data were successively collected with and without ACP compression, and experiments were repeated three times to verify the imaging reproducibility. A template matching algorithm based on normalized cross‐correlation was implemented to track the targets (vessels in the liver, pancreas, and stomach) automatically. The matching algorithm was validated by comparing with the manual references. Automatic tracking was judged as failed if the center‐of‐mass difference from manual tracking was beyond a failure threshold. Based on the locations obtained through the template matching algorithm, the motion correlation between liver and pancreas/stomach was investigated using the Pearson correlation test. Paired Student's t‐test was used to analyze the difference between the results without and with ACP compression. Results: The liver motion amplitude over all 21 volunteers was significantly (p < 0.001) reduced from 14.9 ± 5.5/3.4 ± 1.8 mm in superior–inferior (SI)/anterior–posterior (AP) direction before ACP compression to 7.3 ± 1.5/1.6 ± 0.7 mm after ACP compression. The mean liver motion standard deviation before compression was on average 2.8/1.4 mm in SI/AP direction and was significantly (p < 0.001) reduced to 0.9/0.4 mm after compression. The failure rates of automatic tracking for liver, pancreas, and stomach were reduced for failure thresholds of 1–5 mm after applying ACP. The Pearson correlation coefficients between liver and pancreas/stomach were 0.98/0.97 without ACP and 0.96/0.94 with ACP in the SI direction and were 0.68/0.68 and 0.43/0.42 in the AP direction. The motion prediction errors for pancreas/stomach with ACP have significantly (p < 0.001) reduced to 0.45 ± 0.36/0.52 ± 0.43 mm from 0.69 ± 0.56/0.71 ± 0.66 mm without ACP in the SI direction, and to 0.38 ± 0.33/0.39 ± 0.27 mm from 0.44 ± 0.35/0.61 ± 0.59 mm in the AP direction. Conclusions: The proposed strategy that combines real‐time US imaging and abdominal compression has the potential to reduce the abdominal organ motion while improving both target tracking reliability and motion reproducibility. Furthermore, the observed correlation between liver and pancreas/stomach motion indicates the possibility of indirect pancreas/stomach tracking using liver markers as tracking surrogates. The strategy is expected to provide an alternative for respiratory motion management in the radiation treatment of abdominal tumors. [ABSTRACT FROM AUTHOR]

The effectiveness of abdominal compression for motion management in hepatobiliary-pancreatic (HPB) radiotherapy has not been systematically evaluated. A systematic review was carried out using PubMed/Medline, Cochrane Library, Web of Science, and CINAHL databases up to 1 July 2021. No date restrictions were applied. Additional searches were carried out using the University of Manchester digital library, Google Scholar and of retrieved papers' reference lists. Studies conducted evaluating respiratory motion utilising imaging with and without abdominal compression in the same patients available in English were included. Studies conducted in healthy volunteers or majority non-HPB sites, not providing descriptive motion statistics or patient characteristics before and after compression in the same patients or published without peer-review were excluded. A narrative synthesis was employed by tabulating retrieved studies and organising chronologically by abdominal compression device type to help identify patterns in the evidence. The inclusion criteria were met by 6 studies with a total of 152 patients. Designs were a mix of retrospective and prospective quantitative designs with chronological, non-randomised recruitment. Abdominal compression reduced craniocaudal respiratory motion in the majority of patients, although in four studies there were increases seen in at least one direction. The influence of patient comorbidities on effectiveness of compression, and/or comfort with compression was not evaluated in any study. Abdominal compression may not be appropriate for all patients, and benefit should be weighed with potential increase in motion or discomfort in patients with small initial motion (<5 mm). Patient factors including male sex, and high body mass index (BMI) were found to impact the effectiveness of compression, however with limited evidence. High-quality studies are warranted to fully assess the clinical impact of abdominal compression on treatment outcomes and toxicity prospective in comparison to other motion management strategies. [ABSTRACT FROM AUTHOR]

Abstract Background This study aimed to investigate the effect of abdominal compression on tumour motion and target volume and to determine suitable planning target volume (PTV) margins for patients treated with lung stereotactic body radiotherapy (SBRT) based on four-dimensional computed tomography (4DCT). Methods Twenty-three patients diagnosed to have a peripheral pulmonary tumour were selected and divided into an all lesions group (group A), an upper middle lobe lesions group (group B), and a lower lobe lesions group (group C). Two 4DCT scans were performed in each patient, one with and one without abdominal compression. Cone beam computed tomography (CBCT) was performed before starting treatment. The gross target volumes (GTVs) were delineated and internal gross target volumes (IGTVs) were defined. IGTVs were generated using two methods: (1) the maximum intensity projections (MIPs) based on the 4DCT were reconstructed to form a single volume and defined as the IGTVMIP and (2) GTVs from all 10 phases were combined to form a single volume and defined as the IGTV10. A 5-mm, 4-mm, and 3-mm margin was added in all directions on the IGTVMIP and the volume was constructed as PTVMIP5mm, PTVMIP4mm, and PTVMIP3mm. Results There was no significant difference in the amplitude of tumour motion in the left–right, anterior–posterior, or superior-inferior direction according to whether or not abdominal compression was applied (group A, p = 0.43, 0.27, and 0.29, respectively; group B, p = 0.46, 0.15, and 0.45; group C, p = 0.79, 0.86, and 0.37; Wilcoxon test). However, the median IGTVMIP without abdominal compression was 33.67% higher than that with compression (p = 0.00), and the median IGTV10 without compression was 16.08% higher than that with compression (p = 0.00). The median proportion of the degree of inclusion of the IGTVCBCT in PTVMIP5mm, PTVMIP4mm, and PTVMIP3mm ≥ 95% was 100%, 100%, and 83.33%, respectively. Conclusions Abdominal compression was useful for reducing the size of the IGTVMIP and IGTV10 and for decreasing the PTV margins based on 4DCT. In IGTVMIP with abdominal compression, adding a 4-mm margin to account for respiration is feasible in SBRT based on 4DCT.

Introduction: Stereotactic body radiotherapy (SBRT) with abdominal compression (AC) stands out due to the high tolerance and ease of application in the treatment of liver metastases. The present study aimed to report the safety and efficacy of the AC technique with 10-year follow-up outcomes. Materials and methods: A retrospective review was made of patients in the database who had liver metastases, who did not undergo surgery or any other ablative approach for metastases, and who underwent SBRT with AC. In-field local control (ifLC) and toxicity were evaluated as primary endpoints. Results: The study examined 79 patients who underwent SBRT with AC between 2012 and 2021. Colorectal adenocarcinoma was the most common type of primary tumor (n = 32, 40.5%). The median follow-up was 14 (4-73) months. After treatment, one-year ifLC was 46.4%, six-month ifLC was 76%, one-year out-field local control (ofLC) was 13.6%, and six-month ofLC was 25%. According to the Common Terminology Criteria for Adverse Events Version 5.0, only 8 patients had low-grade acute gastrointestinal toxicity, and no patients had late toxicity. Conclusions: SBRT with AC is a well-tolerated and effective treatment modality for patients with liver metastases. [ABSTRACT FROM AUTHOR]

Interposed abdominal compression CPR is an alternative technique to traditional CPR that can improve perfusion and lead to restoration of circulation in patients with chest wall deformity either acquired through vigorous CPR or co-morbidity such as COPD.  We report a case of out-of-hospital cardiac arrest where IAC-CPR allowed for restoration of spontaneous circulation and eventual full neurologic recovery when traditional CPR was failing to generate adequate pulses with chest compression alone.

Background: This study aimed to investigate the effect of abdominal compression on tumour motion and target volume and to determine suitable planning target volume (PTV) margins for patients treated with lung stereotactic body radiotherapy (SBRT) based on four-dimensional computed tomography (4DCT).Methods: Twenty-three patients diagnosed to have a peripheral pulmonary tumour were selected and divided into an all lesions group (group A), an upper middle lobe lesions group (group B), and a lower lobe lesions group (group C). Two 4DCT scans were performed in each patient, one with and one without abdominal compression. Cone beam computed tomography (CBCT) was performed before starting treatment. The gross target volumes (GTVs) were delineated and internal gross target volumes (IGTVs) were defined. IGTVs were generated using two methods: (1) the maximum intensity projections (MIPs) based on the 4DCT were reconstructed to form a single volume and defined as the IGTVMIP and (2) GTVs from all 10 phases were combined to form a single volume and defined as the IGTV10. A 5-mm, 4-mm, and 3-mm margin was added in all directions on the IGTVMIP and the volume was constructed as PTVMIP5mm, PTVMIP4mm, and PTVMIP3mm.Results: There was no significant difference in the amplitude of tumour motion in the left-right, anterior-posterior, or superior-inferior direction according to whether or not abdominal compression was applied (group A, p = 0.43, 0.27, and 0.29, respectively; group B, p = 0.46, 0.15, and 0.45; group C, p = 0.79, 0.86, and 0.37; Wilcoxon test). However, the median IGTVMIP without abdominal compression was 33.67% higher than that with compression (p = 0.00), and the median IGTV10 without compression was 16.08% higher than that with compression (p = 0.00). The median proportion of the degree of inclusion of the IGTVCBCT in PTVMIP5mm, PTVMIP4mm, and PTVMIP3mm ≥ 95% was 100%, 100%, and 83.33%, respectively.Conclusions: Abdominal compression was useful for reducing the size of the IGTVMIP and IGTV10 and for decreasing the PTV margins based on 4DCT. In IGTVMIP with abdominal compression, adding a 4-mm margin to account for respiration is feasible in SBRT based on 4DCT. [ABSTRACT FROM AUTHOR]

Purpose: Abdominal Compression is one of the methods available to minimize breathing motion during stereotactic body radiotherapy (SBRT), particularly for abdominal malignancies. It might be necessary to treat some tumors with radiation entering through the compression device. One clinically available compression plate device (Elekta BodyFIX Diaphragm Control) was evaluated to understand its impact on dosimetry during clinical treatments. Methods: The BodyFIX compression device was CT scanned following departmental stereo scanning protocols. Treatment planning system (TPS) calculations were used to determine attenuation ratios through each section of the compression device: the outer frame, compression plate, and higher density couch fixation points and compression screw. TPS calculated skin doses where the compression plate will come in contact with the skin were recorded. All attenuation ratio fields were measured on an Elekta Versa HD linear accelerator. Where differences in attenuation were observed, TPS density overrides were found to bring calculated doses into agreement with measurement. Results: The compression plate and frame showed low dose attenuation (3%–4%). Only minor density overrides for the frame were required due to artefacts from the limited CT field‐of‐view. The high‐density materials in the couch fixation points resulted in higher attenuation (14%–20%). Similarly, the compression screw recorded very high attenuation (44%–65%), depending on the length of screw used. Skin doses assessed from the TPS calculations showed dose build‐up under the compression plate that would result in skin receiving the maximum dose. Conclusion: Compression devices can cause significant dose attenuation. Density overrides for TPS calculations are recommended for correcting attenuation in some sections of the device. High‐density structures like the fixation screw and frame fixation points create high levels of dosimetric uncertainty, and beam entry through those areas has been disallowed. [ABSTRACT FROM AUTHOR]

Amaç: Akciğer tümörlerinin SBRT tedavisinde her bir fraksiyon için hasta ve tümör hareketinin kontrolü çok önemlidir. Bu çalışmada solunuma bağlı tümör hareketinin minimize edilmesi için abdomen kompresör ve DIBH tekniği kullanılan iki farklı hasta grubu için fraksiyon içi hasta hareketi (Align-RT) ve fraksiyon içi tümör hareketinin (4D-CBCT) karşılaştırılması amaçlanmıştır. Gereç ve Yöntem: Çalışmaya Mart 2022'den itibaren kliniğimizde akciğer SBRT tedavisi gören toplam 50 hasta dahil edilmiştir. Öncesinde hastalara solunum fonksiyon testi uygulanarak nefes tutabilen hastalara DIBH tekniği, nefes tutamayan hastalara ise abdomen kompresör uygulanmıştır. DIBH tekniği ve abdomen kompresör kullanılarak tedavi edilen hastalar (25/25) için toplam 205 fraksiyonun her birinde tedaviye başlamadan önce Align RT sistemiyle uygun pozisyon verilerek ardından CBCT alınmıştır. Gerekli masa kaydırmasının ardından fraksiyon içi tümör hareketinin takibi için 4D-CBCT çekilmiştir. Sonrasında her iki grup için Align RT ile 3 boyutlu gerçek zamanlı yüzey takibi ile tedaviler tamamlanmıştır. Her iki hasta grubu için kullanılan tekniklerin fraksiyon içi tümör ve hasta hareketine etkisi karşılaştırılmıştır. Hastanın yaşı, vücut kitle indeksi, tümör hacmi ve tümör lokalizasyonunun intrafraksiyonel kayma ile ilişkisi değerlendirilmiştir. Bulgular: Abdomen kompresör ile tedaviye alınan 25 hastada 97/102 fraksiyon için lateral ve longitidunal yönlerde hasta hareketi =2 mm, vertical yönde ise 96/102 fraksiyon için =2 mm bulunmuştur. Lateral, longitidunal ve vertical yönde tümör hareketi 102/102 fraksiyon için =1 mm bulunmuştur. Hasta rotasyonu 102/102 fraksiyon için =2°, 89/102 fraksiyon için =1° bulunmuştur. DIBH tekniği ile tedaviye alınan 25 hastada 97/103 fraksiyon için lateral, 100/103 fraksiyon için longitidunal, vertical yönde ise 96/103 fraksiyon için hasta hareketi =2 mm bulunmuştur. Lateral ve longitidunal yönde tümör hareketi 103/103 fraksiyon için =1 mm ve vertical yönde 102/103 fraksiyon için =1 mm bulunmuştur. Hasta rotasyonu 103/103 fraksiyon için =2°, 91/103 fraksiyon için =1° bulunmuştur. Sonuç: Yapılan çalışmada tedavide kullanılacak olan teknik hastanın nefes tutma potansiyeline göre değerlendirilmiştir. Klinik tecrübemize dayanarak hasta hareketi bireyseldir. DIBH tekniği ile intrafraksiyonel tümör hareketinin değerlendirildiği hasta grubunda sadece 1 hastada tümör hareketi 1mm üzerine çıkmıştır. Bu klinik sınırlar içerisindedir. Hiçbir hastaya yeniden CBCT çekilmemiştir. Hastanın yaşı, vücut kitle indeksi, tümör hacmi gibi parametrelerin intrafraksiyonel kayma ile bir ilişkisi bulunmamıştır. [ABSTRACT FROM AUTHOR]

Aim: This study aimed to evaluate the effect of abdominal corset use on colonoscopy outcomes in patients undergoing colonoscopy. Methods: This randomised controlled trial was conducted between March 2019 and January 2020, with the participation of 60 patients who underwent colonoscopy in the endoscopy unit of a university hospital. Half (n=30) of these patients were included in the experimental group and wore an abdominal corset during colonoscopy. Findings: It was determined that there was no statistically significant difference between the groups according to variables, including caecal intubation time (p=0.371), the need for position change in the colonoscopy process (p=0.554), position change in caecum imaging (p=1.000) and manual abdominal compression during the procedure (p=0.091). Conclusions: The results of this study reveal that abdominal corset usage does not provide a significant extra benefit compared with conventional colonoscopy in improving colonoscopy outcomes. [ABSTRACT FROM AUTHOR]

Purpose: Abdominal compression can minimize breathing motion in stereotactic radiotherapy, though it may impact the positioning of dose‐limiting normal tissues. This study quantified the reproducibility of abdominal normal tissues and respiratory motion with the use of an abdominal compression device using MR imaging. Methods: Twenty healthy volunteers had repeat MR over 3 days under an abdominal compression plate device. Normal tissues were delineated on daily axial T2‐weighted MR and compared on days 2 and 3 relative to day 1, after adjusting for baseline shifts relative to bony anatomy. Inter‐fraction organ deformation was computed using deformable registration of axial T2 images. Deformation > 5 mm was assumed to be clinically relevant. Inter‐fraction respiratory amplitude changes and intra‐fraction baseline drifts during imaging were quantified on daily orthogonal cine‐MR (70 s each), and changes > 3 mm were assumed to be relevant. Results: On axial MR, the mean inter‐fraction normal tissue deformation was > 5 mm for all organs (range 5.1–13.4 mm). Inter‐fraction compression device misplacements > 5 mm and changes in stomach volume > 50% occurred at a rate of 93% and 38%, respectively, in one or more directions and were associated with larger adjacent organ deformation, in particular for the duodenum. On cine‐MR, inter‐fraction amplitude changes > 3 mm on day 2 and 3 relative to day 1 occurred at a rate of < 12.5% (mean superior–inferior change was 1.6 mm). Intra‐fraction baseline drifts > 3 mm during any cine‐MR acquisition occurred at a rate of 23% (mean superior–inferior changes was 2.4 mm). Conclusions: Respiratory motion under abdominal compression is reproducible in most subjects within 3 mm. However, inter‐fraction deformations greater than 5 mm in normal tissues were common and larger than inter‐ and intra‐fraction respiratory changes. Deformations were driven mostly by variable stomach contents and device positioning. The magnitude of this motion may impact normal tissue dosimetry during stereotactic radiotherapy. [ABSTRACT FROM AUTHOR]

We have clinically implemented gated stereotactic body radiotherapy under abdominal compression using an Anzai laser-based gating device with visual guidance in combination with an Elekta linear accelerator. To ensure accuracy, we configured the gating window for each patient by correlating the respiratory curve from the laser sensor and the tumor positions from the 4D computed tomography (CT) images reconstructed with the aid of the respiratory curve. This allowed us to define a patient-specific gating window to keep the tumor displacement below 5 mm from the end-expiration, assuming the reproducibility of the tumor trajectories and the laser-based body surface measurements. Results are summarized as follows: 1) A patient-specific gating window internal target volume (ITV) with a prespecified maximum tumor displacement relative to the end-expiration was obtained by acquiring a 4D CT consisting of 20 phase CT sets and a respiratory curve from the Anzai system. 2) Respiratory hysteresis was managed by setting two different thresholds on the respiratory curve based on the predetermined maximum tumor displacement relative to end-expiration. 3) Abdominal compression increased gating window width, thereby presumably leading to faster gated-beam delivery. 4) Gamma index pass rates in sliding-window gated intensity-modulated radiotherapy (IMRT) were superior to those in gated volumetric modulated arc therapy (VMAT). 5) Intrafraction gated cone-beam computed tomography (CBCT) demonstrated that the tumor appeared to remain within the gating window ITV during the stereotactic gated sliding-window IMRT. In conclusion, we have successfully implemented gated stereotactic body radiotherapy at our clinic and achieved a favorable clinical validation result. More cases need to be evaluated to increase the validity., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2024, Hoshina et al.)

Background Splanchnic venous pooling induced by upright posture triggers a compensatory increase in heart rate (HR), a response that is exaggerated in patients with postural tachycardia syndrome. To assess whether abdominal compression attenuates orthostatic tachycardia and improves symptoms, 18 postural tachycardia syndrome patients (32±2 years) were randomized to receive either abdominal compression (40 mm Hg applied with an inflatable binder ≈2 minutes before standing) or propranolol (20 mg) in a placebo‐controlled, crossover study. Methods and Results Systolic blood pressure, HR, and symptoms were assessed while seated and standing, before and 2 hours postdrug. As expected, propranolol decreased standing HR compared with placebo (81±2 versus 98±4 beats per minute; P

The goal of this retrospective study was to determine the benefit in using abdominal compression to reduce tumor motion for patients treated with lung stereotactic body radiotherapy. Forty-four lung lesions (n = 44) from 37 patients (N = 37) treated at the University of Toledo's Dana Cancer Center were assessed by determining the overall tumor displacement along with possible surrogates such as change in tidal volume and diaphragm displacement, with and without abdominal compression. Measurements of lung capacity were acquired from the 4DCT at maximum and minimum respiration in order to determine the tidal volume, with and without abdominal compression. Tumor centroid and diaphragm apex motion was then assessed in 3 dimensions from phase 0 to phase 50. This was measured in centimeters using the ruler method on MIM software, both with and without the compression belt. Change in overall tumor movement was 0.61 cm ± 0.09 cm with compression, and 0.60 cm ± 0.09 cm without the compression belt. Delta tumor motion was reduced in 5 cases, increased (made worse) in 6 cases, and did not clinically impact the remaining 33 cases. Average tidal volume with abdominal compression was 379.7 mL or 12.0% ± 0.724% of total lung volume while average tidal volume without abdominal compression was 337.7 mL or 10.5% ± 0.649% of total lung volume. Change in diaphragm position throughout the breathing cycle was 1.21 cm ± 0.10 cm with compression, and 1.28 ± 0.13 cm without the compression belt. These findings indicate that abdominal compression may not be an effective method in the reduction of respiratory motion, and can even negatively impact tumor motion by increasing its displacement. Compression decreased tumor motion in 5 out of the 44 cases studied. The 5 cases that benefitted tended to be lesions close to the diaphragm but these 5 corresponded to less than half of the inferior lesions, suggesting that even inferior lung lesions may not be prime candidates for abdominal compression. [ABSTRACT FROM AUTHOR]

Objectives: We evaluated the dosimetric and radiobiological impact of abdominal compression (AC) on nearby gastrointestinal critical structures (GI-CS) and reported toxicities of patients treated with non-hepatic abdominal stereotactic body radiotherapy (SBRT). Methods: Two sets of CT scans, planning scans with AC and pre-treatment diagnostic scans without AC (non-AC) were compared for patients treated with a prescription dose to planning target volume (PTV) =25 Gy/5-fractions at a single institution. Target volumes were delineated on both sets of scans and PTV was expanded isotropically by 2 cm (PTV+2) and 4 cm (PTV+4). All GI-CS were summated to create a composite CS (GI-lumen). Rigid registration of AC and non-AC scans was done using Velocity AI (Varian Medical Systems) to obtain dose distribution information. Lymann-Probit and logit models were used for radiobiological calculations. Toxicity scores were obtained from prospectively collected clinical data. Results: A total of 12 patients were included. Mean PTV volumes were 190.3cc and 196.4cc with AC and non-AC (p=0.95). Significant improvement in V30 of GI-lumen was seen with AC (0.11cc vs. 4.97cc, p=0.04). There were no differences in the normal tissue complication probabilities of the individual GI-CS or the summary indices except a notable trend towards better NTCP for small bowel late effects with AC (0.21% vs. 2.45%; p=0.055). Three patients had acute grade-1 anorexia, one patient had acute grade-2 gastritis. There was no grade =3 GI toxicity. At a median follow-up of 2.6 years, total of 8/12 (66.7%) patients developed local recurrence of whom 4 (33.3%) had isolated local recurrence. Conclusion: Use of AC did not result in any dosimetric or radiobiological inferiority for GI-CS. The current cohort completed their treatment with minimal toxicity. [ABSTRACT FROM AUTHOR]

• Target positions extracted from 2D cine MRI acquired during SBRT. • Pre-treatment 4DCT and online cine MRI-based respiration motion correlates well. • Respiration motion lower in patients treated with abdominal compression. • Target dose coverage reduction as a consequence of motion low in most patients. • More extensive target dose reduction in few patients without abdominal compression. The current study investigated the impact of abdominal compression on motion and the delivered dose during non-gated, magnetic resonance image (MRI)-guided radiation ablation of adrenal gland metastases. Thirty-one patients with adrenal gland metastases treated to 45–60 Gy in 3–8 fractions on a 1.5 T MRI-linac were included in the study. The patients were breathing freely (n = 14) or with motion restricted by using an abdominal compression belt (n = 17). The time-resolved position of the target in online 2D cine MR images acquired during treatment was assessed and used to estimate the dose delivered to the GTV and abutting luminal organs at risk (OAR). The median (range) 3D root-mean-square target position error was significantly higher in patients treated without a compression belt [2.9 (1.9–5.6) mm] compared to patients using the belt [2.1 (1.2–3.5) mm] (P < 0.01). The median (range) GTV V95% was significantly reduced from planned 98.6 (65.9–100) % to delivered 96.5 (64.5–99.9) % due to motion (P < 0.01). Most prominent dose reductions were found in patients showing either large target drift or respiration motion and were mainly treated without abdominal compression. Motion did not lead to an increased number of constraint violations for luminal OAR. Acceptable target coverage and dose to OAR was observed in the vast majority of patients despite intra-fractional motion during adaptive MRI-guided radiation ablation. The use of abdominal compression significantly reduced the target position error and prevented the most prominent target coverage degradations and is, therefore, recommended as motion management at MRI-linacs. [ABSTRACT FROM AUTHOR]

Abstract In patients who had no medical care for years, it is wise to expect the unexpected. Here, a gigantic liver cyst compressed abdominal organs, vessels, and the gut. The patient is thus far doing well in a nursing home, exemplifying the low amount of residual liver tissue necessary for survival.

Background and Purpose: Stereotactic body radiotherapy (SBRT) has emerged as a promising treatment for patients with ventricular tachycardia (VT) who do not respond to standard treatments. However, the management of respiratory motion during treatment remains a challenge. This study aimed to investigate the effect of abdominal compression (AC) on respiratory induced motion in the heart., Materials and Methods: A patient cohort of 18 lung cancer patients was utilized, where two four-dimensional computed tomography (4DCT) scans were performed for each patient, one with and one without AC. The patient setup consisted of an AC plate together with a stereotactic body frame. The left coronary artery, the left anterior descending artery, the lateral wall of the left ventricle, the heart apex, the carina, and the right and left diaphragm were delineated in max expiration and max inspiration phases in both 4DCT scans. The center of mass shift from expiration to inspiration phase was determined to assess the AC's impact on respiratory motion., Results: A significant reduction in motion in the superior-inferior direction was found for all heart structures when AC was used. The median respiratory motion of the heart structures decreased by approximately 1-3 mm with AC in the superior-inferior direction, and approximately 60% of the patients had a motion reduction ≥3 mm in the left ventricle wall., Conclusion: These findings suggest that AC has the potential to improve the motion management of SBRT for VT patients, by reducing the respiratory induced motion in the heart., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Author(s).)

Aim: : To assess the effectiveness of abdominal compression in reducing internal target motion during conformal radiotherapy for stomach cancer.Materials and Methods: A pilot study was conducted on five patients who received adjuvant radiotherapy for stomach cancer. All the patients had surgical clips and were offered radiotherapy and concurrent chemotherapy as per the institutional protocol. An abdominal compression device was developed consisting of a triangular Styrofoam's plate and an inflatable air bladder that was positioned over the patients' abdomen. The pneumatic pressure was set according to the patients' comfort. On the simulation day, patients had two computed tomography (CT)-scanning sessions, with and without abdominal compression. Target volumes and organs at risk (OAR) were delineated on the CT images without compression. On the treatment day, fluoroscopy was acquired with onboard imager (OBI) and movements of surgical clips with and without compression analyzed with the help of a tracker software. Observed values with and without abdominal compression were compared.Results: Abdominal compression usage has reduced the mean breathing excursion (MBE) in medio lateral(ML) direction from 5.92mm to 4.15 mm and in cranio caudal direction (CC) from 11.3mm to 7.2mm. The range of reduction by 29.85% in the ML and 36.86% in CC direction. The average residual breathing excursion was 1.766 mm (SD = 1.33 mm) in the ML and 4.02 mm (SD = 2.18 mm) in the CC direction, respectively.Conclusion: Abdominal compression was useful in reducing internal target motion during stomach cancer conformal radiotherapy. The device we developed is patient friendly and cost-effective. [ABSTRACT FROM AUTHOR]

Abstract: Background: Abdominal compression has been implemented as a provocative maneuver in high‐resolution impedance manometry (HRIM) to “challenge” normal esophageal physiology with the aim of revealing abnormal motor patterns which may explain symptoms. In this study, we measured the effects of abdominal compression on esophageal functioning utilizing novel pressure‐impedance parameters and attempted to identify differences between healthy controls and globus patients. Methods: Twenty‐two healthy volunteers (aged 23‐32 years, 41% female) and 22 globus patients (aged 23‐72 years, 68% female) were evaluated with HRIM using a 3.2‐mm water perfused manometric and impedance catheter. All participants received 10 × 5 mL liquid swallows; healthy controls also received 10 × 5 mL liquid swallows with abdominal compression created using an inflatable cuff. All swallows were analyzed to assess esophageal pressure topography (EPT) and pressure‐flow metrics, indicative of distension pressure, flow timing and bolus clearance were derived. Key Results: The effect of abdominal compression was shown as a greater contractile vigor of the distal esophagus by EPT and higher distension pressure based on pressure‐flow metrics. Age and body mass index also increased contractile vigor and distension pressure. Globus patients were similar to controls. Conclusions and Interferences: Intrabolus pressure and contractile vigor are indicative of the physiological modulation of bolus transport mechanisms. Provocative testing by abdominal compression induces changes in these esophageal bolus dynamics. [ABSTRACT FROM AUTHOR]

Abstract: Introduction: Radiotherapy outcomes are influenced by treatment delivery geometric accuracy and organ‐at‐risk dose. The location of abdominal structures such as the liver, kidneys and tumour volumes can be strongly influenced by respiratory motion. This increases geometric uncertainty and dose to organs‐at‐risk. One common method of minimising respiratory motion is abdominal compression (AC). Methods: Fifteen patients being treated for radiotherapy to upper abdominal tumours were analysed. Each patient underwent 2 four‐dimensional computerised tomography (4D‐CT) scans, one with and one without AC with a pneumatic compression belt. Liver and kidney positions were measured on the 4DCT scans at the peak inspiratory and expiratory respiratory phases. The patient received radiation therapy treatment planned on the CT data set with the technique (compression or no compression) that provided the least respiratory motion. Results: There was no statistically significant motion difference over the sample population with AC for the kidneys or liver. Of the 14 evaluable patients, 4, 6 and 6 saw reduction in superior‐inferior motion for left kidney, right kidney and liver respectively. The remainder either had negligible (<2 mm) or increase in motion with AC. For anterior‐posterior motion, 2, 2 and 1 saw a reduction for left‐kidney, right‐kidney and liver respectively. Conclusion: AC through the use of a pneumatic compression belt was found to result in inconsistent reduction in kidney and liver respiratory motion. It is recommended that the effect of AC is evaluated on a per‐patient basis. [ABSTRACT FROM AUTHOR]

Interposed abdominal compression cardiopulmonary resuscitation (IAC-CPR) is an alternative technique to traditional cardiopulmonary resuscitation (CPR) that can improve perfusion and lead to restoration of circulation in patients with chest wall deformity either acquired through vigorous CPR or co-morbidity such as chronic obstructive pulmonary disease. We report a case of out-of-hospital cardiac arrest where IAC-CPR allowed for restoration of spontaneous circulation and eventual full neurologic recovery when traditional CPR was failing to generate adequate pulses with chest compression alone.

Introduction: Postoperative shoulder pain is a condition associated with laparoscopic surgery and presumably attributed to residual carbon dioxide (CO2) in the abdomen. The intent of the current prospective, observational study was to assess the efficacy of abdominal compression in mitigating this painful complication.Methods: We recruited 30 patients who were treated with laparoscopic surgery for the management of gynecologic disease. All study participants underwent abdominal compression to evacuate the CO2 associated with their pneumoperitoneum. Postoperatively, the subjects' pain intensity was measured via the visual analogue scale at 12, 24, and 48 hours.Results: The patients' mean postoperative visual analogue scale pain scores were the highest during the initial 12 hours (1.93), and thereafter, steadily declined at 24 hours (0.73) and 48 hours (0.70) ( P = .045). Furthermore, toxicity was reasonable, with only 20% of subjects who reported grade ≤2 nausea and vomiting.Conclusion: Abdominal compression is a relatively safe procedure that appears to sufficently evacuate residual CO2, thereby reducing the severity of laparoscopic surgery induced shoulder pain. [ABSTRACT FROM AUTHOR]

Background and purpose Ablative radiation therapy can be beneficial for pancreatic cancer, and motion mitigation helps to reduce dose to nearby organs-at-risk. Here, we compared two competing methods of motion mitigation—abdominal compression and respiratory gating. Materials and methods CBCT scans of 19 pancreatic cancer patients receiving stereotactic body radiation therapy were acquired with and without abdominal compression, and 3D target motion was reconstructed from CBCT projection images. Daily target motion without mitigation was compared against motion with compression and with simulated respiratory gating. Gating was free-breathing and based on an external surrogate. Target coverage was also evaluated for each scenario by simulating reduced target margins. Results Without mitigation, average daily target motion in LR/AP/SI directions was 5.3, 7.3, and 13.9 mm, respectively. With abdominal compression, these values were 5.2, 5.3, and 8.5 mm, and with respiratory gating they were 3.2, 3.9, and 5.5 mm, respectively. Reductions with compression were significant in AP/SI directions, while reductions with gating were significant in all directions. Respiratory gating also demonstrated better coverage in the reduced margins scenario. Conclusion Respiratory gating is the most effective strategy for reducing motion in pancreatic SBRT, and may allow for dose escalation through a reduction in target margin. [ABSTRACT FROM AUTHOR]

We aimed to compare gross tumor volumes (GTV) in 3-dimensional computed tomography (3DCT) simulation and daily cone beam CT (CBCT) with the internal target volume (ITV) in 4-dimensional CT (4DCT) simulation in stereotactic body radiotherapy (SBRT) treatment of patients with early-stage non–small cell lung cancer (NSCLC) under abdominal compression. We retrospectively selected 10 patients with NSCLC who received image-guided SBRT treatments under abdominal compression with daily CBCT imaging. GTVs were contoured as visible gross tumor on the planning 3DCT and daily CBCT, and ITVs were contoured using maximum intensity projection (MIP) images of the planning 4DCT. Daily CBCTs were registered with 3DCT and MIP images by matching of bony landmarks in the thoracic region to evaluate interfractional GTV position variations. Relative to MIP-based ITVs, the average 3DCT-based GTV volume was 66.3 ± 17.1% (range: 37.5% to 92.0%) ( p  < 0.01 in paired t-test), and the average CBCT-based GTV volume was 90.0 ± 6.7% (daily range: 75.7% to 107.1%) ( p  = 0.02). Based on bony anatomy matching, the center-of-mass coordinates for CBCT-based GTVs had maximum absolute shift of 2.4 mm (left-right), 7.0 mm (anterior-posterior [AP]), and 5.2 mm (superior-inferior [SI]) relative to the MIP-based ITV. CBCT-based GTVs had average overlapping ratio of 81.3 ± 11.2% (range: 45.1% to 98.9%) with the MIP-based ITV, and 57.7 ± 13.7% (range: 35.1% to 83.2%) with the 3DCT-based GTV. Even with abdominal compression, both 3DCT simulations and daily CBCT scans significantly underestimated the full range of tumor motion. In daily image-guided patient setup corrections, automatic bony anatomy-based image registration could lead to target misalignment. Soft tissue-based image registration should be performed for accurate treatment delivery. [ABSTRACT FROM AUTHOR]

Objective A comprehensive clinical evaluation was conducted, assessing the Body Pro-Lok immobilization and positioning system to facilitate hypofractionated radiotherapy of intrahepatic hepatocellular carcinoma (HCC), using helical tomotherapy to improve treatment precision. Methods Clinical applications of the Body Pro-Lok system were investigated (as above) in terms of interfractional and intrafractional setup errors and compressive abdominal breath control. To assess interfractional setup errors, a total of 42 patients who were given 5 to 20 fractions of helical tomotherapy for intrahepatic HCC were analyzed. Overall, 15 patients were immobilized using simple vacuum cushion (group A), and the Body Pro-Lok system was used in 27 patients (group B), performing megavoltage computed tomography (MVCT) scans 196 times and 435 times, respectively. Pretreatment MVCT scans were registered to the planning kilovoltage computed tomography (KVCT) for error determination, and group comparisons were made. To establish intrafractional setup errors, 17 patients with intrahepatic HCC were selected at random for immobilization by Body Pro-Lok system, undergoing MVCT scans after helical tomotherapy every week. A total of 46 MVCT re-scans were analyzed for this purpose. In researching breath control, 12 patients, randomly selected, were immobilized by Body Pro-Lok system and subjected to 2-phase 4-dimensional CT (4DCT) scans, with compressive abdominal control or in freely breathing states, respectively. Respiratory-induced liver motion was then compared. Results Mean interfractional setup errors were as follows: (1) group A: X, 2.97 ± 2.47 mm; Y, 4.85 ± 4.04 mm; and Z, 3.77 ± 3.21 mm; pitch, 0.66 ± 0.62°; roll, 1.09 ± 1.06°; and yaw, 0.85 ± 0.82°; and (2) group B: X, 2.23 ± 1.79 mm; Y, 4.10 ± 3.36 mm; and Z, 1.67 ± 1.91 mm; pitch, 0.45 ± 0.38°; roll, 0.77 ± 0.63°; and yaw, 0.52 ± 0.49°. Between-group differences were statistically significant in 6 directions ( p < 0.05). Mean intrafractional setup errors with use of the Body Pro-Lok system were as follows: X, 0.41 ± 0.46 mm; Y, 0.86 ± 0.80 mm; Z, 0.33 ± 0.44 mm; and roll, 0.12 ± 0.19°. Mean liver-induced respiratory motion determinations were as follows: (1) abdominal compression: X, 2.33 ± 1.22 mm; Y, 5.11 ± 2.05 mm; Z, 2.13 ± 1.05 mm; and 3D vector, 6.22 ± 1.94 mm; and (2) free breathing: X, 3.48 ± 1.14 mm; Y, 9.83 ± 3.00 mm; Z, 3.38 ± 1.59 mm; and 3D vector, 11.07 ± 3.16 mm. Between-group differences were statistically different in 4 directions ( p < 0.05). Conclusions The Body Pro-Lok system is capable of improving interfractional and intrafractional setup accuracy and minimizing tumor movement owing to respirations in patients with intrahepatic HCC during hypofractionated helical tomotherapy. [ABSTRACT FROM AUTHOR]

Purpose To determine whether individual liver tumor patients can be safely treated with pencil beam scanning proton therapy. This study reports a planning preparation workflow that can be used for beam angle selection and the evaluation of the efficacy of abdominal compression ( AC) to mitigate motion. Methods Four-dimensional computed tomography scans (4 DCT) with and without AC were available from 10 liver tumor patients with fluoroscopy-proven motion reduction by AC, previously treated using photons. For each scan, the motion amplitudes and the motion-induced variation of water-equivalent thickness (Δ WET) in each voxel of the target volume were evaluated during treatment plan preparation. Optimal proton beam angles were selected after volume analysis of the respective beam-specific planning target volume ( BSPTV). M⊥80 and Δ WET80 derived from the 80th percentiles of perpendicular motion amplitude (M⊥) and Δ WET were compared with and without AC. Proton plans were created on the average CT to achieve target coverage similar to that of the conventional photon treatments. 4D dynamic dose calculation was performed postplan by synchronizing proton beam delivery timing patterns to the 4 DCT phases to assess interplay and fractionation effects, and to determine motion criteria for subsequent patient treatment. Results Selected coplanar beam angles ranged between 180° and 39°, primarily from right lateral (oblique) and posterior (oblique) directions. While AC produced a significant reduction in mean Liver-GTV dose, any reduction in mean heart dose was patient dependent and not significant. Similarly, AC resulted in reductions in M⊥, Δ WET, and BSPTV volumes and improved dose degradation (ΔD95 and ΔD1) within the CTV. For small motion (M⊥80 < 7 mm and Δ WET80 < 5 mm), motion mitigation was not needed. For moderate motion (M⊥80 7-10 mm or Δ WET80 5-7 mm), AC produced a modest improvement. For large motion (M⊥80 > 10 mm or Δ WET80 > 7 mm), AC and/or some other form of mitigation strategies were required. Conclusion A workflow for screening patients' motion characteristics and optimizing beam angle selection was established for the pencil beam scanning proton therapy treatment of liver tumors. Abdominal compression was found to be useful at mitigation of moderate and large motion. [ABSTRACT FROM AUTHOR]